Dizziness

Dizziness is an uncomfortable, troubling sensation that can feel like spinning, unsteadiness, or light-headedness.

While standing still, some people feel as if the world is spinning around them, making them feel nauseated. While walking, some people feel their knees go wobbly, and they feel unsteady and shaky. Just after standing up, some people sway, feel as if their head is swimming, and sometimes drop right back down in the chair. After standing for a while, some people feel light-headed. All of these people may say they feel dizzy.

Because so many different feelings can be described as dizziness, doctors often try to put dizziness into categories. These categories help people understand each other when they talk about dizziness. Four categories are usually used.

Vertigo is a sensation of motion when there is no motion. It is often described as spinning. Vertigo is what some people have just after they ride on a carousel. They briefly feel as though they are still moving, even after they have both feet planted firmly on the ground. People with vertigo may feel that they are moving or that the surroundings are moving while they remain still. Vertigo usually occurs when a person is standing. But it sometimes occurs while a person is sitting, lying down, or changing position. People with vertigo may also have nausea, sometimes with vomiting, and abnormal jerky eye movements (nystagmus).

Dysequilibrium is a sense of unsteadiness or loss of balance that involves the legs or trunk. Dysequilibrium may occur while a person is standing or walking.

Light-headedness is a feeling that fainting may occur in the next few moments. Light-headedness usually occurs when a person gets up quickly after sitting or lying down for a while.

Mixed dizziness is a miscellaneous category. It refers to dizziness that does not fit neatly into one of the other three categories.

The categories seem to work fairly well for dizziness that lasts less than a month (temporary or acute dizziness). But for dizziness that lasts more than a month (persistent or chronic dizziness), the categories start to blur together. For example, dizziness may seem like light-headedness and vertigo at the same time. Or dizziness may seem to change from one category to another over time. Older people usually have chronic dizziness, so the categories are less helpful.

See the table Problems That Can Contribute to Dizziness.

Causes

Dizziness may occur when the brain gets wrong or conflicting information about the body's position in relation to the surroundings and to the body's movements. Several parts of the body provide this information. They include the eyes, a structure in the inner ear (called the vestibular labyrinth), and the nerves that carry information from large joints (in the neck, hips, knees, and ankles) to the brain. The brain constantly uses information from these body parts to direct the activities of muscles and joints so that balance and stability are maintained. When the body cannot maintain balance and stability, dizziness sometimes occurs.

Aging itself can cause some of the body parts involved in balance to function less well. But the effect is not enough to cause dizziness unless a person also has a disorder or takes a drug that adds to the effect. Having problems with several of the body parts involved in balance is a common cause of dizziness in older people. For example, a person may have vision problems, inner ear (vestibular) problems, and nerve damage or arthritis (which can interfere with information sent from the joints to the brain). In such cases, the brain does not get enough information to maintain balance and stability.

Many disorders can cause dizziness. Among older people common causes include two disorders of the inner ear: benign positional vertigo and Meniere's disease.

• Benign positional vertigo: Vertigo occurs when the head is moved—for example, when a person lies down, gets up, turns over in bed, or looks up. Benign positional vertigo develops when particles that are normally distributed evenly in the fluid-filled canals of the inner ear clump together.
• Meniere's disease: Vertigo is usually accompanied by hearing loss and a low roaring or ringing in the ears (tinnitus). Meniere's disease is caused by excess fluid in the inner ear.

Some disorders cause light-headedness only during or after certain activities. For example, an excessive fall in blood pressure after standing up quickly (orthostatic hypotension) or after eating a meal (postprandial hypotension) can make people feel light-headed after those activities. In both cases, the brain does not get enough blood because blood pressure is too low.

Some disorders tend to cause temporary dizziness. For example, a person who has a heart attack may suddenly feel dizzy (usually light-headed) and continue to feel that way for a few days to a few weeks. As the heart heals, the feeling goes away. With other disorders, how long dizziness will last is uncertain. For example, if a person with diabetes develops dysequilibrium, it may go away in a month, or it may last for a lifetime (although its severity may vary). Depression sometimes causes dizziness. People who are depressed may lose confidence in their ability to interact with their surroundings. They may then feel unsteady or light-headed.

A low number of red blood cells (anemia), a low or high level of sugar (glucose), or a low level of vitamin B₁₂ may contribute to dizziness. An underactive thyroid gland (hypothyroidism) can cause dizziness.

