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The online version of The Merck Manual—Second Home
Edition takes advantage of the flexibility of the web to
present updates, changes, and corrections on a regular basis. Thus,
the online version may contain material not yet in print. Details
on updates and new topics appear below.
New and Updated Topics
Rofecoxib, one member of the class of pain and arthritis
drugs known as COX-2 inhibitors (coxibs), appears to increase the
risk of heart attack and stroke after long-term use and has been
withdrawn from the market. The potential for similar adverse effects
with other coxibs is currently being studied. Because one recent
study has shown a 2.5-fold increase in cardiovascular problems with another
member of the class, celecoxib, current FDA recommendations are
to limit use of any coxib to people at high risk of gastrointestinal
bleeding, who have a history of intolerance to other NSAIDs, or
who are not doing well on other NSAIDs. Caution should be taken
with use of coxibs for long periods or by people with risk factors
for heart attack and stroke.
Contributors
Jun 1, 2009
We gratefully acknowledge the expertise of the contributors
to our current online version. The subject(s) that they are responsible
for are listed after their affiliations....
Weights and Measures
May 1, 2009
In medicine, precise measurements are necessary—for example,
when various substances are measured in laboratory tests to evaluate health
or make a diagnosis. Different units of measure may be used depending
on the substance. Usually, the metric syste...
Common
Medical Tests
May 1, 2009
A large number of tests are widely available. Many tests are
specialized for a particular disorder or group of related disorders
(which are usually described with the appropriate disorders in this
book). Other tests are commonly used for a wide range...
Drug Names: Generic
and Trade
May 1, 2009
Most prescription drugs placed on the market are given trade
names (also called proprietary, brand, or specialty names) to distinguish them
as being produced and marketed exclusively by a particular manufacturer.
In the United States, these names are...
Introduction
May 1, 2009
This collection of resources is selective and restricted largely
to national organizations in the United States, many of which have
local chapters. Sites chosen are generally not-for-profit and usually
offer information or support rather than advocac...
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Consultants
Mar 1, 2009
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Reviewers for Selected Chapters
Mar 1, 2009
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Introduction
Feb 1, 2009
Although most infants are
delivered at full term and have no problems, some infants may have
medical problems related to factors that occur before birth, such
as any health problems or habits of the mother. Examples of health
problems are diabetes, h...
Birth
Injury
Feb 1, 2009
Birth injury
is damage sustained during the birthing process, usually occurring
during transit through the birth canal.Many newborns have minor injuries
during birth.
Infrequently, nerves are damaged or bones are broken.
Most injuries get better with...
Prematurity
Feb 1, 2009
A premature
newborn is, by definition, delivered before 37 weeks of development
in the uterus. A premature newborn has underdeveloped organs, which
may not be ready to function outside of the uterus.A previous premature birth,
multiple births, poor n...
Postmaturity
Feb 1, 2009
A postmature
newborn is delivered after more than 42 weeks in the uterus.Near the end of a term pregnancy,
placental function decreases, providing fewer nutrients and less
oxygen to the fetus.
Postmature newborns have dry, peeling, loose skin
and may...
Small
for Gestational Age (SGA)
Feb 1, 2009
A newborn,
whether delivered preterm, term, or postterm, whose weight is less
than that of 90% of newborns of the same gestational age at birth
(below the 10th percentile) is considered small for gestational
age.Newborns
may be small because their pa...
Large
for Gestational Age (LGA)
Feb 1, 2009
A newborn,
whether delivered preterm, term, or postterm, whose weight is above
that of 90% of newborns of the same gestational age at birth (above
the 90th percentile) is considered large for gestational age.Newborns may be large because
the parents ...
Respiratory
Distress Syndrome
Feb 1, 2009
Respiratory
distress syndrome (hyaline membrane disease) is a breathing disorder
of premature newborns in which the air sacs (alveoli) in a newborn's
lungs do not remain open because the production of a substance that
coats the alveoli (surfactant) i...
Transient
Tachypnea
Feb 1, 2009
Transient
tachypnea of the newborn (rapid breathing of the newborn, neonatal
wet lung syndrome) is temporary difficulty with breathing and low
blood oxygen levels due to excessive fluid in the lungs after birth.This disorder can occur after
a schedul...
Meconium
Aspiration Syndrome
Feb 1, 2009
Meconium aspiration
syndrome is respiratory distress in a newborn who has breathed (aspirated)
meconium into the lungs before or around the time of birth.Fetuses may pass stools (meconium)
in response to stress, such as a lack of oxygen.
Stress may a...
Persistent
Pulmonary Hypertension
Feb 1, 2009
Persistent
pulmonary hypertension is a serious disorder in which the arteries
to the lungs remain narrowed (constricted) after delivery, thus
limiting the amount of blood flow to the lungs and therefore the
amount of oxygen in the bloodstream.
This d...
Pneumothorax
Feb 1, 2009
Pneumothorax
is a collection of air between the lung and the chest wall that
develops when air leaks out of the lung.This disorder may develop
in newborns who have lung disorders such as respiratory distress
syndrome or meconium aspiration syndrome, ...
Bronchopulmonary
Dysplasia
Feb 1, 2009
Bronchopulmonary
dysplasia is a chronic lung disorder caused by repetitive lung injury.This disorder most often occurs
in infants who were very premature, have severe lung disease, needed
a ventilator, or have inadequately developed air sacs in the l...
Apnea
of Prematurity
Feb 1, 2009
Apnea of prematurity
is a pause in breathing that lasts for more than 20 seconds.Apnea episodes occur in premature
newborns whose respiratory center in the brain has not matured fully.
Apnea may lower the amount of oxygen in the blood,
resulting in a...
Retinopathy
of Prematurity (ROP)
Feb 1, 2009
Retinopathy
of prematurity is a disorder in which the small blood vessels in
the back of the eye (retina) grow abnormally.Retinopathy of prematurity
is strongly associated with premature birth, with most cases occurring
in infants who are born after ...
Necrotizing
Enterocolitis (NEC)
Feb 1, 2009
Necrotizing
enterocolitis is injury to the inner surface of the intestine. This
disorder occurs most often in very premature newborns.The abdomen may be swollen,
stools may be bloody, and the newborn may vomit a greenish, yellow,
or rust-colored flui...
Hyperbilirubinemia
Feb 1, 2009
Hyperbilirubinemia
is an abnormally high level of bilirubin (a pigment produced from
the breakdown of red blood cells) in the blood.Severe hyperbilirubinemia
is usually caused by illnesses that interfere with feeding, serious
disorders such as sepsis...
Anemia
in the Newborn
Feb 1, 2009
Anemia is
a disorder in which there are too few red blood cells in the blood.Anemia can occur when red
blood cells are broken down too rapidly, too much blood is lost,
or the bone marrow does not produce enough red blood cells.
If red blood cells are...
Polycythemia
in the Newborn
Feb 1, 2009
Polycythemia
is an abnormally high concentration of red blood cells.This disorder may result from
postmaturity, diabetes in the mother, or a low oxygen level in the
fetal blood.
A high concentration of red blood cells makes the
blood thick (hypervisc...
Thyroid Disorders in
the Newborn
Feb 1, 2009
Thyroid disorders occur
if the thyroid gland produces too little thyroid hormone (hypothyroidism)
or too much thyroid hormone (hyperthyroidism)....
Sepsis
in the Newborn
Feb 1, 2009
Sepsis is
bacterial infection in the blood.
Newborns with sepsis are listless, do not feed well,
and often have a low body temperature.
The diagnosis is based on symptoms and the presence
of bacteria in the blood.
Most newborns who recover from sepsi...
Apparent
Life-Threatening Event (ALTE)
Feb 1, 2009
An apparent
life-threatening event (ALTE) is the sudden occurrence of certain
alarming symptoms such as prolonged periods of no breathing (apnea),
change in color or muscle tone, coughing, and gagging in children
under 1 year of age.Known
causes incl...
Introduction
Feb 1, 2009
Children acquire many
skills as they grow. Some skills, such as controlling urine and stool,
depend mainly on the level of maturity of the child's nerves and
brain. Others, such as behaving appropriately at home and in school, are
the result of a com...
Eating
Problems
Feb 1, 2009
Some eating problems are
behavioral in nature. Parents of young children often are concerned
that their children are not eating enough or eating too much, eating
the wrong foods, refusing to eat certain foods, or engaging in inappropriate
mealtime be...
Bed-Wetting
Feb 1, 2009
The most common cause of bed-wetting is a slowly
maturing bladder.
Limiting fluids 2 to 3 hours before bed and restricting
caffeine consumption may help prevent bed-wetting.
Positive reinforcement, bed-wetting alarms, desmopressin,
and imipramine he...
Encopresis
Feb 1, 2009
Encopresis
is the accidental passing of bowel movements that is not caused
by illness or physical abnormality....
Sleep
Problems
Feb 1, 2009
Most children sleep for
a stretch of at least 5 hours by age 3 months but then experience periods
of night waking later in the first years of life, often associated
with illness. As they get older, the amount of rapid eye movement (REM)
sleep increas...
Temper
Tantrums
Feb 1, 2009
Frustration, tiredness, and hunger are the most
common causes.
Children may scream, cry, thrash, and stomp their
feet during a tantrum.
If distraction does not stop the tantrum, the child
may have to be removed from the situation....
Breath-Holding
Spells
Feb 1, 2009
A breath-holding
spell is an episode in which the child stops breathing and loses
consciousness for a short period immediately after a frightening
or emotionally upsetting event or a painful experience.Breath-holding spells usually
are triggered by p...
School
Avoidance
Feb 1, 2009
Some psychologic and social factors may cause school
avoidance.
Children may fake illnesses and make up excuses
to avoid going to school.
Regular attendance at school; open communication
among the child, parents, and school personnel; and sometimes ...
Introduction
Feb 1, 2009
During adolescence (usually
encompassing ages 10 to the late teens or early 20s), children become
young adults. They mature socially and physically. Notably, they
become sexually mature and socially independent. During this time,
the adolescent devel...
Physical
and Sexual Development
Feb 1, 2009
Normal growth during adolescence
includes both an increase in body size and sexual maturation (puberty).
The timing and speed with which these changes occur vary and are affected
by both heredity and environment. During adolescence, boys and girls
re...
Intellectual
and Behavioral Development
Feb 1, 2009
In early adolescence,
a child begins to develop the capacity for abstract, logical thought.
This increased sophistication leads to an enhanced awareness of
self and the ability to reflect on one's own being. Because of the many
noticeable physical ch...
Emotional
Development
Feb 1, 2009
During adolescence, the
regions of the brain that control emotions develop and mature. This
phase is characterized by seemingly spontaneous outbursts that can
be challenging for parents and teachers who often receive the brunt.
Adolescents gradually ...
Social
and Psychologic Development
Feb 1, 2009
The family is the center
of social life for children. During adolescence, the peer group begins
to replace the family as the child's primary social focus. Peer
groups are often established because of distinctions in dress, appearance,
attitudes, hobb...
Development
of Sexuality
Feb 1, 2009
The onset of sexual maturation
(puberty) typically is accompanied by an interest in sexual anatomy,
which may be a source of anxiety. As adolescents mature emotionally
and sexually, they may begin to engage in sexual behaviors. Masturbation
is common...
Preventive
Health Care Visits
Feb 1, 2009
Annual health care visits
allow doctors and other health care practitioners to monitor physical
growth and sexual maturation and provide advice and counseling.
Height, weight, and blood pressure should be monitored at every
yearly health care visit. ...
Introduction
Feb 1, 2009
Respiratory disorders
commonly affect children. The most serious and common are asthma,
bronchiolitis, and croup. An uncommon but very serious respiratory
disorder is bacterial tracheitis....
Asthma in
Children
Feb 1, 2009
Asthma is
a recurring inflammatory lung condition in which certain stimuli
(triggers) inflame the airways and cause them to temporarily narrow,
resulting in difficulty breathing.
Asthma triggers include smoke, perfume, pollen,
mold, dust mites, and v...
Bronchiolitis
Feb 1, 2009
Bronchiolitis
is an infection that affects the lower respiratory tract of infants
and young children under 24 months of age and is almost always caused
by viruses. It is characterized by wheezing and difficulty breathing.Bronchiolitis usually is caus...
Croup
Feb 1, 2009
Croup (laryngotracheobronchitis)
is an inflammation of the windpipe (trachea) and voice box (larynx)
typically caused by a contagious viral infection that causes cough,
a loud squeaking noise (stridor), and sometimes difficulty with
breathing in (ins...
Bacterial
Tracheitis
Feb 1, 2009
Bacterial
tracheitis (pseudomembranous croup) is an infection of the windpipe
(trachea) caused by bacteria....
Introduction
Feb 1, 2009
Most of the foods and drinks
people ingest are complex materials that the body must break down
into simpler substances. This process may involve several steps.
The simpler substances are then used as building blocks, which are
assembled into the mate...
Disorders of Carbohydrate Metabolism
Feb 1, 2009
Carbohydrates are sugars.
Some sugars are simple, and others are more complex. Sucrose (table
sugar) is made of two simpler sugars called glucose and fructose. Lactose (milk sugar)
is made of glucose and galactose. Both sucrose and lactose must
be br...
Disorders of Amino
Acid Metabolism
Feb 1, 2009
Amino acids are the building
blocks of proteins and have many functions in the body. Hereditary
disorders of amino acid processing can result from defects either
in the breakdown of amino acids or in the body's ability to get
amino acids into cells. ...
Disorders of Lipid
Metabolism
Feb 1, 2009
Fats (lipids) are an
important source of energy for the body. The body's store of fat
is constantly broken down and reassembled to balance the body's
energy needs with the food available. Groups of specific enzymes
help the body break down and proces...
Introduction
Feb 1, 2009
Several important mental
health disorders, such as depression, often develop during childhood.
Some disorders, such as autism, develop only during childhood....
Childhood
Schizophrenia
Feb 1, 2009
Childhood
schizophrenia is a chronic disorder involving abnormal thought,
perception, and social behavior.
Schizophrenia is probably caused by chemical abnormalities
in the brain and by problems during the brain's development.
Adolescents withdraw, s...
Depression
in Children
Feb 1, 2009
Depression
is a feeling of sadness or irritability intense enough to interfere
with functioning. It may follow a recent loss or other sad event
but is out of proportion to that event and persists beyond an appropriate
length of time (see ).Physical
d...
Bipolar Disorder in
Children (Manic-Depressive
Illness)
Feb 1, 2009
In bipolar
disorder (sometimes called manic-depressive illness), periods of
intense elation and excitation (mania) alternate with periods of
depression and despair. Mood may be normal in between these periods.Children may rapidly go from
being excite...
Suicidal
Behavior in Children
Feb 1, 2009
Suicidal
behavior is an action intended to harm oneself and includes suicide
gestures, suicide attempts, and completed suicide.A stressful event may trigger
suicide in children who have a mental health disorder such as depression.
Children at risk of...
Conduct
Disorder
Feb 1, 2009
A conduct
disorder involves a repetitive pattern of behavior that violates
the basic rights of others.
Children with a conduct disorder are selfish and
insensitive to the feelings of others and may bully, damage property,
lie, or steal without guilt....
Oppositional
Defiant Disorder
Feb 1, 2009
Oppositional
defiant disorder is a recurring pattern of negative, defiant, and
disobedient behavior, often directed at authority figures....
Anxiety
Disorders in Children
Feb 1, 2009
Anxiety
disorders are characterized by fear, worry, or dread that greatly
impairs the ability to function and is out of proportion to the
circumstances.There
are many types of anxiety disorders, distinguished by the main focus
of the fear or worry.
M...
Tic
Disorders
Feb 1, 2009
Tics
are rapid, repeated involuntary movements that are fundamentally
purposeless....
Somatoform
Disorders in Children
Feb 1, 2009
In somatoform
disorders, an underlying psychologic problem causes distressing
or disabling physical symptoms.
There are several types of somatoform disorders.
Symptoms may resemble those of a neurologic disorder
(such as paralysis or loss of vision) ...
Introduction
Feb 1, 2009
Neurologic disorders
affect the brain, spinal cord, nerves, or a combination. These disorders
include cerebral palsy (see ),
seizures, and disorders that also affect other parts of the body
(such as the skin or eyes), such as neurofibromatosis, tuber...
Seizures in
Children
Feb 1, 2009
Seizures
are a periodic disturbance of the brain's electrical activity, resulting
in some degree of temporary brain dysfunction....
Neurofibromatosis
Feb 1, 2009
Neurofibromatosis
is a genetic disorder in which many soft, fleshy growths of nerve
tissue (neurofibromas) grow under the skin and in other parts of
the body.People
may have freckle-like spots on various parts of the body, lumps
on or under the skin,...
Sturge-Weber
Syndrome
Feb 1, 2009
Sturge-Weber
syndrome is a rare disorder affecting small blood vessels. It is
characterized by a port-wine birthmark on the face, a blood vessel
tumor (angioma) in the tissues that cover the brain, or both.This disorder can cause seizures,
weakness, ...
Tuberous
Sclerosis
Feb 1, 2009
Tuberous
sclerosis is a hereditary disorder that causes abnormalities in
the brain, changes in the skin and sometimes tumors to develop in vital
organs, such as the heart and lungs.
Children may have abnormal skin growths, seizures,
delayed developme...
Von
Hippel-Lindau Disease
Feb 1, 2009
Von Hippel-Lindau
disease is a rare hereditary disorder that causes tumors to develop
in several organs.Children
may have headaches, impaired vision, or high blood pressure and
feel dizzy or weak.
Doctors suspect the disorder based on the person's
fa...
Introduction
Feb 1, 2009
Developmental disorders
(including attention-deficit/hyperactivity disorder, autism spectrum
disorders, learning disabilities, and intellectual disability [see ]) are neurologically based
conditions that can interfere with the acquisition, retention,...
Attention-Deficit/Hyperactivity Disorder
Feb 1, 2009
Attention-deficit/hyperactivity
disorder (ADHD) is poor or short attention span and impulsiveness
inappropriate for the child's age; some children also manifest hyperactivity.ADHD is a brain disorder that
is present from birth or develops shortly aft...
Autism
Spectrum Disorders
Feb 1, 2009
Autism
spectrum disorders are disorders in which young children cannot
develop normal social relationships, use language abnormally or
not at all, behave in compulsive and ritualistic ways, and may fail
to develop normal intelligence.
Affected childr...
Learning
Disorders
Feb 1, 2009
Learning
disorders involve an inability to acquire, retain, or broadly use
specific skills or information, resulting from deficiencies in attention,
memory, or reasoning and affecting academic performance.Affected children may be slow
to learn names ...
Introduction
Feb 1, 2009
Sports injuries
are common among athletes and other people who participate in sports. Certain
injuries that are traditionally considered sports injuries can also
occur in people who do not participate in sports. For example, homemakers
and factory wo...
Shoulder
Injuries
Feb 1, 2009
Rotator cuff injuries
and labral tears are the most common shoulder injuries....
Elbow
Injuries
Feb 1, 2009
Injuries can occur
to the tendons that attach to the elbow....
Knee
Injuries
Feb 1, 2009
Knee sprains,
meniscal injuries, and runner's knee are common knee injuries....
Hamstring
Injury
Feb 1, 2009
The
muscles in the back of the thigh (hamstrings) can be strained (hamstring
pull) in any running activity....
Lower Leg Injuries
Feb 1, 2009
Shin splints,
ankle sprains, Achilles tendinitis, rupture of the Achilles tendon,
and stress fractures of the foot are common injuries to the lower
leg....
Introduction
Feb 1, 2009
Humans,
who are warm-blooded animals, maintain their body temperature within
1 or 2 degrees of 98.6° F (37° C) as measured by mouth and 100.4°
F (38° C) as measured rectally, despite large fluctuations in external temperatures.
This internal temperat...
Heat
Cramps
Feb 1, 2009
Heat cramps
are severe muscle spasms resulting from a combination of prolonged
exercise, heavy sweating, and excessive water replacement in extreme
heat....
Heat
Exhaustion
Feb 1, 2009
Heat exhaustion
is excessive loss of salts (electrolytes) and fluids due to heat,
leading to decreased blood volume that causes many symptoms, sometimes
including fainting or collapse....
Heatstroke
Feb 1, 2009
Heatstroke
is a life-threatening condition that results in very high body temperature
and malfunction of many organ systems.Heatstroke can develop after
hours of exertion in young athletes or after days of hot weather
in rooms without air-conditionin...
Radiation
Injury
Feb 1, 2009
Radiation
injury is damage to tissues caused by exposure to ionizing radiation.Large doses of ionizing radiation
can cause acute illness by reducing the production of blood cells
and damaging the gastrointestinal tract.
A very large dose of ionizing ...
Introduction
Feb 1, 2009
People who engage in deep-sea
or scuba diving are at risk of a number of injuries. Diving in cold
water can rapidly lead to hypothermia (dangerously low body temperature),
which causes clumsiness and poor judgment. Cold water can also rarely
trigger ...
Barotrauma
Feb 1, 2009
Barotrauma
is tissue injury caused by a change in pressure, which compresses
or expands gas contained in various body structures.The lungs, mask (face mask),
ears, or sinuses can be affected.
Symptoms vary and may include breathing problems
or chest ...
Air
Embolism
Feb 1, 2009
Air embolism
is blockage of blood supply to organs caused by bubbles in an artery.Within a few minutes of reaching
the surface, divers can develop symptoms similar to those of a stroke.
People are given oxygen, made recumbent, and sent
as soon as pos...
Decompression
Sickness
Feb 1, 2009
Decompression
sickness (decompression illness, caisson disease, the bends) is
a disorder in which nitrogen dissolved in the blood and tissues
by high pressure forms bubbles as pressure decreases.Symptoms can include fatigue
and pain in muscles and jo...
Immersion
Pulmonary Edema
Feb 1, 2009
Immersion
pulmonary edema is sudden development of fluid in the lungs that
typically occurs early during a dive and at depth....
Gas
Toxicity
Feb 1, 2009
Problems
during diving can result from toxic effects of gases such as nitrogen,
oxygen, carbon dioxide, and carbon monoxide....
Recompression
Therapy
Feb 1, 2009
Recompression
therapy (hyperbaric oxygen therapy) involves giving 100% oxygen
for several hours in a sealed chamber at pressures higher than 1
atmosphere....
Diving Precautions
and Prevention of Diving Injuries
Feb 1, 2009
Diving is a relatively
safe recreational activity for healthy people who have been appropriately
trained and educated. Diving safety courses offered by national
diving organizations are widely available....
Altitude
Illness
Feb 1, 2009
Altitude illness
occurs because of a lack of oxygen at high altitudes.Symptoms include headache,
tiredness, irritability, and in more serious cases, shortness of
breath, confusion, and even coma.
Doctors diagnose altitude illness primarily based
on t...
Introduction
Feb 1, 2009
Many creatures, including
humans, bite when frightened or provoked. Bites may cause injuries
ranging from superficial scratches to extensive wounds and often
become infected with bacteria from the mouth of the biting creature....
Animal
Bites
Feb 1, 2009
Most animal bites in the United States are from
dogs and cats.
Wounds should be cleaned and cared for as soon as
possible....
Human
Bites
Feb 1, 2009
A human bite wound to the hand sustained by punching
someone in the mouth often becomes infected.
Wounds should be cleaned, and antibiotics should
be given....
Snake
Bites
Feb 1, 2009
Venomous snakes in the United States include pit
vipers (rattlesnakes, copperheads, and cottonmouths) and coral snakes.
Severe envenomation can cause damage to the bitten
extremity, bleeding, and vital organ damage.
Venom antidote is given for serio...
Lizard
Bites
Feb 1, 2009
The only two lizards known
to be poisonous are the beaded lizard of Mexico and the Gila monster,
present in Arizona; Sonora, Mexico; and adjacent areas. The venom
of these lizards is somewhat similar in content and effect to that
of some pit vipers, ...
Spider
Bites
Feb 1, 2009
Serious injuries from spider bites can include severe
wounds caused by brown spiders and bodywide poisoning caused by widow
spiders.
Wounds suspected of being caused by the brown spider
are often caused by other problems, some potentially more serio...
Bee,
Wasp, Hornet, and Ant Stings
Feb 1, 2009
Stings by bees, wasps, hornets, and ants usually
cause pain, redness, swelling, and itching.
Allergic reactions are uncommon but may be serious.
Stingers should be removed, and a cream or ointment
can help relieve symptoms....
Puss
Moth Caterpillar (Asp) Stings
Feb 1, 2009
The venomous puss moth
caterpillar (also called the asp) is present in the southern United
States. It is teardrop shaped and has long silky hair, making it
resemble a tuft of cotton or fur. When an asp rubs or is pressed against
a person's skin, its ...
Insect
Bites
Feb 1, 2009
Among the more common
biting and sometimes bloodsucking insects in the United States are
the following:Sand flies
Horseflies
Deerflies
Blackflies
Stable flies
Mosquitoes
Fleas
Lice
Bedbugs
Kissing bugs
Certain water bugs...
Tick
and Mite Bites
Feb 1, 2009
Ticks carry many diseases.
For example, deer ticks may carry the bacteria that cause Lyme disease
(see ).
Other types of ticks may carry the bacteria that cause rickettsial
or ehrlichial infections (see ). The bites of pajaroello ticks, which are
pre...
Centipede
and Millipede Bites
Feb 1, 2009
Some of the larger centipedes
can inflict a painful bite, causing swelling and redness. Symptoms
rarely persist for more than 48 hours. Millipedes do not bite but
may secrete a toxin that is irritating, particularly when accidentally
rubbed into the ...
Scorpion
Stings
Feb 1, 2009
The stings of North American
scorpions are rarely serious and usually result in pain, minimal
swelling, tenderness, and warmth at the sting site. However, the
bark scorpion (Centruroides exilicauda or sculpturatus),
which is present in Arizona and Ne...
Marine
Animal Stings and Bites
Feb 1, 2009
A variety of marine animals
sting or bite....
Surgery
Feb 1, 2009
Surgery is the term traditionally
used for treatments that involve cutting or stitching tissue. However,
advances in surgical techniques have made the definition more complicated.
Sometimes lasers, rather than scalpels, are used to cut tissue,
and wo...
Introduction
Feb 1, 2009
Complementary and alternative
medicine (CAM) includes a variety of healing approaches and therapies
taken from around the world that historically have not been included
in conventional Western medicine. Many aspects of CAM are rooted
in ancient, indi...
Whole Medical Systems
Feb 1, 2009
Whole medical systems
are complete systems of diagnosis and practice. Several whole medical
systems exist, including traditional Chinese medicine, Ayurveda,
and unconventional Western practices of natural healing....
Mind-Body
Techniques
Feb 1, 2009
Mind-body techniques are
based on the theory that mental and emotional factors can influence
physical health. Behavioral, psychologic, social, and spiritual
methods are used to preserve health and prevent or cure disease....
Biologically
Based Therapies
Feb 1, 2009
Biologically based therapies
use naturally occurring substances and include individual biologic
therapies (such as using shark cartilage to treat cancer and glucosamine
to treat osteoarthritis), diet therapy, herbal medicine, orthomolecular
medicine,...
Manipulative and Body-Based Therapies
Feb 1, 2009
Manipulative and body-based
therapies treat various conditions through bodily manipulation.
These therapies include chiropractic, massage, rolfing, reflexology,
and postural reeducation....
Energy
Therapies
Feb 1, 2009
Energy therapies focus
on the energy fields thought to exist in and around the body (biofields).
They also encompass the use of external energy sources (electromagnetic fields)
to influence health and healing. All energy therapies are based
on a core...
Travel Preparations
Feb 1, 2009
Travel preparation is
crucial, even for healthy people. Proper preparations are inexpensive
relative to the costs of getting sick or injured while away from
home....
Problems in Transit
Feb 1, 2009
Several conditions are
common even among healthy people while in transit....
Specific Medical Conditions
and Travel
Feb 1, 2009
People with specific medical
conditions encounter special problems in transit....
Problems at the Destination
Feb 1, 2009
Problems after arrival
are especially important to prevent and avoid in international settings.
Though many people are most concerned about infection when considering
a trip overseas, heart disease is the most common cause of death
among internationa...
Problems After Travel
Feb 1, 2009
Symptoms or problems that
developed during travel and that have not subsided by the time a
person has returned home warrant medical attention. Travel-related
problems also can develop after travel. For example, nitrogen narcosis
(the bends) can occur...
Introduction
Feb 1, 2009
Medicinal
herbs are plant parts, sometimes ground, extracted, or otherwise
prepared, used for health benefits. Nutraceuticals,
a more recent and more general term, are a group of natural substances
that includes certain herbs and such products as cho...
Black Cohosh
Feb 1, 2009
Black cohosh is a plant.
The underground stem of this plant is available in powder, tablet,
or liquid form....
Chamomile
Feb 1, 2009
The daisy-like flower
of this herb is dried and used as tea or in an extract....
Chondroitin
Sulfate
Feb 1, 2009
Chondroitin sulfate is
a natural component of cartilage. It is extracted from shark or
cow cartilage or manufactured synthetically. It is frequently combined
with glucosamine....
Chromium
Feb 1, 2009
Chromium is a mineral
required in small quantities by the body. It enables insulin to function.
Whole-grain products are good sources of chromium. Picolinate often
is paired with chromium in supplements....
Coenzyme
Q10
Feb 1, 2009
Coenzyme Q10 (ubiquinone)
is an enzyme that is naturally produced in the body. It participates
in the energy-managing processes of cells and has an antioxidant
effect. Antioxidants protect cells against damage by free radicals,
which are highly chemi...
Cranberry
Feb 1, 2009
Cranberries are fruit
that can be consumed whole or made into food products such as jellies
and juices....
Creatine
Feb 1, 2009
Creatine is an amino acid
made in the liver and stored in muscles. When combined with phosphate,
it is a readily available source of energy in the body. In the diet,
creatine is found in milk, red meat, and some fish....
Dehydroepiandrosterone (DHEA)
Feb 1, 2009
Dehydroepiandrosterone
(DHEA) is a steroid produced in the adrenal glands and converted into
sex hormones (estrogens and androgens). DHEA's
effects on the body are similar to those of testosterone.
DHEA can be extracted from the Mexican yam....
Echinacea
Feb 1, 2009
Echinacea is a perennial
herb, which contains echinacoside and several other active substances.
Various parts of the plant are used medicinally....
Feverfew
Feb 1, 2009
Feverfew is a bushy perennial
herb. The dried leaves are used in capsules, tablets, and liquid
extracts. Parthenolide and glycosides are thought to be its active
components....
Fish Oil
Feb 1, 2009
Fish oil may be extracted
directly or concentrated and put in capsule form. Active ingredients
are omega-3 fatty acids (eicosapentaenoic acid [EPA] and docosahexaenoic
acid [DHA]). Western diets typically are low in omega-3 fatty acids....
Garlic
Feb 1, 2009
Garlic has long been used
in cooking and in medicine. When a garlic bulb is cut or crushed, an
amino acid byproduct called allicin is released. Allicin is responsible
for garlic's strong odor and medicinal properties....
Ginger
Feb 1, 2009
Like garlic, ginger has
long been used in cooking and in medicine. The stem of this herb
contains substances called gingerols, which give ginger its flavor
and odor....
Ginkgo
Feb 1, 2009
Ginkgo is derived from
the leaves of the ginkgo tree (commonly planted for ornamental purposes).
The leaves contain numerous biologically active substances. Ginkgo
is one of the most commonly used herbal supplements....
Ginseng
Feb 1, 2009
Ginseng is usually derived
from two different species of plant: American ginseng and Asian
ginseng. American ginseng is milder than Asian ginseng. Ginseng
is available in many forms, such as fresh and dried roots, extracts,
solutions, capsules, table...
Glucosamine
Feb 1, 2009
Glucosamine is extracted
from a material (chitin) present in the shells of crabs, oysters, and
shrimp. Glucosamine is taken in tablet or capsule form, usually
as glucosamine sulfate, but sometimes as glucosamine hydrochloride. Glucosamine
often is ta...
Goldenseal
Feb 1, 2009
Goldenseal, an endangered
plant, is related to the buttercup. Its active components are hydrastine
and berberine, which have antiseptic activity. Berberine is also
active against diarrhea....
Green Tea
Feb 1, 2009
Green tea is made from
the dried leaves of the same plant as traditional tea. However, traditional
tea leaves are fermented, and green tea leaves are steamed but unfermented. Green
tea may be brewed and drunk or ingested in tablet or capsule form.
It...
Kava
Feb 1, 2009
Kava comes from the root
of a shrub that grows in the South Pacific. It is ingested as a tea
or in capsule form....
Licorice
Feb 1, 2009
Natural licorice, which
has a very sweet taste, is extracted from the root of a shrub and used
medicinally as a capsule, tablet, or liquid extract. Most licorice
candy made in the United States is artificially flavored and does not
contain natural li...
Melatonin
Feb 1, 2009
Melatonin is a hormone
produced by the pineal gland (located in the middle of the brain)
that regulates the sleep-wake cycle. Melatonin used in supplements
is derived from animals or produced artificially. In some countries,
melatonin is considered a...
Milk Thistle
Feb 1, 2009
The main active ingredient,
silymarin, is found in the seeds of this prickly leafed, purple-flowered
plant....
S-Adenosyl-L-Methionine (SAMe)
Feb 1, 2009
S-adenosyl-L-methionine
(SAMe) is a naturally occurring agent in the human body and also
is manufactured synthetically in supplement form....
Saw Palmetto
Feb 1, 2009
The plant's berries can
be made into tea. Saw palmetto also is available as tablets, capsules,
and a liquid extract....
St.
John's Wort
Feb 1, 2009
The reddish substance
in the plant's flowers contains numerous biologically active compounds,
including hypericin and hyperforin....
Valerian
Feb 1, 2009
The plant's dried root
contains valepotriates, which may have calming effects....
Zinc
Feb 1, 2009
Zinc, a mineral, is required
in small quantities for many metabolic processes. Dietary sources
include oysters, beef, and fortified cereals....
Introduction
Feb 1, 2009
People may be admitted to
a hospital when they have a serious or life-threatening problem (such
as a heart attack) or when a disorder (such as heart failure) suddenly
worsens. They may go to the hospital's emergency department when
a less serious pro...
Being Admitted to the Hospital
Feb 1, 2009
People are admitted to a
hospital only when appropriate treatment cannot be provided in another
place (such as at home or in an outpatient surgery center). The
main goal of hospitalization is to restore or improve health so that
people can return hom...
Problems Due to Hospitalization
Feb 1, 2009
Just being in the hospital
can cause certain problems, such as infections, pressure sores, and
depression. Many hospital-related problems are caused by having
to stay in bed for long periods. Others may result from being in unfamiliar
surroundings or...
Being
Discharged From the Hospital
Feb 1, 2009
When people have recovered
sufficiently or can be appropriately treated elsewhere, they are
discharged from the hospital. Staff members may ask questions to
determine whether people are likely to need extra help after discharge.
A discharge planner o...
Driving
Feb 1, 2009
Driving provides a sense
of freedom, independence, and involvement with the world that many
people take for granted in their earlier adulthood. But the privilege
of driving is based on the ability to drive safely. Because drivers
aged 70 and over are...
Introduction
Feb 1, 2009
The prospect of needing
long-term care services concerns many older people. The likelihood
of needing long-term care increases greatly as people age. Older
people are more likely to develop chronic disorders and to have problems
functioning. Learning...
Care in the Home
Feb 1, 2009
Care in the home is usually
provided by family members, friends, or both. If needed, health
care practitioners, such as visiting nurses, therapists, and home
health aides may come to the home to provide additional care. Home
care that is coordinated ...
Retirement
Communities
Feb 1, 2009
Retirement communities
are designed for people who can live independently but who need
or want some help, mainly with caring for a home. Some older people
choose to move to a retirement community before they need additional
help. They may move becaus...
Assisted
Living Communities
Feb 1, 2009
Assisted living communities
are designed for people who can care for themselves if they have
some help with daily activities. These communities can help older
people who have problems with memory, who get confused, or who have
physical problems. Some...
Board-and-Care
Facilities
Feb 1, 2009
Typically, board-and-care
facilities are similar to assisted living communities. They are for
people who need some help, particularly with personal care. Board-and-care
facilities, sometimes also called rest homes, adult care homes,
or personal care ...
Life-Care
Communities
Feb 1, 2009
Life-care communities (also
called continuing care retirement communities) are for older people
who want to move only once, to a place that will provide as much
care as they need for the rest of their life. These communities
guarantee that residents ...
Nursing Homes
Feb 1, 2009
Nursing homes are for people
who need help with health care for chronic conditions but do not
need to be hospitalized. The decision to move to a nursing home
may be triggered by a change in circumstances. A disorder may suddenly
worsen, or an injury ...
Introduction
Feb 1, 2009
Elder mistreatment
refers to harm or the threat of harm to an older person by another person.
It includes abuse and neglect....
Types of Mistreatment
Feb 1, 2009
Older people may be abused,
neglected, or both....
Prevention of Mistreatment
Feb 1, 2009
Older people who are worried
about mistreatment can take steps to make it less likely to happen,
such as the following:Not
living with someone who has a history of violent behavior or substance abuse
Keeping in touch with friends and former neighbors...
Responding to Mistreatment
Feb 1, 2009
Older people should never
think that mistreatment is part of being old or dependent. Being
mistreated threatens their personal dignity and sense of well-being
and can even cost people their life....
Introduction
Feb 1, 2009
Dealing with the costs of
a serious or chronic disorder can be as distressing as dealing with
the disorder itself. The costs are often beyond the personal resources
of most people. For older people, most health care expenses are
paid for by the follo...
Medicare
Feb 1, 2009
Medicare is a federal government-funded health
insurance program that helps older people pay for health care services.
About 45 million people are covered by Medicare, 38 million who
are age 65 and older and another 7 million who are younger but have...
Medigap
Feb 1, 2009
Medigap is supplemental
insurance designed to pay for medical care not covered by Medicare,
including the deductibles and copayments required by Medicare and
extra charges by doctors who do not accept Medicare as full payment
for a service. To obtain...
Medicaid
Feb 1, 2009
Medicaid is a program funded
jointly by the Federal and State governments that helps pay for
health care. It is intended for people of all ages who have a very
low income and few assets. Eligibility requirements for Medicaid vary
from state to state....
Aging and Drugs
Feb 1, 2009
Drugs, the most common
medical intervention, are an important part of medical care for older
people. Without drugs, many older people would function less well
or die at an earlier age.
Did You Know...Up to half of older people do not take drugs a...
Introduction
Jan 1, 2009
The most common problems
in adolescence relate to growth and development; childhood illnesses
that continue into adolescence; mental health disorders; and the
consequences of risky or illegal behaviors, including injury, legal
consequences, pregnancy...
Delayed
Puberty
Jan 1, 2009
Delayed puberty
is defined as absence of the onset of sexual maturation at the expected time.Some causes of delayed puberty
include disorders, radiation therapy or chemotherapy, excessive
dieting or exercise, genetic disorders, tumors, and certain in...
Short
Stature
Jan 1, 2009
Short stature
is defined as height below the 3rd percentile for the child's age
(according to standard charts for age and height)....
Obesity
Jan 1, 2009
Obesity is
defined as a body mass index (BMI) greater than the 95th percentile
for age and gender.Although
genetics and some disorders cause obesity, most adolescent obesity results
from a lack of physical activity and overeating.
The diagnosis is ba...
School
Problems
Jan 1, 2009
School constitutes a large
part of an adolescent's existence. Difficulties in almost any area
of life often manifest as school problems....
Behavioral
Problems
Jan 1, 2009
Adolescence is a time
for developing independence. Typically, adolescents exercise their independence
by questioning their parents' rules, which at times leads to rule
breaking. Parents and doctors must distinguish occasional errors
of judgment from ...
Drug
and Substance Use and Abuse
Jan 1, 2009
Substance use among adolescents
ranges from experimentation to dependence (see ).
The consequences range from none to minor to life threatening, depending on
the substance, the circumstances, and the frequency of use. However,
even occasional use can...
Contraception
and Adolescent Pregnancy
Jan 1, 2009
Many adolescents engage
in sexual activity but may not be fully informed about contraception,
pregnancy, and sexually transmitted diseases, including human immunodeficiency virus
(HIV) infection. Impulsivity, lack of planning, and concurrent drug
and...
Introduction
Jan 1, 2009
Ear, nose, and throat
disorders, particularly infections, are extremely common among children.Ear infections occur almost
as often as the common cold. They can develop behind the eardrum
(in the middle ear), called otitis media, or in front of the ea...
Middle
Ear Infections
Jan 1, 2009
Middle ear
infection is infection of the space immediately behind the eardrum....
Secretory
Otitis Media
Jan 1, 2009
Secretory
otitis media (serous otitis media) is fluid accumulation behind
the eardrum (see ).
A previous ear infection is the usual cause, although
some children may develop it as a result of gastroesophageal reflux
disease or a blocked eustachian tu...
Pharyngitis (Sore
Throat)
Jan 1, 2009
Pharyngitis
is infection of the throat (pharynx) and sometimes the tonsils.Pharyngitis is usually caused
by a virus and clears up on its own.
Occasionally, it is caused by certain bacteria (particularly
those called streptococci) and results in strep...
Enlarged
Tonsils and Adenoids
Jan 1, 2009
Locating the Tonsils and AdenoidsThe tonsils are two areas of lymphoid tissue located on either side of the throat. The adenoids, also lymphoid tissue, are located higher and further back, behind the palate, where the nasal passages connect...
Hearing
Impairment
Jan 1, 2009
Hearing loss usually results from genetic defects
in newborns and from ear infections or earwax in older children.
If children do not respond to sounds, have difficulty
talking, or are slow starting to talk, their hearing may be impaired.
A handheld...
Objects
in the Ears and Nose
Jan 1, 2009
Cotton, pieces of pencils,
paper, pebbles, and beans are just a few of the many objects children
put in their ears and nose. Insects sometimes crawl into ears and
cause substantial pain....
Neck
Masses
Jan 1, 2009
Neck masses
are swellings that change the shape of the neck....
Laryngeal
Papillomas
Jan 1, 2009
Laryngeal
papillomas are rare noncancerous (benign) tumors of the voice box
(larynx)....
Juvenile
Angiofibroma
Jan 1, 2009
Juvenile
angiofibroma is a rare noncancerous (benign) tumor that grows in
the back of the nose, in the same area where the adenoids are (see )....
Communication
Disorders
Jan 1, 2009
A communication
disorder can involve hearing, voice, speech, language, or a combination....
Introduction
Jan 1, 2009
Cancer is rare among
children, occurring in only 1 of 5,000 children every year. The
most common childhood cancers are leukemia (see ), brain tumors,
and lymphoma (see ).
Leukemia is responsible for about 33% of cases of childhood cancer,
brain tumor...
Brain
Tumors
Jan 1, 2009
The most common brain tumors in children are astrocytomas,
medulloblastomas, and ependymomas.
Brain tumors can cause various symptoms, including
headaches, nausea, vomiting, vision problems, listlessness, and loss
of coordination or balance.
The dia...
Neuroblastoma
Jan 1, 2009
Neuroblastoma
is a common childhood cancer that grows in parts of the nervous
system.What
causes neuroblastoma is not known.
Symptoms depend on where neuroblastomas develop,
such as the abdomen, chest, bone, skin, or spinal cord.
Diagnosis usually in...
Retinoblastoma
Jan 1, 2009
Retinoblastoma
is a cancer of the retina, the light-sensing area at the back of
the eye.Retinoblastomas
result from a genetic mutation.
The child may have a white pupil or cross-eyes or
occasionally vision problems.
Doctors can diagnose retinoblastom...
Rhabdomyosarcoma
Jan 1, 2009
Rhabdomyosarcoma
is a fast-growing cancer that can develop in soft tissues (such
as muscle) almost anywhere in the body.Rhabdomyosarcomas can develop
anywhere, but the head and neck, genital or urinary tract, and limbs
are the most common.
Symptoms d...
Wilms'
Tumor
Jan 1, 2009
Wilms' tumor
(nephroblastoma) is a specific kind of kidney cancer.The cause of Wilms' tumor
is not known, but some children may have a genetic abnormality.
Children usually have a lump in the abdomen, and
they may also have abdominal pain, fever, poo...
Introduction
Jan 1, 2009
Hereditary periodic
fever syndromes are hereditary disorders that periodically cause episodes
of fever and other symptoms that are not due to usual childhood
infections or any other obvious disorder. The more common of these
syndromes includeFamilial...
Familial
Mediterranean Fever
Jan 1, 2009
Familial
Mediterranean fever is a hereditary disorder characterized by episodes
of high fever with abdominal pain or, less commonly, chest pain,
joint pain, or a rash....
PFAPA
Syndrome
Jan 1, 2009
PFAPA
(periodic fevers with aphthous stomatitis, pharyngitis, and adenitis)
causes recurrent episodes of fever that last 3 to 6 days, mouth
sores (stomatitis), a sore throat (pharyngitis), and swollen lymph
glands (adenitis). It typically starts bet...
Introduction
Jan 1, 2009
Injuries can result from
spontaneous atmospheric electricity (lightning injuries) or generated
electricity, such as household or industrial electrical currents
(electrical injuries). Electrical current passing through the body
generates heat, which b...
Electrical
Injuries
Jan 1, 2009
An electrical
injury occurs when a current passes through the body, interfering
with the function of an internal organ or sometimes burning tissue.Often the main symptom is
a skin burn, but not all people have visible injuries.
Doctors check the pers...
Lightning
Injuries
Jan 1, 2009
A lightning
injury occurs after brief exposure to the very intense current of
the strike.About
10% of people who are struck by lightning die because the heart
stops beating and breathing stops.
In some people who survive severe lightning injury,
an e...
Drowning
Jan 1, 2009
Drowning occurs
when submersion in liquid causes suffocation or interferes with
breathing.During
drowning, the body is deprived of oxygen, which can damage organs,
particularly the lungs and brain.
Doctors evaluate people for oxygen deprivation and
p...
Introduction
Jan 1, 2009
Poisoning
is the harmful effect that occurs when a toxic substance is swallowed,
is inhaled, or comes in contact with the skin, eyes, or mucous membranes,
such as those of the mouth or nose.
Possible poisonous substances include prescription
and over...
Acetaminophen
Poisoning
Jan 1, 2009
People sometimes ingest too many products that contain
acetaminophen and accidentally poison themselves.
Depending on the amount of acetaminophen in the
blood, symptoms range from none at all to vomiting and abdominal
pain to liver failure and death...
Aspirin
Poisoning
Jan 1, 2009
Aspirin poisoning can occur acutely after taking
a high dose or develop gradually after taking low doses repeatedly.
Symptoms may include ringing in the ears, nausea,
vomiting, drowsiness, confusion, and rapid breathing.
The diagnosis is based on bl...
Carbon
Monoxide Poisoning
Jan 1, 2009
Carbon monoxide poisoning is common.
Symptoms may include headache, nausea, drowsiness,
and confusion.
The diagnosis is based on blood tests.
Carbon monoxide detectors and adequate venting of
furnaces and other sources of indoor combustion help prev...
Caustic
Substances Poisoning
Jan 1, 2009
When swallowed, caustic substances can burn all
tissues they touch—from the lips to the stomach.
Symptoms may include pain (particularly with swallowing),
coughing, shortness of breath, and vomiting.
A doctor inserts a flexible viewing tube (endosco...
Hydrocarbon
Poisoning
Jan 1, 2009
Sniffing glue or swallowing gasoline, paint thinners,
some cleaning products, or kerosene can cause hydrocarbon poisoning.
Swallowing or inhaling hydrocarbons can cause lung
irritation, with coughing, choking, shortness of breath, and neurologic
pro...
Insecticide
Poisoning
Jan 1, 2009
Many insecticides can cause poisoning after being
swallowed, inhaled, or absorbed through the skin.
Symptoms may include eye tearing, coughing, and
breathing difficulties.
The diagnosis is based on symptoms, blood tests,
and a description of events ...
Iron
Poisoning
Jan 1, 2009
Symptoms develop in stages and begin with vomiting,
diarrhea, and abdominal pain.
Liver failure can develop days later.
The diagnosis is based on the person's history,
symptoms, and the amount of iron in the blood.
People with iron poisoning need to...
Lead
Poisoning
Jan 1, 2009
Some causes of lead poisoning are ingestion of lead
paint and eating or drinking from certain imported, improperly lead-glazed
ceramics.
Very high levels of lead in the blood may cause
personality changes, headaches, loss of sensation, weakness, a m...
Introduction
Jan 1, 2009
Drugs are an integral
part of everyday life for many people—legitimately and illegitmately—and
drug use among adolescents remains high (see )....
Alcohol
Jan 1, 2009
Genetics and personal characteristics may play a
part in the development of alcohol use disorders.
Drinking too much alcohol may make people sleepy
or aggressive, impair coordination and mental function, and interfere with
work, family, and other ac...
Amphetamines
Jan 1, 2009
Amphetamines increase alertness, enhance physical
performance, and produce euphoria and a sense of well-being.
An overdose can cause extreme agitation, delirium,
and a life-threatening heart attack or stroke.
Urine tests can detect most amphetamines...
Anabolic
Steroids
Jan 1, 2009
Users of anabolic steroids are often athletes who
are looking to promote muscle growth and increase their strength
and energy.
Anabolic steroids increase muscle size, but their
use can also have many side effects, including mood swings, aggressive b...
Antianxiety
and Sedative Drugs
Jan 1, 2009
Using prescription drugs to relieve anxiety or help
with sleeping can cause dependence.
An overdose can cause drowsiness, confusion, and
slowed respiration.
Stopping a drug after using it for a long time causes
anxiety, irritability, and sleep probl...
Cocaine
Jan 1, 2009
Cocaine is a strong stimulant that increases alertness,
causes euphoria, and makes people feel powerful.
High doses can cause serious, life-threatening disorders,
such as a heart attack or stroke.
The diagnosis can be confirmed by urine tests.
Sedat...
Gamma
Hydroxybutyrate
Jan 1, 2009
Gamma hydroxybutyrate
(GHB or G) is taken by mouth. It is similar to ketamine or alcohol
in its effects, but its effects last longer and GHB is much more
dangerous....
Hallucinogens
Jan 1, 2009
Hallucinogens distort and intensify sensations,
but the actual effects can depend on the user's mood and expectations.
The chief dangers are the psychologic effects and
impaired judgment they cause.
A dark, quiet room and calm, nonthreatening talk
c...
Ketamine
Jan 1, 2009
Ketamine is a drug used
for anesthesia. People who use it illicitly may snort it or inject
it intravenously, into a muscle, or under the skin....
Marijuana
Jan 1, 2009
Marijuana produces a dreamy state, a sense of well-being,
and distorted perceptions.
Stopping the drug causes only mild symptoms.
Marijuana can be detected in urine for days to weeks
after it was used.
Treatment involves counseling, which is effecti...
Nicotine
Jan 1, 2009
People who stop using nicotine may become irritable,
anxious, and restless.
Smoking harms almost every organ in the body.
Counseling, behavior modification, nicotine replacement
products, and certain drugs can help people quit....
Opioids
Jan 1, 2009
Opioids are used to relieve pain, but they also
cause an exaggerated sense of well-being and, if used too much,
dependence and addiction.
Taking too much of an opioid can be fatal, usually
because breathing stops.
Urine tests can be done to check fo...
Phencyclidine
Jan 1, 2009
Phencyclidine (PCP or
angel dust) is most often smoked after being sprinkled on plant material,
such as parsley, mint leaves, tobacco, or marijuana. Occasionally,
PCP is taken by mouth or injected....
Solvent
Inhalants
Jan 1, 2009
Adolescents use inhalants
more frequently than cocaine or LSD but less frequently than marijuana
or alcohol. In the United States, about 10% of adolescents have
inhaled solvents. Inhalant use is particularly a problem among children
aged 12 and young...
Introduction
Jan 1, 2009
Providing medical care to
older people can be complicated. People often have many different
doctors at different locations. Travel and transportation issues
become more difficult as people age. The drugs that are covered
by the new Medicare prescript...
Continuity
of Care
Jan 1, 2009
Continuity of care is an
ideal in which health care is provided for a person in a coordinated
manner and without disruption despite involvement of different practitioners
in different care settings. Also, all people involved in a person's
health care...
Care
Providers: Practitioners
Jan 1, 2009
People, particularly older
people, often need to see several types of health care practitioners.
Sometimes a group of health care practitioners work together to
provide care. This type of care is called interdisciplinary care....
Care
Providers: Family and Friends
Jan 1, 2009
Some older people have
family members, friends, or neighbors who are willing and able to
provide help and care. Such people may be called caregivers. Occasionally,
members of religious or other groups help or take over the role
of caregiver altogethe...
Settings for Care
Jan 1, 2009
Health care practitioners
may provide care for older people in a variety of settings....
Falls
Jan 1, 2009
Most falls occur when people with a physical condition
that impairs mobility or balance encounter an environmental hazard.
Although many people have no symptoms before a fall,
some do experience dizziness or other symptoms.
After a fall, people may ...
Alpha1-Antitrypsin
Deficiency
Dec 1, 2008
Alpha1-antitrypsin
deficiency is a hereditary disorder in which a lack or low level
of the enzyme alpha1-antitrypsin damages
the lungs and liver.Alpha1-antitrypsin
deficiency is caused by an inherited gene mutation.
Infants may develop jaundice and c...
Introduction
Dec 1, 2008
Complex interactions among
hormones control the start of menstruation during puberty, the rhythms
and duration of menstrual cycles during the reproductive years,
and the end of menstruation at menopause.
Hormonal control of menstruation begins in th...
Premenstrual
Syndrome
Dec 1, 2008
Premenstrual
syndrome (PMS) is a group of physical and psychologic symptoms that
start several days before and usually end a few hours after a menstrual
period begins.PMS
includes any combination of the following: becoming irritable, anxious, moody,
...
Dysmenorrhea
Dec 1, 2008
Dysmenorrhea
is pain in the lowest part of the abdomen (pelvis) during a menstrual
period.The
cause is unidentified in most women.
Pain, usually crampy or sharp, starts a few days
before a menstrual period and subsides after 2 or 3 days.
Doctors base...
Amenorrhea
Dec 1, 2008
Amenorrhea
is the absence of menstrual periods.
Menstrual periods may never start, or they may start,
then stop.
Amenorrhea may result from various disorders or
drugs that disrupt any part of the complex hormonal regulation of
the menstrual cycle.
Sy...
Dysfunctional
Uterine Bleeding
Dec 1, 2008
Dysfunctional
uterine bleeding is abnormal bleeding resulting from changes in
the hormonal control of menstruation.Bleeding occurs frequently
or irregularly, lasts longer, or is heavier.
This disorder is diagnosed when the physical examination,
ultra...
Polycystic
Ovary Syndrome
Dec 1, 2008
Polycystic
ovary syndrome involves disruption of the menstrual cycle and a
tendency to have high levels of male hormones (androgens).Women are typically obese
and have irregular or no menstrual periods, and in some, the voice
deepens, breast size dec...
Fibroids
Dec 1, 2008
A fibroid
is a noncancerous tumor composed of muscle and fibrous tissue.Fibroids can cause pain, vaginal
bleeding, constipation, repeated miscarriages, and an urge to urinate
frequently or urgently.
Doctors do a pelvic examination and usually ultraso...
Pelvic
Floor Disorders
Dec 1, 2008
Pelvic floor
(pelvic support) disorders involve a dropping down (prolapse) of
the bladder, urethra, small intestine, rectum, uterus, or vagina caused
by weakness of or injury to the ligaments, connective tissue, and
muscles of the pelvis.Women
may fe...
Introduction
Dec 1, 2008
There is no formal or
universally accepted definition of a “high-risk” pregnancy. Generally,
however, a high-risk pregnancy involves at least one of the following:The woman or baby is more
likely to become ill or die than usual.
Complications before ...
Risk Factors Present
Before Pregnancy
Dec 1, 2008
Some risk factors are
present before women become pregnant. These risk factors include certain
physical and social characteristics of women, problems that have
occurred in previous pregnancies, and certain disorders women already
have....
Risk Factors That Develop
During Pregnancy
Dec 1, 2008
During pregnancy, a problem
may occur or a condition may develop to make the pregnancy high
risk. For example, pregnant women may be exposed to something that
can cause birth defects (teratogens), such as radiation, certain chemicals,
drugs, or infec...
Introduction
Dec 1, 2008
Although each labor and
delivery is different, most follow a general pattern. Therefore, an
expectant mother can have a general idea of what changes will occur
in her body to enable her to deliver the baby and what procedures will
be followed to help...
Labor
Dec 1, 2008
Labor is
a series of rhythmic, progressive contractions of the uterus that
gradually move the fetus through the lower part of the uterus (cervix)
and birth canal (vagina) to the outside world....
Delivery
Dec 1, 2008
Delivery
is the passage of the fetus and placenta (afterbirth) from the uterus
to the outside world....
Introduction
Dec 1, 2008
Usually, labor and delivery
occur without any problems. Serious problems are relatively rare,
and most can be anticipated and treated effectively. However, problems
sometimes develop suddenly and unexpectedly. Regular visits to a
doctor or certified ...
Labor
and Timing Problems
Dec 1, 2008
Labor may start too early (before the 37th week
of pregnancy) or may start late (after the 42nd week of pregnancy).
As a result, the health or life of the fetus may
be endangered.
Labor may start too early or late when the woman
or fetus has a medic...
Fetus
or Newborn Problems
Dec 1, 2008
If labor does not proceed
normally, the fetus or newborn may have problems....
Problems
Affecting the Woman
Dec 1, 2008
Some complications of
pregnancy also cause problems during labor or delivery. For example,
preeclampsia (see ), which involves high blood pressure accompanied
by protein in the urine, can develop any time from the 20th week
of pregnancy through the 6...
Labor and Delivery Procedures
Dec 1, 2008
Induction
of labor is the artificial starting of labor. Usually, labor
is induced by giving the woman oxytocin, a hormone that makes the uterus
contract more frequently and more forcefully. The oxytocin given
is identical to the natural oxytocin prod...
Introduction
Dec 1, 2008
Noncancerous (benign)
gynecologic growths include cysts, polyps, and myomas. Noncancerous
growths can develop on the vulva or in the vagina, uterus (see and ), or ovaries.
Occasionally, cysts or tumors in an ovary can cause the ovary to
twist—a diso...
Adnexal
Torsion
Dec 1, 2008
Adnexal
torsion is twisting of the ovary and sometimes the fallopian tube,
cutting off the blood supply of these organs.Twisting causes sudden, severe
pain, and often vomiting.
Doctors use an ultrasound device inserted into the
vagina (transvaginal u...
Cervical
Myomas
Dec 1, 2008
Cervical
myomas are smooth, benign tumors in the cervix.A myoma may bleed, become
infected, interfere with urinating, or cause pain during sexual
intercourse.
Doctors can see or feel most myomas during a pelvic
examination.
Myomas that cause symptoms...
Cervical
Stenosis
Dec 1, 2008
Cervical
stenosis is narrowing of the passageway through the cervix (the
lower part of the uterus).
Infertility can occur, or the uterus can fill with
blood or pus.
The opening of the cervix can be widened to relieve
symptoms....
Cysts
Dec 1, 2008
Cysts are closed
sacs that are separate from the tissue around them. They often contain fluid
or semisolid material. Cysts that commonly occur in the genital
organs include Bartholin's gland cysts, endometriomas, inclusion and
epidermal cysts, and Sk...
Noncancerous
Ovarian Growths
Dec 1, 2008
Noncancerous
(benign) ovarian growths include functional cysts and tumors.Most noncancerous cysts and
tumors do not cause any symptoms, but some cause pain or a feeling
of heaviness in the pelvis.
Doctors may detect growths during a pelvic examinatio...
Polyps
of the Cervix
Dec 1, 2008
Cervical
polyps are common fingerlike growths of tissue that protrude into
the passageway through the cervix. Polyps are almost always benign
(noncancerous)....
Introduction
Dec 1, 2008
Certain disorders,
such as diabetes and high blood pressure, can increase the risk
of problems during pregnancy. If women who have such a disorder
wish to become pregnant, they should first talk with a doctor and
try to get in the best physical condi...
Anemia
During Pregnancy
Dec 1, 2008
Anemia develops in
most pregnant women to some degree. The most common cause is an iron
deficiency....
Asthma
During Pregnancy
Dec 1, 2008
The effect of pregnancy
on asthma varies. Worsening of the disease is slightly more common
than improvement, but most pregnant women do not have severe asthma
attacks. The effect of asthma on pregnancy also varies, but risk
of preterm delivery and fe...
Autoimmune
Disorders During Pregnancy
Dec 1, 2008
Autoimmune disorders,
including Graves' disease (see ), are
more common among women, particularly pregnant women. The abnormal
antibodies produced in autoimmune disorders can cross the placenta
and cause problems in the fetus. Pregnancy affects diffe...
Cancer
During Pregnancy
Dec 1, 2008
Because cancer tends
to be life threatening and because delays in treatment may reduce the
likelihood of successful treatment, cancer is usually treated the
same way whether the woman is pregnant or not. Some of the usual treatments
(surgery, chemoth...
Diabetes
During Pregnancy
Dec 1, 2008
For women who have
diabetes before they become pregnant, the risks of complications during
pregnancy depend on how long diabetes has been present and whether
complications of diabetes, such as high blood pressure and kidney
damage, are present....
Fevers
During Pregnancy
Dec 1, 2008
A temperature greater
than 103° F (39.5° C) during the 1st trimester increases the risk
of a miscarriage and defects of the brain or spinal cord in the
baby. Fever late in pregnancy increases the risk of preterm labor....
Fibroids
During Pregnancy
Dec 1, 2008
Fibroids in the uterus
(see ),
which are relatively common noncancerous tumors, may increase the
risk of preterm labor, abnormal presentation of the fetus, a mislocated
placenta (placenta previa), and repeated miscarriages. Rarely, fibroids
interfere...
Heart
Disorders During Pregnancy
Dec 1, 2008
Most women who have
heart disorders—including heart valve disorders (such as mitral valve
prolapse) and some birth defects of the heart—can safely give birth
to healthy children, without any permanent ill effects on heart
function or life span. Howev...
High
Blood Pressure During Pregnancy
Dec 1, 2008
High blood pressure
(hypertension) during pregnancy is classified as one of following:Chronic hypertension: Blood
pressure was high before the pregnancy.
Gestational hypertension: Blood pressure became
high for the first time during pregnancy, usuall...
Infections
During Pregnancy
Dec 1, 2008
Most common infections
that occur during pregnancy, such as those of the skin and respiratory
tract, cause no serious problems. However, some infections can be
passed to the fetus before or during birth and damage the fetus
or cause a miscarriage or ...
Kidney
Disorders During Pregnancy
Dec 1, 2008
Women with a severe
kidney disorder before pregnancy are more likely to have problems during
pregnancy. If high blood pressure develops, kidney function may
rapidly worsen during pregnancy. High blood pressure commonly occurs
in people with a kidney ...
Liver
and Gallbladder Disorders During Pregnancy
Dec 1, 2008
Women who have chronic
viral hepatitis or scarring of the liver (cirrhosis) are more likely to
miscarry or to give birth prematurely. Cirrhosis can cause varicose
veins to develop around the esophagus (esophageal
varices). Pregnancy slightly increase...
Seizure
Disorders During Pregnancy
Dec 1, 2008
Women who have seizures
are slightly more likely to develop preeclampsia (a type of high blood
pressure that develops during pregnancy) and to have a stillbirth
or a fetus who does not grow as much as expected. On the other hand, taking
anticonvulsan...
Disorders
That Require Surgery During Pregnancy
Dec 1, 2008
During pregnancy,
a disorder that requires surgery involving the abdomen may develop. This
type of surgery often slightly increases the risk of preterm labor
and can cause a miscarriage, especially early in pregnancy. Thus, surgery
is usually delayed...
Thromboembolic
Disorders During Pregnancy
Dec 1, 2008
In the United States,
thromboembolic disorders are the leading cause of death in pregnant women.
In thromboembolic disorders, blood clots form in blood vessels.
They may travel through the bloodstream and block an artery. The
risk of developing a thr...
Thyroid
Disorders During Pregnancy
Dec 1, 2008
Thyroid disorders
may be present before women become pregnant or develop during pregnancy.
Being pregnant does not change the symptoms of thyroid disorders.
How the fetus is affected depends on which thyroid disorder is present
and which drugs are us...
Urinary
Tract Infections During Pregnancy
Dec 1, 2008
Urinary tract infections
are common during pregnancy, probably because the enlarging uterus
and hormones slow the flow of urine in the tubes that connect the
kidneys to the bladder (ureters). When urine flow is slow, bacteria may
not be flushed out o...
Introduction
Dec 1, 2008
Pregnancy complications
are problems that occur only during pregnancy. They may affect the
woman, the fetus, or both and may occur at different times during
the pregnancy. For example, complications such as a mislocated placenta
(placenta previa) or ...
Problems
With Amniotic Fluid
Dec 1, 2008
Amniotic fluid is
the fluid that surrounds the fetus in the uterus. The fluid and
fetus are contained in membranes called the amniotic sac. There
may be too much or too little amniotic fluid....
Cervical
Incompetence
Dec 1, 2008
Cervical
incompetence is painless opening of the cervix that results in delivery
of the baby between 16 and 22 weeks of pregnancy.Connective tissue disorders
present at birth and injuries can make tissues of the cervix weak.
Cervical incompetence is ...
Ectopic
Pregnancy
Dec 1, 2008
Ectopic
pregnancy is attachment (implantation) of a fertilized egg in an
abnormal location.Women
may have abdominal pain and vaginal bleeding.
Ultrasonography is done, mainly to determine the
location of the fetus.
Usually, surgery is done to remove ...
Hyperemesis
Gravidarum
Dec 1, 2008
Hyperemesis
gravidarum is extremely severe nausea and excessive vomiting during
pregnancy....
Miscarriage
Dec 1, 2008
A miscarriage
(spontaneous abortion) is the loss of a fetus due to natural causes
before 20 weeks of pregnancy.
Miscarriages may occur because of a problem in the
fetus or the woman (such as structural abnormalities, infections,
certain disorders, us...
Stillbirth
Dec 1, 2008
Stillbirth
is death and delivery of a fetus after 20 weeks of pregnancy....
Placenta
Previa
Dec 1, 2008
Placenta
previa is attachment (implantation) of the placenta over or near
the cervix, in the lower rather than the upper part of the uterus.Women may have painless, sometimes profuse
bleeding late in the pregnancy.
Ultrasonography can usually confir...
Placental
Abruption (Abruptio Placentae)
Dec 1, 2008
Placental
abruption (abruptio placentae) is the premature detachment of a
normally positioned placenta from the wall of the uterus.Women may have vaginal bleeding
and severe abdominal pain and go into shock.
Bed rest may be all that is needed, but i...
Preeclampsia
Dec 1, 2008
Preeclampsia
is high blood pressure accompanied by protein in the urine that
develops after the 20th week of pregnancy.Preeclampsia can cause the
placenta to detach and the baby to be born too early, increasing
the risk that the baby will have probl...
Rh
Incompatibility
Dec 1, 2008
Rh
incompatibility occurs when a pregnant woman has Rh-negative blood
and the fetus has Rh-positive blood.
Rh incompatibility can result in destruction of
the fetus's red blood cells, sometimes causing anemia that can be
severe.
The fetus is checked...
Introduction
Dec 1, 2008
Chromosomes are structures
within cells that contain a person's genes. A gene is a segment
of DNA and contains the code for a specific protein that functions
in one or more types of cells in the body (see for a discussion
about genetics)....
Down
Syndrome (Trisomy 21; Trisomy G)
Dec 1, 2008
Down syndrome
(trisomy 21, trisomy G) is a chromosomal disorder resulting in mental
retardation and physical abnormalities.Most cases of Down syndrome
are caused by an extra copy of chromosome 21.
Children with Down syndrome have delayed physical
and...
Fragile
X Syndrome
Dec 1, 2008
Fragile X
syndrome is a genetic abnormality in the X chromosome that leads
to delayed development and other symptoms....
Turner's
Syndrome
Dec 1, 2008
In Turner's
syndrome (gonadal dysgenesis), girls are born with one of their
two X chromosomes partially or completely missing.Turner's syndrome is caused
by the deletion of or partial formation of one of the two X chromosomes.
Girls with the syndrome...
Noonan's
Syndrome
Dec 1, 2008
Noonan's syndrome
is a genetic defect that causes a number of physical abnormalities,
including short stature, heart defects, and an abnormal appearance....
Triple
X Syndrome
Dec 1, 2008
Triple X (trisomy
X, XXX) syndrome is a rare disorder in which female infants are
born with three X chromosomes....
Klinefelter's
Syndrome
Dec 1, 2008
Klinefelter's
syndrome is a disorder in which male infants are born with an extra
X chromosome (XXY).Klinefelter's
syndrome is caused by an extra X chromosome.
Children may have learning disabilities, long arms
and legs, small testes, and infertility...
XYY
Syndrome
Dec 1, 2008
The XYY syndrome
is a disorder in which a male infant is born with an extra Y chromosome....
Long
QT Syndrome
Dec 1, 2008
Long QT syndrome
is an abnormality of the heart's electrical system (see ), which may
cause loss of consciousness or sudden death.Long QT syndrome can be caused
by a genetic abnormality, drug use, or a disorder.
This syndrome causes the heart to beat...
Introduction
Dec 1, 2008
A fracture
is a crack or break in a bone, usually accompanied by injury to
the surrounding tissues.Fractures
cause pain and swelling.
Complications may involve damage to nerves, blood
vessels, muscles, and internal organs and can be serious.
Most fra...
Foot
and Ankle Fractures
Dec 1, 2008
Fractures of the
foot bones are common and are caused by falls, twisting injuries,
or direct impact of the foot against hard objects. Foot fractures
cause considerable pain, which is almost always made worse by attempting
to walk or put weight on the...
Leg
Fractures
Dec 1, 2008
...
Hip
Fractures
Dec 1, 2008
Hip fractures, which occur most frequently among
older people, can be caused by minor falls, particularly among people
with osteoporosis.
Most people with a hip fracture cannot move the
leg, stand, or walk.
Hip fractures are diagnosed with x-rays or...
Pelvis
Fractures
Dec 1, 2008
The pelvis is made
up of pairs of large broad (iliac) bones in the back joined by two
smaller connecting bone struts (the pubic and ischial rami) in the
front. In young adults, major fractures of the entire pelvis can
occur as a result of high-speed ...
Compression Fractures
of the Spine
Dec 1, 2008
Compression fractures may occur with only slight
trauma in older people with osteoporosis.
The area around the fracture is painful, and the
pain worsens with walking, standing, and prolonged sitting.
Doctors diagnose spinal compression fractures wit...
Rib
Fractures
Dec 1, 2008
Rib fractures usually
result from a strong force, such as falls, motor vehicle accidents,
or a hit with a baseball bat. However, sometimes in older people,
only a slight force (such as a minor fall) is required. The fracture
itself is rarely serious,...
Clavicle
Fractures
Dec 1, 2008
Clavicle fractures
occur commonly after a fall on an outstretched arm or after a direct blow.
Because the clavicle lies just under the skin and has little muscle
covering, swelling and deformity are easily seen after a fracture. Most
of these injurie...
Humerus
Fractures
Dec 1, 2008
Fractures of the
upper arm bone (humerus) usually occur near the shoulder. These
fractures are common after a fall on an outstretched arm or after
a direct blow. Symptoms include pain and an inability to raise the
arm. Fractures of the middle of the ...
Elbow Fractures
Dec 1, 2008
Elbow
fractures can involve any of the three bones that make up the joint
(radius, ulna, and humerus). Fractures of the radial head or neck (the
upper end of the radius) occur commonly in active adults after a
fall on an outstretched arm. The outer s...
Wrist Fractures
Dec 1, 2008
Wrist
fractures involve the radius, and sometimes also the ulna. These
occur commonly after a fall on an outstretched arm, particularly
in older people. People have pain, swelling, and tenderness, and
often the wrist appears in an unnatural position....
Hand
Fractures
Dec 1, 2008
Hand fractures involve
the bones that form part of the wrist (carpals), bones of the palm (metacarpals),
or bones of the fingers and thumb (phalanges). Normal hand function results
from a complex interaction of an intricate arrangement of muscles,
te...
Introduction
Dec 1, 2008
Many people have disorders
for which no specific cause has been identified. Some doctors believe
that some of these disorders of unknown cause are due to psychologic
factors. Others believe that the disorders are caused by infections
(such as viral i...
Chronic
Fatigue Syndrome
Dec 1, 2008
Chronic fatigue
syndrome refers to long-standing severe and disabling fatigue without
a proven physical or psychologic cause.Unexplained fatigue lasts
for 6 months or longer.
Sometimes symptoms begin with a coldlike illness.
No treatments have proved...
Gulf
War Syndrome
Dec 1, 2008
Gulf War syndrome
consists of a group of symptoms experienced by more than 100,000 American,
British, and Canadian veterans of the 1992 Persian Gulf War.Some Gulf War veterans have
developed various symptoms.
Although the veterans have been exposed ...
Multiple
Chemical Sensitivity Syndrome
Dec 1, 2008
Multiple chemical
sensitivity syndrome is a disorder that seems to be triggered by
exposure to low levels of multiple identifiable or unidentifiable
chemical substances commonly present in the environment.Symptoms may include rapid
heart rate, chest ...
Introduction
Dec 1, 2008
As people grow older, they
face many changes. With aging, the ability to carry out the tasks
of everyday life (functional ability) declines to some degree in
every person, and older people, on average, tend to have more disease
and disability than do...
Life-Changing Events
Dec 1, 2008
...
Staying Connected
Dec 1, 2008
Studies have shown that
people who remain active and who interact with other people during
old age live longer, happier, healthier lives. Volunteering, taking
classes, joining social groups, engaging in hobbies, and pursuing some
type of spiritual or...
Introduction
Nov 1, 2008
The cornea and lens focus
light onto the retina, the transparent, light-sensitive
membrane on the inner surface of the back of the eye. The central
area of the retina, called the macula, contains a high density of
color-sensitive photoreceptor (light...
Age-Related
Macular Degeneration
Nov 1, 2008
Age-related
macular degeneration (also called age-related maculopathy) causes
progressive damage to the macula, the central and most vital area
of the retina, resulting in gradual loss of central vision.Central vision becomes washed
out and loses det...
Epiretinal
Membrane
Nov 1, 2008
Epiretinal
membrane (cellophane maculopathy, macular pucker, or premacular
fibrosis) is formation of a thin membrane over the retina, which
interferes with vision....
Detachment
of the Retina
Nov 1, 2008
Retinal detachment
is separation of the retina from the underlying layer to which it
is attached.People
notice a sudden increase in floaters, a sudden onset of flashing
lights, a curtain or veil across vision, or sudden loss of vision.
Doctors make t...
Retinitis
Pigmentosa
Nov 1, 2008
Retinitis
pigmentosa is a rare, progressive degeneration of the retina that
eventually causes moderate to severe vision loss....
Blockage
of Central Retinal Arteries and Veins
Nov 1, 2008
A blood vessel
in the retina may become blocked, causing sudden, painless loss
of vision.Doctors
typically make the diagnosis by looking in the eye with an ophthalmoscope.
Sometimes tests are done.
Treatment often is unsuccessful....
Hypertensive
Retinopathy
Nov 1, 2008
Hypertensive
retinopathy is damage to the retina caused by high blood pressure....
Diabetic
Retinopathy
Nov 1, 2008
Diabetic retinopathy
is damage to the retina as a result of diabetes.Blood vessels in the retina
can leak.
New blood vessels may develop, sometimes leading
to hemorrhage, scar formation, or retinal detachment.
The diagnosis is based on findings of an...
Endophthalmitis
Nov 1, 2008
Endophthalmitis
is infection inside the eye.
Eye surgery, eye injury, or infection in the bloodstream
can cause the infection.
Severe eye pain, eye redness, and loss of vision
may occur.
Cultures are taken of eye fluids, and antibiotics
are given as ...
Cancers
Affecting the Retina
Nov 1, 2008
Cancers affecting the
retina usually occur in the choroid, a dense layer of blood vessels
that supplies the retina. The choroid is sandwiched between the
retina and the sclera (the outer white part of the eye). Because
the retina depends on the choro...
Introduction
Nov 1, 2008
Sexual dysfunction
includes painful intercourse, painful contraction (spasm) of the
vaginal muscles, or a problem with sexual desire, arousal, or orgasm
that causes distress.Depression
or anxiety, other psychologic factors, disorders, and drugs can
c...
Dyspareunia
Nov 1, 2008
Dyspareunia
is pain when women try to begin sexual intercourse or during intercourse.The pain may be superficial
or deep. It may result from vaginal dryness or disorders of the
genital organs.
The diagnosis is based on symptoms and a pelvic
examinati...
Vaginismus
Nov 1, 2008
Vaginismus
is involuntary contraction of muscles around the opening of the
vagina in women with no abnormalities identified during examination.
The tight muscle contraction makes sexual intercourse painful or
impossible.Most
women with vaginismus can...
Low
Sexual Desire Disorder
Nov 1, 2008
Low sexual
desire disorder (sexual desire/interest disorder) is lack of interest
in sexual activity and sexual thoughts.Depression, anxiety, stress,
relationship problems, past experiences, drugs, and, less often,
hormonal changes can reduce sexual d...
Sexual
Arousal Disorders
Nov 1, 2008
Sexual arousal
disorders involve a lack of response to sexual stimulation—mental
or emotional (subjective), physical (such as swelling, tingling,
or throbbing in the genital area or vaginal wetness), or both.Depression, low self-esteem,
anxiety, stre...
Orgasmic
Disorder
Nov 1, 2008
Orgasmic disorder
is lack of or delay in sexual climax (orgasm) even though sexual
stimulation is sufficient and the woman is sexually aroused.Women may not have an orgasm
if lovemaking ends too soon, there is not enough foreplay, or they
are afraid ...
Introduction
Nov 1, 2008
Breast disorders may be
noncancerous (benign) or cancerous (malignant). Most are noncancerous
and not life threatening. Often, they do not require treatment.
In contrast, breast cancer can mean loss of a breast or of life.
Thus, for many women, breas...
Breast Cysts
Nov 1, 2008
Breast cysts
are fluid-filled sacs that develop in the breast....
Fibroadenomas
Nov 1, 2008
Fibroadenomas
are small, solid, rubbery noncancerous lumps composed of fibrous
and glandular tissue....
Fibrocystic
Changes
Nov 1, 2008
Fibrocystic
changes (formerly called fibrocystic breast disease) include breast
pain, cysts, and lumpiness that are not due to cancer....
Breast Infection
and Abscess
Nov 1, 2008
A breast infection (mastitis)
is rare, except around the time of childbirth (see ) or
after an injury or surgery. The most common symptom is a swollen,
red area that feels warm and tender. An uncommon type of breast
cancer called inflammatory breast ...
Breast Cancer
Nov 1, 2008
Among women, breast cancer is the second most common
cancer and the second most common cause of cancer deaths.
Typically, the first symptom is a painless lump,
usually noticed by the woman.
Monthly self-examination, yearly breast examination
by a do...
Introduction
Nov 1, 2008
Cancers can occur in any
part of the female reproductive system—the vulva, vagina, cervix,
uterus, fallopian tubes, or ovaries. These cancers are called gynecologic
cancers....
Cancer
of the Uterus
Nov 1, 2008
Cancer of
the uterus develops in the lining of the uterus (endometrium) and
is thus also called endometrial cancer.Endometrial cancer usually
affects women after menopause.
It sometimes causes abnormal vaginal bleeding.
To diagnosis this cancer, doct...
Ovarian
Cancer
Nov 1, 2008
Ovarian cancer may not cause symptoms until it is
large or has spread.
If doctors suspect ovarian cancer, ultrasonography,
magnetic resonance imaging, or computed tomography is done.
Usually, both ovaries, both fallopian tubes, and
the uterus are re...
Cervical
Cancer
Nov 1, 2008
Cervical
cancer develops in the cervix (the lower part of the uterus).Cervical cancer usually results
from infection with the human papillomavirus (HPV), transmitted
during sexual intercourse.
Cervical cancer may cause irregular vaginal bleeding,
but...
Vulvar
Cancer
Nov 1, 2008
Vulvar cancer,
usually a skin cancer, develops in the area around the female genital
organs.The
cancer may appear to be a lump, an itchy area, or a sore that does
not heal.
A sample of the abnormal tissue is removed and examined
(biopsied).
All or pa...
Vaginal
Cancer
Nov 1, 2008
Cancer of the vagina,
an uncommon cancer, is usually a squamous cell skin cancer (vaginal carcinoma),
which typically develops in older women.
Vaginal cancer may cause abnormal vaginal bleeding,
particularly after sexual intercourse.
If doctors suspe...
Fallopian
Tube Cancer
Nov 1, 2008
Fallopian
tube cancer develops in the tubes that lead from the ovaries to
the uterus.Most
cancers that affect the fallopian tubes have spread from other parts
of the body.
At first, women may have vague symptoms, such as
abdominal discomfort or bloat...
Hydatidiform
Mole
Nov 1, 2008
A hydatidiform
mole is growth of an abnormal fertilized egg or an overgrowth of
tissue from the placenta.
Women appear to be pregnant, but the uterus enlarges
much more rapidly than in a normal pregnancy.
Most women have severe nausea and vomiting, v...
Introduction
Nov 1, 2008
Before women become pregnant, they and their partner
should speak with their health care practitioner about their risk
of having a baby with a genetic disorder.
Risk factors include older age in the woman, a family
history of genetic abnormalities, ...
Genetic
Screening
Nov 1, 2008
Screening involves assessing the couple's family
history and, if needed, analysis of blood or tissue samples....
Prenatal
Diagnostic Testing
Nov 1, 2008
Measurement of certain substances in the pregnant
woman's blood plus ultrasonography can help estimate the risk of
genetic abnormalities in the fetus.
These blood tests and ultrasonography may be done
as part of routine care during pregnancy.
If res...
Introduction
Nov 1, 2008
The postdelivery
(postpartum) period is the 6 weeks after delivery of a baby, when
the mother's body returns to its prepregnancy state....
Hospital
(What to Expect)
Nov 1, 2008
Immediately after delivery
of a baby, the mother is monitored. If a general anesthetic was
used during delivery, she is monitored for 2 to 3 hours after delivery,
usually in a well-equipped recovery room with access to oxygen,
intravenous fluids, and...
Continuing From Hospital
to Home
Nov 1, 2008
Coping with some changes
begins in the hospital, depending on how soon hospital discharge
occurs, and then continues at home....
Home (What to Expect)
Nov 1, 2008
A new mother may resume
normal daily activities when she feels ready. Eating a healthy diet
and exercising regularly can help a new mother return to her prepregnancy weight....
Infections
Nov 1, 2008
Immediately after delivery,
the woman's temperature often increases. A temperature of 101° F
(38.3° C) or higher during the first 12 hours after delivery could
indicate an infection but may not. Nonetheless, in such cases, the woman
should be evaluat...
Blood
Clots
Nov 1, 2008
The risk of developing
blood clots (thrombophlebitis) is increased after delivery. Typically,
blood clots occur in the legs or pelvis (a disorder called deep
vein thrombosis—see ). Sometimes one of these clots breaks loose
and travels through the blo...
Thyroid
Disorders
Nov 1, 2008
In 4 to 7% of women,
the thyroid gland malfunctions during the first 6 months after delivery.
Thyroid hormone levels may be high or low, usually temporarily.
Women who have a family history of thyroid disorders or diabetes are
particularly susceptibl...
Postpartum Depression
Nov 1, 2008
Postpartum
depression is a feeling of extreme sadness and related psychologic
disturbances during the first few weeks or months after delivery.Women who have had depression
are more likely to develop postpartum depression.
Women feel extremely sad, c...
Introduction
Oct 1, 2008
Common tooth disorders
include cavities (caused by tooth decay), pulpitis, periapical abscess,
impacted teeth, and malocclusion. Fractured, loosened, and knocked-out
teeth are considered urgent dental problems, as are some toothaches
(see ).
Tooth de...