Dizziness can also be a temporary side effect of certain drugs, including many taken for high blood pressure. This type of dizziness often goes away after a person takes the drug for a week or two. Antihistamines and sleep aids, including nonprescription ones, can contribute to dizziness.

Certain situations can cause temporary dizziness in healthy people. For example, turning around or standing up very quickly can cause a brief period of dizziness. Wearing bifocals may cause dizziness when a person goes down stairs or looks down.

Diagnosis

People who experience dizziness should report it to their doctor. A doctor tries to identify what is causing the dizziness and whether the dizziness fits into a specific category, such as vertigo. To do so, the doctor asks the person to describe the dizziness. For example, the doctor asks whether the dizziness is accompanied by other symptoms, such as nausea. The doctor also asks how long the dizziness has been present. If dizziness has been present for less than a month, the doctor may ask whether the person started taking any new prescription or nonprescription drugs and whether the dosages of any drugs have changed recently. If the dizziness has lasted more than a month, the doctor checks for certain disorders that may be causing the dizziness.

The doctor performs a physical examination. Hearing is tested to help determine if an ear is malfunctioning. If one ear hears better than the other, the person may have an inner ear disorder, which may be contributing to dizziness. Vision is tested, and the eyes are checked for specific problems that can limit vision, such as cataracts.

The doctor sometimes observes the eyes for abnormal jerking movements (nystagmus), which may indicate an inner ear disorder. The doctor may perform a simple maneuver, called the Hallpike maneuver. For this maneuver, the person sits on a table. The doctor rapidly lays the person down with the person's head hanging over the edge of the table. In the same movement, the doctor turns the person's head to the right or left. If the dizziness is caused by an inner ear disorder, the Hallpike maneuver may quickly produce nystagmus and dizziness.

The doctor uses a stethoscope to check the rate, rhythm, and sound of the heartbeat. Blood pressure is measured after the person has been lying down for about 5 minutes and immediately after the person stands up. Sometimes it is measured again after 3 minutes. These measurements help determine whether the cause of the dizziness is orthostatic hypotension.

The doctor checks some aspects of brain and nerve function, particularly the senses of position and balance. For example, a person may be asked to stand still with the eyes open, then with the eyes closed. If the person sways more than expected, the dizziness may be caused by an inner ear disorder, a brain disorder, or a problem with the body's ability to send information from the large joints to the brain.

Blood tests may be done. Typically, the number of red blood cells and levels of sugar, vitamin B₁₂, and thyroid hormones are measured.

If evidence suggests a heart disorder, especially an abnormal heart rhythm, electrocardiography (ECG) may be done to record the electrical activity of the heart. The person may be asked to wear a small, battery-powered ECG device (Holter monitor) for 1 or 2 days. If evidence suggests a brain disorder, computed tomography (CT) or magnetic resonance imaging (MRI) may be done to obtain images of the brain.

Treatment and Prevention

The goals of treatment are correcting or controlling possible causes of dizziness and enabling people to prevent or control dizziness so that they can do daily activities safely.

Sometimes dizziness can be cured. For example, if a drug is causing it, the drug can be stopped and changed to something else. If the cause is benign positional vertigo, the Epley maneuver may provide a cure. The Epley maneuver resembles the Hallpike maneuver, which is used for diagnosis. If persistent light-headedness is related to episodes of low blood pressure that occur when a person stands up or after a person eats, wearing support stockings (compression stockings) may help. Drugs such as fludrocortisone and midodrine may be used.

See the figure The Epley Maneuver: A Possible Cure for Vertigo?

People who have experienced dizziness should not take nonprescription drugs that may contribute to dizziness, such as antihistamines or sleep aids. Antihistamines can worsen dizziness in older people, even though low doses of these drugs help a few younger adults who have persistent vertigo.

If dizziness persists despite treatment, people can learn how to avoid movements that tend to trigger dizziness. Examples are looking up, reaching up, or bending down. One way to avoid these movements is to store household items between waist and eye level. Getting up slowly after sitting or lying down for a while can help. Clenching the hands and flexing the feet sometimes helps, especially if the dizziness feels like light-headedness.

Outlook

For some people, dizziness goes away or lessens without treatment. For others, dizziness goes away or lessens only after the cause is corrected. For still others, dizziness, even when treated, lasts for months or years. However, most of these people can cope and continue everyday activities, especially when treatment controls the dizziness to some degree.