Cavities
Oct 1, 2008
Cavities (dental
caries) are decayed areas in the teeth, the result of a process
that gradually dissolves a tooth's hard outer surface (enamel) and
progresses toward the interior.
Bacteria and debris build up on tooth surfaces,
and the bacteria produ...
Pulpitis
Oct 1, 2008
Pulpitis is
painful inflammation of the tooth pulp, the innermost part of the
tooth that contains the nerves and blood supply....
Periapical
Abscess
Oct 1, 2008
A periapical
abscess is a collection of pus, usually from an infection that has
spread from a tooth to the surrounding tissues....
Impacted
Teeth
Oct 1, 2008
Impacted teeth
are teeth that are unable to emerge (erupt) properly from the gum....
Malocclusion
Oct 1, 2008
Malocclusion
is an abnormal alignment of the teeth or upper and lower jaws that
prevents the teeth from meeting properly.If teeth are out of alignment,
abnormal pressure is put on them, making them more likely to loosen
or fracture.
Malocclusion may ...
Introduction
Oct 1, 2008
Periodontal
diseases inflame and destroy the structures surrounding and supporting
the teeth, primarily the gums, the jawbones, and the outer layer
of the tooth root....
Gingivitis
Oct 1, 2008
Gingivitis
is inflammation of the gums (gingivae).Gingivitis results most often
from inadequate brushing and flossing but may result from medical
disorders or the use of certain drugs.
The gums are red and swollen and bleed easily.
Good oral hygiene,...
Periodontitis
Oct 1, 2008
Periodontitis
(pyorrhea) is a severe form of gingivitis in which the inflammation
of the gums extends to the supporting structures of the tooth.Plaque and tartar build up
between the teeth and gums, then spread to the bone under the teeth.
The gums s...
Trench
Mouth
Oct 1, 2008
Trench mouth
(Vincent's infection, acute necrotizing ulcerative gingivitis) is
a painful, noncontagious infection of the gums, causing pain, fever,
and sometimes fatigue.If
the normal bacteria in the mouth overgrow, the gums can become infected.
The ...
Gum
Recession
Oct 1, 2008
Gum recession
is the loss of gum tissue from the base of a tooth with exposure
of the root surface....
Introduction
Oct 1, 2008
Certain dental problems
require prompt treatment to relieve discomfort and minimize damage
to the structures of the mouth. Such urgent dental problems includeToothaches
Fractured, loosened, and knocked-out teeth
Jaw fractures
A dislocated jaw
Infecti...
Toothaches
Oct 1, 2008
Most toothaches are caused
by cavities (tooth decay). Some toothaches are caused by a tooth
abscess or by inflammation of the gum around the crown of a tooth
(pericoronitis). Much less commonly, toothaches result from inflammation
of the nasal sinuse...
Teeth
That Have Been Fractured, Loosened, or Knocked Out
Oct 1, 2008
The upper front teeth
are prone to injury and fracture. A person who has brief, sharp
pain while chewing or while eating something cold may have an incomplete
fracture of a tooth. As long as the fracture is incomplete and part
of the tooth has not sp...
Jaw
Fracture
Oct 1, 2008
The term “jaw fracture”
usually refers to fracture of the lower jaw (mandible). A fractured
jaw causes pain and usually changes the way the teeth fit together.
Often, the mouth cannot be opened wide, or it shifts to one side when
opening or closing....
Jaw
Dislocation
Oct 1, 2008
A dislocated jaw (dislocated
mandible) generally is very painful. The mouth cannot be closed,
and the jaw may be twisted to one side. A dislocated jaw is typically
caused by the following:Opening
the mouth excessively wide (such as with yawning, vomi...
After
Dental Treatment
Oct 1, 2008
Swelling
is common after certain dental procedures, particularly tooth extractions
and periodontal surgery. Holding an ice pack—or better yet, a plastic
bag of frozen peas or corn (which adapts to facial contours)—to
the cheek can prevent much of the...
Introduction
Oct 1, 2008
Microorganisms are
tiny living creatures, such as bacteria and viruses. Microorganisms are
present everywhere. Despite their overwhelming abundance, relatively
few of the thousands of species of microorganisms invade, multiply,
and cause disease in p...
Resident
Flora
Oct 1, 2008
Healthy people live in harmony
with most microorganisms that establish themselves on (colonize)
the body. The microorganisms that usually occupy a particular body
site are called the resident flora. Microorganisms that colonize
people for hours to we...
Development
of Infection
Oct 1, 2008
Infectious diseases are
usually caused by microorganisms that invade the body and multiply.
Invasion by most microorganisms begins when they adhere to cells
in a person's body. Adherence is a very specific process, involving "lock-and-key"
connection...
Defenses
Against Infection
Oct 1, 2008
Physical barriers and the
immune system defend the body against organisms that can cause infection.
Physical barriers include the skin, mucous membranes, tears, earwax, mucus,
and stomach acid. Also, the normal flow of urine washes out microorganisms...
Prevention
of Infection
Oct 1, 2008
Several measures help protect
people against infection. Hand washing is an effective way of preventing
the spread of infectious microorganisms from one person to another. Hand washing
is particularly important for people who handle food or who have
f...
Infections
in People With Impaired Defenses
Oct 1, 2008
Many disorders, drugs,
and other treatments can cause a breakdown in the body's natural defenses.
Such a breakdown can lead to infections, which can even be caused
by microorganisms that normally live harmlessly on or in the body.
A breakdown can res...
Tuberculosis
Oct 1, 2008
Tuberculosis
is a contagious infection caused by the airborne bacteria Mycobacterium
tuberculosis.
Tuberculosis is spread only when people breathe
air contaminated by a person who has active disease.
Cough is the most common symptom, but people may
a...
Leprosy
Oct 1, 2008
Leprosy (Hansen's
disease) is a chronic infection caused by the bacteria Mycobacterium
leprae. It results in damage primarily to the peripheral
nerves (the nerves outside the brain and spinal cord), skin, testes,
eyes, and mucous membrane of the nose...
Introduction
Oct 1, 2008
Because fungal spores are often present in the air
or in the soil, fungal infections usually begin in the lungs or
on the skin.
Fungal infections are rarely serious unless the
immune system is weakened, usually by drugs or disorders.
Fungal infectio...
Aspergillosis
Oct 1, 2008
Aspergillosis
is infection, usually of the lungs, caused by the fungus Aspergillus.A ball of fungus fibers, blood
clots, and white blood cells may form in the lungs or sinuses.
People may have no symptoms or may cough up blood,
have a fever, chest pa...
Blastomycosis
Oct 1, 2008
Blastomycosis
(North American blastomycosis, Gilchrist's disease) is infection,
mainly of the lungs, caused by the fungus Blastomyces dermatitidis.People have a fever, chills,
and drenching sweats and sometimes chest pain, difficulty breathing,
and a...
Candidiasis
Oct 1, 2008
Candidiasis
(candidosis, moniliasis, yeast infection) is infection caused by
several species of Candida, especially Candida
albicans.
The most common type of candidiasis is a superficial
infection of the mouth, vagina, or skin that causes white or re...
Coccidioidomycosis
Oct 1, 2008
Coccidioidomycosis
(San Joaquin fever, valley fever) is infection, usually of the lungs,
caused by the fungus Coccidioides immitis.The infection is caused by
inhaling spores of the fungus.
If mild, the lung infection causes flu-like symptoms
and some...
Cryptococcosis
Oct 1, 2008
Cryptococcosis
is infection caused by the fungus Cryptococcus neoformans.People may have no symptoms
or may have headache and confusion, a cough and an achy chest, or
a rash, depending on where the infection is.
The diagnosis is based on culture and ...
Histoplasmosis
Oct 1, 2008
Histoplasmosis
is infection caused by the fungus Histoplasma capsulatum.
It occurs mainly in the lungs but can sometimes spread throughout
the body.The
infection is caused by inhaling spores of the fungus.
Most people do not have symptoms, but some f...
Mucormycosis
Oct 1, 2008
Mucormycosis
(zygomycosis) is infection caused by a fungus of the group Mucorales.The infection is caused by
inhaling spores produced by the mold.
The infection causes pain, fever, and sometimes
cough and can destroy structures in the face.
Doctors d...
Paracoccidioidomycosis
Oct 1, 2008
Paracoccidioidomycosis
(South American blastomycosis) is infection caused by the fungus Paracoccidioides
brasiliensis....
Sporotrichosis
Oct 1, 2008
Sporotrichosis
is infection caused by the fungus Sporothrix schenckii.The infection develops when
the fungi enter the body through a puncture wound.
Usually, the skin and lymph nodes are infected,
resulting in bumps on the skin and swollen lymph node...
Human Immunodeficiency
Virus Infection
Oct 1, 2008
Human immunodeficiency virus (HIV) is transmitted
through contact with a body fluid that contains the virus.
HIV destroys certain types of white blood cells,
weakening the body's defenses against infections and cancers.
When people are first infecte...
Introduction
Oct 1, 2008
Sexually transmitted
(venereal) diseases are infections that are typically, but not exclusively,
passed from person to person through sexual contact.Sexually transmitted diseases
may be caused by bacteria, viruses, or protozoa.
Some infections can be...
Chancroid
Oct 1, 2008
Chancroid
is a sexually transmitted disease caused by the bacteria Haemophilus
ducreyi, which causes painful genital sores....
Chlamydial and Other
Infections
Oct 1, 2008
Chlamydial
infections include sexually transmitted diseases of the urethra
and cervix that are caused by the bacteria Chlamydia
trachomatis. Less commonly, other bacteria, such
as Ureaplasma and mycoplasmas, cause
infection of the urethra.
Symptoms i...
Genital
Warts
Oct 1, 2008
Genital warts
(condylomata acuminata) are growths in or around the vagina, penis,
or rectum caused by human papillomavirus, which is sexually transmitted.Some types of human papillomavirus (HPV)
cause visible genital warts, and other types cause less...
Gonorrhea
Oct 1, 2008
Gonorrhea
is a sexually transmitted disease caused by the bacteria Neisseria
gonorrhoeae, which infect the lining of the urethra,
cervix, rectum, and throat or the membranes that cover the front
part of the eye (conjunctiva and cornea).Gonorrhea is u...
Granuloma
Inguinale
Oct 1, 2008
Granuloma
inguinale is a rare sexually transmitted disease caused by the bacteria Calymmatobacterium
granulomatis, which leads to chronic inflammation
and scarring of the genitals....
Lymphogranuloma
Venereum
Oct 1, 2008
Lymphogranuloma
venereum is a sexually transmitted disease caused by Chlamydia
trachomatis, which causes painful, swollen lymph glands
in the groin and sometimes infection of the rectum....
Syphilis
Oct 1, 2008
Syphilis is
a sexually transmitted disease caused by the bacteria Treponema
pallidum.
Syphilis can occur in three stages of symptoms,
separated by periods of apparent good health.
It begins with a painless sore at the infection
site and, in the secon...
Trichomoniasis
Oct 1, 2008
Trichomoniasis
is a sexually transmitted infection of the vagina or urethra caused
by the protozoa Trichomonas vaginalis,
which causes vaginal irritation and discharge.Women may have a greenish
yellow, frothy, fishy-smelling vaginal discharge with ir...
Other Sexually Transmitted
Diseases
Oct 1, 2008
Some
bacteria (Shigella, Campylobacter, and Salmonella),
viruses (hepatitis A, B, and C), and parasites (Giardia and
some amebas) are sometimes transmitted during sexual intercourse,
although they are typically transmitted in other ways. These organi...
Pressure
Sores
Oct 1, 2008
Pressure sores
(bedsores, decubitus ulcers, pressure ulcers) are areas of skin
damage resulting from a lack of blood flow due to pressure.Sores often result from pressure
but may also result from pulling on the skin or friction, particularly
over bon...
Introduction
Oct 1, 2008
Various
shades and colors of human skin are created by the brown pigment,
melanin. Without melanin, the skin would be pale white with varying
shades of pink caused by the blood flowing through it. Fair-skinned
people produce very little melanin, dark...
Albinism
Oct 1, 2008
Albinism is
a rare hereditary disorder in which little or no melanin is formed....
Vitiligo
Oct 1, 2008
Vitiligo is
a disorder in which a localized loss of melanocytes causes patches
of skin to turn white.Patches
of whitened skin are present on various parts of the body.
Doctors usually base the diagnosis on the appearance
of the skin.
Corticosteroid c...
Melasma
Oct 1, 2008
Melasma causes
dark brown patches of pigmentation to appear on sun-exposed areas, usually
the face....
Introduction
Oct 1, 2008
Many viral infections—such
as measles, chickenpox, and rubella—cause rashes, spots, or sores
on the skin, as well as other symptoms. Herpesviruses often cause
rashes and sores (see ). However, in two common viral infections,
warts and molluscum conta...
Warts
Oct 1, 2008
Warts (verrucae)
are small skin growths caused by any of 100 or more related human papillomaviruses.Raised or flat growths appear
on any part of the skin.
Most warts are painless.
Doctors identify warts by sight or rarely do a biopsy.
Warts that do n...
Molluscum
Contagiosum
Oct 1, 2008
Molluscum
contagiosum is infection of the skin by a poxvirus that causes flesh-colored
or white smooth, waxy bumps....
Introduction
Oct 1, 2008
Skin cancer
is the most common form of cancer in the United States. The three
main types of skin cancer—basal cell carcinoma, squamous cell carcinoma,
and melanoma—are caused, at least in part, by long-term sun exposure.
Lymphoma can also develop in ...
Basal
Cell Carcinoma
Oct 1, 2008
Basal cell
carcinoma is a cancer that originates in cells of the outer layer
of skin (epidermis).Usually,
a small, shiny bump appears on the skin and enlarges slowly.
The bumps may break open and form a scab, sometimes
with bleeding, or become flat, ...
Squamous
Cell Carcinoma
Oct 1, 2008
Squamous cell
carcinoma is cancer that originates in the squamous cells (keratinocytes).Thick, scaly growths appear
on the skin and do not heal.
To diagnose the cancer, doctors do a biopsy.
Treatment with surgery, chemotherapy drugs applied
to the sk...
Melanoma
Oct 1, 2008
Melanoma is
a cancer that originates in the pigment-producing cells of the skin
(melanocytes).Melanomas
can begin on normal skin or in existing moles.
They may be irregular, flat or raised brown patches
of skin with spots of different colors or firm ...
Kaposi's
Sarcoma
Oct 1, 2008
Kaposi's sarcoma
is a cancer that produces multiple flat pink, brown, or purple patches
or bumps on the skin. It is caused by herpesvirus type 8.One or a few spots may appear
on the toes or a leg, or spots may appear anywhere on the body,
then spread...
Paget's
Disease of the Nipple
Oct 1, 2008
Paget's disease
of the nipple is a rare type of skin cancer that originates in glands
in or under the skin....
Introduction
Oct 1, 2008
The cornea is the domed,
transparent covering in the front of the eye that protects the iris and
lens and helps focus light on the retina. It is composed of cells,
protein, and fluid. The cornea looks fragile but is almost as stiff
as a fingernail. H...
Superficial
Punctate Keratitis
Oct 1, 2008
Superficial
punctate keratitis is death of small groups of cells on the surface
of the cornea.The
eyes become red, watery, and sensitive to light.
Most people recover fully.
Symptoms can be relieved....
Corneal
Ulcer
Oct 1, 2008
A corneal
ulcer is an infected open sore on the cornea.Contact lenses, injuries,
disorders, drugs, and nutritional deficiencies can cause open sores.
Pain, foreign body sensation, redness, tearing,
and light sensitivity are common.
Antibiotic, antivi...
Keratoconjunctivitis
Sicca
Oct 1, 2008
Keratoconjunctivitis
sicca (dry eye) is dryness of the conjunctiva and cornea.Too few tears may be produced,
or tears may evaporate too quickly.
The eyes become irritated and sensitive to light
and usually burn and itch.
Tear production may be measur...
Keratomalacia
Oct 1, 2008
Keratomalacia
(xerophthalmia, xerotic keratitis) is drying and clouding of the
cornea due to vitamin A deficiency and insufficient protein and
calories in the diet....
Herpes
Simplex Keratitis
Oct 1, 2008
Herpes simplex
keratitis is infection of the cornea caused by herpes simplex virus....
Herpes
Zoster Ophthalmicus
Oct 1, 2008
Herpes zoster
ophthalmicus is infection of the eye caused by varicella-zoster
virus....
Peripheral
Ulcerative Keratitis
Oct 1, 2008
Peripheral
ulcerative keratitis is inflammation and ulceration of the cornea
that often occurs in people who have connective tissue diseases such
as rheumatoid arthritis....
Keratoconus
Oct 1, 2008
Keratoconus
is a gradual change in the shape of the cornea that causes it to
become irregular and cone-shaped....
Bullous
Keratopathy
Oct 1, 2008
Bullous keratopathy
is a blister-like swelling of the cornea....
Introduction
Oct 1, 2008
The penis and testes (testicles)
can be affected by inflammation, scar tissue, infection (including
sexually transmitted diseases), or injury. Skin cancer can also
develop on the penis. Birth defects can cause difficulty in urinating
and in engaging ...
Inflammation
of the Penis
Oct 1, 2008
The foreskin of the penis
and the glans penis (the cone-shaped end of the penis) can be inflamed.Balanitis is
inflammation of the glans penis.
Posthitis is inflammation of the foreskin.
Balanoposthitis is inflammation of
both the glans penis and the ...
Phimosis and Paraphimosis
Oct 1, 2008
...
Urethral
Stricture
Oct 1, 2008
A urethral
stricture is scarring that narrows the urethra....
Growths
on the Penis
Oct 1, 2008
Growths on the penis are
sometimes caused by infections. One example is syphilis
(see ),
which may cause flat pink or gray growths (condylomata lata). Also,
certain viral infections
can produce one or more small, firm, raised skin growths (genital
wa...
Priapism
Oct 1, 2008
Priapism is
a painful, persistent erection unaccompanied by sexual desire or
excitement....
Peyronie's
Disease
Oct 1, 2008
Peyronie's
disease is a fibrous thickening that contracts and deforms the penis,
distorting the shape of an erection....
Injuries
to the Penis and Scrotum
Oct 1, 2008
Several types of injuries
can affect the penis....
Testicular
Cancer
Oct 1, 2008
Testicular cancer is common among young men.
Usually a painless lump is present.
Ultrasound scans and blood tests are done.
The testis is removed, and sometimes radiation therapy
or chemotherapy is given....
Testicular
Torsion
Oct 1, 2008
Testicular
torsion is the twisting of a testis on its spermatic cord so that
the testis's blood supply is blocked.
What Is Testicular Torsion?
...
Inguinal
Hernia
Oct 1, 2008
An inguinal
hernia is a protrusion of a piece of intestine through an opening
in the abdominal wall in the groin....
Epididymitis
and Epididymo-orchitis
Oct 1, 2008
Epididymitis
is inflammation of the epididymis (the coiled tube on top of the
testis that provides the space and environment for sperm to mature),
and epididymo-orchitis is inflammation of the epididymis and testes....
Swelling
in the Scrotum
Oct 1, 2008
The scrotum can swell for
many reasons. Possible causes include cancer (see ), testicular
torsion (see ),
inguinal hernia (see ), epididymitis (see ), hydrocele,
edema, orchitis, spermatocele, and varicocele....
Introduction
Oct 1, 2008
The prostate gland lies
just under the bladder and surrounds the tube that carries urine from
the bladder (the urethra). It produces the fluid in the semen that
nourishes sperm. Walnut-sized in young men, the prostate gland enlarges
with aging. Three...
Benign
Prostatic Hyperplasia (BPH)
Oct 1, 2008
Benign prostatic
hyperplasia (benign prostatic hypertrophy) is a noncancerous (benign)
enlargement of the prostate gland that can make urination difficult.The prostate gland enlarges
as men age.
Men may have difficulty urinating and feel the need
to ...
Prostate
Cancer
Oct 1, 2008
The risk of prostate cancer increases as men age.
Symptoms, such as difficulty urinating, a need to
urinate frequently and urgently, and blood in the urine, usually
occur only after the cancer is advanced.
The cancer can spread, usually to the bone,...
Prostatitis
Oct 1, 2008
Prostatitis
is pain and swelling, inflammation, or both, of the prostate gland.The cause is sometimes a bacterial
infection.
Pain can occur in the area between the scrotum and
anus or in the lower back, penis, or testes.
Men feel a frequent, urgent n...
Introduction
Oct 1, 2008
Infertility
is the inability of a couple to achieve a pregnancy after repeated
intercourse without contraception for 1 year....
Problems
With Sperm
Oct 1, 2008
Sperm may
be too few in number, move too slowly, or be structurally abnormal,
or their passage out of the body may be blocked or disrupted.An increase in the testes'
temperature, certain disorders, injuries, and some drugs and toxins
can cause proble...
Problems
With Ovulation
Oct 1, 2008
The ovaries
do not release an egg each month (see ).Ovulation problems can result
from dysfunction of the part of the brain and the glands that control
ovulation or dysfunction of the ovaries.
Women can determine whether ovulation is occurring
and es...
Problems
With the Fallopian Tubes
Oct 1, 2008
The fallopian
tube may be blocked or damaged, preventing the egg from moving from
the ovary to the uterus to be implanted.To identify the problem, doctors
may use x-rays taken after a radiopaque dye is injected through
the cervix or may choose to loo...
Problems
With Mucus in the Cervix
Oct 1, 2008
If mucus
in the cervix is abnormal, it may prevent sperm from entering the
uterus or may promote the destruction of sperm....
Problems
With Eggs
Oct 1, 2008
The number
of eggs may be low, or the quality may be poor....
Unidentified
Factors
Oct 1, 2008
Unidentified
factors are considered the explanation for infertility when semen
in the man and ovulation and fallopian tubes in the woman are normal....
Assisted
Reproductive Techniques
Oct 1, 2008
Assisted
reproductive techniques involve manipulating sperm and eggs in a
culture dish (in vitro) with the goal of producing an embryo....
Introduction
Sep 1, 2008
The immune
system is designed to defend the body against foreign or dangerous
cells or substances that invade it. Such invaders include microorganisms
(commonly called germs, such as bacteria, viruses, and fungi), parasites
(such as worms), cancer ce...
Innate
Immunity
Sep 1, 2008
Innate (natural) immunity
is so named because it is present at birth and does not have to
be learned through exposure to an invader. It thus provides an immediate
response to foreign cells. However, its components treat all foreign
substances in much...
Acquired
Immunity
Sep 1, 2008
Acquired (adaptive or specific)
immunity is not present at birth. It is learned. As a person's immune
system encounters foreign substances (antigens), the components
of acquired immunity learn the best way to attack each antigen and
begin to develop ...
Effects
of Aging
Sep 1, 2008
The immune system changes
throughout life. At birth, specific immunity is not fully developed.
However, newborns
have some antibodies, which crossed the placenta from the mother
during pregnancy. These antibodies protect newborns against infections
u...
Introduction
Sep 1, 2008
Immunodeficiency
disorders involve malfunction of the immune system, resulting in
infections that develop and recur more frequently, are more severe,
and last longer than usual.
Immunodeficiency disorders usually result from use
of a drug or from a l...
Ataxia-Telangiectasia
Sep 1, 2008
Ataxia-telangiectasia
is a hereditary disorder characterized by incoordination, dilated
capillaries, and increased susceptibility to infections....
Chronic
Granulomatous Disease
Sep 1, 2008
Chronic granulomatous
disease is a hereditary immunodeficiency disorder in which phagocytes
(a type of white blood cell) malfunction....
Chronic
Mucocutaneous Candidiasis
Sep 1, 2008
Chronic mucocutaneous
candidiasis is a hereditary immunodeficiency disorder due to malfunction
of T cells (lymphocytes)....
Common
Variable Immunodeficiency
Sep 1, 2008
Common variable
immunodeficiency is a congenital immunodeficiency disorder characterized
by very low antibody (immunoglobulin) levels despite a normal number
of B cells (lymphocytes)....
DiGeorge
Syndrome
Sep 1, 2008
DiGeorge syndrome
is a congenital immunodeficiency disorder in which the thymus gland is
absent or underdeveloped at birth....
Hyperimmunoglobulinemia
E Syndrome
Sep 1, 2008
Hyperimmunoglobulinemia
E syndrome (hyper-IgE syndrome, or Buckley syndrome) is a hereditary
immunodeficiency disorder characterized by early onset of recurrent
boils and pneumonia but with very high levels of immunoglobulin
E (IgE) and normal levels...
Selective
Immunoglobulin Deficiency
Sep 1, 2008
Selective immunoglobulin
deficiency is a congenital immunodeficiency disorder resulting in
a low level of one type (class) of antibody (immunoglobulin), even
though the levels of other immunoglobulins are normal....
Severe
Combined Immunodeficiency
Sep 1, 2008
Severe combined
immunodeficiency is a congenital immunodeficiency disorder resulting in
low levels of antibodies (immunoglobulins,) and no T cells (lymphocytes)....
Spleen
Disorders and Immunodeficiency
Sep 1, 2008
The spleen is crucial
to the function of the immune system. The spleen filters the blood, removing
and destroying bacteria and other infectious organisms in the bloodstream.
It also produces antibodies (immunoglobulins). For people whose
spleen is ab...
Transient
Hypogammaglobulinemia of Infancy
Sep 1, 2008
In transient
hypogammaglobulinemia of infancy, production of normal amounts of
antibodies (immunoglobulins) in infants is delayed....
Wiskott-Aldrich
Syndrome
Sep 1, 2008
Wiskott-Aldrich
syndrome is a hereditary immunodeficiency disorder characterized
by abnormal antibody (immunoglobulin) production, T-cell (lymphocyte)
malfunction, a low platelet count, and eczema....
X-Linked
Agammaglobulinemia
Sep 1, 2008
X-linked agammaglobulinemia
(Bruton's disease) is a hereditary immunodeficiency disorder due
to an abnormality in the X chromosome. It results in few or no B
cells (lymphocytes) and very low levels of antibodies (immunoglobulins)....
Introduction
Sep 1, 2008
Allergic reactions
(hypersensitivity reactions) are inappropriate responses of the
immune system to a normally harmless substance.Usually, allergies make the
eyes water and itch, the nose run, the skin itch, rashes develop,
and people sneeze.
Some sy...
Seasonal
Allergies
Sep 1, 2008
Seasonal allergies
result from exposure to airborne substances (such as pollens) that
appear only during certain times of the year.Seasonal allergies cause itchy
skin, a runny nose, watery and bloodshot eyes, and sneezing,
Symptoms and their seasonal...
Year-Round
Allergies (Perennial Allergies)
Sep 1, 2008
Year-round
(perennial) allergies result from exposure to airborne substances
(such as house dust) that are present throughout the year.The nose is congested, itchy,
and sometimes runny, and the mouth and throat are itchy
The symptoms and activities t...
Food
Allergy
Sep 1, 2008
A food allergy
is an allergic reaction to a particular food.Food allergies are commonly
triggered by certain nuts, peanuts, shellfish, fish, milk, eggs, wheat,
and soybeans.
Symptoms vary by age and may include rashes, wheezing,
a runny nose, and, oc...
Mastocytosis
Sep 1, 2008
Mastocytosis
is an uncommon abnormal accumulation of mast cells in the skin and
sometimes in various other parts of the body.People may have itchy spots
and bumps, flushing, digestive upset, and sometimes bone pain.
Symptoms suggest the diagnosis, an...
Physical
Allergy
Sep 1, 2008
A physical
allergy is an allergic reaction triggered by a physical stimulus....
Exercise-Induced
Allergic Reactions
Sep 1, 2008
Exercise-induced
allergic reactions occur during or after exercise....
Hives and
Angioedema
Sep 1, 2008
Hives, also
called urticaria, is a skin reaction characterized by pale, slightly
elevated swellings (wheals) that are surrounded by a red area and
have clearly defined borders. Angioedema is swelling
of larger areas of tissue under the skin, sometime...
Anaphylactic
Reactions
Sep 1, 2008
Anaphylactic
reactions (anaphylaxis) are sudden, widespread, potentially severe
and life-threatening allergic reactions.These reactions begin with
a feeling of uneasiness, followed by tingling sensations and dizziness.
People then rapidly develop sev...
Introduction
Sep 1, 2008
Transplantation
is the removal of living, functioning cells, tissues, or organs
from the body and then their transfer back into the same body or
into a different body....
Kidney
Transplantation
Sep 1, 2008
For people of all ages
who have irreversible kidney failure, kidney transplantation is
a lifesaving alternative to dialysis. In the United States, more
than 17,000 kidneys are transplanted each year. Over 95% of kidneys
from living donors are functio...
Liver
Transplantation
Sep 1, 2008
Liver transplantation
is the only option for people whose livers no longer function. A whole
liver can be obtained only from a person who has died, but a living
donor can provide a part of the liver. A donated liver can be stored for
8 to 15 hours. M...
Heart
Transplantation
Sep 1, 2008
Heart transplantation
is reserved for people who have severe heart failure and who cannot be
treated effectively with drugs or other forms of surgery. In some
medical centers, heart machines can keep people alive for weeks
or months until a compatibl...
Lung
and Heart-Lung Transplantation
Sep 1, 2008
Lung transplants are
done for people whose lungs no longer function. Most recipients
are people who have severe chronic obstructive pulmonary disease,
idiopathic pulmonary fibrosis, cystic fibrosis, α1-antitrypsin
deficiency, and primary pulmonary hy...
Pancreas
Transplantation
Sep 1, 2008
Pancreas transplantation
is done for people with diabetes whose pancreas cannot make any insulin. It is a major
operation, requiring a long incision in the abdomen and a general anesthetic.
The recipient's pancreas is not removed. Typically, the oper...
Stem
Cell Transplantation
Sep 1, 2008
Stem cells are unspecialized
cells from which other more specialized cells can be derived. Stem
cells obtained from embryos and fetuses are thought to be best because
they are more likely to survive transplantation than those obtained
from children o...
Transplantation of Other
Organs
Sep 1, 2008
Skin grafts
can be used in people who have lost large areas of skin—for example,
because of extensive burns. Skin grafting is most successful when
healthy skin is removed from one part of the body and grafted to
another part. When such grafting is no...
Introduction
Sep 1, 2008
Bacteria are microscopic, single-celled organisms.
There are thousands of different kinds, and they live in every conceivable
environment all over the world. They live in soil, seawater, and
deep within the earth's crust. Some bacteria have been repo...
Actinomycosis
Sep 1, 2008
Actinomycosis
is a chronic infection caused mainly by Actinomyces israelii, anaerobic bacteria
that normally reside on the enamel of teeth, gums, tonsils, and
the membranes lining the intestines and vagina.Infection occurs only when
tissue is broken,...
Anthrax
Sep 1, 2008
Anthrax is
a potentially fatal infection with Bacillus anthracis,
which may affect the skin, the lungs, or, rarely, the digestive
(gastrointestinal) tract.
Infection in people usually results from skin contact
but can result from inhaling spores or e...
Bejel, Yaws,
and Pinta
Sep 1, 2008
Bejel, yaws
(frambesia), and pinta are infections caused by bacteria (called
treponemal spirochetes) that are closely related to Treponema
pallidum, which causes the sexually transmitted
disease syphilis.These
very contagious infections are usually s...
Campylobacter Infections
Sep 1, 2008
Several species
of Campylobacter (most commonly Campylobacter jejuni)
can infect the digestive tract, often causing diarrhea.People can be infected when
they consume contaminated food or drink or have contact with infected
people or animals.
These in...
Cholera
Sep 1, 2008
Cholera is
a serious infection of the intestine that is caused by the bacteria Vibrio
cholerae and that causes severe diarrhea.People are infected when they
consume contaminated food, often seafood, or water.
Cholera is rare except in areas where san...
Gas
Gangrene
Sep 1, 2008
Gas gangrene
(clostridial myonecrosis) is a life-threatening infection of muscle
tissue caused mainly by the anaerobic bacteria Clostridium
perfringens and several other species of clostridia.Gas gangrene can develop after
certain types of surgery or...
Klebsiella, Enterobacter,
and Serratia Infections
Sep 1, 2008
Klebsiella, Enterobacter,
and Serratia are closely related
gram-negative bacteria that occasionally infect people in hospitals
or in long-term care facilities.
These bacteria may infect the urinary or respiratory
tract, intravenous catheters used to ...
Escherichia
coli Infections
Sep 1, 2008
Escherichia
coli (E. coli) is
a gram-negative bacterium that normally resides in the intestine
of healthy people, but some strains can cause infection.People develop intestinal E.
coli infections by eating contaminated food, touching infected
animals...
Haemophilus
influenzae Infections
Sep 1, 2008
Haemophilus
influenzae can cause infection in the respiratory
tract, which can spread to other organs.Infection is spread through
sneezing, coughing, or touching.
The bacteria can cause middle ear infections, sinusitis,
and more serious infections, i...
Leptospirosis
Sep 1, 2008
Leptospirosis
is a potentially serious disorder caused by Leptospira bacteria.Most people are infected through
contact with contaminated soil or water during outdoor activities.
Fever, headache, and other symptoms occur in two
phases, separated by a ...
Listeriosis
Sep 1, 2008
Listeriosis
is infection caused by the gram-positive bacteria Listeria
monocytogenes.
People may consume the bacteria in commercially
prepared foods that require no further cooking.
People have fever, chills, and muscle aches plus
nausea, vomiting, a...
Lyme
Disease
Sep 1, 2008
Lyme disease
is caused by the bacteria Borrelia burgdorferi,
which is usually transmitted to people by deer ticks.Most people are infected when
they go outdoors in wooded areas where the disease is common.
Typically, a large, red spot appears at the ...
Meningococcal
Infections
Sep 1, 2008
Meningococcal
infections are caused by Neisseria meningitidis (meningococci)
and include meningitis and bloodstream infections.Infection is spread by direct
contact with nasal and throat secretions.
People feel generally ill and have other, often
ser...
Plague
Sep 1, 2008
Plague is
a severe infection caused by the gram-negative bacteria Yersinia
pestis.The
bacteria are spread by the rat flea.
Depending on the form, plague can cause fever, chills,
swollen lymph nodes, headache, a rapid heartbeat, cough, difficulty brea...
Pneumococcal
Infections
Sep 1, 2008
Pneumococcal
infections are caused by the gram-positive bacteria Streptococcus
pneumoniae (pneumococcus).Bacteria are dispersed in
the air when infected people cough or sneeze.
The most common infections are pneumonia, meningitis,
sinusitis, and midd...
Pseudomonas Infections
Sep 1, 2008
Pseudomonas
infections are caused by any of several types of the gram-negative
bacteria Pseudomonas, especially Pseudomonas
aeruginosa.
Infections range from mild external ones (affecting
the ear or hair follicles) to serious internal infections (aff...
Salmonella
Infections
Sep 1, 2008
Salmonella
infections are caused by the gram-negative bacteria Salmonella.People are usually infected
when they eat contaminated food, such as undercooked chicken or
eggs.
The bacteria usually infect the digestive tract
but can travel through the blo...
Shigellosis
Sep 1, 2008
Shigellosis
is infection that is caused by the gram-negative bacteria Shigella and
that results in watery diarrhea or dysentery (the frequent and often
painful passage of small amounts of stool that contains blood, pus,
and mucus).The
bacteria are ex...
Staphylococcus
aureus Infections
Sep 1, 2008
Staphylococcus
aureus is the most dangerous of all of the many
common staphylococcal bacteria.
These bacteria are spread by having direct contact
with an infected person, by using a contaminated object, or by inhaling infected
droplets dispersed by s...
Streptococcal
Infections
Sep 1, 2008
Streptococcal
infections are caused by any one of several species of Streptococcus.Different groups of these
bacteria are spread in different ways—for example, through coughing
or sneezing, through contact with infected or sores, or during vaginal
de...
Tetanus
Sep 1, 2008
Tetanus (lockjaw)
results from a toxin produced by the anaerobic bacteria Clostridium tetani.
The toxin makes muscles become rigid and contract involuntarily
(spasm).Tetanus
is rare in the United States but is common in developing countries.
Diagnosi...
Toxic
Shock Syndrome
Sep 1, 2008
Toxic shock
syndrome is a group of rapidly progressive and severe symptoms that
include fever, rash, dangerously low blood pressure, and failure
of several organs. It is caused by toxins produced by Staphylococcus
aureus or group A streptococci.Using...
Tularemia
Sep 1, 2008
Tularemia
(rabbit fever, deer fly fever) is infection that is caused by the
bacteria Francisella tularensis,
which is acquired from wild animals, usually rabbits.Handling carcasses, being
bitten by a tick, inhaling infected sprayed particles, and eat...
Introduction
Sep 1, 2008
Bacteremia, sepsis, and
septic shock are related:Bacteremia: Bacteria
are present in the bloodstream. Bacteremia can result from a serious infection
or from something as harmless as vigorous toothbrushing. Most often,
only a small number of bacteria ...
Bacteremia
Sep 1, 2008
Bacteremia
is the presence of bacteria in the bloodstream (see also ).Bacteremia may result from
ordinary activities (such as toothbrushing), dental or medical procedures,
or from infections (such as pneumonia or a urinary tract infection).
Having an...
Sepsis
and Septic Shock
Sep 1, 2008
Sepsis is
a serious bodywide response to bacteremia or another infection. Septic
shock is life-threatening low blood pressure (shock) due
to sepsisUsually,
sepsis results from certain bacterial infections, often acquired
in a hospital.
Having certain...
Antibiotics
Sep 1, 2008
Although doctors try to use antibiotics for specific
bacterial infections, they sometimes start antibiotics without waiting
for tests that identify the specific bacteria.
Bacteria can develop resistance to the effects of antibiotics.
Taking antibiot...
Introduction
Sep 1, 2008
A blister (bulla) is a
bubble of fluid that forms beneath a thin layer of dead skin. The fluid
is a mixture of water and proteins that oozes from injured tissue.
Blisters most commonly form in response to a specific injury, such
as a burn or irritati...
Bullous
Pemphigoid
Sep 1, 2008
Bullous pemphigoid
is an autoimmune disease that causes blistering of the skin.Bullous pemphigoid occurs
when the immune system attacks the skin and causes blistering.
People develop large, itchy blisters with areas
of inflamed skin.
Doctors can diag...
Dermatitis
Herpetiformis
Sep 1, 2008
Dermatitis
herpetiformis is an autoimmune disease causing clusters of intensely
itchy small blisters and hivelike swellings.In dermatitis herpetiformis,
glutens in wheat, rye, and barley products cause the immune system
to attack the skin.
People hav...
Pemphigus
Vulgaris
Sep 1, 2008
Pemphigus
vulgaris is a rare, severe autoimmune disease in which blisters
of varying sizes break out on the skin, the lining of the mouth, the
genitals, and other mucous membranes.Pemphigus vulgaris occurs
when the immune system mistakenly attacks pr...
Introduction
Sep 1, 2008
Most skin parasites are
tiny insects or worms that burrow into the skin and make their home
there. Some parasites live in the skin for part of their life cycle;
others, for their entire life cycle. Parasitic skin infections frequently
cause severe it...
Scabies
Sep 1, 2008
Scabies is
a mite infestation of the skin that produces tiny reddish bumps
and severe itching.Scabies
usually spreads from person to person through physical contact.
People with scabies have severe itching, even though
there are typically few mites o...
Lice
Infestation
Sep 1, 2008
Lice infestation
(pediculosis) is a skin infestation by tiny wingless insects.Lice spread most frequently
through person-to-person contact.
People with lice usually have severe itching.
Lice and their eggs can be found by looking through
hair on the ...
Cutaneous
Larva Migrans
Sep 1, 2008
Cutaneous
larva migrans (creeping eruption) is a hookworm infection transmitted
from warm, moist soil to exposed skin....
Cutaneous Myiasis
Sep 1, 2008
Cutaneous
myiasis is skin infestation by the larvae (maggots) of certain fly
species....
Introduction
Sep 1, 2008
Cells of the skin and
underlying tissue may accumulate and cause growths. Growths may be
raised or flat and range in color from dark brown or black to flesh-colored
to red. They may be present at birth or develop later....
Moles
Sep 1, 2008
Moles (nevi)
are small, usually dark, skin growths that develop from pigment-producing cells
in the skin (melanocytes).
Most people have some moles, but the tendency to
develop atypical moles is hereditary.
Moles and atypical moles that change drasti...
Skin
Tags
Sep 1, 2008
Skin tags
are soft, small, flesh-colored or slightly darker skin growths that
develop mostly on the neck, in the armpits, or in the groin area....
Lipomas
Sep 1, 2008
Lipomas are
soft deposits of body fat that grow under the skin, causing round
or oval lumps....
Dermatofibromas
Sep 1, 2008
Dermatofibromas
are small red-to-brown bumps (nodules) that result from an accumulation
of collagen, which is a protein made by the cells (fibroblasts)
that populate the soft tissue under the skin....
Growths
and Malformations of the Vessels
Sep 1, 2008
Growths and
malformations of the vessels (angiomas) are collections of abnormally
dense blood or lymph vessels, usually located in and below the skin,
that cause red or purple discolorations.Many growths and malformations
of the vessels appear at bir...
Seborrheic
Keratoses
Sep 1, 2008
Seborrheic
keratoses (seborrheic warts) are warty, flesh-colored, brown, or
black growths that can appear anywhere on the skin....
Keratoacanthomas
Sep 1, 2008
Keratoacanthomas
are round, firm, usually flesh-colored or slightly reddish growths
that have a central crater that is scaly or crusted....
Keloids
Sep 1, 2008
Keloids are
smooth, shiny, flesh-colored, raised growths of scar-like tissue
that form over areas of injury or surgical wounds....
Epidermal
Cysts
Sep 1, 2008
An epidermal
cyst is a common slow-growing bump due to an enlarging sac under
the skin that accumulates a cheesy substance composed of skin secretions....
Introduction
Sep 1, 2008
The eye sockets (orbits)
are bony cavities that contain and protect the eyes and their supporting
structures. Disorders affecting the orbits include fractures (see ), infections,
inflammation, vascular disorders, and tumors. Thyroid disease can
also ...
Infections
of the Orbit
Sep 1, 2008
Infections may involve
the tissues around or within the eye. These infections are most common
among children....
Inflammation
of the Orbit
Sep 1, 2008
Any or all of the structures
within the orbit may become inflamed....
Tumors
of the Orbit
Sep 1, 2008
Rarely, tumors, either
cancerous (malignant) or noncancerous (benign), occur in the tissues behind
the eye. Tumors can form within these tissues, or cancerous tumors
from elsewhere in the body can spread (metastasize) to these tissues....
Proptosis
Sep 1, 2008
Proptosis
(exophthalmos) is an abnormal bulging of one or both eyes.Disorders such as Graves'
disease and orbital inflammation or tumors can push the eye outward.
Testing may include measurement of the amount of
bulging, computed tomography (CT), mag...
Introduction
Sep 1, 2008
Vaginal infections are caused by microorganisms,
but women can take precautions, such as wearing loose, absorbent underwear,
to reduce their risk of getting infections.
Infections usually cause a discharge with itching,
redness, and sometimes burnin...
Bacterial Vaginosis
Sep 1, 2008
Bacterial
vaginosis is a vaginal infection that occurs when the balance of
bacteria in the vagina is altered.
Women who have a sexually transmitted disease, who
have several sex partners, or who use an intrauterine device are
more likely to get bacte...
Trichomonas
Vaginitis
Sep 1, 2008
Trichomonas
vaginitis is a vaginal infection due to the protozoa Trichomonas
vaginalis.
The infection is usually sexually transmitted.
The green or yellow discharge may be profuse, smell
fishy, and be accompanied by itching.
Always using a condom can...
Yeast
Infection (Candidiasis)
Sep 1, 2008
The vagina may be infected by a yeast called Candida,
usually Candida albicans, resulting in
a yeast infection called candidiasis. Being pregnant or overweight
or having diabetes or a weakened immune system increases the risk of
yeast infections.
Th...
Introduction
Aug 1, 2008
Minerals are necessary
for the normal functioning of the body's cells. The body needs large
quantities of calcium, chloride, magnesium, phosphate, potassium,
and sodium. These minerals are called macrominerals. Bone,
muscle, heart, and brain function...
Calcium
Aug 1, 2008
About 99% of the body's
calcium is stored in the bones, but cells (particularly muscle cells)
and blood also contain calcium. Calcium is essential for the following:Formation of bone and teeth
Muscle contraction
Normal functioning of many enzymes
Blo...
Chromium
Aug 1, 2008
Chromium enables insulin (which
controls blood sugar levels) to function and helps in the processing
(metabolism) and storage of carbohydrates, protein, and fat. Only
a small amount of the chromium in food is absorbed. Chromium is
absorbed better whe...
Copper
Aug 1, 2008
Most of the copper in
the body is located in the liver, bones, and muscle, but traces
of copper occur in all tissues of the body. The liver excretes excess
copper into the bile for elimination from the body. Copper is a
component of many enzymes, inc...
Fluoride
Aug 1, 2008
In the body, most fluoride
is contained in bones and teeth. Fluoride is necessary for the formation
and health of bones and teeth....
Iodine
Aug 1, 2008
The thyroid gland contains
most of the iodine in the body. Iodine in the thyroid gland is necessary
for the formation of thyroid hormones. Iodine occurs in seawater.
A small amount of iodine enters the atmosphere and, through rain,
enters ground wate...
Iron
Aug 1, 2008
Much of the iron in the
body is contained in hemoglobin. Hemoglobin is the
component of red blood cells that enables them to carry oxygen and
deliver it to the body's tissues. Iron also is an important component
of muscle cells. It is also necessary ...
Magnesium
Aug 1, 2008
Bone contains most of
the body's magnesium. Blood contains very little. Magnesium is necessary
for the formation of bone and teeth and for normal nerve and muscle
function. Many enzymes in the body depend on magnesium to function
normally. The body o...
Molybdenum
Aug 1, 2008
Molybdenum is required
for processing (metabolizing) nitrogen, activating certain enzymes,
and enabling cells to function normally. Molybdenum also helps break
down sulfites (which occur in foods naturally and are added as preservatives)....
Phosphate
Aug 1, 2008
In the body, almost all
phosphorus is combined with oxygen, forming phosphate. Bone contains
about 85% of the body's phosphate. The rest is located primarily
inside cells, where it is involved in energy production....
Potassium
Aug 1, 2008
Most of the body's potassium
is located inside the cells. Potassium is necessary for the normal
functioning of cells, nerves, and muscles....
Selenium
Aug 1, 2008
Selenium occurs in all
tissues. Selenium works with vitamin E as an antioxidant. It helps
protect cells against damage by free radicals, which are reactive
by-products of normal cell activity. Selenium may help protect against
some cancers. Selenium ...
Sodium
Aug 1, 2008
Most of the body's sodium
is located in blood and in the fluid around cells. Sodium helps
the body keep fluids in a normal balance (see ).
Sodium plays a key role in normal nerve and muscle function....
Zinc
Aug 1, 2008
Zinc is widely distributed
in the body—in bones, teeth, hair, skin, liver, muscle, white blood
cells, and testes. It is a component of more than 100 enzymes, including
those involved in the formation of RNA (ribonucleic acid) and DNA
(deoxyribonuclei...
Obesity
Aug 1, 2008
Obesity is
the accumulation of excessive body fat.Obesity usually results from
consuming too many calories and not burning enough calories in physical
activity.
Being obese increases the risk of many disorders,
such as diabetes, high blood pressure, ...
Bariatric
Surgery
Aug 1, 2008
Bariatric
surgery alters the stomach, intestine, or both to produce weight
loss....
Metabolic
Syndrome
Aug 1, 2008
Metabolic
syndrome (also called syndrome X or insulin resistance syndrome)
is characterized by excess abdominal fat, resistance to the effects
of insulin (insulin resistance), abnormal levels of fats in the
blood, and high blood pressure.
Excess abdo...
Introduction
Aug 1, 2008
Cholesterol and triglycerides
are important fats (lipids) in the blood. Cholesterol is an essential
component of cell membranes, brain and nerve cells, and bile, which
helps the body absorb fats and fat-soluble vitamins. The body uses
cholesterol to ...
Dyslipidemia
Aug 1, 2008
Dyslipidemia
is abnormal levels of lipids (cholesterol, triglycerides, or both)
carried by lipoproteins in the blood. This term includes hyperlipoproteinemia
(hyperlipidemia), which refers to abnormally high levels of total
cholesterol, low density l...
Hypolipoproteinemia
Aug 1, 2008
Hypolipoproteinemia
is abnormally low levels of lipids in the blood.Low lipid levels may result
from rare genetic abnormalities or other disorders.
People with these genetic abnormalities may have
fatty stools, grow poorly, and be mentally retarded.
...
Introduction
Aug 1, 2008
Water accounts for about
one half to two thirds of an average person's weight. Fat tissue has
a lower percentage of water and women tend to have more fat, so
the percentage of water in the average woman is lower (52 to 55%)
than it is in the average ...
Dehydration
Aug 1, 2008
Dehydration
is a deficiency of water in the body.Vomiting, diarrhea, excessive
sweating, and use of diuretics may cause dehydration.
People feel thirsty, and as dehydration worsens,
they may sweat less and excrete less urine.
If dehydration is severe...
Overhydration
Aug 1, 2008
Overhydration
is an excess of water in the body.
People can have overhydration if they drink too
much or if they have a disorder that decreases the body's ability
to excrete water.
Often, no symptoms occur, but people may become
confused or have seiz...
Introduction
Aug 1, 2008
Porphyrias
are a group of disorders caused by deficiencies of enzymes involved
in the production of heme....
Porphyria
Cutanea Tarda
Aug 1, 2008
Porphyria
cutanea tarda is the most common porphyria and causes blistering
and fragility of skin exposed to sunlight.People have chronically recurring
blisters on the sun-exposed areas of their bodies.
Doctors test urine and stool samples for high le...
Acute
Intermittent Porphyria
Aug 1, 2008
Acute intermittent
porphyria, which causes abdominal pain and neurologic symptoms,
is the most common acute porphyria.
Many people never experience symptoms.
Symptoms may include acute onset of vomiting, abdominal
or back pain, weakness in arms or le...
Erythropoietic
Protoporphyria
Aug 1, 2008
Erythropoietic
protoporphyria is a condition characterized by photosensitivity.The heme precursor protoporphyrin
accumulates in the bone marrow and red blood cells.
People have severe skin pain and swelling soon after
exposure to sunlight.
Doctors te...
Introduction
Aug 1, 2008
A cancer is an abnormal
growth of cells (usually derived from a single cell). The cells have
lost normal control mechanisms and thus are able to expand continuously,
invade adjacent tissues, migrate to distant parts of the body, and
promote the growt...
Development
and Spread
Aug 1, 2008
Cancerous cells develop
from healthy cells in a complex process called malignant transformation....
Risk
Factors for Cancer
Aug 1, 2008
Many genetic and environmental
factors increase the risk of developing cancer. However, not all
people who are exposed to carcinogens or who have other risk factors
develop cancer....
Defenses
Against Cancer
Aug 1, 2008
Even when a cell becomes
cancerous, the immune system is thought to be able to recognize
it as abnormal and destroy it before it replicates or spreads. Cancer
is more likely to progress in people whose immune system is altered
or impaired, as in peop...
Acne
Aug 1, 2008
Acne is a
common skin condition producing pimples on the face and upper torso.Acne is caused by a buildup
of dead skin cells, bacteria, and dried sebum that block the hair
follicles in the skin.
Pimples, cysts, and sometimes abscesses form on
the ski...
Introduction
Aug 1, 2008
Hair originates in the
hair follicles. These follicles are located in the dermis, the skin layer
just below the surface layer and above the subcutaneous fat. Hair
follicles are present everywhere on the surface of the body except the
lips, palms of t...
Hirsutism
and Hypertrichosis
Aug 1, 2008
Hirsutism is
the excessive growth of thick or dark hair in women in locations
that are more typical of male hair patterns (for example, mustache,
beard, central chest, shoulders, lower abdomen, back, and inner
thighs). Hypertrichosis is an increase i...
Alopecia
Aug 1, 2008
Alopecia is
the loss of hair on the head or on any other part of the body.Hair loss may occur because
of changes in hormone levels, the use of certain drugs, stress,
and some skin disorders.
Doctors diagnose the type of hair loss by examining
the hai...
Ingrown
Beard Hairs
Aug 1, 2008
Pseudofolliculitis
barbae (ingrown beard hairs) is inflammation caused by hairs that curl
so that the tips puncture the skin....
Introduction
Aug 1, 2008
Fungi usually make their
homes in moist areas of the body where skin surfaces meet: between
the toes, in the genital area, and under the breasts. Many fungi
that infect the skin (dermatophytes) live only in the topmost layer
of the epidermis (stratum...
Candidiasis
Aug 1, 2008
Candidiasis
(yeast infection, moniliasis) is infection by the yeast Candida.Candidiasis tends to occur
in moist areas of the skin.
Candidiasis may cause rashes, scaling, itching,
and swelling.
Doctors examine the affected areas and view skin
samples ...
Ringworm (Tinea)
Aug 1, 2008
Ringworm (tinea)
is a fungal skin infection caused by several different fungi and
generally classified by its location on the body.The fungi that cause ringworm
infections tend to spread in moist areas of the skin.
Symptoms include rashes, scaling, a...
Tinea
Versicolor
Aug 1, 2008
Tinea versicolor
(pityriasis versicolor) is a fungal infection of the topmost layer
of the skin causing scaly, discolored patches....
Glaucoma
Aug 1, 2008
Glaucoma is
optic nerve damage (often, but not always, associated with increased
eye pressure) that leads to progressive, irreversible loss of vision.Damage to the optic nerve
can occur when pressure within the eye increases.
The vision loss occurs s...
Cystic
Fibrosis
Aug 1, 2008
Cystic
fibrosis is a hereditary disease that causes certain glands to produce
abnormal secretions, resulting in tissue and organ damage, especially
in the lungs and the digestive tract.Cystic fibrosis is caused
by certain inherited genetic mutations ...
Introduction
Aug 1, 2008
The
skin and the tissues under it are kept at a constant temperature
(about 98.6° F, or 37° Celsius
[C]) by the circulating blood and other mechanisms. The blood gets
its heat mainly from the energy given off by cells when they burn
(metabolize) food...
Hypothermia
Aug 1, 2008
Hypothermia
is a dangerously low body temperature.Being surrounded by too cold
of an environment, having certain disorders, being unable to move,
or a combination can cause body temperature to become too low.
The person shivers but then may become co...
Nonfreezing Tissue Injuries
Aug 1, 2008
In nonfreezing
tissue injuries, parts of the skin are chilled but not frozen....
Frostbite
Aug 1, 2008
Frostbite is
a cold injury in which an area of the body is frozen.Extreme cold may freeze tissues,
destroying them and sometimes surrounding tissues.
The area may be numb, white, swollen, blistered, or
black and leathery.
The area is rewarmed in warm...
Temporomandibular
Disorders
Jul 1, 2008
Temporomandibular disorders are caused by problems
with the muscles or joints or fibrous tissue connecting them.
People may have headaches and tenderness of the
chewing muscles or may hear clicking of the joints.
Doctors or dentists can usually diag...
Introduction
Jul 1, 2008
Nutrition is
the process of consuming, absorbing, and using nutrients needed
by the body for growth, development, and maintenance of life....
Carbohydrates, Proteins,
and Fats
Jul 1, 2008
Carbohydrates, proteins,
and fats supply 90% of the dry weight of the diet and 100% of its
energy. All three provide energy (measured in calories), but the
amount of energy in 1 gram (1/28 ounce)
differs: 4 calories in a gram of carbohydrate or prote...
Vitamins
and Minerals
Jul 1, 2008
Vitamins and minerals are
essential nutrients. That is, they cannot be synthesized by the
body and so must be consumed in the diet....
Fiber
Jul 1, 2008
Some foods contain fiber,
which is a tough complex carbohydrate. Fiber may be partly soluble:
It dissolves in water, and the body may be able to digest some of
it. Or it may be insoluble: It does not dissolve in water, and the body
cannot digest it. ...
Food
Additives and Contaminants
Jul 1, 2008
...
Calories
Jul 1, 2008
A calorie is a measure
of energy. Foods have calories. That is, foods supply the body with energy,
which is released when foods are broken down during digestion. Energy
enables cells to do all of their functions, including building proteins
and other...
Nutritional
Requirements
Jul 1, 2008
General guidelines for
a healthy diet have been developed even though daily nutritional requirements,
including those for essential nutrients, vary, depending on age,
sex, height, weight, physical activity, and the rate at which the
body burns calori...
Diets
Jul 1, 2008
A diet is whatever a person
eats, regardless of the goal—whether it is losing weight, gaining
weight, reducing fat intake, avoiding carbohydrates, or having no
particular goal. However, the term is often used to imply a goal
of losing weight, which i...
Introduction
Jul 1, 2008
An important property
of blood is its degree of acidity or alkalinity. Body acidity increases when
the level of acidic compounds in the body rises (through increased
intake or production, or decreased elimination) or when the level
of basic (alkaline...
Acidosis
Jul 1, 2008
Acidosis is
excessive blood acidity caused by an overabundance of acid in the
blood or a loss of bicarbonate from the blood (metabolic acidosis),
or by a buildup of carbon dioxide in the blood that results from
poor lung function or slow breathing (r...
Alkalosis
Jul 1, 2008
Alkalosis
is excessive blood alkalinity caused by an overabundance of bicarbonate
in the blood or a loss of acid from the blood (metabolic alkalosis),
or by a low level of carbon dioxide in the blood that results from
rapid or deep breathing (respira...
Introduction
Jul 1, 2008
Plasma cell disorders
(plasma cell dyscrasias) are uncommon. They begin when a single group
(clone) of plasma cells multiplies excessively and produces a large
quantity of a single type of antibody (immunoglobulin). Plasma cells
develop from B lympho...
Monoclonal Gammopathies
of Undetermined Significance
Jul 1, 2008
A monoclonal
gammopathy of undetermined significance is a buildup of monoclonal
antibodies produced by abnormal but noncancerous plasma cells....
Multiple
Myeloma
Jul 1, 2008
Multiple myeloma
is a cancer of plasma cells in which abnormal plasma cells multiply
uncontrollably in the bone marrow and occasionally in other parts
of the body.People
often have bone pain and fractures, and they may also have kidney
problems, immu...
Macroglobulinemia
Jul 1, 2008
Macroglobulinemia
(Waldenström's macroglobulinemia) is a plasma cell cancer in which a
single clone of plasma cells produces excessive amounts of a certain
type of large antibody (IgM) called macroglobulins.Although many people have
no symptoms, some...
Heavy
Chain Diseases
Jul 1, 2008
Heavy chain
diseases are plasma cell cancers in which a clone of plasma cells
produces a large quantity of pieces of abnormal antibodies called
heavy chains....
Introduction
Jul 1, 2008
Lymphomas
are cancers of lymphocytes, which reside in the lymphatic system
and in blood-forming organs....
Hodgkin
Lymphoma
Jul 1, 2008
Hodgkin lymphoma
is a type of lymphoma distinguished by the presence of a particular kind
of cancer cell called a Reed-Sternberg cell.The cause is unknown.
Lymph nodes enlarge but are not painful.
Other symptoms, such as muscle weakness, fever,
and s...
Non-Hodgkin
Lymphomas
Jul 1, 2008
Non-Hodgkin
lymphomas are a diverse group of cancers that develop in B or T
lymphocytes.Often,
lymph nodes in the neck, under the arms, or in the groin enlarge
rapidly and painlessly.
People may have pain or shortness of breath or other
symptoms when...
Introduction
Jul 1, 2008
In myeloproliferative
disorders (myelo = bone marrow, proliferative = rapid multiplication),
the blood-producing cells in the bone marrow (precursor cells) develop
and reproduce excessively or are crowded out by an overgrowth of
fibrous tissue. Typic...
Polycythemia
Vera
Jul 1, 2008
Polycythemia
vera (primary polycythemia) is a disorder of the blood-producing
cells of the bone marrow that results in overproduction of red blood
cells.The cause
is not known.
People may feel tired and weak, light-headed, or
short of breath.
Blood t...
Myelofibrosis
Jul 1, 2008
Myelofibrosis
is a disorder in which fibrous tissue replaces the blood-producing
cells in the bone marrow, resulting in abnormally shaped red blood
cells, anemia, and an enlarged spleen.Myelofibrosis may occur on
its own or as a result of other blood...
Thrombocythemia
Jul 1, 2008
Thrombocythemia
(primary thrombocythemia) is a disorder in which excess platelets
are produced, leading to abnormal blood clotting or bleeding.The cause is not known.
The hands and feet may tingle, and the fingertips
may feel cold.
Routine blood test...
Introduction
Jul 1, 2008
Immunization enables the
body to better defend itself against diseases caused by certain bacteria
or viruses. Immunization may occur on its own (when people are exposed
to bacteria or viruses), or doctors may provide it. When people
are immunized aga...
Common Vaccinations
Jul 1, 2008
Children typically are
given a number of vaccines according to a standard schedule (see ). If vaccines are
missed, most can be given later, according to a catch-up schedule.
Adults may also be advised to receive certain vaccines. When advising
adults...
Vaccination
Before Foreign Travel
Jul 1, 2008
Residents of the United
States may be required to receive specific vaccines before traveling
to areas that have infectious diseases not normally found in the
United States (see ).
Recommendations change frequently in response to disease outbreaks.
Th...
Introduction
Jul 1, 2008
The outer ear consists
of the external part of the ear (pinna or auricle) and the ear canal (external
auditory meatus—see ).
Disorders of the outer ear include blockages, infections (external
otitis and perichondritis), eczema, and tumors. The outer ...
Blockages
Jul 1, 2008
Earwax (cerumen) may block
the ear canal. Even large amounts of earwax often cause no symptoms.
Symptoms can range from itching to a loss of hearing. A doctor may
remove the earwax by gently flushing out the ear canal with warm
water (irrigation).
Ho...
External
Otitis
Jul 1, 2008
External otitis
is infection of the ear canal.
External otitis is caused by bacteria or, rarely,
fungi.
Typical symptoms are itching, pain, and discharge.
A doctor looks in the ear with an otoscope (a device
for viewing the canal and eardrum) for red...
Perichondritis
Jul 1, 2008
Perichondritis
is infection of the tissue surrounding the cartilage of the earlobe
(pinna), ear canal, or both....
Tumors
Jul 1, 2008
Tumors of the ear may
be noncancerous (benign) or cancerous (malignant). Most ear tumors
are found when people see them or when a doctor looks in the ear
because people notice their hearing seems decreased....
Injury
Jul 1, 2008
A number of different
injuries can affect the outer ear. A blunt blow to the external
ear can cause bruising between the cartilage and the layer of connective
tissue around it (perichondrium). When blood collects in this area,
the external ear become...
Introduction
Jul 1, 2008
The upper part of the
nose consists mostly of bone. The lower part of the nose gains its support
from cartilage. Inside the nose is a hollow cavity (nasal cavity),
which is divided into two passages by a thin sheet of cartilage
and bone called the na...
Fractures
of the Nose
Jul 1, 2008
Typically, a broken nose bleeds, hurts, and swells.
To diagnose a broken nose, a doctor looks at and
feels the bridge of the nose.
Doctors sometimes need to push the broken pieces
of bone back into place....
Deviated
Septum
Jul 1, 2008
Usually, the nasal septum
is straight, lying about in the middle of the two nostrils. Occasionally,
it may be bent (deviated) because of a birth defect or injury and
positioned so that one nostril is much smaller than the other. Most
people have some...
Perforations
of the Septum
Jul 1, 2008
Ulcers and holes (perforations)
in the nasal septum may occur as a result of nasal surgery; repeated
injury such as that resulting from picking the nose; cosmetic piercing;
exposure to toxins (such as acids, chromium, phosphorus, and copper
vapor); c...
Nosebleeds
Jul 1, 2008
Nose picking and injuries are the most common causes
of nosebleeds.
People typically bleed from the front part of the
nose.
Avoiding nose picking, humidifying the air during
the winter, and, for some people, moistening the front of the nasal
septum ...
Nasal
Vestibulitis
Jul 1, 2008
Nasal vestibulitis
is infection of the area just inside the opening of each nostril
(the nasal vestibule)....
Rhinitis
Jul 1, 2008
Rhinitis is
inflammation and swelling of the mucous membrane of the nose, characterized by
a runny nose and stuffiness and usually caused by the common cold
(see )
or an allergy (see ).
Colds and allergies are the most common causes of
rhinitis.
Symp...
Nasal
Polyps
Jul 1, 2008
Nasal polyps
are fleshy outgrowths of the mucous membrane of the nose.Nasal polyps are more likely
to develop in people who have allergies or asthma.
Some of the symptoms caused by polyps are nasal
obstruction and congestion.
Doctors usually diagnose...
Sinusitis
Jul 1, 2008
Sinusitis
is inflammation of the sinuses, most commonly caused by a viral
or bacterial infection or by an allergy.Some of the most common symptoms
of sinusitis are pain, tenderness, nasal congestion, and headache.
The diagnosis is based on symptoms, ...
Introduction
Jul 1, 2008
Disorders of the throat
(pharynx) and voice box (larynx) may represent short-lived (acute) inflammation
and infections, persistent (chronic) inflammation, or abnormal growths. Specific
disorders include vocal cord polyps and nodules, contact ulcers,
...
Tonsillar
Cellulitis and Abscess
Jul 1, 2008
Tonsillar
cellulitis is a bacterial infection of the tissues around
the tonsils. A tonsillar abscess is a collection of
pus behind the tonsils.Sometimes,
bacteria that infect the throat spread deep into surrounding tissues.
Typical symptoms include s...
Epiglottitis
Jul 1, 2008
Epiglottitis
is a bacterial infection of the epiglottis.Epiglottitis may block the
windpipe (trachea) and be fatal
The main symptoms are severe sore throat and noisy,
difficult breathing.
Doctors make the diagnosis by looking at the epiglottis
in the...
Laryngitis
Jul 1, 2008
Laryngitis
is inflammation of the voice box (larynx).A virus is usually what causes
the inflammation.
Typical symptoms include hoarseness and loss of
voice.
The diagnosis is based on symptoms and changes of
the voice.
Usually, resting the voice and a...
Vocal
Cord Nodules and Polyps
Jul 1, 2008
Vocal cord
nodules and polyps are noncancerous (benign) growths that cause
hoarseness and a breathy voice....
Vocal
Cord Contact Ulcers
Jul 1, 2008
Contact ulcers
are raw sores on the mucous membrane covering the cartilage to which
the vocal cords are attached....
Vocal
Cord Paralysis
Jul 1, 2008
Vocal cord
paralysis is the inability to move the muscles that control the
vocal cords.Paralysis
can be caused by tumors, injuries, or nerve damage caused by infection
or toxins.
Typical symptoms include voice changes and possible
difficulty breathin...
Laryngoceles
Jul 1, 2008
Laryngoceles
are outpouchings of the mucous membrane of a part of the voice box
(larynx)....
Introduction
Jul 1, 2008
Often, cancers of the
nose and throat are considered together by doctors because of certain
similarities. Among the similarities are the causes. Most people
who have cancers of the nose and throat use tobacco, drink alcohol, or
both....
Laryngeal
Cancer
Jul 1, 2008
People may be hoarse or have a lump in the neck
or difficulty breathing or swallowing.
A biopsy is needed for diagnosis.
Prognosis depends on how advanced the cancer is.
Treatment is usually with surgery and radiation
therapy, but sometimes chemothe...
Paranasal
Sinus Cancer
Jul 1, 2008
Cancer of the paranasal
sinuses occurs mainly in the maxillary and ethmoid sinuses (see ). Although rare
in the United States, these cancers are more common in Japan and
among the Bantu people of South Africa. Doctors are not sure what
causes these c...
Nasopharyngeal
Cancer
Jul 1, 2008
Cancer of the nasal passages
and upper throat (nasopharynx) may occur in people of any age group.
Although rare in North America, cancer of the nasopharynx is one
of the most common cancers in Asia. This cancer is also more common
among Chinese peopl...
Tonsillar
Cancer
Jul 1, 2008
Cancer of the tonsils
occurs predominantly in men. It is strongly linked to smoking and alcohol
consumption. Recent evidence suggests that human papillomavirus
(HPV) is associated with tonsil cancer as well. People who have
HPV-related tumors and who...
Cataract
Jul 1, 2008
A cataract
is a clouding (opacity) of the lens of the eye that causes a progressive,
painless loss of vision.Vision
may be blurred, contrast may be lost, and halos may be visible around
lights.
Doctors can recognize cataracts by looking at the eye
wi...
Uveitis
Jul 1, 2008
Uveitis is
inflammation anywhere in the pigmented inside lining of the eye,
known as the uvea, or uveal tract.
The uvea may become inflamed because of infection,
a bodywide autoimmune disorder (which causes the body to attack
its own tissues), or for...
Introduction
Jul 1, 2008
The small photoreceptors
of the retina (the inner surface at the back of the eye) sense light and
transmit impulses to the optic nerve.
The optic nerve from each eye carries impulses to the brain, where
visual information is interpreted. Damage to an...
Papilledema
Jul 1, 2008
Papilledema
is a condition in which increased pressure in or around the brain
causes the optic nerve to swell where it enters the eye.Symptoms may be fleeting disturbances
in vision, headache, vomiting, or a combination.
Doctors make the diagnosis by...
Optic
Neuritis
Jul 1, 2008
Optic neuritis
is inflammation of the optic nerve anywhere along its course.Multiples sclerosis is the
most common cause.
Loss of vision may develop, and moving the eye may
hurt.
Magnetic resonance imaging (MRI) is done.
If multiple sclerosis seems p...
Ischemic Optic
Neuropathy
Jul 1, 2008
Ischemic optic
neuropathy is damage of the optic nerve caused by a blockage of
its blood supply.Blockage
can occur with or without inflammation of the arteries (typically
in association with a disorder called temporal arteritis)
Vision may suddenly d...
Toxic
Amblyopia (Nutritional Amblyopia)
Jul 1, 2008
Toxic amblyopia
(nutritional amblyopia) is damage to the optic nerve caused by undernutrition
or by exposure to a substance that is harmful to the optic nerve,
such as lead, wood alcohol, antifreeze, or certain drugs.A nutritional deficiency or
toxic...
Introduction
Jun 1, 2008
Somatoform
disorders include several mental health disorders. In some, people
report physical symptoms or concerns that suggest but are not fully
explained by a physical disorder. In one, people are preoccupied
with a slight or nonexistent defect in ...
Body
Dysmorphic Disorder
Jun 1, 2008
In body dysmorphic
disorder, a preoccupation with a nonexistent or slight defect in
appearance results in significant distress or impairs functioning.People typically spend hours
a day worrying about their perceived defect, which may involve any
body...
Conversion
Disorder
Jun 1, 2008
In conversion
disorder, physical symptoms that resemble those of a neurologic
disorder develop. The symptoms are triggered by mental factors such
as conflicts or other stresses.
An arm or leg may be paralyzed, or people may lose
their sense of touch,...
Hypochondriasis
Jun 1, 2008
In hypochondriasis,
people are preoccupied with the fear of having a serious disease
or are preoccupied with the belief that they actually have a disease.
These feelings are usually based on a misinterpretation of normal
bodily sensations or minor ph...
Somatization
Disorder
Jun 1, 2008
Somatization
disorder is a chronic, severe disorder characterized by many recurring
physical symptoms that cannot be fully explained by a physical disorder.
These symptoms include some combination of pain and digestive, sexual,
and neurologic symptom...
Introduction
Jun 1, 2008
Mood disorders
are mental health disorders involving emotional disturbances consisting
of long periods of excessive sadness (depression) or excessive joyousness
or elation (mania). Depression and mania represent the two extremes,
or poles, of mood di...
Depression
Jun 1, 2008
The disorder
depression is a feeling of sadness intense enough to interfere with
functioning. It may follow a recent loss or other sad event but is
out of proportion to that event and lasts beyond an appropriate
length of time.Heredity,
side effects ...
Bipolar Disorder (Manic-Depressive Illness)
Jun 1, 2008
In bipolar
disorder (formerly called manic-depressive illness), episodes of
depression alternate with episodes of mania or a less severe form
of mania called hypomania. Mania is characterized by excessive physical
activity and feelings of elation tha...
Cyclothymic
Disorder
Jun 1, 2008
In cyclothymic
disorder, relatively mild and short episodes of elation (hypomania)
alternate with mild and short episodes of sadness (depression)....
Introduction
Jun 1, 2008
Eating disorders are grouped
into three categories:Anorexia
nervosa: Refusing to maintain a minimally normal body weight,
with or without bingeing and purging
Bulimia nervosa: Bingeing and purging
without weight loss
Binge eating disorder: Bingeing w...
Anorexia
Nervosa
Jun 1, 2008
Anorexia nervosa
is characterized by a relentless pursuit of thinness, a distorted
body image, an extreme fear of obesity, refusal to maintain a minimally
normal body weight, and, in women, the absence of menstrual periods.Anorexia nervosa usually be...
Bulimia
Nervosa
Jun 1, 2008
Bulimia nervosa
is characterized by the repeated rapid consumption of large amounts
of food (bingeing), followed by attempts to rid the body of the
excess food consumed (purging).
People eat large amounts of food, then induce vomiting,
use laxatives,...
Binge
Eating Disorder
Jun 1, 2008
Binge eating
disorder is characterized by the consumption of large amounts of
food with a feeling of loss of control (bingeing). Bingeing is not
followed by attempts to rid the body of the excess food consumed
(purging).Binge
eating disorder is more ...
Introduction
Jun 1, 2008
Occasionally everyone
has minor problems integrating their memories, perceptions, identity,
and consciousness. For example, people may drive somewhere and then
realize that they do not remember the drive. They may not remember
it because they are abs...
Depersonalization
Disorder
Jun 1, 2008
Depersonalization
disorder involves a persistent or recurring feeling of being detached from
one's body or mental processes (depersonalization) and a feeling
of being an outside observer of one's life.The disorder is usually triggered
by life-threate...
Dissociative
Amnesia
Jun 1, 2008
Dissociative
amnesia is amnesia caused by trauma or stress, resulting in an inability
to recall important personal information.People have gaps in their
memory, which may span a few minutes to years.
After tests are done to rule out other possible
ca...
Dissociative
Fugue
Jun 1, 2008
Dissociative
fugue involves one or more episodes of sudden, unexpected, but purposeful travel
from home during which people cannot remember some or all of their
past life, including who they are (their identity). These episodes
are called fugues.Unbe...
Dissociative
Identity Disorder
Jun 1, 2008
In dissociative
identity disorder, formerly called multiple personality disorder,
two or more identities alternate within the same person.Extreme stress during childhood
may prevent some children from integrating their experiences into
one cohesive i...
Introduction
Jun 1, 2008
Schizophrenia and delusional
disorder are distinct disorders that may share certain features,
such as paranoia, suspiciousness, and unrealistic thinking. However,
schizophrenia is associated with psychosis—a loss of contact with
reality—and with a de...
Schizophrenia
Jun 1, 2008
Schizophrenia
is a mental disorder characterized by loss of contact with reality
(psychosis), hallucinations (usually, hearing voices), firmly held
false beliefs (delusions), abnormal thinking, a restricted range
of emotions (flattened affect), dimin...
Delusional
Disorder
Jun 1, 2008
Delusional
disorder is characterized by one or more false beliefs that persist
for at least 1 month.The
false beliefs tend to be ordinary things that could occur, such
as being deceived by a spouse.
This disorder may develop in people with a paranoid...
Introduction
Jun 1, 2008
Anemia is a
condition in which the number of red blood cells or the amount of
hemoglobin (the protein that carries oxygen in them) is low....
Anemia
Due to Excessive Bleeding
Jun 1, 2008
Anemia from
excessive bleeding results when loss of red blood cells through
bleeding exceeds production of new red blood cells.When blood loss is rapid,
blood pressure falls, and people may be dizzy.
When blood loss occurs gradually, people may be
ti...
Iron
Deficiency Anemia
Jun 1, 2008
Iron deficiency
anemia results from low or depleted stores of iron, which is needed
to produce red blood cells.
Excessive bleeding is the most common cause.
People may be weak, short of breath, and pale.
Blood tests can detect low levels of iron.
Iro...
Vitamin
Deficiency Anemia
Jun 1, 2008
Vitamin deficiency
anemia results from low or depleted levels of vitamin B12 or
folate (folic acid).People
may be weak, short of breath, and pale.
Nerves may also malfunction.
Blood tests can detect abnormal cells that indicate
vitamin deficiency ane...
Anemia
of Chronic Disease
Jun 1, 2008
In anemia
of chronic disease, some chronic disorder slows the production of
red blood cells, the result of production of proteins called cytokines
that interfere with the production of red blood cells....
Autoimmune
Hemolytic Anemia
Jun 1, 2008
Autoimmune
hemolytic anemia is a group of disorders characterized by a malfunction
of the immune system that produces autoantibodies, which attack
red blood cells as if they were substances foreign to the body.Some people have no symptoms,
and other ...
Sickle
Cell Disease
Jun 1, 2008
Sickle cell
disease is an inherited condition characterized by sickle (crescent)-shaped
red blood cells and chronic anemia caused by excessive destruction
of red blood cells.People
usually have anemia and jaundice.
Worsening anemia, fever, and shortn...
Hemoglobin C, S-C, and
E Diseases
Jun 1, 2008
Hemoglobin
C, S-C, and E diseases are inherited conditions characterized by
abnormally shaped red blood cells and chronic anemia that is caused
by excessive destruction of red blood cells....
Thalassemias
Jun 1, 2008
Thalassemias
are a group of inherited disorders resulting from an imbalance in
the production of one of the four chains of amino acids that make
up hemoglobin (the oxygen-carrying protein found in red blood cells).Symptoms depend on the type
of thala...
Introduction
Jun 1, 2008
White
blood cells (leukocytes) are an important part of the body's defense
against infectious organisms and foreign substances. To defend the
body adequately, a sufficient number of white blood cells must receive
a message that an infectious organism...
Neutropenia
Jun 1, 2008
Neutropenia
is an abnormally low number of neutrophils in the blood.Neutropenia significantly
increases the risk of life-threatening infection.
Neutropenia is often caused by cancer chemotherapy
or radiation therapy.
Doctors suspect neutropenia in pe...
Neutrophilic
Leukocytosis
Jun 1, 2008
Neutrophilic
leukocytosis is an abnormally high number of neutrophils in the
blood....
Lymphocytopenia
Jun 1, 2008
Lymphocytopenia
is an abnormally low number of lymphocytes in the blood.Many disorders can decrease
the number of lymphocytes in the blood, but AIDS and malnutrition
are the most common.
People may have no symptoms, or they may have fever
and other s...
Lymphocytic
Leukocytosis
Jun 1, 2008
Lymphocytic
leukocytosis is an abnormally high number of lymphocytes in the
blood....
Monocyte
Disorders
Jun 1, 2008
Monocytes help other white
blood cells remove dead or damaged tissues, destroy cancer cells,
and regulate immunity against foreign substances. Monocytes are
produced in the bone marrow and then enter the bloodstream, where
they account for about 1 to...
Eosinophilic
Disorders
Jun 1, 2008
Eosinophils usually account
for less than 7% of the circulating leukocytes (100 to 500 eosinophils
per microliter of blood). These cells have a role in the protective
immunity against certain parasites but also contribute to the inflammation
that occ...
Basophilic
Disorders
Jun 1, 2008
Basophils account for
less than 3% of the circulating leukocytes (0 to 300 basophils per microliter
of blood). These cells have some role in immune surveillance and
wound repair. Basophils can release histamine and other mediators
and play a role in ...
Introduction
Jun 1, 2008
Leukemias
are cancers of white blood cells or of cells that develop into white
blood cells....
Acute
Lymphocytic Leukemia (ALL)
Jun 1, 2008
Acute lymphocytic
(lymphoblastic) leukemia is a life-threatening disease in which
the cells that normally develop into lymphocytes become cancerous
and rapidly replace normal cells in the bone marrow.People may have symptoms,
such as fever, weakness,...
Acute
Myelocytic Leukemia (AML)
Jun 1, 2008
Acute myelocytic
(myeloid, myelogenous, myeloblastic, myelomonocytic) leukemia is
a life-threatening disease in which the cells that normally develop
into neutrophils, basophils, eosinophils, and monocytes become cancerous and
rapidly replace normal ...
Chronic
Lymphocytic Leukemia (CLL)
Jun 1, 2008
Chronic lymphocytic
leukemia is a disease in which mature lymphocytes become cancerous and
gradually replace normal cells in lymph nodes.People may have no symptoms
or they may have general symptoms such as tiredness.
People may also have enlarged ly...
Chronic
Myelocytic Leukemia (CML)
Jun 1, 2008
Chronic myelocytic
(myeloid, myelogenous, granulocytic) leukemia is a disease in which cells
that normally would develop into neutrophils, basophils, eosinophils,
and monocytes become cancerous.
People pass through a phase in which they have nonspeci...
Introduction
Jun 1, 2008
The spleen, a spongy, soft
organ about as big as a person's fist, is located in the upper left part
of the abdomen, just under the rib cage. The splenic artery brings
blood to the spleen from the heart. Blood leaves the spleen through
the splenic vei...
Enlarged
Spleen
Jun 1, 2008
Many disorders, including infections, anemias, and
cancers, can cause an enlarged spleen.
Symptoms are usually not very specific but can include
fullness or pain in the upper left abdomen or back.
Usually doctors can feel an enlarged spleen, but x-r...
Spleen
Injury
Jun 1, 2008
An injured spleen is usually painful.
Imaging tests such as ultrasonography or computed
tomography are used to diagnose an injured spleen.
Blood transfusions are often needed to treat a spleen
injury, and sometimes surgery to remove or repair the sp...
Diabetes
Mellitus
Jun 1, 2008
Diabetes mellitus
is a disorder in which blood sugar (glucose) levels are abnormally
high because the body does not produce enough insulin to meet its
needs.Urination
and thirst are increased, and people lose weight when they are not
trying to.
Diabe...
Multiple
Endocrine Neoplasia Syndromes
Jun 1, 2008
Multiple endocrine
neoplasia syndromes are rare, inherited conditions in which several
endocrine glands develop noncancerous (benign) or cancerous (malignant)
tumors or grow excessively without forming tumors.Multiple endocrine neoplasia
syndromes ar...
Introduction
Jun 1, 2008
The conjunctiva
is the thin, transparent lining that covers the back of the eyelid
and loops back to cover the sclera (the white of the eye), right
up to the edge of the cornea (see ). The conjunctiva helps protect
the eye by keeping small foreign ob...
Infectious Conjunctivitis
Jun 1, 2008
Infectious
conjunctivitis is inflammation of the conjunctiva usually caused
by viruses or bacteria.Bacteria
and viruses can infect the conjunctiva.
Redness, irritation, tearing or discharge, and sensitivity
to light are common.
Good hygiene helps pre...
Trachoma
Jun 1, 2008
Trachoma (granular
conjunctivitis, Egyptian ophthalmia) is a prolonged infection of
the conjunctiva caused by the higher bacterium Chlamydia
trachomatis.
Chlamydia trachomatis can
infect the eye, usually in children who live in lesser-developed,
hot,...
Allergic
Conjunctivitis
Jun 1, 2008
Allergic conjunctivitis
is inflammation of the conjunctiva caused by an allergic reaction.Allergic reactions may inflame
the conjunctiva.
Redness, irritation, swelling, and discharge are
common.
Various eye drops may help decrease inflammation....
Episcleritis
Jun 1, 2008
Episcleritis
is inflammation of the tissue lying between the sclera and the conjunctiva....
Scleritis
Jun 1, 2008
Scleritis
is a deep, extremely painful inflammation and purple discoloration
of the sclera (the white of the eye) that may severely damage vision....
Noncancerous
Growths
Jun 1, 2008
Two kinds of noncancerous
(benign) growths commonly develop on the conjunctiva—pinguecula
and pterygium. They both are more common among older people and
probably occur as a result of long-term ultraviolet radiation exposure.
Doctors easily recognize...
Introduction
May 1, 2008
The brain and spinal cord
are remarkably resistant to infection, but when they become infected,
the consequences are often very serious. Infections may be caused
by bacteria, viruses, fungi, or, occasionally, protozoa or parasites.
Another group of b...
Acute
Bacterial Meningitis
May 1, 2008
Acute bacterial
meningitis is rapidly developing inflammation of the subarachnoid
space (located within the layers of tissue covering the brain and
spinal cord) that is caused by bacteria.Older children and adults
develop a stiff neck, usually with a...
Chronic
Meningitis
May 1, 2008
Chronic meningitis
is a slowly developing inflammation of the subarachnoid space (located
within the layers of tissues covering the brain and spinal cord)
that lasts a month or longer.
People may have a fever, a stiff neck, a headache,
double vision,...
Aseptic
Meningitis
May 1, 2008
Aseptic meningitis
is inflammation of the subarachnoid space (located within the tissues the
layers of covering the brain and spinal cord) that is diagnosed
when standard testing does not detect bacteria.Viruses, often those frequently
present in the...
Rabies
May 1, 2008
Rabies is
a viral infection of the brain that is transmitted by animals and
that causes inflammation of the brain and spinal cord. Once the
virus reaches the spinal cord and brain, rabies is fatal.The virus can be transmitted
when people are bitten b...
Encephalitis
May 1, 2008
Encephalitis
is inflammation of the brain that occurs when a virus directly infects
the brain or when a virus or something else triggers inflammation.
The spinal cord may also be involved, resulting in a disorder called encephalomyelitis.People may h...
Lymphocytic
Choriomeningitis
May 1, 2008
Lymphocytic
choriomeningitis is a flu-like disorder caused by an arenavirus
and often followed by meningitis. It occurs when the tissues covering
the brain and spinal cord become inflamed.Rodents can transmit the virus
to people through contaminated ...
Progressive
Multifocal Leukoencephalopathy
May 1, 2008
Progressive
multifocal leukoencephalopathy is a rare infection of the brain
that is caused by the JC virus.
People with a weakened immune system are most likely
to get the disorder.
People may become clumsy, have trouble speaking,
and become partiall...
Abscess
of the Brain
May 1, 2008
A brain abscess
is a localized collection of pus in the brain.An abscess may form in the
brain when bacteria from an infection elsewhere in the head or in
the bloodstream or from a wound enter the brain.
Headache, sleepiness, nausea, weakness on one ...
Subdural
Empyema
May 1, 2008
A subdural
empyema is a collection of pus that develops under the top layer
of tissue (dura mater) covering the brain, rather than in the brain
itself....
Parasitic
Infections
May 1, 2008
In some parts of the
world, brain infections may be due to worms or other parasites.
These infections are more common in developing countries and rural
areas. They are less common in the United States....
Suicidal
Behavior
May 1, 2008
Suicidal behavior
includes three types of self-destructive acts: completed suicide,
attempted suicide, and suicide gestures. Thoughts and plans about
suicide are called suicide ideation.
Suicide usually results from the interaction of many
factors, u...
Introduction
May 1, 2008
The thyroid
is a small gland, measuring about 2 inches (5 centimeters) across,
that lies just under the skin below the Adam's apple in the neck.
The two halves (lobes) of the gland are connected in the middle
(called the isthmus), giving the thyroid ...
Hyperthyroidism
May 1, 2008
Hyperthyroidism
is overactivity of the thyroid gland that leads to high levels of
thyroid hormones and speeding up of vital body functions.Graves' disease is the most
common cause of hyperthyroidism.
Heart rate and blood pressure may increase, heart
...
Hypothyroidism
May 1, 2008
Hypothyroidism
is underactivity of the thyroid gland that leads to inadequate production of
thyroid hormones and a slowing of vital body functions.Facial expressions become
dull, the voice is hoarse, speech is slow, eyelids droop, and the eyes
and fa...
Hashimoto's
Thyroiditis
May 1, 2008
Hashimoto's
thyroiditis (autoimmune thyroiditis) is chronic, autoimmune inflammation
of the thyroid.Hashimoto's
thyroiditis results when the body attacks the cells of the thyroid
gland—an autoimmune reaction.
Usually, people feel tired and cannot tol...
Subacute
Thyroiditis
May 1, 2008
Subacute
thyroiditis (granulomatous thyroiditis) is acute inflammation of
the thyroid, probably caused by a virus....
Silent
Lymphocytic Thyroiditis
May 1, 2008
Silent lymphocytic
thyroiditis (postpartum thyroiditis) is painless, autoimmune inflammation
of the thyroid that typically develops after childbirth and goes
away on its own....
Cancer
May 1, 2008
The cause of thyroid cancer
is not known, but the thyroid gland is very sensitive to radiation.
Thyroid cancer is more common among people who were treated with
radiation to the head, neck, or chest, most often for noncancerous
(benign) conditions, w...
Carcinoid
Tumors
May 1, 2008
Carcinoid
tumors are noncancerous (benign) or cancerous (malignant) growths
that sometimes produce excessive amounts of hormonelike substances,
resulting in the carcinoid syndrome.
People with carcinoid tumors may have cramping pain
and changes in bo...
Acute Bronchitis
Apr 1, 2008
Bronchitis
is inflammation of the large airways that branch off the trachea
(bronchi), usually caused by infection but sometimes caused by irritation
from inhaling gases, smoke, dust particles, or some types of pollution.Acute bronchitis is usually
c...
Introduction
Apr 1, 2008
Pneumonia
is an infection of the small air sacs of the lungs (alveoli) and
the tissues around them....
Community-Acquired
Pneumonia
Apr 1, 2008
Community-acquired
pneumonia develops in people with limited or no contact with medical
institutions or settings....
Hospital-Acquired
and Institution-Acquired Pneumonia
Apr 1, 2008
Hospital-acquired
pneumonia develops in people who have been hospitalized,
typically after about 2 days or more of hospitalization. Institution-acquired
pneumonia develops in people who reside in nursing homes
or who have contact with medical setting...
Pneumonia
in Immunocompromised People
Apr 1, 2008
Pneumonia
in people whose immune system is weakened (for example, by AIDS,
organ transplantation, or the use of certain drugs) is usually caused
by different organisms than those that cause pneumonia in healthy
people.Pneumocystis
jiroveci pneumonia ...
Aspiration
Pneumonia
Apr 1, 2008
Aspiration
pneumonia is lung infection caused by inhaling mouth secretions,
stomach contents, or both. Chemical pneumonitis is
lung irritation caused by inhalation of substances toxic to the
lungs.Symptoms
include cough and shortness of breath.
Docto...
Asthma
Apr 1, 2008
Asthma is
a condition in which the airways narrow—usually reversibly—in response
to certain stimuli....
Introduction
Apr 1, 2008
Environmental lung diseases
are caused by harmful particles, mists, vapors, or gases that are
inhaled, usually while people work. If the lung disease is due to
inhaled particles, the term pneumoconiosis is often
used. Where within the airways or lung...
Asbestosis
Apr 1, 2008
Asbestosis
is widespread scarring of lung tissue caused by breathing asbestos
dust....
Beryllium
Disease
Apr 1, 2008
Beryllium
disease (sometimes called berylliosis) is a lung inflammation caused
by inhaling dust or fumes that contain beryllium....
Building-Related
Illnesses
Apr 1, 2008
Building-related
illnesses are disorders that affect the lungs as well as other parts
of the body and are caused by exposure to substances within modern
airtight buildings....
Byssinosis
Apr 1, 2008
Byssinosis
is a narrowing of the airways caused by inhaling cotton, flax, or
hemp particles....
Coal
Workers' Pneumoconiosis
Apr 1, 2008
Coal workers'
pneumoconiosis (black lung) is a lung disease caused by deposits
of coal dust in the lungs....
Gas
and Chemical Exposure
Apr 1, 2008
Symptoms depend on which gas or chemical is inhaled
and how deeply and for how long it was inhaled.
Symptoms may include irritation of the eyes or nose,
cough, blood in the sputum, and shortness of breath.
Chest x-rays, computed tomography, and brea...
Occupational
Asthma
Apr 1, 2008
Occupational
asthma is a reversible narrowing of the airways caused by inhaling
work-related particles or vapors that act as irritants or cause
an allergic reaction....
Silicosis
Apr 1, 2008
Silicosis
is permanent scarring of the lungs caused by inhaling silica (quartz)
dust....
Introduction
Apr 1, 2008
Bone tumors
are growths of abnormal cells in bones.Bone tumors may be cancerous
(malignant) or noncancerous (benign) and may develop within the
bone or spread to the bone.
Tumors may cause unexplained, progressively worsening
bone pain, swelling, or ...
Other Bone Abnormalities
Apr 1, 2008
Many noncancerous (benign)
bone abnormalities may resemble bone tumors but are not....
Joint
Tumors
Apr 1, 2008
Tumors rarely affect
joints unless the joints are near a bone or soft-tissue tumor. However, two
conditions—synovial chondromatosis and pigmented villonodular synovitis—occur
in the lining (synovium) of joints. These tumors are noncancerous
(benign) ...
Introduction
Apr 1, 2008
Vasculitic
disorders are characterized by inflammation of the blood vessels
(vasculitis).Usually,
what triggers vasculitis is unknown, but sometimes certain viruses or
drugs trigger it.
People may have general symptoms, such as fever
or fatigue, foll...
Polyarteritis
Nodosa
Apr 1, 2008
Polyarteritis
nodosa is inflammation of medium-sized arteries that damages the
arteries and impairs blood flow through them.Any organ (except the lungs)
can be affected.
Polyarteritis nodosa can be rapidly fatal or develop
gradually.
Symptoms vary de...
Giant
Cell Arteritis
Apr 1, 2008
Giant cell
(temporal) arteritis is chronic inflammation of large arteries of
the head, neck, and upper body. Typically affected are the temporal
arteries, which run through the temples and provide blood to part
of the scalp, the jaw muscles, and sali...
Wegener's
Granulomatosis
Apr 1, 2008
Wegener's
granulomatosis often begins with inflammation of small and medium-sized blood
vessels and tissues in the nose, sinuses, throat, or lungs. It may
progress to inflammation of blood vessels throughout the body (generalized
vasculitis).The
caus...
Behçet's
Syndrome
Apr 1, 2008
Behçet's syndrome
is chronic inflammation that can cause painful mouth sores, skin
blisters, genital sores, and swollen joints. The eyes, blood vessels,
nervous system, and digestive tract may also become inflamed.Typically, sores appear, disappear,
...
Takayasu's
Arteritis
Apr 1, 2008
Takayasu's
arteritis causes chronic inflammation, mainly of the aorta (the
artery that connects directly with the heart), the arteries that branch
off from it, and the pulmonary arteries.The cause is unknown.
People may have general symptoms, such as...
Churg-Strauss
Syndrome
Apr 1, 2008
Churg-Strauss
syndrome is inflammation of small blood vessels that damages organs
and that usually occurs in people with a history of asthma, nasal
allergies, or both.The
cause is unknown.
At first, people may have a runny nose or asthma
for months o...
Henoch-Schönlein
Purpura
Apr 1, 2008
Henoch-Schönlein
purpura is inflammation mainly of small vessels, usually occurring
in children.A
rash of reddish purple bumps and spots on the lower legs is usually
the first symptom, followed by joint aches, digestive upset, and
kidney malfunction....
Microscopic
Polyangiitis
Apr 1, 2008
Microscopic
polyangiitis is inflammation of mainly small vessels throughout
the body.People
have a fever, lose weight, and have achy muscles and joints, as
well as various other symptoms depending on the organs affected.
Biopsy is done to confirm the...
Introduction
Apr 1, 2008
The muscles, bursas, tendons,
and bones must be healthy and functioning correctly for the body
to move normally. Muscles, which contract to produce movement, are
connected to the bones by tendons. Bursas are flat sacs containing
joint (synovial) flui...
Muscle
Cramps
Apr 1, 2008
A cramp is
a sudden, brief, usually painful contraction of a muscle or group
of muscles....
Fibromyalgia
Apr 1, 2008
Fibromyalgia
is characterized by poor sleep, fatigue, and widespread aching and
stiffness in soft tissues, including muscles, tendons, and ligaments.Poor sleep, stress, strains,
injury, and possibly certain personality characteristics may increase
th...
Bursitis
Apr 1, 2008
Bursitis is
painful inflammation of a bursa (a flat, fluid-filled sac that provides
cushioning where skin, muscles, tendons, and ligaments rub over
bones).Movement
is painful, and bursas near the skin may become swollen and tender.
Pain around bursas...
Tendinitis
and Tenosynovitis
Apr 1, 2008
Tendinitis is
inflammation of a tendon. Tenosynovitis is tendinitis
accompanied by inflammation of the protective covering around the tendon
(tendon sheath).Tendons
are painful, particularly when moved, and sometimes swollen.
The diagnosis is usually...
Baker's
Cysts
Apr 1, 2008
Baker's cysts
(popliteal cysts) are tiny sacs filled with joint (synovial) fluid
that form in an extension of the joint capsule behind the knee....
Introduction
Apr 1, 2008
Headaches are a very common
medical problem and a common cause of disability among men and women.
Headaches interfere with the ability to work and do daily tasks.
Some people have frequent headaches. Other people hardly ever have
them....
Tension-Type
Headaches
Apr 1, 2008
A tension-type
headache is usually mild to moderate pain that feels like a band
tightening around the head.
Pain in other parts of the head and neck may trigger
these headaches.
Headaches may occur several or many days each month.
Doctors base the di...
Migraines
Apr 1, 2008
A migraine
headache is a pulsating or throbbing pain that usually ranges from
moderate to severe. It can affect one or both sides of the head.
It is worsened by physical activity, light, sounds, or smells and
is accompanied by nausea, vomiting, and s...
Cluster
Headaches
Apr 1, 2008
A cluster
headache causes severe pain that is felt at the temple or around
the eye on one side of the head and that lasts a relatively short time
(usually 30 minutes to 1 hour). Headaches usually occur regularly
during a 1- to 3-month period, followe...
Idiopathic
Intracranial Hypertension
Apr 1, 2008
Idiopathic
intracranial hypertension (benign intracranial hypertension, pseudotumor
cerebri) involves increased pressure within the skull (intracranial
pressure), without any evidence of a cause.People have daily headaches,
sometimes with nausea, blu...
Low-Pressure
Headache
Apr 1, 2008
Low-pressure
headaches result when cerebrospinal fluid is removed during a spinal
tap (lumbar puncture) or leaks out because of a cyst or tear. Loss
of this fluid, which flows around the brain, reduces pressure around
the brain....
Introduction
Apr 1, 2008
Low back and neck pain
are among the most common reasons for health care visits. The pain
usually results from problems with the spine, including the bones
of the spine (vertebrae) and the muscles and ligaments that support
it. Occasionally, low back...
Low
Back Pain
Apr 1, 2008
Common causes include sprains and strains, osteoarthritis,
osteoporosis, a ruptured or herniated disk, fibromyalgia, and, in
older people, spinal stenosis.
Pain may be intermittent or constant, superficial
or deep, or dull or sharp, depending on the...
Neck
Pain
Apr 1, 2008
Neck pain usually results from strains and sprains.
Pain from the neck may shoot down an arm or cause
a headache.
Doctors base the diagnosis on symptoms, results
of a physical examination, and sometimes x-rays or other imaging
tests.
Treatment inclu...
Amyloidosis
Apr 1, 2008
Amyloidosis
is a rare disease in which a protein called amyloid accumulates
in various tissues and organs, impairing normal function.The symptoms and severity
of amyloidosis depend on which organs are affected.
Diagnosis is made by examining a small ...
Introduction
Apr 1, 2008
Imaging tests provide
a picture of the body's interior—of the whole body or part of it.
Most imaging tests are painless, relatively safe, and noninvasive
(that is, they do not require an incision in the skin or the insertion
of an instrument into the...
Angiography
Apr 1, 2008
In angiography, x-rays
are used to produce detailed images of blood vessels. It is sometimes
called conventional angiography to distinguish it from computed
tomography (CT) angiography and magnetic resonance angiography.
During angiography, doctors c...
Computed
Tomography
Apr 1, 2008
In computed tomography
(CT), an x-ray source and x-ray detector rotate around a person.
In modern scanners, the x-ray detector usually has 4 to 64 or more
rows of sensors that record the x-rays that pass through the body.
Data from the sensors repres...
Magnetic
Resonance Imaging
Apr 1, 2008
In magnetic resonance
imaging (MRI), a strong magnetic field and very high frequency radio
waves are used to produce highly detailed images. MRI does not use
x-rays and is usually very safe....
Plain
X-Rays
Apr 1, 2008
X-rays are high-energy
radiation waves that can penetrate most substances (to varying degrees).
In low doses, x-rays are used to produce images that help doctors
diagnose disease. In high doses, x-rays (radiation therapy) is used
to treat cancer. X-r...
Radionuclide
Scanning
Apr 1, 2008
In radionuclide
scanning, radionuclides are used to produce images. A radionuclide
is an unstable atom that becomes more stable by releasing energy
as radiation. Most radionuclides release high-energy photons as
gamma rays (which are similar to x-ray...
Ultrasonography
Apr 1, 2008
Ultrasonography
uses high-frequency sound (ultrasound) waves to produce images of
internal organs and other tissues. A device called a transducer
converts electrical current into sound waves, which are sent into
the body's tissues. Sound waves bounce...
Introduction
Mar 1, 2008
Interstitial lung disease
(also called diffuse parenchymal or infiltrative lung disease) is
a term used to describe a number of different disorders that affect
the interstitial space. The interstitial space consists of the air
sacs of the lungs (alve...
Idiopathic
Interstitial Pneumonias
Mar 1, 2008
Idiopathic
interstitial pneumonias are interstitial lung diseases that have
no known cause and that affect the lungs similarly....
Pulmonary
Langerhans' Cell Granulomatosis
Mar 1, 2008
Pulmonary
Langerhans cell granulomatosis (histiocytosis or eosinophilic granuloma)
is a disorder in which cells called histiocytes and eosinophils
proliferate in the lung, often causing scarring....
Lymphoid
Interstitial Pneumonia
Mar 1, 2008
Lymphoid interstitial
pneumonia is an uncommon lung disease in which mature lymphocytes
(a type of white blood cell) accumulate in the alveoli....
Sarcoidosis
Mar 1, 2008
Sarcoidosis
is a disease in which abnormal collections of inflammatory cells
(granulomas) form in many organs of the body....
Pulmonary
Alveolar Proteinosis
Mar 1, 2008
Pulmonary
alveolar proteinosis is a rare disorder in which the air sacs of
the lungs (alveoli) become plugged with a protein-rich fluid....
Pulmonary
Hypertension
Mar 1, 2008
Pulmonary
hypertension is a condition in which blood pressure in the arteries
of the lungs (the pulmonary arteries) is abnormally high....
Lung
Cancer
Mar 1, 2008
Cigarette smoking is the most common cause of lung
cancer.
One common presenting symptom is a persistent cough.
Chest x-rays can detect most lung cancers, but other
additional imaging tests and biopsies are needed.
Surgery, chemotherapy, targeted a...
Osteonecrosis
Mar 1, 2008
Osteonecrosis,
also referred to avascular necrosis of bone, aseptic necrosis, ischemic
necrosis, or osteochondritis dissecans, is the death of a segment
of bone caused by an impaired blood supply....
Introduction
Mar 1, 2008
A number of different
disorders may affect the hands, including ganglia, deformities,
disorders related to nerves or blood vessels, injuries, and infections.
Some other disorders that affect the hands are covered elsewhere
in the book, including frac...
Ganglia
Mar 1, 2008
Ganglia (ganglion
cysts) are gelatinous swellings on the hands and wrists....
Deformities
Mar 1, 2008
Hand deformities may be
caused by an injury or may result from another disorder (for example,
rheumatoid arthritis—see ). Deformities should be treated promptly,
if possible. Otherwise, they tend not to respond to simple treatments,
such as splinting...
Nerve
Compression Syndromes
Mar 1, 2008
Carpal tunnel syndrome,
cubital tunnel syndrome, and radial tunnel syndrome are nerve compression
syndromes. In these disorders, something (usually bone or connective
tissue) presses on a nerve, causing abnormalities of sensation,
movement, or both. ...
Kienböck's
Disease
Mar 1, 2008
Kienböck's
disease is the death of bone tissue due to an impaired blood supply
(avascular necrosis—see ) affecting the lunate bone in the
hand....
Injuries
Mar 1, 2008
Hand injuries cause swelling,
pain, stiffness, and sometimes limited movement. The most common
injuries are tears (ruptures) of ligaments or fractures of bone.
When a ligament is ruptured, bones can move out of position, resulting
in a dislocated joi...
Infections
Mar 1, 2008
Human and animal bites
can cause an infection of the hands. Some other infections are felon
and herpetic whitlow. Paronychia is discussed elsewhere (see )....
Introduction
Mar 1, 2008
Some foot problems start
in the foot itself, for example, from a foot injury. Others result from
disorders that affect many parts of the body, such as diabetes,
gout, or other types of arthritis. Problems can occur in any bone, joint,
muscle, tendon,...
Pain
in the Ball of the Foot (Metatarsalgia)
Mar 1, 2008
Pain in the ball of the
foot (called metatarsalgia) may have many different causes (including
arthritis, poor circulation, pinching of the nerves between the
toes, posture problems, and various disorders). However, most often
the pain is caused by ne...
Tarsal
Tunnel Syndrome
Mar 1, 2008
Tarsal tunnel
syndrome (posterior tibial neuralgia) is pain in the ankle, foot,
and toes caused by compression of or damage to the nerve supplying
the heel and sole (posterior tibial nerve)....
Medial
Plantar Nerve Entrapment
Mar 1, 2008
Medial plantar
nerve entrapment is compression of a nerve at the inner heel (the
medial plantar nerve) that causes pain, numbness, or tingling....
Tibialis
Posterior Tendinosis
Mar 1, 2008
Tibialis posterior
tendinosis is wear and tear of a tendon that passes behind and around
the inner ankle....
Plantar
Fasciosis
Mar 1, 2008
Plantar fasciosis
is pain originating from the dense band of tissue called the plantar
fascia that extends from the bottom of the heel bone to the base
of the toes (ball of the foot)....
Inferior
Calcaneal Bursitis
Mar 1, 2008
Bursitis is painful inflammation
of a bursa (a flat sac containing joint [synovial] fluid that reduces
friction in areas where skin, muscles, tendons, and ligaments rub
over bones). Bursitis can develop at the bottom of the heel. The heel
may throb, ...
Achilles
Tendon Bursitis
Mar 1, 2008
Achilles tendon
bursitis is inflammation of the fluid-filled sac (bursa) located
either between the skin of the heel and the Achilles tendon (posterior
Achilles tendon bursitis) or in front of the attachment of the Achilles
tendon to the heel bone (a...
Achilles
Tendon Enthesopathy
Mar 1, 2008
Achilles tendon
enthesopathy is pain where the Achilles tendon attaches to the back
of the heel....
Corns
and Calluses
Mar 1, 2008
Corns are
hard cone-shaped bumps of skin commonly found on the upper surface
of the smaller toes, particularly over a joint. Calluses are
somewhat rounded flat thickenings of the skin located on the under-surface
of the foot....
Bunion
Mar 1, 2008
In bunion,
the joint of the base of the big toe appears to stick out (becomes
prominent)....
Hammer
Toe
Mar 1, 2008
Hammer toe
is a toe that is in a fixed (rigid) contracted position....
Plantar
Fibromatosis
Mar 1, 2008
Plantar fibromatosis
is a noncancerous (benign) growth of connective tissue in the sole (the
plantar fascia)....
Introduction
Mar 1, 2008
Sleep disorders
are disturbances that affect the ability to fall asleep, stay asleep,
or stay awake or that cause abnormal behaviors during sleep, such
as night terrors or sleepwalking....
Insomnia
Mar 1, 2008
Insomnia is
difficulty falling asleep or staying asleep or a disturbance in
sleep quality that makes sleep seem inadequate or unrefreshing.People are sleepy and tired
during the day and have trouble functioning.
Doctors base the diagnosis on a detail...
Circadian
Rhythm Sleep Disorders
Mar 1, 2008
Circadian
rhythm sleep disorders occur when people's internal sleep-wake schedule
(clock) does not align with the earth's cycle of darkness (night)
and light (day).Jet
lag and shift work commonly disturb the usual rhythms of sleep and
waking.
People ...
Hypersomnia
and Excessive Daytime Sleepiness
Mar 1, 2008
Hypersomnia
is a substantial increase in total sleeping time. Excessive daytime
sleepiness (EDS) is the inability to stay awake and alert during
the day, resulting in unintended lapses into drowsiness or sleep....
Narcolepsy
Mar 1, 2008
Narcolepsy
is a sleep disorder marked by excessive sleepiness during the day
or recurring, uncontrollable episodes of sleep during normal waking
hours, plus sudden episodes of muscle weakness (cataplexy). Sometimes sleep
paralysis, vivid dreams, and ...
Periodic
Limb Movement Disorder and Restless Legs
Syndrome
Mar 1, 2008
Periodic
limb movement disorder involves repetitive movements of the arms,
legs, or both during sleep. Restless legs syndrome involves an irresistible
urge to move and usually abnormal sensations in the legs, arms,
or both when people sit still or li...
Parasomnias
Mar 1, 2008
Parasomnias
are unusual behaviors that occur during sleep....
Sleep
Disorders in Dementia
Mar 1, 2008
In people with dementia
(see ),
such as Alzheimer's disease, sleep patterns are often abnormal.
As dementia progresses, the time spent in light sleep increases,
so people are easily awakened.People with dementia may have disorders that
contribute to ...
Introduction
Mar 1, 2008
Brain damage can cause
many types of dysfunction. Such dysfunction ranges from complete
loss of consciousness (as occurs in a coma), to disorientation and
an inability to pay attention (as occurs in delirium), to impairment
of one or several of the m...
Dysfunction
by Location
Mar 1, 2008
Because different areas
of the brain control specific functions (see ), the location of brain damage determines
the type of dysfunction that results. Which side of the brain is
affected is also important because the functions of the two halves
of the...
Specific Types of Dysfunction
Mar 1, 2008
Many functions of the
brain are performed by several areas of the brain working together (networks),
not by a single area in the brain. Damage to these networks can
cause aphasia, apraxia, agnosia, or amnesia....
Seizure Disorders
Mar 1, 2008
In seizure
disorders, the brain's electrical activity is periodically disturbed,
resulting in some degree of temporary brain dysfunction....
Introduction
Mar 1, 2008
Most nerve fibers
inside and outside the brain are wrapped with many layers of tissue composed
of a fat (lipoprotein) called myelin. These layers form the myelin
sheath. Much like the insulation around an electrical wire, the
myelin sheath enables el...
Multiple
Sclerosis (MS)
Mar 1, 2008
In multiple
sclerosis, patches of myelin and underlying nerve fibers in the
eyes, brain, and spinal cord are damaged or destroyed....
Other
Primary Demyelinating Diseases
Mar 1, 2008
...
Introduction
Feb 1, 2008
Coronary artery
disease is a condition in which the blood supply to the heart muscle
is partially or completely blocked....
Angina
Feb 1, 2008
Angina, also
called angina pectoris, is temporary chest pain or a sensation of
pressure that occurs while the heart muscle is not receiving enough
oxygen.A person
with angina has discomfort or pressure beneath the breastbone (sternum).
Angina typical...
Acute
Coronary Syndromes (Heart Attack; Myocardial Infarction; Unstable
Angina)
Feb 1, 2008
Acute coronary
syndromes result from a sudden blockage in a coronary artery. This
blockage causes unstable angina or heart attack (myocardial infarction)
depending on the location and amount of blockage.People who experience an acute
coronary syndrom...
Introduction
Feb 1, 2008
Veins return blood to
the heart from all the organs of the body. The large veins parallel
the large arteries and often share the same name, but the pathways
of the venous system are more difficult to trace than those of the
arteries. Many unnamed sma...
Deep
Vein Thrombosis (DVT)
Feb 1, 2008
Deep vein
thrombosis is the formation of blood clots (thrombi) in the deep
veins.Blood
clots may form in veins if the vein is injured, a disorder causes
the blood to clot, or something slows the return of blood to the
heart.
Blood clots may cause the...
Superficial
Thrombophlebitis
Feb 1, 2008
Superficial
thrombophlebitis (superficial phlebitis) is inflammation and clotting
in a superficial vein.The
skin over the vein becomes red, swollen, and painful.
Doctors examine the area, but tests are not usually
needed.
People may need to take anal...
Varicose
Veins
Feb 1, 2008
Varicose
veins are abnormally enlarged superficial veins in the legs.Varicose veins may ache or
cause itching or a sensation of tiredness.
Doctors can detect varicose veins by examining the
skin.
Surgery or injection therapy can remove varicose
veins...
Arteriovenous
Fistula
Feb 1, 2008
An arteriovenous
fistula is an abnormal channel between an artery and a vein.Although doctors may be able
to hear the distinctive sound of blood flow though a fistula by
using a stethoscope, imaging tests are often needed.
Fistulas can be cut out or ...
Introduction
Feb 1, 2008
Like the venous system,
the lymphatic system transports fluids throughout the body. The
lymphatic system consists of thin-walled lymphatic vessels, lymph
nodes, and two collecting ducts (see ). Lymphatic
vessels, located throughout the body, are larg...
Lymphedema
Feb 1, 2008
Lymphedema
is the accumulation of lymph resulting in swelling....
Bronchiectasis
Feb 1, 2008
Bronchiectasis
is an irreversible widening (dilation) of portions of the breathing
tubes or airways (bronchi) resulting from damage to the airway wall....
Introduction
Feb 1, 2008
The pleura
is a thin, transparent, two-layered membrane that covers the lungs
and also lines the inside of the chest wall. The layer that covers
the lungs lies in close contact with the layer that lines the chest
wall. Between the two thin flexible l...
Pleural
Effusion
Feb 1, 2008
Pleural effusion
is the abnormal accumulation of fluid in the pleural space.Fluid can accumulate in the
pleural space as a result of a large number of disorders, including
infections, injuries, heart or liver failure, blood clots in the
lung blood ve...
Pneumothorax
Feb 1, 2008
A pneumothorax
is the presence of air between the two layers of pleura, resulting
in partial or complete collapse of the lung.Symptoms include difficulty
breathing and chest pain.
Diagnosis is by chest x-ray.
Treatment is usually draining the air wit...
Viral
Pleuritis
Feb 1, 2008
Viral pleuritis
is a viral infection of the pleurae, which typically causes chest
pain when breathing or coughing....
Osteoporosis
Feb 1, 2008
Osteoporosis
is a condition in which a progressive decrease in the density of
bones weakens the bones, making fractures likely....
Introduction
Feb 1, 2008
Bones and the fluid and
tissues of joints can become infected. Such infections include osteomyelitis
and infectious arthritis....
Osteomyelitis
Feb 1, 2008
Osteomyelitis
is a bone infection usually caused by bacteria, including mycobacteria, but
is sometimes caused by fungi.
Bacteria or fungi can infect bones by spreading
through the bloodstream, spreading from nearby tissue, or directly invading
the bo...
Infectious
Arthritis
Feb 1, 2008
Infectious
arthritis (septic arthritis) is infection in the fluid and tissues
of a joint usually caused by bacteria, but sometimes caused by viruses
or fungi.Bacteria
or sometimes viruses or fungi may spread through the bloodstream
or from nearby inf...
Osteoarthritis (OA)
Feb 1, 2008
Osteoarthritis
(sometimes called degenerative arthritis, degenerative joint disease,
osteoarthrosis, hypertrophic osteoarthritis) is a chronic disorder
associated with damage to the cartilage and surrounding tissues
and characterized by pain, stiffne...
Rheumatoid
Arthritis (RA)
Feb 1, 2008
Rheumatoid
arthritis is an inflammatory arthritis in which joints, usually
including those of the hands and feet, are inflamed, resulting in
swelling, pain, and often destruction of joints....
Other
Types of Inflammatory Arthritis
Feb 1, 2008
Several connective tissue
diseases, including the spondyloarthropathies (also called spondyloarthritides),
cause prominent joint inflammation. The spondyloarthropathies affect
the joints and spine. These disorders share certain characteristics.
For e...
Charcot's
Joints
Feb 1, 2008
Charcot's
joints (neurogenic arthropathy, neuropathic arthropathy) is progressive
joint destruction, often very rapid, that develops because people
cannot sense pain and thus are not aware of the early signs of joint
damage....
Introduction
Feb 1, 2008
In an autoimmune disorder,
antibodies or cells produced by the body attack the body's own tissues
(see ).
Many autoimmune disorders affect connective tissue in a variety
of organs. Connective tissue is the structural tissue that gives
strength to joi...
Systemic
Lupus Erythematosus (SLE)
Feb 1, 2008
Systemic lupus
erythematosus (disseminated lupus erythematosus, lupus) is a chronic
inflammatory connective tissue disorder that can involve joints,
kidneys, mucous membranes, and blood vessel walls....
Systemic
Sclerosis (Scleroderma)
Feb 1, 2008
Systemic sclerosis
(scleroderma) is a rare, chronic disorder characterized by degenerative
changes and scarring in the skin, joints, and internal organs and
by blood vessel abnormalities....
Sjögren's
Syndrome
Feb 1, 2008
Sjögren's
syndrome is characterized by excessive dryness of the eyes, mouth,
and other mucous membranes....
Polymyositis
and Dermatomyositis
Feb 1, 2008
Polymyositis is
characterized by inflammation and degeneration of the muscles. Dermatomyositis is
polymyositis accompanied by skin inflammation....
Mixed
Connective Tissue Disease (MCTD)
Feb 1, 2008
Mixed connective
tissue disease is a term used by some doctors to describe a disorder
characterized by features of systemic lupus erythematosus, systemic
sclerosis, and polymyositis....
Relapsing
Polychondritis
Feb 1, 2008
Relapsing
polychondritis is characterized by episodes of painful, destructive
inflammation of the cartilage and other connective tissues in many
organs....
Eosinophilic
Fasciitis
Feb 1, 2008
Eosinophilic
fasciitis is a rare disorder in which the skin of the arms and legs
becomes painfully inflamed and swollen and gradually hardens....
Introduction
Feb 1, 2008
Gout and pseudogout are
characterized by joint inflammation (arthritis) and pain. Both disorders
are caused by deposits of crystals in the joints, although the type
of crystal differs....
Gout
Feb 1, 2008
Gout is a
disorder that results from deposits of sodium uric acid crystals,
which accumulate in the joints because of high blood levels of uric
acid (hyperuricemia), leading to attacks of painful joint inflammation.Accumulations of uric acid
crystal ...
Pseudogout
Feb 1, 2008
Pseudogout
(calcium pyrophosphate dihydrate crystal deposition disease) is
a disorder caused by deposits of calcium pyrophosphate dihydrate
crystals in the cartilage and then in the fluid of the joints, leading
to intermittent attacks of painful join...
Introduction
Feb 1, 2008
Delirium
and dementia are the most common causes of mental (cognitive) dysfunction—the
inability to acquire, retain, and use knowledge normally. Although
delirium and dementia may occur together, they are quite different.
Delirium begins suddenly, ca...
Delirium
Feb 1, 2008
Delirium is
a sudden, fluctuating, and usually reversible disturbance of mental
function. It is characterized by inability to pay attention, disorientation,
an inability to think clearly, and fluctuations in the level of
alertness (consciousness)....
Dementia
Feb 1, 2008
Dementia is
a slow, progressive decline in mental function including memory,
thinking, judgment, and the ability to learn....
Stupor and Coma
Feb 1, 2008
Stupor is
unresponsiveness from which a person can be aroused only by vigorous,
physical stimulation. Coma is unresponsiveness from which
a person cannot be aroused. In coma, the person's eyes remain closed....
Introduction
Feb 1, 2008
A tumor is an abnormal
growth, whether noncancerous (benign) or cancerous (malignant).
In many parts of the body, a noncancerous tumor causes few or no
problems. However, any abnormal growth or mass in the brain or spinal
cord can cause considerable ...
Brain
Tumors
Feb 1, 2008
A brain tumor
is a noncancerous (benign) or cancerous (malignant) growth in the
brain. It may originate in the brain or have spread (metastasized)
to the brain from another part of the body.Symptoms may include headaches,
personality changes (such as...
Spinal
Cord Tumors
Feb 1, 2008
A spinal cord
tumor is a noncancerous (benign) or cancerous (malignant) growth
in or around the spinal cord.
People may have weak muscles, lose sensation in
particular areas of the body, or become unable to control bowel
and bladder function.
Magneti...
Radiation
Damage
Feb 1, 2008
Radiation therapy is one
component in the treatment of tumors of the nervous system. It is
directed at the general area (such as the whole head) when people
have several tumors or a tumor that does not have distinct borders. When
the tumor has distin...
Introduction
Feb 1, 2008
The peripheral nervous
system refers to the parts of nervous system outside the central nervous
system, that is, those outside the brain and spinal cord. The nerves
that connect the head, face, eyes, nose, muscles, and ears to the
brain (cranial nerv...
Muscle
Stimulation Disorders
Feb 1, 2008
Muscle stimulation
(motor neuron) disorders are characterized by progressive deterioration of
the nerves and other structures involved in muscle movement. These
disorders develop when motor nerves do not stimulate muscles normally.Amyotrophic lateral...
Neuromuscular
Junction Disorders
Feb 1, 2008
Nerves connect with muscles
at the neuromuscular
junction. There, the ends of nerve fibers connect to special sites
on the muscle's membrane called motor end plates. These plates contain
receptors that enable the muscle to respond to acetylcholine, a...
Plexus
Disorders
Feb 1, 2008
The networks
of interwoven nerve fibers from different spinal nerves (plexuses)
may be damaged by injury, tumors, collections of blood, or autoimmune
reactions.Pain,
weakness, and loss of sensation occur in all or part of an arm or
a leg.
Electromyog...
Thoracic
Outlet Syndromes
Feb 1, 2008
Thoracic
outlet syndromes are a group of disorders caused by pressure on
nerves as they pass between the neck and chest. These disorders
cause pain and pins-and-needles sensations (paresthesias) in the
hand, shoulder, and arm.Nerves
and blood vessels...
Mononeuropathy
Feb 1, 2008
Mononeuropathy
is damage to a single peripheral nerve.Pressure on a nerve for a
long time can damage it.
The affected area may tingle, feel prickly, or be
numb, and the affected muscle may be weak.
Usually, the diagnosis is based on symptoms and
resu...
Multiple
Mononeuropathy
Feb 1, 2008
Multiple
mononeuropathy (mononeuritis multiplex) is the simultaneous malfunction
of two or more peripheral nerves in separate areas of the body.
It causes abnormal sensations and weakness....
Polyneuropathy
Feb 1, 2008
Polyneuropathy
is the simultaneous malfunction of many peripheral nerves throughout
the body.Infections,
toxins, drugs, cancers, nutritional deficiencies, and disorders
can cause many peripheral nerves to malfunction.
Sensation, strength, or both may...
Hereditary
Neuropathies
Feb 1, 2008
Hereditary
neuropathies affect the peripheral nerves, causing subtle symptoms
that worsen gradually....
Spinal
Muscular Atrophies
Feb 1, 2008
Spinal muscular
atrophies are hereditary disorders in which nerve cells in the spinal
cord and brain stem degenerate, causing progressive muscle weakness
and wasting....
Introduction
Feb 1, 2008
The middle ear consists
of the eardrum (tympanic membrane) and an air-filled chamber containing
a chain of three bones (ossicles) that connect the eardrum to the
inner ear (see ). The fluid-filled inner ear (labyrinth)
consists of two major parts: th...
Eardrum
Perforation
Feb 1, 2008
A perforation
is a hole in the eardrum.
Eardrum perforations are often caused by middle
ear infections.
Perforation causes sudden ear pain, sometimes with
bleeding from the ear, hearing loss, or noise in the ear.
Doctors can see the perforation with ...
Barotrauma
Feb 1, 2008
Barotrauma
(barotitis media or aerotitis media) is damage to the middle ear
caused by unequal air pressure on the two sides of the eardrum....
Infectious
Myringitis
Feb 1, 2008
Infectious
myringitis is infection of the eardrum by a virus or bacteria....
Otitis
Media (Acute)
Feb 1, 2008
Acute otitis
media is a bacterial or viral infection of the middle ear....
Otitis
Media (Secretory)
Feb 1, 2008
Secretory
otitis media is an accumulation of fluid in the middle ear.Secretory otitis media occurs
when acute otitis media has not completely resolved or allergies
cause blockage of the eustachian tube.
People may have fullness and some temporary hea...
Otitis
Media (Chronic)
Feb 1, 2008
Chronic otitis
media is a long-standing infection of the middle ear.Chronic otitis media is caused
by a cholesteatoma or by an eardrum perforation that has not healed.
A flare up may occur after an ear infection or after
water enters the middle ear.
...
Mastoiditis
Feb 1, 2008
Mastoiditis
is a bacterial infection in the mastoid process, the prominent bone
behind the ear....
Meniere's
Disease
Feb 1, 2008
Meniere's
disease is a disorder characterized by recurring attacks of disabling
vertigo (a whirling sensation), hearing loss, and noise in the ear
(tinnitus)....
Vestibular
Neuronitis
Feb 1, 2008
Vestibular
neuronitis is a disorder characterized by a sudden severe attack
of vertigo (a whirling sensation), caused by inflammation of the
nerve to the semicircular canals....
Temporal
Bone Fracture
Feb 1, 2008
The temporal
bone (the skull bone containing part of the ear canal, the middle
ear, and the inner ear) can be fractured by a blow to the head....
Auditory
Nerve Tumors
Feb 1, 2008
An auditory
nerve tumor (acoustic neuroma, acoustic neurinoma, vestibular schwannoma, eighth
nerve tumor) is a noncancerous (benign) tumor that originates in
the cells that wrap around the auditory nerve (Schwann cells)....
Tinnitus
Feb 1, 2008
Tinnitus is
noise originating in the ear rather than in the environment.Tinnitus can be a symptom
of ear damage, an ear infection, eustachian tube blockage, or hearing
loss.
People have a ringing or buzzing in the ears, especially
in quiet environmen...
Introduction
Feb 1, 2008
Bone disorders can be caused by injury or cancer,
can be inherited, occur as part of a child's growth, or can occur
for no known reason.
Some bone disorders can cause pain and difficulties
walking, whereas others cause no symptoms.
Doctors base the ...
Scoliosis
Feb 1, 2008
Scoliosis
is abnormal curvature of the spine....
Kyphosis
Feb 1, 2008
Kyphosis
(Scheuermann's disease) is an abnormal curving of the spine that
causes a humpback....
Slipped
Capital Femoral Epiphysis (SCFE)
Feb 1, 2008
Slipped capital
femoral epiphysis is a separation within the thighbone (femur) at
its growth plate in the hip joint....
Legg-Calvé-Perthes
Disease
Feb 1, 2008
Legg-Calvé-Perthes
disease is destruction of the growth plate of the thighbone....
Osgood-Schlatter
Disease
Feb 1, 2008
Osgood-Schlatter
disease is inflammation of the bone and cartilage at the top of
the shinbone (tibia)....
Köhler's
Bone Disease
Feb 1, 2008
Köhler's
bone disease is inflammation of the tarsal navicular bone (a bone
at the arch of the foot)....
Sever's
Disease
Feb 1, 2008
Sever's
disease is inflammation of the heel bone (calcaneus)....
Chondromalacia
Patellae
Feb 1, 2008
Chondromalacia
patellae (patellofemoral syndrome) is softening of the cartilage
under the kneecap (patella)....
Osteopetroses
Feb 1, 2008
The osteopetroses
are a group of rare disorders that increase the density of bones....
Introduction
Feb 1, 2008
Muscles, bones, cartilage,
ligaments, and tendons are built mostly of connective tissue. Connective
tissue is also found in other parts of the body, such as the skin
and internal organs. Connective tissue is strong and thus able to
support weight and...
Cutis
Laxa
Feb 1, 2008
Cutis laxa
is a rare disorder of connective tissue that causes the skin to
stretch easily and hang in loose folds....
Ehlers-Danlos
Syndrome
Feb 1, 2008
Ehlers-Danlos
syndrome is a rare disorder of connective tissue that results in
unusually flexible joints, very elastic skin, and fragile tissues....
Marfan
Syndrome
Feb 1, 2008
Marfan syndrome
is a rare disorder of connective tissue, resulting in abnormalities
of the eyes, bones, heart, blood vessels, and central nervous system....
Osteochondrodysplasias
Feb 1, 2008
The osteochondrodysplasias
are a group of rare disorders of bone or cartilage that cause the skeleton
to develop abnormally....
Osteogenesis
Imperfecta
Feb 1, 2008
Osteogenesis
imperfecta is a group of disorders of bone formation that make the
bones abnormally fragile....
Pseudoxanthoma
Elasticum
Feb 1, 2008
Pseudoxanthoma
elasticum is a disorder of connective tissue that causes abnormalities
in the skin, eyes, and blood vessels....
Heart Failure
Jan 1, 2008
Heart failure
is a disorder in which the heart pumps blood inadequately, leading
to reduced blood flow, back-up (congestion) of blood in the veins
and lungs, and other changes that may further weaken the heart.Many disorders that affect
the heart can...
Introduction
Jan 1, 2008
Cardiomyopathy
refers to progressive impairment of the structure and function of
the muscular walls of the heart chambers.
Types of CardiomyopathyThere are three main types of cardiomyopathy—dilated, hypertrophic, and restrictive.
...
Dilated
Cardiomyopathy
Jan 1, 2008
Dilated (congestive)
cardiomyopathy is a group of heart muscle disorders in which the ventricles
enlarge but are not able to pump enough blood for the body's needs,
resulting in heart failure....
Hypertrophic
Cardiomyopathy
Jan 1, 2008
Hypertrophic
cardiomyopathy includes a group of heart disorders in which the
walls of the ventricles thicken (hypertrophy) and become stiff,
even though the workload of the heart is not increased....
Restrictive Cardiomyopathy
Jan 1, 2008
Restrictive
(infiltrative) cardiomyopathy includes a group of heart disorders
in which the walls of the ventricles become stiff, but not necessarily
thickened, and resist normal filling with blood between heartbeats....
Introduction
Jan 1, 2008
Abnormal heart
rhythms (arrhythmias) are sequences of heartbeats that are irregular,
too fast, too slow, or conducted via an abnormal electrical pathway
through the heart.Heart
disorders are the most common cause of an abnormal heart rhythm.
Sometime...
Atrial
Premature Beats
Jan 1, 2008
An atrial
premature beat (atrial ectopic beat, premature atrial contraction)
is an extra heartbeat caused by electrical activation of the atria
from an abnormal site before a normal heartbeat would occur....
Atrial
Fibrillation and Atrial
Flutter
Jan 1, 2008
Atrial fibrillation
and atrial flutter are very fast electrical discharge patterns that
make the atria contract very rapidly, with some of the electrical
impulses reaching the ventricles and causing them to contract faster
and less efficiently than n...
Paroxysmal
Supraventricular Tachycardia (SVT, PSVT)
Jan 1, 2008
Paroxysmal
supraventricular (atrial) tachycardia is a regular, fast (160 to
220 beats per minute) heart rate that begins and ends suddenly and
originates in heart tissue other than that in the ventricles.Most people have uncomfortable
palpations, sho...
Wolff-Parkinson-White (WPW) Syndrome
Jan 1, 2008
Wolff-Parkinson-White
syndrome is a disorder in which an extra electrical connection between
the atria and the ventricles is present at birth. People may have
episodes of a very rapid heartbeat.
Most people have palpitations, and some feel weak
or sh...
Ventricular
Premature Beats
Jan 1, 2008
A ventricular
premature beat (ventricular ectopic beat, premature ventricular
contraction) is an extra heartbeat resulting from abnormal electrical
activation originating in the ventricles before a normal heartbeat
would occur.The
main symptom is a p...
Ventricular
Tachycardia
Jan 1, 2008
Ventricular
tachycardia is a heart rhythm that originates in the ventricles
and produces a heart rate of at least 120 beats per minute.People almost always have
palpitations.
Electrocardiography (ECG) is used to make the diagnosis.
Drugs and procedur...
Ventricular
Fibrillation
Jan 1, 2008
Ventricular
fibrillation is a potentially fatal, uncoordinated series of very
rapid, ineffective contractions of the ventricles caused by many chaotic
electrical impulses.Ventricular
fibrillation causes unconsciousness in seconds, and if the disorder...
Pacemaker
Dysfunction
Jan 1, 2008
People may have no symptoms, or they may feel weak
or tired or have palpitations.
Electrocardiography (ECG) is used to make the diagnosis.
A permanent artificial pacemaker is usually needed....
Heart
Block
Jan 1, 2008
Heart block
is a delay in the conduction of electrical current as it passes
through the atrioventricular node, bundle of His, or both bundle
branches, all of which are located between the atria and the ventricles.Some types of heart block
cause no sy...
Bundle
Branch Block
Jan 1, 2008
Bundle branch
block is a type of conduction block involving partial or complete
interruption of the flow of electrical impulses through the right
or left bundle branches....
Atherosclerosis
Jan 1, 2008
Atherosclerosis
is a condition in which patchy deposits of fatty material (atheromas
or atherosclerotic plaques) develop in the walls of medium-sized
and large arteries, leading to reduced or blocked blood flow.Atherosclerosis is caused
by repeated i...
Introduction
Jan 1, 2008
Peripheral
arterial disease results in reduced blood flow in the arteries of
the trunk, arms, and legs....
Occlusive
Peripheral Arterial Disease
Jan 1, 2008
Occlusive peripheral arterial disease often results
from atherosclerosis.
Symptoms depend on which artery is blocked and how
severe the blockage is.
To make a diagnosis, doctors measure blood flow
to affected areas.
Drugs, angioplasty, or surgery is...
Functional
Peripheral Arterial Disease
Jan 1, 2008
Functional peripheral
arterial disease is much less common than occlusive peripheral arterial
disease. Normally, the arteries of the arms and legs widen (dilate)
and narrow (constrict) in response to changes in the environment,
such as a change in te...
Introduction
Jan 1, 2008
The aorta, which is about
1 inch (2.5 centimeters) in diameter, is the largest artery of the body.
It receives oxygen-rich blood from the left ventricle and distributes
it to all of the body except the lungs (which receive blood from
the right ventri...
Aneurysms
Jan 1, 2008
An aneurysm
is a bulge (dilation) in the wall of an artery, usually the aorta....
Aortic
Dissection
Jan 1, 2008
An aortic
dissection (dissecting aneurysm, dissecting hematoma) is an often
fatal disorder in which the inner layer (lining) of the aortic wall tears.Most aortic dissections occur
because high blood pressure causes the artery's wall to deteriorate.
P...
Abscess
in the Lungs
Jan 1, 2008
A lung abscess
is a pus-filled cavity in the lung surrounded by inflamed tissue
and caused by an infection.
A lung abscess is usually caused by bacteria that
normally live in the mouth and are inhaled into the lungs.
Symptoms include fatigue, loss of...
Introduction
Jan 1, 2008
Lung (or respiratory)
failure is a condition in which the level of oxygen in the blood becomes
too low or the level of carbon dioxide in the blood becomes too
high. Acute respiratory distress syndrome (ARDS) is a cause of sudden
and severe lung failu...
Respiratory
Failure
Jan 1, 2008
Respiratory
failure (lung failure) is a condition in which the level of oxygen
in the blood becomes dangerously low or the level of carbon dioxide
becomes dangerously high....
Acute
Respiratory Distress Syndrome (ARDS)
Jan 1, 2008
Acute respiratory
distress syndrome is a type of respiratory (lung) failure resulting
from many different disorders that cause fluid to accumulate in
the lungs and oxygen levels in the blood to be too low....
Mechanical Ventilation
Jan 1, 2008
Mechanical
ventilation is use of a machine to aid the movement of air into
and out of the lungs....
Introduction
Jan 1, 2008
Muscular dystrophies are
a group of inherited muscle disorders in which one or more genes
needed for normal muscle function are defective, leading to muscle
weakness (see ) of varying
severity. Other inherited muscle disorders include congenital myop...
Duchenne
and Becker Muscular Dystrophies
Jan 1, 2008
Duchenne muscular
dystrophy and Becker muscular dystrophy cause weakness in the muscles
closest to the torso....
Other Forms of Muscular
Dystrophy
Jan 1, 2008
Several uncommon forms
of muscular dystrophy, all inherited, also cause progressive muscle
weakness....
Congenital
Myopathies
Jan 1, 2008
Congenital
myopathies is a term used to describe a wide variety of inherited
disorders of the muscles, nerves, or both, which are present at
birth or infancy....
Periodic
Paralysis
Jan 1, 2008
Periodic paralysis
is an autosomal dominant inherited disorder (only one affected parent
is needed to pass the trait on to offspring) that causes sudden
attacks of weakness and paralysis. There are several forms....
Introduction
Jan 1, 2008
About half of head injuries result from motor vehicle
crashes; falls, assaults, and mishaps during sports and recreational activities
are also common causes.
People with minor head injuries may have a headache
or dizziness.
People with more severe h...
Cerebral Contusions and
Lacerations
Jan 1, 2008
Cerebral
contusions are bruises on the brain, usually caused by a
direct, strong blow to the head. Cerebral lacerations are
tears in brain tissue, caused by a foreign object or pushed-in bone
fragment from a skull fractures.
Motor vehicle crashes and...
Concussion
Jan 1, 2008
A concussion
is an injury-induced alteration in mental function or level of awareness
that may involve a loss of consciousness, can occur without obvious
damage to brain structures, and lasts less than 6 hours....
Diffuse
Axonal Injury
Jan 1, 2008
Diffuse axonal
injury is widespread injury to axons, a part of the nerve cells
in the brain....
Intracranial
Hematomas
Jan 1, 2008
Intracranial
hematomas are accumulations of blood within the brain or between
the brain and the skull....
Skull
Fracture
Jan 1, 2008
A skull fracture
is a break in a bone surrounding the brain.Skull fracture can occur with
or without brain damage.
Symptoms may include pain, symptoms of brain damage,
and, in certain fractures, fluid leaking from the nose or ears or bruises
behind t...
Paget's
Disease of Bone
Dec 1, 2007
(Osteitis Deformans)...
Introduction
Dec 1, 2007
Malabsorption
syndrome refers to a number of disorders in which nutrients from
food are not absorbed properly in the small intestine....
Lactose
Intolerance
Dec 1, 2007
Lactose intolerance
is the inability to digest the sugar lactose (which is present in
all dairy products) because of a deficiency of the digestive enzyme
lactase, leading to diarrhea and abdominal cramping....
Celiac
Sprue
Dec 1, 2007
Celiac sprue
(nontropical sprue, gluten enteropathy, celiac disease) is a hereditary
intolerance to gluten, a protein found in wheat, barley, and oats,
which causes characteristic changes in the lining of the small intestine,
resulting in malabsorpti...
Tropical
Sprue
Dec 1, 2007
Tropical sprue
is a disorder of unknown cause affecting people living in tropical
and subtropical areas who develop abnormalities of the lining of
the small intestine, leading to malabsorption and deficiencies of
many nutrients....
Whipple's
Disease
Dec 1, 2007
Whipple's
disease (intestinal lipodystrophy) is the result of a rare bacterial
infection that damages the lining of the small intestine and may
involve other organs of the body....
Intestinal
Lymphangiectasia
Dec 1, 2007
Intestinal
lymphangiectasia (idiopathic hypoproteinemia) is a disorder in which
the lymph vessels supplying the lining of the small intestine become
enlarged and obstructed....
Short
Bowel Syndrome
Dec 1, 2007
Short bowel
syndrome is a disorder causing diarrhea and poor absorption of nutrients
(malabsorption), which often occurs after surgical removal of a
large portion of the small intestine....
Bacterial
Overgrowth Syndrome
Dec 1, 2007
Bacterial
overgrowth syndrome is a disorder in which poor movement of intestinal
contents allows certain normal intestinal bacteria to grow excessively,
causing diarrhea and poor absorption of nutrients (malabsorption)....
Introduction
Dec 1, 2007
A variety of abnormal
growths (tumors) can develop throughout the digestive system, from the
esophagus to the anus, as well as in the liver (see ),
gallbladder (see ), and pancreas. Some of these tumors
are noncancerous (benign), whereas others are c...
Esophageal
Tumors That Are Noncancerous
Dec 1, 2007
Noncancerous (benign)
tumors of the esophagus are rare and are usually more bothersome than
harmful....
Esophageal
Cancer
Dec 1, 2007
Esophageal cancers usually develop in the cells
that line the wall of the esophagus (the tube that connects the
throat to the stomach).
Tobacco and alcohol use, certain infections, disorders,
and other cancers are major risk factors for certain type...
Stomach
Tumors That Are Noncancerous
Dec 1, 2007
Noncancerous (benign)
tumors of the stomach are unlikely to cause symptoms or medical
problems, so they often remain undiagnosed and untreated. Occasionally, however,
some bleed and are then removed during endoscopy (in which a flexible
viewing tube ...
Stomach
Cancer
Dec 1, 2007
A Helicobacter pylori infection
seems to be the cause of most stomach cancer.
Vague abdominal discomfort, weight loss, and weakness
are some typical symptoms.
The best diagnostic procedure is an endoscopy.
The survival rate is low because the cancer...
Small
Intestine Tumors That Are Noncancerous
Dec 1, 2007
Most tumors of the small
intestine are noncancerous (benign). These include tumors of fat
cells (lipomas),
nerve cells (neurofibromas), connective
tissue cells (fibromas),
and muscle cells (leiomyomas)....
Small
Intestine Cancer
Dec 1, 2007
Blood in the stool is a common symptom, but sometimes
the cancer blocks the intestine causing crampy abdominal pain, and
vomiting.
The diagnosis is based on various intestinal viewing
techniques, including endoscopy and barium x-rays.
Surgical remov...
Colorectal
Polyps
Dec 1, 2007
Some polyps are caused by hereditary conditions.
Bleeding from the rectum is the most common symptom.
A colonoscopy is performed to make the diagnosis.
Surgical removal is the best form of treatment....
Colorectal
Cancer
Dec 1, 2007
Family history and some dietary factors increase
a person's risk of colorectal cancer.
Typical symptoms include bleeding during a bowel
movement, fatigue, and weakness.
Screening tests are important for people over 50.
Colonoscopy is often used to m...
Anal
Cancer
Dec 1, 2007
Risk factors for anal cancer include certain sexually
transmitted diseases.
Bleeding with bowel movements, pain, and sometimes
itching around the anus are typical symptoms.
A manual examination and a biopsy are performed
to verify the diagnosis.
Tre...
Pancreatic
Cancer
Dec 1, 2007
Smoking, chronic pancreatitis, and possibly long-standing
diabetes are risk factors for pancreatic cancer.
Pain, weight loss, jaundice, and vomiting are some
typical symptoms.
Computed tomography is the most accurate diagnostic
technique.
Pancreatic...
Pancreatic
Endocrine Tumors
Dec 1, 2007
Pancreatic endocrine
tumors are those that arise from the types of pancreatic cells that produce
hormones. These tumors may or may not secrete hormones themselves
and may or may not be cancerous (malignant). Even if they do not
secrete hormones (nonf...
Introduction
Dec 1, 2007
The liver
receives the oxygen and nutrients it needs in blood that comes from
two large blood vessels. The portal vein, provides about two thirds
of the blood. This blood contains oxygen and many nutrients brought
to the liver from the intestine for ...
Ischemic
Hepatitis
Dec 1, 2007
Ischemic
hepatitis is damage throughout the liver caused by an inadequate
blood or oxygen supply....
Ischemic
Cholangiopathy
Dec 1, 2007
Ischemic
cholangiopathy is damage to one or more bile ducts caused by inadequate
blood flow....
Budd-Chiari
Syndrome
Dec 1, 2007
Budd-Chiari
syndrome is caused by blood clots that completely or partially block
the large veins that carry blood from the liver (hepatic veins)
into the inferior vena cava....
Veno-occlusive
Disease of the Liver
Dec 1, 2007
Veno-occlusive
disease of the liver is blockage of the very small (microscopic)
veins in the liver....
Portal
Vein Thrombosis
Dec 1, 2007
Portal vein
obstruction results from thrombosis (blood clot) or narrowing of
the portal vein, which brings blood to the liver from the intestines....
Congestive
Hepatomegaly
Dec 1, 2007
Congestive
hepatomegaly is a backup of blood in the liver, resulting from heart
failure....
Introduction
Dec 1, 2007
The liver produces bile, a greenish yellow, thick,
sticky fluid. Bile aids digestion by making cholesterol, fats, and
fat-soluble vitamins easier to absorb from the intestine. Bile also helps
eliminate certain waste products (mainly bilirubin and exc...
Gallstones
Dec 1, 2007
Gallstones
are collections of solid material (predominantly crystals of cholesterol)
in the gallbladder. ...
Cholecystitis
Dec 1, 2007
Cholecystitis
is inflammation of the gallbladder, usually resulting from a gallstone
blocking the cystic duct....
Tumors
of the Bile Ducts and Gallbladder
Dec 1, 2007
Cancer of the bile ducts or gallbladder is rare.
Ultrasonography can usually detect a tumor in the
bile ducts or gallbladder.
These cancers are usually fatal, but symptoms can
be treated....
Introduction
Dec 1, 2007
The blood flow to the
kidneys needs to be intact for the kidneys to function properly. Any
interruption of or reduction in the blood flow can cause kidney
damage or dysfunction and, if long-standing, increased blood pressure. When
blood flow in the a...
Blockage
of the Renal Arteries
Dec 1, 2007
Gradual narrowing or sudden, complete blockage may
affect arteries that supply the right or the left kidney, their
branches, or a combination.
Kidney failure or high blood pressure may result.
An imaging study can show the narrowing or blockage.
Eli...
Atheroembolic
Kidney Disease
Dec 1, 2007
In atheroembolic
kidney disease, numerous small pieces of fatty material (atheroemboli) travel
from arteries above the kidneys to clog the smallest branches of
the renal arteries, causing the kidneys to fail.Usually atheroemboli occur
as a complicati...
Renal
Cortical Necrosis
Dec 1, 2007
Renal (kidney)
cortical necrosis is death of the tissue in the outer part of kidney
(cortex) that results from blockage of the small arteries that supply
blood to the cortex and that causes acute kidney failure.Usually the cause is a major,
catastrop...
Malignant
Hypertensive Nephrosclerosis
Dec 1, 2007
In malignant
hypertensive nephrosclerosis, severe high blood pressure (malignant
hypertension) damages the smallest arteries in the kidneys, and
kidney failure progresses rapidly....
Renal
Vein Thrombosis
Dec 1, 2007
Renal vein
thrombosis is blockage of the renal vein, which carries blood away
from the kidney, by a blood clot....
Introduction
Dec 1, 2007
Most tumors of the kidney
and urinary tract affect men and women alike and may occur in people
of any age. Most of these tumors are cancerous (malignant)....
Kidney
Cancer
Dec 1, 2007
Kidney cancer may cause blood in the urine, pain
in the side, or fever.
Cancer may be detected by accident when an imaging
test is done for another reason.
Diagnosis is by computed tomography or magnetic
resonance imaging.
If cancer has not spread, ...
Renal
Pelvis and Ureter Cancer
Dec 1, 2007
Cancers may cause blood in the urine or crampy pain
in the side.
Diagnosis is by computed tomography.
Treatment is removal of the kidney and ureter....
Bladder
Cancer
Dec 1, 2007
Bladder cancer most often causes blood in the urine.
To make the diagnosis, a thin, flexible viewing
tube (cystoscope) is inserted through the urethra into the bladder.
Many cancers are treated with removal, using a cystoscope
(for surface cancers) ...
Urethral
Cancer
Dec 1, 2007
Cancer of the urethra
(the channel that carries urine from the bladder out of the body)
is rare, occurring most commonly after age 50. It can occur in men
and women. Certain types of human papillomavirus are implicated
as the cause of cancer of the u...
Refractive
Disorders
Dec 1, 2007
In refractive
disorders, the eye focuses light rays incorrectly on the retina,
causing blurred vision.The
shape of the eye or cornea or age-related stiffness of the lens
may decrease the focusing power of the eye.
Objects may appear blurry when far a...
Introduction
Dec 1, 2007
Children can develop
a variety of digestive disorders. All digestive disorders involve
varying degrees of pain, vomiting, or changes in appetite and bowel
function. The challenge for parents is to provide information that
will help doctors distinguis...
Gastroenteritis
Dec 1, 2007
Gastroenteritis
is inflammation of the digestive tract that results in vomiting,
diarrhea, or both and is sometimes accompanied by fever or abdominal
cramps....
Gastroesophageal Reflux
Dec 1, 2007
Gastroesophageal
reflux is the backward movement of food and acid from the stomach into
the esophagus and sometimes into the mouth (see )....
Peptic
Ulcer
Dec 1, 2007
A peptic
ulcer is erosion of the lining of the stomach or small intestine
(duodenum) due to excess stomach acid, breakdown of the stomach's
protective lining, or both....
Hernia
Dec 1, 2007
A hernia
is a protrusion of a piece of the intestine through an abnormal
opening....
Hypertrophic
Pyloric Stenosis
Dec 1, 2007
Hypertrophic
pyloric stenosis is blockage of the passage out of the stomach due
to overdevelopment (hypertrophy) of the muscle at the junction between
the stomach and the intestines. It occurs in early infancy and causes vomiting
after feeding, which...
Intussusception
Dec 1, 2007
Intussusception
is a disorder in which one segment of the intestine slides into
another, much like the parts of a telescope. The affected segments
obstruct the bowel and block blood flow.The cause of intussusception
is unknown.
Symptoms include sudde...
Appendicitis
Dec 1, 2007
Appendicitis
is inflammation and infection of the appendix.Appendicitis seems to develop
when the appendix becomes blocked either by hard fecal material
(called a fecalith) or swollen lymph nodes in the intestine that
can occur with various infection...
Meckel's
Diverticulum
Dec 1, 2007
Meckel's
diverticulum is a saclike outpouching of the wall of the small intestine
present in some children at birth.
Most children do not have symptoms, but sometimes
painless rectal bleeding occurs or the diverticulum becomes infected.
Doctors base ...
Constipation
Dec 1, 2007
Constipation
refers to delay or difficulty in passing stool or an increase in
the hardness and size of stool.
Constipation is the result of behavior or a lack
of fluids and fiber in the diet.
Hard or large stools can cause abdominal discomfort
and ca...
Chronic
and Recurring Abdominal Pain
Dec 1, 2007
Chronic and
recurring abdominal pain occurs for more than 3 months and interferes
with the child's life.The
cause can be anxiety or other psychologic distress but may be a
physical disorder.
Functional abdominal pain is most commonly vague
and locate...
Introduction
Nov 1, 2007
Drug
administration is the giving of a drug by one of several
means (routes). Drug kinetics (pharmacokinetics) involves
what the body does to a drug, including the processes of absorption,
distribution, metabolism, and elimination, and how long these...
Administration
Nov 1, 2007
Drugs are introduced into
the body by several routes. They may be taken by mouth (orally);
given by injection into a vein (intravenously), into a muscle (intramuscularly),
into the space around the spinal cord (intrathecally), or beneath
the skin (su...
Absorption
Nov 1, 2007
Drug absorption
is the movement of a drug into the bloodstream....
Distribution
Nov 1, 2007
Drug distribution
refers to the movement of drug to and from the blood and various
tissues of the body (for example, fat, muscle, and brain tissue)
and the relative proportions of drug in the tissues....
Metabolism
Nov 1, 2007
Drug metabolism
is the chemical alteration of a drug by the body....
Elimination
Nov 1, 2007
Drug elimination
is the removal of drugs from the body....
Introduction
Nov 1, 2007
Drug dynamics
(pharmacodynamics) involves what a drug does to the body....
Site
Selectivity
Nov 1, 2007
After being swallowed,
injected, inhaled, or absorbed through the skin, most drugs enter the
bloodstream and circulate throughout the body. Some drugs are administered
directly to the area where they are wanted—for example, to the eyes
in eyedrops. T...
Drug
Action
Nov 1, 2007
Drugs affect only the rate
at which existing biologic functions proceed. Drugs do not change
the basic nature of these functions or create new functions. For
example, drugs can speed up or slow down the biochemical reactions
that cause muscles to con...
Sleep Apnea
Nov 1, 2007
Sleep
apnea is a serious disorder in which breathing repeatedly stops
long enough to disrupt sleep and temporarily decrease the amount
of oxygen and increase the amount of carbon dioxide in the blood.People with sleep apnea often
are very sleepy duri...
Introduction
Nov 1, 2007
The nervous system has two
distinct parts: the central nervous system (the brain and spinal
cord) and the peripheral nervous system (the nerves outside the
brain and spinal cord)....
Brain
Nov 1, 2007
The brain's functions are
both mysterious and remarkable. All thoughts, beliefs, memories,
behaviors, and moods arise within the brain. The brain is the site
of thinking and the control center for the rest of the body. The brain
coordinates the abili...
Spinal
Cord
Nov 1, 2007
The spinal cord is a long,
fragile tubelike structure that begins at the end of the brain stem
and continues down almost to the bottom of the spine (spinal column).
The spinal cord consists of nerves that carry incoming and outgoing
messages between ...
Nerves
Nov 1, 2007
The peripheral nervous
system consists of more than 100 billion nerve cells that run throughout
the body like strings, making connections with the brain, other
parts of the body, and often with each other. Peripheral nerves
consist of bundles of nerv...
Effects
of Aging
Nov 1, 2007
...
Introduction
Nov 1, 2007
A stroke occurs
when an artery to the brain becomes blocked or ruptures, resulting
in death of an area of brain tissue (cerebral infarction) and causing
sudden symptoms....
Transient
Ischemic Attacks
Nov 1, 2007
A transient
ischemic attack (TIA) is a disturbance in brain function that lasts
less than 1 hour and results from a temporary blockage of the brain's
blood supply....
Ischemic
Stroke
Nov 1, 2007
An ischemic
stroke is death of an area of brain tissue (cerebral infarction)
resulting from an inadequate supply of blood and oxygen to the brain
due to blockage of an artery....
Hemorrhagic
Stroke
Nov 1, 2007
Hemorrhagic
strokes include bleeding within the brain (intracerebral hemorrhage)
and bleeding between the inner and outer layers of the tissue covering
the brain (subarachnoid hemorrhage)....
Introduction
Nov 1, 2007
Sexuality is a normal
part of human experience. However, the types of sexual behavior that
are considered normal vary greatly within and among different cultures.
In fact, defining “normal” sexuality may be impossible. There are
wide variations in pe...
Gender
Identity
Nov 1, 2007
Gender identity is how
people see themselves, whether masculine, feminine, or somewhere
in-between. Gender role is how people present themselves in public
in terms of gender. It includes the way people dress, speak, wear
their hair, in fact everythin...
Paraphilias
Nov 1, 2007
Paraphilias
are frequent, intense, sexually arousing fantasies or behaviors
that involve inanimate objects, children or nonconsenting adults,
or suffering or humiliation of oneself or the partner....
Introduction
Nov 1, 2007
Diverticular
disease is characterized by small, balloon-like sacs (diverticula)
protruding through the muscular layer of the gastrointestinal (digestive)
tract....
Diverticulosis
Nov 1, 2007
Diverticulosis
is the presence of multiple balloon-like sacs (diverticula), usually
in the large intestine....
Diverticulitis
Nov 1, 2007
Diverticulitis
is inflammation or infection of one or more balloon-like sacs (diverticula)....
Dialysis
Nov 1, 2007
Dialysis
is an artificial process for removing waste products and excess
fluids from the body, a process that is needed when the kidneys
are not functioning properly....
Introduction
Nov 1, 2007
The body has two adrenal
glands, one near the top of each kidney. The inner part (medulla)
of the adrenal glands secretes hormones, such as adrenaline (epinephrine),
that help control blood pressure, heart rate, sweating, and other
activities also re...
Addison's
Disease
Nov 1, 2007
In Addison's
disease, the adrenal glands are underactive, resulting in a deficiency
of adrenal hormones.Addison's
disease may be caused by an autoimmune reaction, cancer, an infection,
or some other disease.
A person with Addison's disease feels weak...
Cushing's
Syndrome
Nov 1, 2007
In Cushing's
syndrome, the level of corticosteroids is excessive, usually from
overproduction by the adrenal glands.Cushing's syndrome usually
results from a tumor that causes the adrenal glands to produce excessive
corticosteroids.
People with Cushi...
Virilization
Nov 1, 2007
Virilization
is the development of exaggerated masculine characteristics, usually
in women, often as a result of the adrenal glands overproducing
androgens (testosterone and similar hormones).Virilization is caused by
excess production of androgens u...
Hyperaldosteronism
Nov 1, 2007
In hyperaldosteronism,
overproduction of aldosterone leads to fluid retention and increased
blood pressure, weakness, and, rarely, periods of paralysis.Hyperaldosteronism can be
caused by a tumor in the adrenal gland or may be a response to some
dise...
Pheochromocytoma
Nov 1, 2007
A pheochromocytoma
is a tumor that usually originates from the adrenal glands' chromaffin cells,
causing overproduction of catecholamines, powerful hormones that
induce high blood pressure and other symptoms.High blood pressure is the
most important ...
Introduction
Nov 1, 2007
Rickettsial
infections and related infections (such as ehrlichiosis and Q fever)
are caused by an unusual type of bacteria that can live only in
another organism.Most
of these infections are spread through ticks, mites, fleas, or lice.
A fever, a sev...
Rocky
Mountain Spotted Fever
Nov 1, 2007
Rocky Mountain
spotted fever (spotted fever, tick fever, tick typhus) is a rickettsial
infection that is transmitted by dog ticks and wood ticks. It causes
a rash, headache, and high fever.
People become infected when a tick carrying the
infection bi...
Ehrlichioses
Nov 1, 2007
Ehrlichioses
are tick-borne infections that cause fever, chills, headache, and
a general feeling of illness (malaise). These symptoms begin suddenly....
Introduction
Nov 1, 2007
The eyelids play a key
role in protecting the eyes. They sweep away debris when the eyes close
and help spread moisture (tears) over the surface of the eyes when
they open. The eyelids provide a mechanical barrier against injury
by closing rapidly wh...
Blepharitis
Nov 1, 2007
Blepharitis
is inflammation of the edges of the eyelids, possibly with thickening
scales, crusts, shallow ulcers, or redness and swelling at the edges
of the eyelids....
Canaliculitis
Nov 1, 2007
Canaliculitis
is infection of the lacrimal canaliculus, also called the lacrimal
duct (see )....
Chalazion
Nov 1, 2007
A chalazion
is an enlargement of an oil gland deep in the eyelid caused by an
obstruction of the gland's opening....
Dacryocystitis
Nov 1, 2007
Dacryocystitis
is infection of the lacrimal sac....
Dacryostenosis
Nov 1, 2007
Dacryostenosis
(nasolacrimal duct obstruction) is narrowing of the nasolacrimal
duct, which drains tears away from the eye....
Entropion
and Ectropion
Nov 1, 2007
Entropion is
a condition in which the eyelid is turned inward (inverted), causing
the eyelashes to rub against the eyeball. Ectropion is
a condition in which the eyelid is turned outward (everted) so that
its edge does not touch the eyeball....
Eyelid
Tumors
Nov 1, 2007
Noncancerous (benign)
and cancerous (malignant) growths can form on the eyelids. One of
the most common types of benign tumor is xanthelasma, a yellow-white, flat growth
that consists of fatty material. Because xanthelasmas may indicate
elevated chol...
Stye (Hordeolum)
Nov 1, 2007
A stye (hordeolum)
is a rapidly developing infection of one or more of the tiny glands
at the edge of the eyelid or underneath the eyelid that sometimes
develops a small abscess....
Trichiasis
Nov 1, 2007
Trichiasis
is misalignment of eyelashes, which rub against the eyeball, in
a person who does not have entropion....
Introduction
Nov 1, 2007
Pregnancy begins when
an egg is fertilized by a sperm. For about 9 months, a pregnant woman's
body provides a protective, nourishing environment in which the
fertilized egg can develop into a fetus. Pregnancy ends at delivery,
when a baby is born....
Detecting
and Dating a Pregnancy
Nov 1, 2007
If a menstrual period
is a week or more late in a woman who usually has regular menstrual
periods, she may be pregnant. Sometimes a woman may guess she is
pregnant because she has typical symptoms. They include the following:Enlarged and tender breas...
Stages of Development
Nov 1, 2007
A baby goes through several
stages of development, beginning as a fertilized egg. The egg develops
into a blastocyst, an embryo, then a fetus....
Physical
Changes
Nov 1, 2007
Pregnancy causes many
changes in a woman's body. Most of them disappear after delivery.
These changes cause some symptoms, which are normal. However, certain
disorders, such as gestational diabetes (see ), develop
during pregnancy, and some symptoms ...
Medical
Care
Nov 1, 2007
Ideally, a couple who
is thinking of having a baby should see a doctor or other health
care practitioner to discuss whether pregnancy is advisable. Usually,
pregnancy is very safe. However, some disorders can become severe during
pregnancy. Also, for...
Self-Care
Nov 1, 2007
There is much a pregnant
woman can do to take care of herself during pregnancy. If she has
any questions about diet, the use of drugs or nutritional supplements,
physical activity, and sexual intercourse during pregnancy, she can
talk with her doctor...
Introduction
Oct 1, 2007
A century ago, most people
who suffered major injuries or contracted serious infections died
soon afterward. Most people expected little more than comfort measures
from doctors. Today, because medical procedures commonly extend
the lives of people wh...
Time
Course of Dying
Oct 1, 2007
A prognosis is a prediction
of the probable course and outcome of a disease or the likelihood
of recovery from a disease. People often think that the doctor knows
and can predict how long an ill person will live but is withholding
this information fr...
Choices
to Make Before Death
Oct 1, 2007
Sick people and their
families may feel swept along by the fatal illness and the various treatments,
as if they have no control over the events. Some people seem to
prefer this sense of having no control because it relieves them of
the responsibility...
Treatment
Options
Oct 1, 2007
...
Hospice
Care
Oct 1, 2007
Hospice programs focus on symptom relief, comfort
care, and emotional support for the patient and family.
Hospice programs do not emphasize diagnostic testing
and prolonging life....
Symptoms
During a Fatal Illness
Oct 1, 2007
Many fatal illnesses cause
similar symptoms, including pain, shortness of breath, digestive
problems, incontinence, skin breakdown, and fatigue. Depression,
anxiety, confusion, unconsciousness, and disability may also occur....
Financial
Concerns
Oct 1, 2007
Medicare does not pay
for some services dying people need, such as long-term care in nursing
homes or home health aides at home. Services provided by a hospice
program are the exception in that they are usually quite comprehensive.
However, hospice p...
Legal
and Ethical Concerns
Oct 1, 2007
Advance directives instruct family members and health
care practitioners about a person's decisions for medical care,
if the person is unable to make such decisions when they are needed.
The Death with Dignity Act in Oregon allows “terminally
ill” c...
Acceptance
Oct 1, 2007
Dying people and their family members can often
achieve a deep sense of peace by mending relationships.
Grieving often progresses through these five emotional
stages: denial, anger, bargaining, depression, and acceptance....
When Death Is Near
Oct 1, 2007
At some point, deciding
not to undergo cardiopulmonary resuscitation (CPR—an emergency procedure
that restores heart and lung function) is appropriate for virtually
all people who are dying and who can accept death. Dying people,
families, and the ca...
When
Death Occurs
Oct 1, 2007
Death must be pronounced
in an official and timely way by an authorized person (such as a doctor
or nurse), and the cause and circumstances of death must be certified.
Fulfilling these requirements varies substantially in different
parts of the Unite...
Introduction
Oct 1, 2007
The law has a lot to say
about personal decision-making. For example, people have the legal
right to make their own health care decisions. However, poor health
can jeopardize people's ability to defend their legal rights. Safeguarding
these rights re...
Capacity
to Make Health Care Decisions
Oct 1, 2007
The law recognizes that
adults—in most states, people over age 18—have the right to manage
their own affairs and conduct business, including the right to make
health care decisions. Emancipated minors are people below the age
of adulthood (usually 18...
Informed
Consent
Oct 1, 2007
Before performing any
invasive tests or providing medical treatment, doctors must obtain permission
from the patient in a manner that is informed, voluntary, and competent.
The process is known as informed consent. Patients have the right
to informat...
Confidentiality
and HIPAA
Oct 1, 2007
Health care practitioners
have a duty to keep personal medical information confidential. Communication
between the patient and doctor is strictly confidential. Even well-meaning
family members are not necessarily allowed to have information about
a p...
Advance
Directives
Oct 1, 2007
Health care advance directives
are documents that communicate a person's wishes about health care
decisions in the event the person becomes incapable of making health care
decisions. There are two basic kinds of advance directives: living
wills and d...
Surrogate
Decision Making
Oct 1, 2007
If a person is unable
to make decisions about personal health care, some other person
or persons must provide direction in decision making. Such a person
is called the surrogate decision-maker. If there is a durable power
of attorney for health care,...
Do-Not-Resuscitate (DNR) Orders
Oct 1, 2007
A do-not-resuscitate (DNR)
order placed in a person's medical record by a doctor informs the
medical staff that cardiopulmonary resuscitation (CPR—see ) should not
be performed. This order has been useful in preventing unnecessary
and unwanted invasi...
Medical
Malpractice
Oct 1, 2007
People can sue health
care practitioners if they feel they have been injured. A wide variety
of causes of action and legal proceedings may be involved. However,
successful medical malpractice lawsuits generally require proof
of all of the following:...
Introduction
Oct 1, 2007
A neurologic examination
can detect disorders of the brain, spinal cord, and nerves in other
parts of the body (peripheral nerves, which include motor and sensory
nerves). This examination can also help detect muscle disorders
because muscle contract...
History
Oct 1, 2007
Before doing a physical
examination, doctors interview the person. Doctors ask the person
to describe current symptoms:What
they are like precisely
Where and how often they occur
How severe they are
How long they last
What makes symptoms worse
What m...
Physical
Examination
Oct 1, 2007
When a neurologic disorder
is suspected, doctors usually evaluate all of the body systems during
the physical examination, but they focus on the nervous system.
They do a neurologic examination, which includes evaluation of mental
status, cranial ner...
Procedures
Oct 1, 2007
Diagnostic procedures may
be needed to confirm a diagnosis suggested by the medical history
and physical examination. Imaging tests such as computed tomography
(CT), magnetic resonance imaging (MRI), angiography, positron emission
tomography (PET), a...
Introduction
Oct 1, 2007
Dizziness is a vague term
used to describe various sensations, including faintness, light-headedness,
a loss of balance, a sense of spinning, a vague spaced-out feeling,
and weakness. Vertigo is a specific type of dizziness. In vertigo,
people feel a...
Dizziness
Oct 1, 2007
Dizziness may result from a disorder that affects
any of the many body parts involved in balance (such as the inner
ear and eyes) or from certain drugs.
The person's description of the problem and the
results of a physical examination may suggest a ...
Vertigo
Oct 1, 2007
Vertigo is
a false sensation that the self, the surroundings, or both are moving
or spinning, usually accompanied by nausea and loss of balance.Vertigo results from disorders
that affect the inner ear or parts of the brain involved in balance.
In add...
Motion
Sickness
Oct 1, 2007
Motion sickness
(also known as car, sea, train, or air sickness) involves a group
of symptoms, particularly nausea, caused by movement during travel....
Benign
Paroxysmal Positional Vertigo (Benign Positional Vertigo)
Oct 1, 2007
Benign paroxysmal
positional vertigo, or BPPV, is a common disorder causing short
episodes of vertigo in response to changes in head position that
stimulate the posterior semicircular canal of the inner ear....
Introduction
Oct 1, 2007
The esophagus is the
hollow tube that leads from the throat (pharynx) to the stomach.
The walls of the esophagus propel food to the stomach not by gravity,
but by rhythmic waves of muscular contractions called peristalsis.
How the Esophagus W...
Abnormal
Propulsion of Food
Oct 1, 2007
The movement of food from
mouth to stomach requires normal and coordinated action of the mouth
and throat, propulsive waves of the esophagus, and relaxation of
the sphincters. A problem with any of these functions can cause difficulty
swallowing (dys...
Infection
Oct 1, 2007
Infection
of the esophagus occurs mainly in people who have impaired host
defenses. The main causes are Candida albicans,
herpes simplex virus infections, and cytomegalovirus infection....
Injury
Oct 1, 2007
The esophagus is relatively
impervious to injury but can be harmed gradually by backflow of
acid from the stomach (gastroesophageal reflux or GERD—see ). The esophagus
may also be harmed suddenly, by caustic or acidic chemicals, irritating
drugs, a s...
Obstruction
Oct 1, 2007
The esophagus can be narrowed
or completely blocked. In rare cases, the cause is hereditary (for
example, congenital rings). In most cases, the cause is progression
of an injury to the esophagus or tumor growth. Food and foreign
bodies may obstruct t...
Introduction
Oct 1, 2007
The anus is the opening
at the end of the digestive tract where stool leaves the body. The rectum
is the section of the digestive tract above the anus where stool
is held before it passes out of the body through the anus....
Anal
Fissure
Oct 1, 2007
An anal fissure
is a tear or ulcer in the lining of the anus....
Anal
Itching
Oct 1, 2007
Itchy skin around the
anus (pruritus ani) can have many causes.
Causes of Anal Itching
Category
Examples
Disorders
Anal disorders
Bowen's disease
Fistulas that drain
Inflammation of a follicle in the rectum (cryptiti...
Anorectal
Abscess
Oct 1, 2007
An anorectal
abscess is a pus-filled cavity caused by bacteria invading a mucus-secreting
gland in the anus and rectum....
Anorectal
Fistula
Oct 1, 2007
An anorectal
fistula is an abnormal channel that leads from the anus or rectum
usually to the skin near the anus but occasionally to another organ,
such as the vagina.Anorectal
fistulas are common among people who have an anorectal abscess, Crohn's
d...
Foreign
Objects
Oct 1, 2007
Swallowed objects, such
as toothpicks, chicken bones, or fish bones, may become lodged at
the junction between the anus and rectum (anorectal junction—see ). Also,
enema tips, surgical sponges or instruments, thermometers, and objects
used for sexual...
Hemorrhoids
Oct 1, 2007
Hemorrhoids
are dilated, twisted (varicose) veins located in the wall of the
rectum and anus.The
swollen veins are caused by an increase in pressure.
Lumps form inside or outside of the anus, which
can cause pain or bleeding.
The diagnosis is based o...
Levator
Syndrome
Oct 1, 2007
Levator syndrome
is sporadic pain in the rectum caused by spasm of a muscle near
the anus (the levator ani muscle)....
Pilonidal
Disease
Oct 1, 2007
Pilonidal
disease is an infection caused by a hair that injures the skin at
the top of the cleft between the buttocks....
Proctitis
Oct 1, 2007
Proctitis
is inflammation of the lining of the rectum (rectal mucosa).The inflammation has many
causes ranging from infection to radiation therapy.
Depending on its cause, proctitis can be painless
or very painful.
A doctor makes the diagnosis after ...
Rectal
Prolapse
Oct 1, 2007
Rectal prolapse
is a painless protrusion of the rectum through the anus.A rectal prolapse is often
caused while straining, such as during a bowel movement.
The diagnosis is based on an examination and various
viewing and imaging tests.
Rectal prolaps...
Introduction
Oct 1, 2007
Kidney (renal)
failure is the inability of the kidneys to adequately filter metabolic
waste products from the blood....
Acute
Kidney Failure
Oct 1, 2007
Acute kidney
failure is a rapid (days to weeks) decline in the kidneys' ability
to filter metabolic waste products from the blood.Causes include disorders that
decrease blood flow to the kidneys, that damage the kidneys themselves,
or that block drai...
Chronic
Kidney Failure
Oct 1, 2007
Chronic kidney
failure (also called chronic kidney disease) is a slowly progressive (months
to years) decline in the kidneys' ability to filter metabolic waste
from the blood.Major
causes are diabetes and high blood pressure.
Blood becomes more acidi...
Introduction
Oct 1, 2007
Urinary incontinence
is the uncontrollable loss of urine....
Incontinence
in Children
Oct 1, 2007
The pattern of incontinence helps the doctor determine
the likely cause.
The child's history and results of a physical examination,
laboratory tests, and imaging tests help the doctor determine the specific cause.
Treatment includes behavioral chang...
Introduction
Oct 1, 2007
Sweat is made by sweat
glands in the skin and carried to the skin's surface by ducts. Sweating
helps keep the body cool. Thus, people sweat more when it is warm.
They also sweat when they are nervous, under stress, or exercising....
Prickly
Heat
Oct 1, 2007
Prickly heat
(miliaria) is an itchy skin rash caused by trapped sweat....
Excessive
Sweating
Oct 1, 2007
People with excessive
sweating (hyperhidrosis) sweat profusely, and some sweat almost constantly.
Although people with a fever or those exposed to very warm environments sweat,
people with excessive sweating tend to sweat even without these
circumsta...
Diminished
Sweating
Oct 1, 2007
Some people sweat too
little (a condition called hypohidrosis). Diminished sweating is usually
limited to a specific area of the body. It can be caused by a skin
injury (such as from trauma, radiation, infection [such as leprosy], or
inflammation) or...
Introduction
Oct 1, 2007
The skin provides a remarkably
good barrier against bacterial infections. Although many bacteria
come in contact with or reside on the skin, they are normally unable
to establish an infection. When bacterial skin infections do occur,
they can range i...
Cellulitis
Oct 1, 2007
Cellulitis
is a spreading bacterial infection of the skin and the tissues immediately
beneath the skin....
Erysipelas
Oct 1, 2007
Erysipelas
is a superficial form of cellulitis typically caused by streptococci....
Erythrasma
Oct 1, 2007
Erythrasma
is infection of the top layers of the skin caused by the bacterium Corynebacterium
minutissimum....
Folliculitis
and Skin Abscesses
Oct 1, 2007
Folliculitis
and skin abscesses are pus-filled pockets in the skin resulting
from bacterial infection. They may be superficial or deep, affecting
just hair follicules or deeper structures within the skin....
Hidradenitis
Suppurativa
Oct 1, 2007
Hidradenitis
suppurativa is inflammation of the apocrine sweat glands, resulting
in painful accumulations of pus under the skin....
Impetigo
Oct 1, 2007
Impetigo is
a skin infection, caused by Staphylococcus aureus, Streptococcus
pyogenes, or both, that leads to the formation of
scabby, yellow-crusted sores and, sometimes, small blisters filled
with yellow fluid....
Lymphadenitis
Oct 1, 2007
Lymphadenitis
is inflammation of one or more lymph nodes, which usually become
swollen and tender....
Lymphangitis
Oct 1, 2007
Lymphangitis
is inflammation of one or more lymphatic vessels, usually caused
by a streptococcal infection....
Necrotizing
Skin Infections
Oct 1, 2007
Necrotizing
skin infections, including necrotizing cellulitis and necrotizing
fasciitis, are severe forms of cellulitis characterized by death
of infected tissue (necrosis)....
Staphylococcal
Scalded Skin Syndrome
Oct 1, 2007
Staphylococcal
scalded skin syndrome is a reaction to a staphylococcal skin infection
in which the skin blisters and peels off as though burned....
Introduction
Sep 1, 2007
Traditional medical care
focuses on improving health by identifying and treating health problems
that have already produced symptoms or complications. In contrast,
preventive medical care focuses on preventing health problems from
occurring. Preventi...
Tools of Prevention
Sep 1, 2007
Prevention includes four
major tools. One tool is establishing a healthful lifestyle, which includes
habits such as wearing a seat belt, eating a healthy diet, getting
enough physical exercise, wearing sunscreen, and not smoking. Another
tool is gett...
Prevention
in Pregnant Women
Sep 1, 2007
Prenatal care is focused
on recognizing and preventing problems that can complicate pregnancy
(see ).
For example, pregnant women are screened for high blood pressure, diabetes,
sexually transmitted diseases, RhO(D) blood
incompatibility (which can c...
Prevention
in Older Adults
Sep 1, 2007
The goals of prevention
in an older adult usually depend on the person's health, level of function,
and risk profile. For example, a healthy, independent person with
no serious disorders may focus mainly on preventing disorders from
developing. A per...
Introduction
Sep 1, 2007
Exercise is physical activity
done regularly to improve, maintain, or slow the loss of fitness.
Physical fitness is the capacity to perform physical activities
with vigor and alertness and without undue fatigue. Fit people have
more energy to pursue ...
Benefits
of Exercise
Sep 1, 2007
Regular exercise makes
the heart stronger and the lungs fitter, enabling the cardiovascular
system to deliver more oxygen to the body with every heartbeat and
the pulmonary system to increase the maximum amount of oxygen that
the lungs can take in. E...
Starting an Exercise
Program
Sep 1, 2007
People should consult
their doctors before beginning competitive sports or an exercise program.
Doctors ask about known medical disorders in the person and family
members and symptoms the person has. They do a physical examination,
including listenin...
Exercising
Safely
Sep 1, 2007
Exercising without proper
safety precautions often leads to injury. Scheduling workouts 48
hours apart, to allow muscles to recover, and keeping workouts varied
in regard to exercise method and equipment choices may help prevent
muscle overuse and re...
Choosing
the Right Exercise
Sep 1, 2007
There are many forms of
exercise, and each type has its advantages and disadvantages. Some
people prefer to exercise in a gym or at home, whereas others prefer
to exercise outdoors. Some people have a very structured exercise
routine, whereas others ...
Introduction
Sep 1, 2007
Gastroenteritis
is inflammation of the lining of the stomach and small and large
intestines. It is usually caused by infection with a microorganism
but can also be caused by ingestion of chemical toxins or drugs.The infection is usually caused
by an ...
Hemorrhagic
Colitis
Sep 1, 2007
Hemorrhagic
colitis is a type of gastroenteritis in which certain strains of
the bacterium Escherichia coli (E. coli) infect
the large intestine and produce a toxin (Shiga toxin) that causes bloody
diarrhea and other serious complications....
Staphylococcal
Food Poisoning
Sep 1, 2007
Staphylococcal
food poisoning results from eating food contaminated with toxins
produced by certain types of staphylococci, resulting in diarrhea
and vomiting....
Clostridium
perfringens Food Poisoning
Sep 1, 2007
Clostridium
perfringens food poisoning results from eating food
contaminated by the bacterium Clostridium perfringens. Once
in the small intestine, the bacterium releases a toxin that often
causes diarrhea....
Traveler's
Diarrhea
Sep 1, 2007
Traveler's
diarrhea (turista) is characterized by diarrhea, nausea, and vomiting
that commonly occur in travelers to areas of the world with poor
water purification....
Chemical Food
Poisoning
Sep 1, 2007
Chemical food
poisoning results from eating a plant or animal that contains a
toxin.The poisoning
occurs after ingesting poisonous species of mushrooms or plants
or contaminated fish or shellfish.
The most common symptoms are diarrhea, nausea, and
vo...
Introduction
Sep 1, 2007
Certain gastrointestinal
disorders can be life threatening and require emergency treatment—surgery,
in many cases....
Abdominal
Abscesses
Sep 1, 2007
An abscess
is a pocket of pus, usually caused by a bacterial infection....
Abdominal
Wall Hernias
Sep 1, 2007
An abdominal
wall hernia is a protrusion of the intestine through an opening
or area of weakness in the abdominal wall....
Acute
Mesenteric Ischemia
Sep 1, 2007
Acute mesenteric
ischemia is sudden blockage of blood flow to part of the intestines,
which may lead to gangrene and perforation (puncture)....
Appendicitis
Sep 1, 2007
Appendicitis
is inflammation and infection of the appendix....
Ileus
Sep 1, 2007
Ileus (paralytic
ileus, adynamic ileus) is temporary absence of the normal contractile movements
of the intestinal wall....
Intestinal
Obstruction
Sep 1, 2007
An obstruction
of the intestine is a blockage that completely stops or seriously
impairs the passage of intestinal contents....
Ischemic
Colitis
Sep 1, 2007
Ischemic
colitis is injury of the large intestine that results from an interruption
of its blood supply....
Perforation
Sep 1, 2007
Any of the
hollow digestive organs may become perforated (punctured), which
causes a release of gastrointestinal contents and leads to shock
and death if surgery is not performed immediately....
Introduction
Sep 1, 2007
Most liver diseases, including
fatty liver, cirrhosis, primary biliary cirrhosis and primary sclerosing
cholangitis, result from injury to the liver. If damage is acute
(sudden) and limited, the liver commonly repairs itself by regenerating
new liver...
Fatty
Liver
Sep 1, 2007
Fatty liver
(steatosis) is an abnormal accumulation of certain fats (triglycerides)
inside liver cells....
Cirrhosis
Sep 1, 2007
Cirrhosis
is the irreversible replacement of a large amount of normal liver
tissue with nonfunctioning scar tissue. It develops because the
liver is damaged. Attempts at regenerating new liver cells are not
effective....
Primary
Biliary Cirrhosis
Sep 1, 2007
Primary biliary
cirrhosis is inflammation with progressive scarring of the bile
ducts in the liver. Eventually, the ducts are blocked, the liver becomes
scarred, and liver failure develops....
Primary
Sclerosing Cholangitis
Sep 1, 2007
Primary sclerosing
cholangitis is inflammation with progressive scarring and narrowing of
the bile ducts in and outside the liver. Eventually, the ducts become
blocked and then obliterated. Cirrhosis, liver failure, and sometimes
bile duct cancer dev...
Introduction
Sep 1, 2007
Liver tumors may be noncancerous
(benign) or cancerous (malignant). Cancerous liver tumors are classified
as primary (originating in the liver) or metastatic (spreading from
elsewhere in the body). Most liver cancers are metastatic. Cancers
often spr...
Hemangioma
Sep 1, 2007
A hemangioma
is a noncancerous liver tumor composed of a mass of abnormal blood
vessels....
Hepatocellular
Adenoma
Sep 1, 2007
A hepatocellular
adenoma is a relatively uncommon noncancerous liver tumor that may be
mistaken for cancer. Rarely, it ruptures and bleeds or becomes cancerous....
Hepatic
Granulomas
Sep 1, 2007
Hepatic granulomas
are abnormal small clumps of cells that form when certain disorders
are present....
Primary Liver Cancers
Sep 1, 2007
Primary liver cancers
are cancers that originate in the liver. The most common is a hepatoma
(hepatocellular carcinoma). At first, liver cancer usually causes
only vague symptoms (such as weight loss, loss of appetite, and fatigue).
As a result, the ...
Metastatic
Liver Cancer
Sep 1, 2007
Metastatic
liver cancer is a cancer that has spread to the liver from elsewhere
in the body.Weight
loss and a poor appetite may be the first symptoms.
Doctors base the diagnosis on results of blood tests
and usually biopsy.
Chemotherapy drugs and rad...
Introduction
Sep 1, 2007
In healthy people, urine
in the bladder is sterile—no bacteria or other infectious organisms
are present. The tube that carries urine from the bladder out of
the body (urethra) contains no bacteria or too few to cause an infection.
However, any part ...
Urethritis
Sep 1, 2007
Urethritis
is infection of the urethra, the tube that carries urine from the
bladder out of the body....
Bladder
Infection (Cystitis)
Sep 1, 2007
Cystitis is
infection of the bladder....
Kidney
Infection (Pyelonephritis)
Sep 1, 2007
Pyelonephritis
is a bacterial infection of one or both kidneys....
Asymptomatic Bacteriuria
Sep 1, 2007
Asymptomatic
bacteriuria is a condition in which larger than normal numbers of
bacteria are present in the urine but symptoms do not result....
Introduction
Sep 1, 2007
In men, sexual dysfunction
refers to difficulties engaging in sexual intercourse. Sexual dysfunction
encompasses a variety of disorders that affect sex drive (libido),
the ability to achieve or maintain an erection (erectile dysfunction,
or impotence...
Decreased
Libido
Sep 1, 2007
Decreased
libido is a reduction in sex drive....
Erectile
Dysfunction (ED)
Sep 1, 2007
Erectile
dysfunction (impotence) is the inability to achieve or maintain
an erection adequate for penetration....
Inability
to Ejaculate
Sep 1, 2007
Inability to ejaculate
(anejaculation) is usually caused by inability to reach orgasm.
It usually occurs as part of erectile dysfunction. Causes, diagnosis,
and treatment are the same as for erectile dysfunction (see ). Retrograde
ejaculation can som...
Premature
Ejaculation
Sep 1, 2007
Premature
ejaculation is ejaculation that occurs too early, usually before,
upon, or shortly after penetration....
Retrograde
Ejaculation
Sep 1, 2007
Retrograde
ejaculation is a condition in which semen is ejaculated backward
into the bladder rather than out through the penis....
Introduction
Sep 1, 2007
Violence against women
is broadly defined as any act that is likely to cause physical,
sexual, or psychologic harm or extreme suffering to a woman. Violence
can occur in the home, workplace, or community. Two common forms
of violence against women ar...
Domestic
Violence
Sep 1, 2007
Domestic violence includes physical, sexual, and
psychologic abuse between intimate partners.
The victim is usually a woman.
Physical injuries, psychologic problems, social
isolation, loss of a job, financial difficulties, and even death
can result....
Rape
Sep 1, 2007
Rape refers to unwanted
penetration of the vagina, anus, or mouth.
Victims may have tears in the vagina, cuts and bruises,
upsetting emotions, and difficulty sleeping.
Sexual transmitted diseases, including HIV (human
immunodeficiency virus) infectio...
Introduction
Aug 1, 2007
A person's genetic makeup
is a complete set of instructions on how the body is “supposed” to
be built. The body's genetic material consists of genes, made up
of coils of deoxyribonucleic acid (DNA). Genes are contained in chromosomes,
which are mainl...
Chromosomes
and Genes
Aug 1, 2007
A gene is a segment of DNA containing the code used
to synthesize a protein.
A chromosome contains hundreds to thousands of genes.
Every human cell contains 23 pairs of chromosomes,
for a total of 46 chromosomes.
A trait is any gene-determined chara...
Inheritance
of Single-Gene Disorders
Aug 1, 2007
The traits produced by
a gene can be characterized as dominant or recessive. Dominant traits
can be expressed when only one copy of the gene for that trait is
present. Recessive traits carried on autosomal chromosomes can be
expressed only when two c...
Gene
Technology
Aug 1, 2007
Gene technology is rapidly
improving. The polymerase
chain reaction (PCR) is a laboratory technique that can produce
large numbers of copies
of a gene, which makes studying the gene much easier. A specific
segment of deoxyribonucleic acid (DNA), such...
Uses
of Genetics
Aug 1, 2007
The potential for understanding
human genetics increased greatly when the Human Genome
Project successfully identified and mapped all the genes on human
chromosomes in 2003. Genetic techniques can be used to study individual
genes to learn more about...
Gene
Therapy
Aug 1, 2007
Although gene therapy
is defined as any treatment that changes gene function, it is often
thought of as the insertion of normal genes into the cells of a
person who lacks such normal genes because of a specific genetic
disorder (gene insertion therap...
Ethical
Controversies
Aug 1, 2007
With the new genetic diagnostic
and therapeutic capabilities come many controversies about how they
should be used. Concerns have been raised that knowledge of a person's genetic
information might be used improperly. For instance, people whose
geneti...
Introduction
Aug 1, 2007
In the early 1900s, German
scientist Paul Ehrlich described an ideal drug as a "magic bullet."
Such a drug would be aimed precisely at a disease site and would
not harm healthy tissues. Although many new drugs are aimed more
accurately than their pre...
Types of Adverse Drug
Reactions
Aug 1, 2007
Many adverse drug reactions
represent an exaggeration of the drug's therapeutic effects (called
type 1 or overdose reactions). For example, a person taking a drug
to reduce high blood pressure may feel dizzy or light-headed if
the drug reduces blood ...
Severity of Adverse Drug
Reactions
Aug 1, 2007
There is no universal
scale for describing or measuring the severity of an adverse drug
reaction. Assessment is largely subjective. Reactions can be described
as mild, moderate, severe, or lethal....
Benefits
Versus Risks
Aug 1, 2007
Every drug has the potential
to do harm as well as good. When doctors consider prescribing a
drug, they must weigh the possible risks against the expected benefits.
Use of a drug is not justified unless the expected benefits outweigh
the possible ris...
Risk Factors
Aug 1, 2007
Many factors can increase
the likelihood of an adverse drug reaction. They include the simultaneous
use of several drugs, very young or old age, pregnancy, and breastfeeding. Hereditary
factors make some people more susceptible to the toxic effects o...
Allergies
to Drugs
Aug 1, 2007
People sometimes mistake
many adverse drug reactions for allergies. For example, people who
experience stomach discomfort after taking aspirin (a common adverse
reaction) often say they are "allergic" to aspirin. However, this
is not a true allergic ...
Overdose
Toxicity
Aug 1, 2007
Overdose toxicity refers
to serious, often harmful, and sometimes fatal toxic reactions to
an accidental overdose of a drug (because of a doctor's, pharmacist's,
or patient's error) or to an intentional overdose (homicide or suicide)....
Pulmonary
Embolism
Aug 1, 2007
Pulmonary
embolism is the sudden blocking of an artery of the lung (pulmonary
artery) by a collection of solid material brought through the bloodstream
(embolus)—usually a blood clot (thrombus) or rarely other foreign material....
Atelectasis
Aug 1, 2007
Atelectasis
is a condition in which all or part of a lung becomes airless and
collapses....
Introduction
Aug 1, 2007
Pain is an
unpleasant sensation signaling actual or possible injury....
Types
Aug 1, 2007
There are several types
of pain, including neuropathic pain (such as sciatica—see ), nociceptive pain (such
as pain after surgery and pain due to cancer), and psychogenic pain....
Evaluation
Aug 1, 2007
Neither examinations
nor tests can prove that a person is in pain. Consequently, doctors ask
the person about the history and characteristics of pain. The person's
answers help them identify the cause and develop a treatment strategy.
Questions can i...
Treatment
Aug 1, 2007
In some cases, treating
the underlying disorder eliminates or minimizes the pain. For example,
setting a broken bone in a cast or giving antibiotics for an infected
joint helps reduce pain. However, even if the underlying disorder
can be treated, pai...
Introduction
Aug 1, 2007
Every body movement,
from raising a hand to smiling, involves a complex interaction between
the central nervous system (brain and spinal cord), nerves, and
muscles. Damage to or malfunction of any of these components may
result in a movement disorder...
Myoclonus
Aug 1, 2007
Myoclonus
refers to quick, lightning-like jerks (contractions) of a muscle
or a group of muscles....
Tremor
Aug 1, 2007
A tremor
is an involuntary, rhythmic, shaking movement produced when muscles
repeatedly contract and relax....
Parkinson's
Disease
Aug 1, 2007
Parkinson's
disease is a slowly progressive degenerative disorder of the central
nervous system. It is characterized by tremor when muscles are at
rest (resting tremor), increased muscle tone (rigidity), slowness
of voluntary movements, and difficult...
Parkinsonism
Aug 1, 2007
Parkinsonism
refers to symptoms of Parkinson's disease (such as slow movements
and tremors) that are caused by another condition....
Progressive
Supranuclear Palsy
Aug 1, 2007
Progressive
supranuclear palsy is characterized by muscle stiffness (rigidity),
inability to move the eyes, weakness of the throat muscles, and
a tendency to fall backward....
Multiple
System Atrophy
Aug 1, 2007
Multiple
system atrophy is a progressive, fatal disorder that makes muscles
stiff (rigid) and causes problems with movement, loss of coordination,
and malfunction of internal body processes (such as blood pressure
and bladder control).The
parts of th...
Tics
Aug 1, 2007
Tics are
rapid, purposeless, repetitive but not rhythmic involuntary movements
that are virtually identical to one another. They can be suppressed
but only for a short time and only with conscious effort....
Chorea, Athetosis,
and Hemiballismus
Aug 1, 2007
Chorea is
repetitive, brief, jerky, rapid involuntary movements that start
in one part of the body and move abruptly, unpredictably, and often
continuously to another part. Athetosis is a continuous
stream of slow, flowing, writhing involuntary movem...
Huntington's
Disease
Aug 1, 2007
Huntington's
disease (Huntington's chorea) is a hereditary disease that begins
with occasional involuntary jerking or spasms, then progresses to
more pronounced involuntary movements (chorea and athetosis), mental
deterioration, and death.
Part of th...
Dystonia
Aug 1, 2007
Dystonia
is characterized by involuntary sustained muscle contractions that
may make people freeze in the middle of an action or make the entire
body, the trunk, or another part of the body twist or turn....
Coordination
Disorders
Aug 1, 2007
Coordination
disorders result from malfunction of the cerebellum, the part of
the brain that coordinates voluntary movements.The cerebellum malfunctions,
causing loss of coordination.
Often, people cannot control their arms and legs,
making them take...
Fragile
X–Associated Tremor/Ataxia Syndrome
Aug 1, 2007
Fragile X–associated
tremor/ataxia syndrome is a genetic disorder that affects mostly
men and causes tremor, loss of coordination, and dementia....
Introduction
Aug 1, 2007
Causes of spinal cord disorders include injuries,
infections, a blocked blood supply, and compression by a fractured
bone or a tumor.
Typically, muscles are weak or paralyzed, sensation
is abnormal or lost, and controlling bladder and bowel function...
Injuries
of the Spinal Cord and Vertebrae
Aug 1, 2007
Most spinal cord injuries result from motor vehicle
accidents.
Symptoms, such as loss of sensation and loss of
muscle control, may be temporary or permanent.
Magnetic resonance imaging (MRI) or computed tomography
(CT) is the best way to identify th...
Compression
of the Spinal Cord
Aug 1, 2007
Injuries
and disorders can put pressure on the spinal cord, causing back
pain, tingling, muscle weakness, and other symptoms....
Cervical
Spondylosis
Aug 1, 2007
Cervical
spondylosis is degeneration of the disks and vertebrae in the neck,
putting pressure on (compressing) the spinal cord in the neck....
Syrinx
Aug 1, 2007
A syrinx
is a fluid-filled cavity that develops in the spinal cord (called
a syringomyelia), in the brain stem (called a syringobulbia), or
in both....
Hereditary
Spastic Paraparesis
Aug 1, 2007
Hereditary
spastic paraparesis is a rare hereditary disorder that causes gradual
weakness with muscle spasms (spastic weakness) in the legs....
Acute
Transverse Myelitis
Aug 1, 2007
Acute transverse
myelitis is inflammation that affects the spinal cord across its
entire width (transversely) and thus blocks transmission of nerve
impulses traveling up or down the spinal cord....
Blockage
of the Spinal Cord's Blood Supply
Aug 1, 2007
Blockage
of an artery carrying blood to the spinal cord prevents the cord
from getting blood and thus oxygen. As a result, tissues can die (called
infarction)....
Subacute
Combined Degeneration
Aug 1, 2007
Subacute
combined degeneration is progressive degeneration of the spinal
cord due to vitamin B12 deficiency. Symptoms
include muscle weakness, clumsiness, tingling, and other abnormal
sensations....
Tropical
Spastic Paraparesis/HTLV-1–Associated Myelopathy
Aug 1, 2007
Tropical
spastic paraparesis/HTLV-1–associated myelopathy is a slowly progressive
disorder of the spinal cord caused by the human T-lymphotrophic
virus 1 (HTLV-1). It causes weakness with muscle spasms (spastic
weakness) in both legs....
Introduction
Aug 1, 2007
Anxiety disorders
involve a state of distressing chronic but fluctuating nervousness
that is inappropriately severe for the person's circumstances....
Generalized
Anxiety Disorder
Aug 1, 2007
Generalized
anxiety disorder consists of excessive, usually daily, nervousness
and worry (lasting 6 months or longer) about many activities or
events....
Anxiety Induced by Physical Disorders
or Drugs
Aug 1, 2007
Anxiety
can be caused by a physical disorder or the use or discontinuation
of a drug. Physical disorders that can cause anxiety include the
following:Brain and nerve
(neurologic) disorders, such as head injuries, brain infections,
and some inner ear ...
Panic
Attacks and Panic Disorder
Aug 1, 2007
Panic is acute,
short-lived, extreme anxiety with accompanying physical symptoms....
Phobic Disorders
Aug 1, 2007
Phobias involve
persistent, unrealistic, intense anxiety about and fear of certain
situations, circumstances, or objects....
Obsessive-Compulsive
Disorder (OCD)
Aug 1, 2007
Obsessive-compulsive
disorder is characterized by recurring, unwanted, anxiety-provoking,
intrusive ideas, images, or impulses (obsessions) that may even
seem silly, weird, nasty, or horrible to the person experiencing them.
The person also has urges...
Posttraumatic
Stress Disorder (PTSD)
Aug 1, 2007
Posttraumatic
stress disorder is characterized by recurrent, intrusive recollections
of an overwhelming traumatic event....
Acute Stress Disorder
Aug 1, 2007
Acute stress
disorder is a brief period of intrusive recollections occurring
shortly after an overwhelming traumatic event. It is similar to posttraumatic
stress disorder, except that it begins within 4 weeks of the traumatic
event and lasts only 2 d...
Introduction
Aug 1, 2007
Pancreatitis
is inflammation of the pancreas....
Acute
Pancreatitis
Aug 1, 2007
Acute pancreatitis
is sudden inflammation of the pancreas that may be mild or life
threatening but that usually subsides....
Chronic
Pancreatitis
Aug 1, 2007
Chronic pancreatitis
is long-standing inflammation of the pancreas that results in irreversible
deterioration of pancreatic structure and function....
Undernutrition
Aug 1, 2007
Undernutrition
is a deficiency of calories or of one or more essential nutrients....
Introduction
Aug 1, 2007
Vitamins
are a vital part of a healthy diet. The recommended dietary allowance
(RDA)—the amount most healthy people need each day to remain healthy—has
been determined for most vitamins. A safe upper limit (tolerable
upper intake level) has been dete...
Folate
Aug 1, 2007
Folate (folic acid), with
vitamin B12, is necessary for the formation
of normal red blood cells and the synthesis of DNA (deoxyribonucleic
acid), which is the genetic material of cells. Folate is also necessary
for normal development of a fetus's ner...
Niacin
Aug 1, 2007
Niacin (nicotinic acid)
is essential for the metabolism of carbohydrates, fats, and many other
substances in the body. Foods rich in tryptophan (an amino acid),
such as dairy products, can compensate for not consuming enough
niacin in the diet becaus...
Riboflavin
Aug 1, 2007
Riboflavin (vitamin B2)
is essential for the metabolism of carbohydrates (to produce energy)
and amino acids. It also helps keep mucous membranes (such as those
lining the mouth) healthy. Riboflavin is not toxic....
Thiamin
Aug 1, 2007
Thiamin (vitamin B1)
is widely available in the diet. It is essential for the metabolism
of carbohydrates (to produce energy) and for normal nerve and heart
function. Thiamin is not toxic....
Vitamin
A
Aug 1, 2007
Vitamin A (retinol) is
necessary for the function of light-sensitive nerve cells (photoreceptors)
in the eye's retina. It also helps keep the skin and the lining
of the lungs, intestine, and urinary tract healthy and protects
against infections. Caro...
Vitamin
B6
Aug 1, 2007
Vitamin B6 (pyridoxine)
is essential for the metabolism of carbohydrates, amino acids, and
fats (lipids), as well as for normal nerve function and for the
formation of red blood cells. It also helps keep the skin healthy....
Vitamin
B12
Aug 1, 2007
Vitamin B12 (cobalamins),
with folate, is necessary for the formation and maturation of red
blood cells and the synthesis of DNA (deoxyribonucleic acid), which
is the genetic material of cells. Vitamin B12 is
also necessary for normal nerve function....
Vitamin
C
Aug 1, 2007
Vitamin C (ascorbic acid)
is essential for the formation, growth, and repair of bone, skin, and
connective tissue (which binds other tissues and organs together
and includes tendons, ligaments, and blood vessels). Vitamin C helps maintain
healthy tee...
Vitamin D
Aug 1, 2007
Two forms of vitamin
D are important for nutrition:Vitamin D2 (ergocalciferol): This
form is synthesized from plants and yeast precursors. It is also
the form used in very high dose supplements.
Vitamin D3 (cholecalciferol): This
form is the most act...
Vitamin
E
Aug 1, 2007
Vitamin E (tocopherol)
is an antioxidant: It protects cells against damage by free radicals, which
are by-products of normal cell activity that participate in chemical
reactions. Some of these reactions can be harmful. Many people take
vitamin E supp...
Vitamin K
Aug 1, 2007
Vitamin K has two forms:Phylloquinone: This
form occurs in plants and is consumed in the diet. It is absorbed better
when it is consumed with fat. Phylloquinone is not toxic.
Menaquinone: This form is produced
by bacteria in the intestine, but only s...
Introduction
Aug 1, 2007
An obstruction anywhere
along the urinary tract—from the kidneys, where urine is produced,
to the urethra, through which urine leaves the body—can increase
pressure inside the urinary tract and slow the flow of urine. An
obstruction may occur suddenl...
Hydronephrosis
Aug 1, 2007
Hydronephrosis
is distention (dilation) of the kidney with urine, caused by backward
pressure on the kidney when the flow of urine is obstructed....
Stones
in the Urinary Tract
Aug 1, 2007
Stones (calculi)
are hard masses that form anywhere in the urinary tract and may
cause pain, bleeding, obstruction of the flow of urine, or an infection....
Introduction
Aug 1, 2007
There are many different
types of cancer, and people have different risks for the different cancers.
Therefore, no set of prevention strategies is effective in every
person. However, some general strategies do reduce risk of cancer
in many people. Tr...
Prevention
Aug 1, 2007
Reducing the risk
of certain cancers may be possible through dietary (see ) and other lifestyle changes.
How risk can be reduced depends on the specific cancer. Tobacco
use is directly associated with one third of all cancers. Not smoking
and avoidin...
Treatment
Principles
Aug 1, 2007
Treating cancer is one
of the most complex aspects of medical care. It involves a team
that encompasses many types of doctors working together (for example,
primary care doctors, gynecologists, medical oncologists, surgeons, radiotherapists,
and path...
Surgery
Aug 1, 2007
Surgery is a traditional
form of cancer treatment. It is the most effective in eliminating most
types of cancer before it has spread to lymph nodes or distant sites
(metastasized). Surgery may be used alone or in combination with
other treatments, su...
Radiation
Therapy
Aug 1, 2007
Radiation is a form of
intense energy generated by a radioactive substance, such as cobalt, or
by specialized equipment, such as an atomic particle (linear) accelerator....
Chemotherapy
Aug 1, 2007
Chemotherapy involves the
use of drugs to destroy cancer cells. Although an ideal drug would
destroy cancer cells without harming normal cells, most drugs are
not that selective. Instead, drugs are designed to inflict greater damage
on cancer cells t...
Immunotherapy
Aug 1, 2007
Immunotherapy is used to
stimulate the body's immune system against cancer. For example,
vaccines composed of antigens derived from tumor cells can boost
the body's production of antibodies or immune cells (T lymphocytes).
Extracts of weakened tuberc...
Combination Therapy
Aug 1, 2007
Chemotherapy drugs are
most effective when given in combination (combination chemotherapy).
The rationale for combination chemotherapy is to use drugs that
work by different mechanisms of action, thereby decreasing the likelihood
that resistant cance...
Alternative
Medicine
Aug 1, 2007
Some people turn to alternative
medicine, including certain medicinal herbs (see ),
to treat their cancer, instead of or in addition to standard treatment.
However, most types of alternative medicine have not been subjected
to careful scientific stud...
Diet
and Cancer
Aug 1, 2007
Many studies have tried
to determine whether eating specific foods increases or decreases
a person's risk of getting cancer. Unfortunately, different studies
sometimes have conflicting results, so it is hard to know what effect
foods or dietary suppl...
Introduction
Aug 1, 2007
The skin shields the rest
of the body from the sun's rays....
Sunburn
Aug 1, 2007
Brief overexposure to ultraviolet light causes
sunburn.
Sunburn causes painful reddened skin and sometimes
causes blisters, fever and chills.
People can prevent sunburn by avoiding excessive
sun exposure and by using sunscreens.
Cold water compresse...
Photosensitivity
Reactions
Aug 1, 2007
Sunlight can trigger immune reactions.
People develop itchy eruptions or areas of redness
and inflammation on patches of sun-exposed skin.
These reactions typically resolve on their own.Photosensitivity,
sometimes referred to as a sun allergy, is an...
Introduction
Aug 1, 2007
The nail unit is made
up of the nail plate and the surrounding structures. These structures
include the nail bed, which underlies the nail and forms the attachment
of the nail to the finger; the nail matrix, which is located at the
base of the nail a...
Deformities
and Discoloration
Aug 1, 2007
About 50% of nail
deformities are caused by a fungal infection (see ). The
remainder result from various causes, including trauma, psoriasis,
lichen planus, and occasionally cancer. Drugs, infections, and diseases
can cause discoloration of the nails...
Infections
Aug 1, 2007
Infections may involve
the nail itself, the bed under the nail, or the skin around the
nail. Most nail infections are fungal (onychomycosis), but bacterial
and viral infections can occur. Bacterial infections may occur in
the cuticle or nail folds (p...
Ingrown
Toenail
Aug 1, 2007
An ingrown
toenail is a condition in which the edges of the nail grow into
the surrounding skin....
Trauma
Aug 1, 2007
Even minor trauma
to the finger may cause changes in the nail. The nail may develop
a small spot of white discoloration that starts at the injury location
and grows up with the nail....
Tumors
Aug 1, 2007
Benign and malignant
tumors can affect the nail unit, causing a deformity. These tumors include
noncancerous myxoid cysts, pyogenic granulomas, glomus tumors, Bowen's
disease (an early form of skin cancer), squamous cell carcinoma,
and malignant mela...
Smell
and Taste Disorders
Aug 1, 2007
Smell may be lost temporarily when a person smokes
or has a cold or seasonal allergy.
Smell may be lost permanently after a head injury.
People may lose their sense of taste if they have
a condition that causes a very dry mouth.
Doctors can test sme...
Introduction
Aug 1, 2007
The external structures
of the male reproductive system include the penis and scrotum. The
internal structures include the vas deferens, testes (testicles),
urethra, prostate gland, and seminal vesicles....
Structure
Aug 1, 2007
The penis and the urethra are part of the urinary
and reproductive systems.
The scrotum, testes, vas deferens, and prostate
gland comprise the rest of the reproductive system....
Function
Aug 1, 2007
The penis becomes erect through a complex interaction
of physiologic and psychologic factors.
Contractions during ejaculation impel semen into
the urethra and out of the penis....
Puberty
Aug 1, 2007
Puberty may begin as early as age 9 and continue
until age 16.
At puberty, the testes start to produce testosterone.
Testosterone causes reproductive
organs to mature, facial and pubic hair to appear, and the voice
to deepen....
Effects
of Aging
Aug 1, 2007
It is not clear whether
aging itself or the disorders associated with aging cause the gradual changes
that occur in men's sexual functioning. The frequency, duration,
and rigidity of erections gradually decline throughout adulthood.
Levels of the mal...
Introduction
Aug 1, 2007
Family planning involves
using various methods to control the number and timing of pregnancies.
A couple may use contraception to avoid pregnancy temporarily or
sterilization to avoid pregnancy permanently. Abortion may be used
to end an unwanted pre...
Contraception
Aug 1, 2007
Contraception
is prevention of fertilization of an egg by a sperm (conception)
or attachment of the fertilized egg to the lining of the uterus (implantation)....
Sterilization
Aug 1, 2007
Sterilization
involves making a person incapable of reproduction....
Abortion
Aug 1, 2007
Induced abortion
is the intentional ending of a pregnancy by surgery or drugs.A pregnancy may be ended by
surgically removing the contents of the uterus or by taking certain
drugs.
Complications are uncommon when an abortion is done
by a trained heal...
Introduction
Aug 1, 2007
The goal of first aid
is to save life, to prevent an injury or illness from worsening,
or to help speed recovery. First aid for cardiac arrest, choking,
bleeding, minor wounds, and minor soft tissue injuries is discussed
in this chapter. Other chapte...
Emergency
First Aid Priorities
Aug 1, 2007
The first priority is
to assess a person's airway, breathing, and circulation (the ABCs).
A problem in any of these areas is always fatal if not corrected.
The airway (A)—the passage through which air travels to the lungs—can become
blocked. Various ...
Cardiac
Arrest
Aug 1, 2007
Cardiac
arrest is what happens when a person dies. The heart does not beat
and breathing ceases, which starves the body of oxygen. Sometimes
a person can be revived during the first several minutes after cardiac
arrest. However, the more time that pa...
Choking
Aug 1, 2007
Maneuvers to relieve choking
are frequently life saving. Adults most often choke on a piece of
food, such as a large piece of meat. Infants do not have well-developed
swallowing reflexes and may choke if given small, rounded foods
such as peanuts or ...
Internal
Bleeding
Aug 1, 2007
Heavy internal bleeding
may occur in the abdominal cavity, chest cavity, digestive tract, or
tissues surrounding broken large bones, such as the thigh bone (femur)
and pelvis....
Wounds
Aug 1, 2007
Cuts or tears in tissue
(lacerations), scrapes (abrasions), and puncture wounds can be caused
by bites (see ) or other injuries. Wounds that
are not caused by bites and are not extensive usually heal rapidly
without any problems. However, some wounds...
Soft
Tissue Injuries
Aug 1, 2007
Soft tissue injuries include
bumps and bruises (contusions) and small tears of muscles (minor
strains) or of ligaments and tendons near joints (minor sprains)....
Severed
or Constricted Limbs or Digits
Aug 1, 2007
Body parts such as fingers
and toes can become severed. Also, tissue may die because blood
flow has been cut off by rings or other constricting devices. Rings
cut off blood flow when parts of the body near the ring swell, often
as the result of an in...
Introduction
Aug 1, 2007
Aging is a gradual, continuous
process of spontaneous change that begins at birth and continues
throughout all stages of life. It involves maturation and development
for children, adolescents, and young adults. Then, during middle
and late age, many ...
Changes
in the Body
Aug 1, 2007
The body changes with
aging because changes occur in individual cells and in whole organs.
These changes result in changes in function and in appearance....
Disorders
in Older People
Aug 1, 2007
Some disorders occur almost
exclusively in older people. They are sometimes called geriatric
syndromes (geriatric refers to the medical care of older people)....
Indirect
Influences on Health
Aug 1, 2007
People who live alone
have more health problems than those who live with someone....
Disorders
of Accelerated Aging
Aug 1, 2007
Certain disorders have
the some of the same effects of aging. Scientists study what happens in
these disorders to try to learn what causes aging. For example,
they identify the genes that are defective in these disorders and
compare them with the sam...
Introduction
Jul 1, 2007
Rehabilitation services
are needed by people who have lost the ability to function normally, often
because of trauma, a stroke, an infection, a tumor, surgery, or
a progressive disorder (such as arthritis). A pulmonary rehabilitation program
(see )
i...
Treatment of Pain
and Inflammation
Jul 1, 2007
Therapists treat pain
and inflammation. Such treatment makes movement easier and enables
people to participate more fully in rehabilitation. Techniques used
include heat therapy, cold therapy, electrical stimulation, traction,
massage, and acupunctur...
Physical
Therapy (PT)
Jul 1, 2007
Physical therapy involves
exercising and manipulating the body. It can improve joint and muscle
function, helping people stand, balance, walk, and climb stairs
better. Techniques include range-of-motion exercises, muscle-strengthening
exercises, coor...
Occupational
Therapy (OT)
Jul 1, 2007
Occupational therapy is
intended to enhance a person's ability to do basic self-care activities,
useful work, and leisure activities. This therapy focuses on the
coordination of many abilities required for even simple activities:...
Specific Problems
Jul 1, 2007
For many problems—for
example, heart disorders, stroke, other brain injuries, spinal injuries,
hip fractures, amputation, and loss of hearing, speech, or vision—specific
rehabilitation programs are available. Rehabilitation is sometimes
needed for ot...
Introduction
Jul 1, 2007
The musculoskeletal system
provides form, stability, and movement to the human body. It consists
of the body's bones (which make up the skeleton), muscles, tendons,
ligaments, joints, cartilage, and other connective tissue. The term
"connective tissu...
Bones
Jul 1, 2007
Bone, although strong, is
a constantly changing tissue that has several functions. Bones serve
as rigid structures to the body and as shields to protect delicate
internal organs. They provide housing for the bone marrow, where
the blood cells are for...
Muscles
Jul 1, 2007
There are three types of
muscles: skeletal, smooth, and cardiac (heart). Two of these kinds—skeletal
and smooth—are part of the musculoskeletal system....
Tendons and Bursas
Jul 1, 2007
Tendons are tough bands of connective
tissue made up mostly of a rigid protein called collagen. Tendons
firmly attach each end of a muscle to a bone. They are often located within
sheaths, which are lubricated to allow the tendons to move without
fri...
Ligaments
Jul 1, 2007
Ligaments are tough fibrous
cords composed of connective tissue that contains both collagen
and elastic fibers. The elastic fibers allow the ligaments to stretch
to some extent. Ligaments surround joints and bind them together.
They help strengthen a...
Joints
Jul 1, 2007
Joints are the junction
between two or more bones. Some joints do not normally move, such
as those located between the plates of the skull. Other joints allow
a large and complex range of motion. The configuration of a joint determines
the degree and...
Effects of Aging
Jul 1, 2007
From
about age 30, the density of bones begins to diminish in men and
women. This loss of bone density accelerates in women after menopause.
As a result, bones become more fragile and are more likely to break
(see ),
especially in old age....
Introduction
Jul 1, 2007
Twelve pairs of nerves—the
cranial nerves—lead directly from the brain to various parts of the
head, neck, and trunk. Some of the cranial nerves are involved in
the special senses (such as seeing, hearing, and taste), and others
control muscles in th...
Internuclear
Ophthalmoplegia
Jul 1, 2007
Internuclear
ophthalmoplegia is impairment of horizontal eye movements caused
by damage to certain connections between nerve centers in the brain
stem....
Conjugate
Gaze Palsies
Jul 1, 2007
In conjugate
gaze palsies, the two eyes cannot move in one direction (side to
side, up, or down) at the same time....
Palsies
of Cranial Nerves That Control Eye Movement
Jul 1, 2007
These disorders
involve paralysis of cranial nerves that control eye movement (the
3rd, 4th, or 6th nerves), impairing the ability to move the eyes.
How eye movement is affected depends on which nerve is affected....
Trigeminal
Neuralgia
Jul 1, 2007
Trigeminal
neuralgia (tic douloureux) is severe facial pain due to malfunction
of the 5th cranial nerve (trigeminal nerve). This nerve carries sensory
information from the face to the brain and controls the muscles
involved in chewing....
Bell's
Palsy
Jul 1, 2007
Bell's palsy
is sudden weakness or paralysis of muscles on one side of the face
due to malfunction of the 7th cranial nerve (facial nerve). This
nerve moves the facial muscles, stimulates the salivary and tear
glands, and enables the front part of th...
Hemifacial
Spasm
Jul 1, 2007
Hemifacial
spasm is painless involuntary twitching of one side of the face
due to malfunction of the 7th cranial nerve (facial nerve). This
nerve moves the facial muscles, stimulates the salivary and tear
glands, and enables the front part of the ton...
Glossopharyngeal
Neuralgia
Jul 1, 2007
Glossopharyngeal
neuralgia consists of recurring attacks of severe pain in the back
of the throat, the area near the tonsils, the back of the tongue,
and part of the ear. The pain is due to malfunction of the 9th cranial
nerve (glossopharyngeal nerve...
Hypoglossal
Nerve Disorders
Jul 1, 2007
Disorders
of the 12th cranial nerve (hypoglossal nerve) cause weakness or
wasting (atrophy) of the tongue on the affected side. This nerve moves
the tongue....
Introduction
Jul 1, 2007
A blood transfusion
is the transfer of blood or a blood component from one person (a
donor) to another (a recipient)....
Donation
Process
Jul 1, 2007
Donating blood is very
safe. The entire process of donating whole blood (that is, blood with
all component cells) takes about 1 hour. Blood donors must be at
least 17 years old and weigh at least 110 pounds. In addition, they must
be in good health: ...
Types
of Transfusions
Jul 1, 2007
Most blood donations are
divided (fractionated) into their components: red blood cells, platelets,
clotting factors, plasma, antibodies (immunoglobulins), and white
blood cells. Depending on the situation, people may receive only
the cells from blood...
Special Donation Procedures
Jul 1, 2007
...
Precautions
and Adverse Reactions
Jul 1, 2007
To minimize the chance
of an adverse reaction during a transfusion, health care practitioners
take several precautions. Before starting the transfusion, usually
a few hours or even a few days beforehand, a technician mixes a drop
of the donor's blood...
Autoimmune
Disorders
Jul 1, 2007
An autoimmune
disorder is a malfunction of the body's immune system that causes
the body to attack its own tissues.
Autoimmune disorders can be triggered in many ways.
Symptoms vary depending on which disorder develops
and which part of the body is a...
Introduction
Jul 1, 2007
The female reproductive
system consists of the external and internal genital organs. The breasts
are sometimes considered part of the reproductive system (see ).
However, other parts of the body also affect the development and
functioning of the repr...
External
Genital Organs
Jul 1, 2007
The external genital organs
include the mons pubis, labia majora, labia minora, Bartholin's
glands, and clitoris. The area containing these organs is called
the vulva. The external genital organs have three main functions: Enabling sperm to enter the...
Internal Genital Organs
Jul 1, 2007
The internal genital organs
form a pathway (the genital tract). This pathway consists of the
following:...
Puberty
Jul 1, 2007
Puberty is a sequence of
events in which physical changes occur, resulting in adult physical
characteristics and capacity to reproduce. These physical changes
are regulated by changes in the levels of hormones that are produced
by the pituitary gland...
Menstrual
Cycle
Jul 1, 2007
Menstruation is the shedding
of the lining of the uterus (endometrium) accompanied by bleeding.
It occurs in approximately monthly cycles throughout a woman's reproductive life,
except during pregnancy. Menstruation starts during puberty (at
menarche...
Effects
of Aging
Jul 1, 2007
Around menopause (see ),
changes in the genital organs occur rapidly. Menstrual cycles stop,
and the ovaries stop producing estrogen. After menopause, the tissues
of the labia minora, clitoris, vagina, and urethra thin (atrophy). This thinning
can re...
Pelvic
Inflammatory Disease (PID)
Jul 1, 2007
Pelvic inflammatory
disease is an infection of the upper female reproductive organs....
Introduction
Jul 1, 2007
In order to thrive, a
child must experience the consistent and ongoing care by a loving, nurturing
caregiver, whether that person is a parent or substitute caregiver.
The security and support that such an adult can provide gives a
child the self-conf...
Illness
and Death in Infants
Jul 1, 2007
The medical needs of
premature newborns or ill infants often require that they be separated
from their parents temporarily. Although doctors may allow parents
to hold their infant some of the time, medical care often sharply limits
the opportunity fo...
Illness
in Children
Jul 1, 2007
Severe illness, even
if temporary, can provoke a great deal of anxiety for children and their
families. Chronic problems, such as asthma, diabetes, hearing or
vision impairments, and cerebral palsy, or disability usually cause
even more emotional dis...
Divorce
Jul 1, 2007
Separation and divorce,
and the events leading up to them, interrupt the stability and predictability
that children need. Other than the death of an immediate family
member, divorce is the most stressful event that can affect a family.
Because the wo...
Childcare
Jul 1, 2007
About 80% of children
receive childcare outside the home before they start school. Many
children aged 5 to 12 also receive care outside the home before
or after school. Sources of care include relatives, neighbors, licensed
and unlicensed private hom...
Foster
Care
Jul 1, 2007
Foster care is care provided
for children whose families are temporarily unable to care for them.
The local government determines the process of arranging foster
care. Foster care is surprisingly common in the United States—about
750,000 children are...
Adoption
Jul 1, 2007
Adoption is the legal
process of adding a person to an existing family. Adoption, unlike foster
care, is meant to be permanent. The goal of adoption is to provide
lifelong security to the child and the adoptive family....
Introduction
Jun 1, 2007
The kidneys and the rest
of the urinary tract may become injured in a number of ways. Examples
include injuries from a blunt force (most commonly motor vehicle
collisions, falls, or sports injuries) or a pentrating force (most
commonly gunshot or sta...
Bladder
Injuries
Jun 1, 2007
A bladder injury often
occurs when the pelvis is injured, as in a high-speed motor vehicle collision
or a fall. Penetrating wounds, usually from gunshots, also can injure
the bladder. In addition, a bladder injury may occur unintentionally
during sur...
Kidney
Injuries
Jun 1, 2007
The kidney is injured
more often than any of the organs along the urinary tract. Blunt
force due to motor vehicle collisions, falls, or sports injuries
is the usual cause of injury. Penetrating kidney injuries can result
from gunshot or stab wounds. ...
Ureteral
Injuries
Jun 1, 2007
Most injuries to the ureter
occur during pelvic or abdominal operations, such as removal of
the uterus (hysterectomy) or the colon (colectomy) or repair of
an abdominal aortic aneurysm, or during ureteroscopy (an examination
of the ureter with a rigi...
Urethral
Injuries
Jun 1, 2007
Most urethral injuries
occur in men. Common causes include pelvic fractures and straddle
injuries (injuries to the area between the legs). The urethra can
also be injured unintentionally during surgical procedures performed directly
on the urethra or...
Introduction
Jun 1, 2007
Menopause
is the permanent end of menstrual periods and thus of fertility.For up to several years before
and just after menopause, estrogen levels fluctuate widely, periods
become irregular, and symptoms (such as hot flashes) may occur.
After menopau...
Premature
Menopause
Jun 1, 2007
Premature
menopause (premature ovarian failure) is the permanent end of menstrual
periods before age 40 because the ovaries become unable to produce
hormones because ovulation stops.
Symptoms are the same as those of natural menopause.
Tests are done...
Introduction
Jun 1, 2007
Making decisions about medical
care is most effective when doctors and patients work together.
The best and most appropriate decisions are reached when the doctor's
experience and knowledge of medicine are combined with the person's
knowledge, wishes...
Information
Sources
Jun 1, 2007
Most doctors
rely on their education and experience: what they have learned from
their training, from their colleagues, and from diagnosing and treating
people with similar problems. Doctors also read medical books and journals,
consult with colleagu...
Medical
Testing Decisions
Jun 1, 2007
Tests are performed to
screen for disease, diagnose disease, classify and measure the severity
or stage of disease, and monitor the course of a disease, especially
its response to treatment....
Treatment Decisions
Jun 1, 2007
Before recommending a course
of action, doctors weigh the potential risk of harm from a treatment
against its potential benefit. ...
Participating
in Decision Making
Jun 1, 2007
To participate fully in
the medical decision making process, people need to work closely with
their doctors. People may wish to obtain additional information
about a recommended test or treatment before making a decision (see ). Information
can be ob...
Realities of Decision
Making
Jun 1, 2007
Whenever a decision must
be made about diagnosis or treatment, two tasks must be accomplished.
The first is to choose those information resources that are most
appropriate to help determine the best course of action. The second
is to apply what is le...
Introduction
May 1, 2007
Gone are the days when people
can rely solely on their family doctor with the help of a nurse
to take charge of their health care. To obtain the best health care
today, people must participate actively in the process. Active participation
means many ...
Where
to Start
May 1, 2007
Typically, the entry point
into the health care system is a primary care practitioner, usually
a doctor but sometimes a nurse practitioner or physician's assistant.
Having a primary care doctor has many advantages that can lead to
better care. People...
When
to See a Doctor
May 1, 2007
...
Making
the Most of a Health Care Visit
May 1, 2007
Preparing for a health
care visit helps people get the most out of time spent with a doctor
or another health care practitioner. Preparing ahead also helps
people communicate with a practitioner more effectively. Information
and questions for the pra...
Getting
a Second Opinion
May 1, 2007
Despite many similarities
in training, doctors may vary in their opinions about how to diagnose
or treat certain disorders. Such differences can occur among the
best of doctors. Differences often occur because the evidence for
benefits and risks is n...
Handling
Medical Records
May 1, 2007
People may not have total
access to their medical record kept in the doctor's office. But usually
the person owns the medical information, and the doctor or institution
owns the document itself. The courts can require submission of copies
or summarie...
Researching
a Disorder
May 1, 2007
When a disorder is first
diagnosed, the doctor often gives a handout that summarizes key points
of information. People may also have some general knowledge of the
disorder from newspaper or magazine articles or television or radio
shows....
How
Health Care Is Paid For
May 1, 2007
Health care, particularly
hospitalization, advanced technologies, and complicated treatments,
is so expensive that most people cannot afford to pay for it by
themselves. Total health care costs annually in the United States were
about $1.9 trillion i...
Introduction
May 1, 2007
A drug is defined by U.S.
law as any substance (other than a food or device) intended for
use in the diagnosis, cure, relief, treatment, or prevention of
disease or intended to affect the structure or function of the body.
(Oral contraceptives are an...
Design
and Development
May 1, 2007
Many of the drugs in current
use were discovered by experiments conducted in animals and humans.
However, many drugs are now being designed with the specific disorder
in view. Abnormal biochemical and cellular changes caused by disease
are identified...
Placebos
May 1, 2007
Placebos are
substances that are made to resemble drugs but do not contain an
active drug....
Effectiveness
and Safety
May 1, 2007
The main goals of drug
development are effectiveness (efficacy) and safety. Because all drugs
can harm as well as help, safety is relative. The difference between
the usual effective dose and the dose that produces severe or life-threatening
side eff...
Adherence
to Drug Treatment
May 1, 2007
Adherence
is the degree to which a person takes prescribed drugs as directed....
Introduction
May 1, 2007
Low blood
pressure (hypotension) is blood pressure low enough to cause symptoms
such as dizziness and fainting....
Fainting
May 1, 2007
Fainting (syncope)
is a sudden, brief loss of consciousness....
Orthostatic
Hypotension
May 1, 2007
Orthostatic
hypotension is an excessive decrease in blood pressure that occurs
when a person stands up, resulting in reduced blood flow to the
brain and dizziness or fainting....
Postprandial
Hypotension
May 1, 2007
Postprandial
hypotension is an excessive decrease in blood pressure that occurs
after a meal....
Introduction
May 1, 2007
Pulmonary rehabilitation
is a program designed for people who have chronic lung disease.
Its primary goal is to enable people to achieve and maintain their
maximum level of independence and functioning. Although most pulmonary
rehabilitation programs...
Enrollment and Goal Setting
May 1, 2007
The first step for the
team members is to determine the person's short-term and long-term
goals. For example, an older person may desire to travel by air
to visit a grandchild. If the person can walk only 300 feet (about
90 meters) because of shortne...
Exercise
Training
May 1, 2007
Exercise training is probably
the most important component of pulmonary rehabilitation. It reduces
the effects of inactivity and deconditioning, resulting in less
shortness of breath and an increased ability to exercise. However,
physical limitations...
Psychosocial
Counseling
May 1, 2007
Because strong emotions
tend to worsen shortness of breath, some people suppress their emotions,
but depression and anxiety are common reactions to the life changes
a person with lung disease experiences. In addition, shortness of
breath itself itsel...
Nutritional
Evaluation and Counseling
May 1, 2007
People who have lung disease
often need nutritional evaluation and counseling. For example, those
with the most severe chronic obstructive pulmonary disease often
experience weight loss. Pulmonary rehabilitation programs help people
avoid weight loss...
Drug
Use and Education
May 1, 2007
People with severe lung
disease usually take several drugs. Often these drugs must be taken according
to precise instructions and a complex schedule. Through a rehabilitation
program, people can learn about the appropriate timing and doses
of all dru...
Oxygen
Therapy
May 1, 2007
Some people with chronic
lung disease need only a brief period of oxygen therapy during an acute
exacerbation of their lung disease. Others, in whom oxygen levels
in the blood are consistently low, may require oxygen therapy on
a daily basis. In thes...
Chest
Physical Therapy
May 1, 2007
Respiratory therapists
use several different techniques to help treat lung disease, including
postural drainage, suctioning, and breathing exercises. The choice
of therapy is based on the underlying disease and the person's overall
condition....
Introduction
May 1, 2007
Mental health (psychiatric
or psychologic) disorders involve disturbances in thinking, emotion,
or behavior. Small disturbances in these aspects of life are common,
but when such disturbances interfere with daily life, they are considered
mental illn...
Mental
Illness in Society
May 1, 2007
About 30 to 50% of adults
will experience a mental illness at some point in their lives. More
than 50% of them experience moderate to severe symptoms. In fact,
4 of the 10 leading causes of disability among people aged 5 and
older are mental health d...
Classification
and Diagnosis of Mental Illness
May 1, 2007
In 1952, the American Psychiatric
Association first published the Diagnostic
and Statistical Manual of Mental Disorders (DSM-I), marking
the first attempt to approach the diagnosis of mental illness through
standardized definitions and criteria. The ...
Treatment
of Mental Illness
May 1, 2007
Extraordinary advances
have been made in the treatment of mental illness. Understanding
what causes some mental health disorders helps doctors tailor treatment
to those disorders. As a result, many mental health disorders can
now be treated nearly as...
Introduction
May 1, 2007
Disorders that affect the
digestive (gastrointestinal) system are called digestive disorders.
Some disorders simultaneously affect several parts of the digestive
system, whereas others affect only one part or organ....
Symptoms
May 1, 2007
Some symptoms, such as diarrhea,
constipation, bleeding from the digestive tract, regurgitation,
and difficulty swallowing, usually suggest a digestive disorder.
More general symptoms, such as abdominal pain, flatulence, loss
of appetite, and nausea,...
Diagnosis
May 1, 2007
Usually, a doctor can
determine whether a person has a digestive disorder based on a medical
history and a physical examination. The doctor can then select appropriate
procedures that help to confirm the diagnosis, determine the extent
and severity o...
Irritable
Bowel Syndrome (IBS)
May 1, 2007
Irritable bowel
syndrome (IBS) is a disorder of the entire digestive tract that
causes abdominal pain and constipation or diarrhea....
Introduction
May 1, 2007
Hepatitis
is inflammation of the liver....
Acute Viral Hepatitis
May 1, 2007
Acute viral
hepatitis is inflammation of the liver caused by infection with
one of the five hepatitis viruses. In most people, the inflammation
begins suddenly and lasts only a few weeks....
Chronic Hepatitis
May 1, 2007
Chronic hepatitis
is inflammation of the liver that lasts at least 6 months....
Introduction
May 1, 2007
The structure of the face
and eyes is well suited for protecting the eyes from injury. The eyeball
is set into the orbit, a socket surrounded by a strong, bony ridge.
The eyelids close quickly to form a barrier to foreign objects,
and the eye can tol...
Blunt Injuries to the Eye
May 1, 2007
A blunt impact may damage
the structures at the front of the eye (the eyelid, conjunctiva, sclera,
cornea, iris, and lens) and those at the back of the eye (retina
and optic nerve). Such an impact may also break (fracture) the bones that
surround the...
Fractures
of the Orbit
May 1, 2007
Pain and swelling develop and double vision or decreased
vision may occur.
Computed tomography (CT) is usually done.
Sometimes the fracture is repaired surgically....
Lacerated
Eyeball
May 1, 2007
Most cuts (lacerations)
around the eyes affect the eyelids rather than the eyeball. Of those
that affect the eyeball, many are superficial and minor. However,
some cuts go through the white of the eye (sclera) or the transparent
dome on the front sur...
Eyelid
Lacerations
May 1, 2007
If the skin around the
eye or on the eyelid has been cut, stitches may be needed. When possible,
stitches near the edge of the eyelid should be placed by an ophthalmologist
(a medical doctor who specializes in eye disorders) to ensure that
no deformi...
Corneal
Abrasions and Foreign Bodies
May 1, 2007
The most common eye injuries
involve the surface the transparent dome on the front surface of
the eye (cornea). They include scratches (abrasions) and foreign
bodies. Foreign bodies in the cornea leave abrasions behind after
they are removed. Most of...
Chemical Burns
to the Eye
May 1, 2007
The eyelids close quickly
in a reflex reaction to protect the eyes from harm. However, irritating
or harmful chemicals still sometimes get onto the surface of the
eye, causing burns. The most dangerous chemical burns involve strong
acids or alkali. A...
Traumatic Iritis and Chemical
Iritis
May 1, 2007
Iritis (also
known as iridocyclitis or uveitis) is inflammation of the pigmented
inside lining of the eye (uvea), iris, or both....
Endometriosis
May 1, 2007
Endometriosis
is a noncancerous disorder in which patches of endometrial tissue—normally
occurring only in the lining of the uterus (endometrium)—appear
outside the uterus....
Drug
Use During Pregnancy
May 1, 2007
More than 90% of pregnant
women take prescription or nonprescription (over-the-counter) drugs
or use social drugs (such as tobacco and alcohol) or illicit drugs
at some time during pregnancy. In general, drugs, unless absolutely
necessary, should not...
Introduction
May 1, 2007
Viral infections are common
among people of all ages but often seem to be concentrated in infants
and children. Most childhood viral infections are not serious and
include such diverse illnesses as colds with a sore throat, vomiting
and diarrhea, and...
Central
Nervous System Infections
May 1, 2007
Central nervous
system infections are extremely serious. Meningitis affects
the membranes surrounding the brain and spinal cord. Encephalitis affects
the brain itself....
Chickenpox
May 1, 2007
Chickenpox
(varicella) is a highly contagious infection with the varicella-zoster
virus that produces a characteristic itchy rash, consisting of small,
raised, blistered, or crusted spots....
Erythema
Infectiosum
May 1, 2007
Erythema infectiosum
(fifth disease, parvovirus B19 infection) is a contagious viral
infection that causes a blotchy or raised red rash with mild illness....
Human
Immunodeficiency Virus (HIV) Infection
May 1, 2007
Human immunodeficiency
virus (HIV) infection is a viral infection that progressively destroys
certain white blood cells and causes acquired immunodeficiency syndrome (AIDS)....
Measles
May 1, 2007
Measles (rubeola,
9-day measles) is a highly contagious viral infection that produces
various symptoms and a characteristic rash....
Mumps
May 1, 2007
Mumps (epidemic
parotitis) is a contagious viral infection that causes painful enlargement of
the salivary glands. The infection may also affect the testes, brain,
and pancreas, especially in adults....
Polio
May 1, 2007
Polio (poliomyelitis,
infantile paralysis) is a highly contagious, sometimes fatal, viral
infection that affects nerves and can produce permanent muscle weakness,
paralysis, and other symptoms....
Respiratory
Tract Infections
May 1, 2007
Respiratory
tract infections affect the nose, throat, and airways and may be
caused by any of several different viruses....
Roseola Infantum
May 1, 2007
Roseola infantum
(exanthem subitum, pseudorubella) is a viral infection of infants
or very young children that causes a high fever followed by a rash....
Rotavirus
Infection
May 1, 2007
Rotavirus
is a common and contagious virus that causes vomiting and diarrhea....
Rubella
May 1, 2007
Rubella (German
measles, 3-day measles) is a contagious viral infection that produces
mild symptoms, such as joint pain and a rash....
Subacute
Sclerosing Panencephalitis (SSPE)
May 1, 2007
Subacute
sclerosing panencephalitis, a progressive and usually fatal disorder,
is a rare complication of measles that appears months or years later
and produces mental deterioration, muscle jerks, and seizures....
Juvenile
Idiopathic Arthritis (JIA)
May 1, 2007
Juvenile
idiopathic arthritis is persistent or recurring inflammation of
the joints similar to rheumatoid arthritis (see ) but beginning
at or before age 16....
Introduction
May 1, 2007
A prosthesis
is an artificial device that replaces a missing body part....
Prosthetic
Parts and Options
May 1, 2007
A limb prosthesis
has three main parts: the interface, the components, and the cover....
Preparing
to Use a Prosthesis
May 1, 2007
Before surgery, a
surgeon, prosthetist, and physical therapist discuss plans and goals
with the person who requires amputation. Also before surgery, everyone
who requires an amputation should, if possible, discuss what happens
after surgery with a pe...
Fitting
the Prosthesis
May 1, 2007
A prosthetist custom
designs the interface (socket and frame), then constructs it by
hand. The fit of the interface, particularly the socket, is crucial
to success—much more so than the type of prosthesis, including the
components. If the interface f...
Skin
Care
May 1, 2007
Skin that comes in
contact with the prosthesis must be cared for meticulously to prevent skin
damage such as irritation, skin breakdown, and infection. Skin breakdown
is the process of skin being worn away, possibly resulting in sores....
Swelling
May 1, 2007
The stump tends to
swell when the liner is not worn, as occurs during sleep. Consequently,
people may have difficulty putting the prosthesis on after they
wake up. Wearing a shrinker (an elastic sock used to control swelling)
or an elastic bandage wh...
Loss
of Suction
May 1, 2007
Sometimes a prosthesis
becomes loose while it is being worn. The cause may be malfunction
of part of the prosthesis. The one-way valve on the socket (used
to form a tight seal) may leak, breaking the seal required to keep the
prosthesis on. Or other ...
Pain
May 1, 2007
Many people experience
phantom pain at some time. The phantom aspect is not the pain, which
is real, but the location of the pain—a limb that has been amputated.
Phantom pain is more likely if the pain before amputation was severe
or lasted a long ti...
Introduction
Apr 1, 2007
Everyone responds to drugs
differently. The way a person responds to a drug is affected by many
factors, including genetic makeup, age, body size, the use of other
drugs and dietary supplements (such as medicinal herbs—see ),
the consumption of food ...
Genetic
Makeup
Apr 1, 2007
Differences in genetic
(inherited) makeup among individuals affect what the body does to
a drug and what the drug does to the body. The study of genetic
differences in the response to drugs is called pharmacogenetics....
Drug
Interactions
Apr 1, 2007
The effect a drug has
on a person may be different than expected because that drug interacts
withAnother drug the person is
taking (drug-drug interaction)
Food, beverages, or supplements the person is consuming
(drug-nutrient interaction)
Another dis...
Tolerance and Resistance
Apr 1, 2007
Tolerance is
a person's diminished response to a drug, which occurs when the
drug is used repeatedly and the body adapts to the continued presence
of the drug. Resistance refers
to the ability of microorganisms or cancer cells to withstand the
effect...
Introduction
Apr 1, 2007
Drugs often have several
names. When a drug is first discovered, it is given a chemical name,
which describes the atomic or molecular structure of the drug. The
chemical name is thus usually too complex and cumbersome for general
use. Next, a shortha...
Bioequivalence
and Interchangeability of Generic Drugs
Apr 1, 2007
When a company develops
a generic version of a trade-name drug, the company's experts in drug
formulation must figure out how to make it. It is not enough for
them to simply reproduce the trade-name drug's chemical structure or
to buy the active ingr...
Generic
Biologic Drugs
Apr 1, 2007
Traditional drugs are
called small-molecule agents because the active ingredient is usually a
single, discrete chemical entity. Biologic drugs are complex products
that can be derived from viruses, blood and body tissues, antibodies,
toxins and antit...
Introduction
Apr 1, 2007
Over-the-counter
(OTC) drugs are those available without a prescription....
Precautions
With Over-the-Counter Drugs
Apr 1, 2007
Certain groups of people,
such as the very young, the very old, the very sick, and pregnant
and breastfeeding women, are more vulnerable to harm from drugs,
including OTC drugs. When such people use drugs, special precautions,
which may include a doc...
High Blood
Pressure
Apr 1, 2007
High blood
pressure (hypertension) is abnormally high pressure in the arteries....
Chronic Obstructive
Pulmonary Disease
Apr 1, 2007
Chronic obstructive
pulmonary disease is persistent obstruction of the airways occurring with
emphysema, chronic bronchitis, or both disorders....
Hearing
Loss and Deafness
Apr 1, 2007
Hearing
loss is deterioration in hearing. Deafness is profound hearing
loss....
Diabetes
Mellitus (DM)
Apr 1, 2007
Diabetes
mellitus is a disorder in which blood sugar (glucose) levels are
abnormally high because the body does not produce enough insulin....
Shock
Mar 1, 2007
Shock is a
life-threatening condition in which blood pressure is too low to
sustain life....
Introduction
Mar 1, 2007
Kidney and urinary tract
disorders can affect one or both kidneys, one or both ureters, the bladder,
or the urethra....
Symptoms
Mar 1, 2007
Some urinary tract disorders
rarely cause symptoms until the problem is very advanced; these
include kidney failure, tumors and stones that do not block urine
flow, and some low-grade infections. Sometimes, symptoms occur but
are very general and dif...
Diagnosis
Mar 1, 2007
During a physical
examination of a person whose symptoms may indicate a kidney disorder,
a doctor may attempt to feel the kidneys. Normal kidneys cannot
usually be felt in children or adults (though they may be felt in
newborn infants). Enlarged kidn...
Introduction
Mar 1, 2007
Each kidney contains about 1 million filtering
units (glomeruli). The glomeruli are made up of many microscopic
clusters of tiny blood vessels (capillaries) with small pores. These blood
vessels are designed to leak fluid from the bloodstream into a ...
Glomerulonephritis
(Nephritic Syndrome)
Mar 1, 2007
Glomerulonephritis
(nephritic syndrome) is a disorder of glomeruli (clusters of microscopic blood
vessels in the kidneys with small pores through which blood is filtered).
It is characterized by body tissue swelling (edema), high blood
pressure, and ...
Nephrotic
Syndrome
Mar 1, 2007
Nephrotic
syndrome is a disorder of the glomeruli (clusters of microscopic
blood vessels in the kidneys that have small pores through which
blood is filtered) in which excessive amounts of protein are excreted
in the urine. This typically leads to ac...
Tubulointerstitial
Nephritis
Mar 1, 2007
Tubulointerstitial
nephritis is inflammation that affects the tubules of the kidneys
and the tissues that surround them (interstitial tissue). ...
Introduction
Mar 1, 2007
Parasitic infections are more common in rural or
developing areas than in industrialized areas.
In industrialized areas, these infections may occur
in immigrants or people with a weakened immune system.
Parasites usually enter the body through the m...
Amebiasis
Mar 1, 2007
Amebiasis
is an infection of the large intestine and sometimes the liver and
other organs caused by the single-celled, protozoan parasite Entamoeba
histolytica, an ameba. Amebiasis may cause diarrhea,
cramping abdominal pain, pain over the liver, and...
Amebic
Infections Due to
Free-Living Amebas
Mar 1, 2007
Free-living amebas are
protozoa that live in soil or water and do not need to live in people or
animals. Although they rarely cause human infection, certain types
of these amebas can cause serious, life-threatening diseases. The most
common disorders...
Ascariasis
Mar 1, 2007
Ascariasis
is infection caused by Ascaris lumbricoides, an
intestinal roundworm. The infection often causes no symptoms but
may cause fever, coughing, and wheezing, followed by abdominal cramps.
In severe infections, children may not grow normally, o...
Babesiosis
Mar 1, 2007
Babesiosis
is infection of red blood cells caused by the single-celled protozoan
parasite Babesia. The infection may
cause fever, headache, body aches, and fatigue....
Cryptosporidiosis
Mar 1, 2007
Cryptosporidiosis
is an intestinal infection caused by Cryptosporidium,
a protozoan. The main symptoms are abdominal cramping and diarrhea.People acquire the infection
by consuming contaminated water or food or by having contact with
contaminated peo...
Giardiasis
Mar 1, 2007
Giardiasis
is an infection of the small intestine caused by the single-celled
protozoan parasite Giardia lamblia.
The main symptoms are abdominal cramping and diarrhea.People may have abdominal
cramping, gas, belching, diarrhea, and nausea and feel v...
Hookworm
Infection
Mar 1, 2007
Hookworm
infection (ancylostomiasis) is an infection of the intestines that
can cause an itchy rash, respiratory and gastrointestinal problems,
and eventually chronic blood loss and iron deficiency anemia.People can become infected
when walking baref...
Leishmaniasis
Mar 1, 2007
Leishmaniasis
is caused by several species of Leishmania protozoa.
Leishmaniasis includes disorders that affect internal organs and
those that affect the skin and sometimes mucous membranes of the
nose and mouth, causing bumps or sores.The protozoa a...
Malaria
Mar 1, 2007
Malaria is
infection of red blood cells with one of four species of Plasmodium, a
protozoan. Malaria causes fever, chills, sweating, an enlarged spleen,
and anemia (due to the breakdown of infected red blood cells).Usually, malaria is spread
through ...
Microsporidiosis
Mar 1, 2007
Microsporidiosis
is infection caused by Microsporidia protozoa.
It causes diarrhea and eye symptoms.
This infection usually causes symptoms only in people
with a weakened immune system, such as people with AIDS.
Symptoms vary but include chronic diar...
Onchocerciasis
Mar 1, 2007
Onchocerciasis
(river blindness) is infection with the roundworm Onchocerca
volvulus. It causes itching, a rash, sometimes with
scarring, as well as eye symptoms that may lead to blindness.The infection is spread through
the bite of female blackflies...
Pinworm
Infection
Mar 1, 2007
Pinworm infection
(enterobiasis) is caused by the intestinal roundworm Enterobius
vermicularis and may cause itching in the area around
the anus. It usually affects children.People acquire the infection
when they swallow eggs of the roundworm.
Often,...
Schistosomiasis
Mar 1, 2007
Schistosomiasis
(bilharziasis) is infection caused by flatworms (flukes). It often
causes rash, fever, chills, and muscle ache and sometimes causes
abdominal pain and diarrhea or urinary pain and bleeding.People acquire the infection
by swimming or b...
Tapeworm
Infection
Mar 1, 2007
Tapeworm infection
of the intestine occurs when people eat raw, contaminated pork,
beef, or freshwater fish. Most people with tapeworms have no symptoms,
but some report abdominal discomfort, diarrhea, and loss of appetite.
Anemia may develop in peop...
Toxocariasis
Mar 1, 2007
Toxocariasis
(visceral larva migrans) is infection caused by larvae of the roundworms Toxocara
canis or Toxocara cati.
Symptoms may include fever and cough or wheezing.Young children can acquire
the infection when they eat soil contaminated animal fe...
Toxoplasmosis
Mar 1, 2007
Toxoplasmosis
is infection caused by the single-celled protozoan parasite Toxoplasma
gondii. Symptoms may include swollen lymph nodes,
fever, a vague ill feeling, and sometimes a sore throat, blurred
vision, and eye pain.People
acquire the infection ...
Trichinosis
Mar 1, 2007
Trichinosis
is infection caused by the roundworm Trichinella
spiralis. Symptoms include diarrhea, abdominal cramps,
muscle pain, and fever.People
acquire the infection by eating undercooked contaminated meat.
At first, people have nausea, diarrhea, a...
Whipworm
Infection
Mar 1, 2007
Whipworm infection
(trichuriasis) is an intestinal infection caused by the roundworm Trichuris
trichiura. Severe infection causes gastrointestinal
symptoms.People
acquire the infection by eating foods contaminated with soil that
contains the roundwor...
Introduction
Mar 1, 2007
Disorders that affect the
female reproductive system are called gynecologic disorders. Breast
disorders are often also considered gynecologic disorders....
Symptoms
Mar 1, 2007
The most common symptoms
of gynecologic disorders include vaginal itching, a vaginal discharge,
abnormal bleeding from the vagina, pain in the pelvic area, and
breast pain and lumps (see ).
The significance of gynecologic symptoms often depends on th...
Gynecologic
Evaluation
Mar 1, 2007
Preventive healthcare includes
having regular gynecologic examinations, even when no symptoms are
present, and screening tests. Screening tests are done before people
have any symptoms to check for disorders that can be prevented or
treated effective...
Committed to Providing
Medical Information: Merck and The Merck Manuals
Mar 1, 2007
In 1899, the American drug manufacturer Merck & Co. first
published a small book titled Merck's Manual of the Materia
Medica. It was meant as an aid to physicians and pharmacists,
reminding doctors that “Memory is treacherous.” Compact in size,
easy ...
Preface
Mar 1, 2007
In this, the "information age," an interested reader can easily
locate information on everything from movies to medical care. When
it comes to health and disease, however, the quality of
information is vital. A reader should ask: Is the information I...
Editorial Board
Mar 1, 2007
...
Editors
Mar 1, 2007
...
Editorial Staff
Mar 1, 2007
...
Web Site Development and Production Staff
Mar 1, 2007
...
A Guide for Readers
Mar 1, 2007
The Merck Manual of Medical Information—Home Edition is
organized into sections, chapters, and topics, all of which are listed
alphabetically in this online version. The names of some chapters
and topics have been edited (and may be different from th...
Herpes
Simplex Virus Infections
Feb 4, 2007
Herpes simplex
virus infection causes recurring episodes of small, painful, fluid-filled
blisters on the skin, mouth, lips (cold sores), eyes, or genitals.This very contagious infection
is spread by direct contact with sores or sometimes with the aff...
Introduction
Feb 1, 2007
The pituitary
is a pea-sized gland that is housed within a bony structure (sella
turcica) at the base of the brain. The sella turcica protects the
pituitary but allows very little room for expansion....
Enlargement
of the Pituitary Gland
Feb 1, 2007
Enlargement of the pituitary
gland is usually due to a tumor but may be due to bleeding into the
gland or involvement by some other disease, such as tuberculosis
or sarcoidosis. An enlarged pituitary gland may produce symptoms
such as headaches. Beca...
Hypopituitarism
Feb 1, 2007
Hypopituitarism
is an underactive pituitary gland that results in deficiency of
one or more pituitary hormones....
Central
Diabetes Insipidus
Feb 1, 2007
Central diabetes
insipidus is a lack of antidiuretic hormone that causes excessive
production of very dilute urine (polyuria)....
Acromegaly
and Gigantism
Feb 1, 2007
Overproduction
of growth hormone causes excessive growth. In children, the condition
is called gigantism. In adults, it is called acromegaly....
Galactorrhea
Feb 1, 2007
Galactorrhea
is the production of breast milk in men or in women who are not
breastfeeding....
Empty
Sella Syndrome
Feb 1, 2007
In empty sella
syndrome, the sella turcica (the bony structure at the base of the
brain that houses the pituitary gland) enlarges, but the pituitary
remains normal-sized or shrinks....
Introduction
Feb 1, 2007
A virus is a small infectious organism—much
smaller than a fungus or bacterium—that must invade a living cell
to reproduce (replicate). The virus attaches to a cell (called the
host cell), enters it, and releases its DNA or RNA inside the cell.
The v...
Smallpox
Feb 1, 2007
Smallpox (variola)
is a highly contagious, very deadly disease caused by the smallpox
virus.People
can acquire the infection by breathing air exhaled or coughed out
by an infected person.
People have a fever, headache, backache, and rash,
sometimes w...
Common
Cold
Feb 1, 2007
The common
cold is a viral infection of the lining of the nose, sinuses, throat,
and large airwaysUsually,
colds are spread when a person's hands come in contact with nasal
secretions from an infected person.
Colds often start with a scratchy or sore...
Influenza
Feb 1, 2007
Influenza
(flu) is infection of the lungs and airways with one of the influenza
viruses. It causes a fever, runny nose, sore throat, cough, headache,
muscle aches (myalgias), and a general feeling of illness (malaise).The virus is spread by inhaling
...
Shingles
Feb 1, 2007
Shingles (herpes
zoster) is infection that results from reactivation of the varicella-zoster virus,
the virus that causes chickenpox. Shingles causes a painful skin
eruption of fluid-filled blisters and sometimes results in chronic pain
in the affect...
Epstein-Barr
Virus (EBV) Infection
Feb 1, 2007
Epstein-Barr
virus causes a number of diseases, including infectious mononucleosis.The infection is spread through
kissing or other close contact with an infected person.
Symptoms vary, but the most common are extreme fatigue,
fever, sore throat, and...
Cytomegalovirus (CMV) Infection
Feb 1, 2007
Cytomegalovirus
infection is a common herpesvirus infection with a wide range of
symptoms: from no symptoms to fever and fatigue (resembling infectious
mononucleosis) to severe symptoms involving the eyes, brain, or other
internal organs.This
virus i...
Hemorrhagic
Fevers
Feb 1, 2007
Hemorrhagic
fevers are serious viral infections characterized by bleeding. These
infections occur primarily in parts of Africa and South America.These infections may be spread
through contact with skin or body fluids of an infected person,
through th...
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