Pain

Some people may think that English novelist Daniel Defoe should have included pain alongside death and taxes on his list of unavoidable evils. However, including pain would have been a mistake: Pain is not an unavoidable consequence of aging.

Almost every older person has pain now and then, and some are unfortunate enough to have pain almost every waking minute. Some older people assume that pain is a normal part of old age and do not seek treatment. Or they may think that admitting to pain is a sign of weakness. Others fear the side effects of drugs used to treat pain.

Feeling pain is bad enough, but pain can also wreak havoc on a person's quality of life and ability to function. Older people with pain may lose sleep and become exhausted. Pain may affect appetite, which can then result in undernutrition. Pain may prevent people from interacting with others, causing them to become isolated and depressed. Some people become so irritable because of pain that they alienate others. When pain interferes with the ability to carry out daily activities, older people become more dependent on others.

Sometimes pain is severe enough to confine a person to a chair or bed, increasing the risk of problems such as pressure sores. The risk of falls may also increase: a chair- or bed-bound person grows progressively weaker, creating a potential hazard when trying to get up.

Causes

The causes of pain are almost limitless. Finding the specific cause of pain in older people often proves to be particularly difficult. Sometimes pain has more than one possible cause. And sometimes no cause can be identified.

To make thinking about possible causes easier, doctors often describe pain as acute or chronic. Acute pain develops suddenly and does not last very long. Acute pain is often caused by an event that has a clear beginning and end, such as an accident or surgery. Chronic pain develops gradually and lasts a long time. Chronic pain often has no clear beginning or end, especially when the cause is a chronic disease (for example, arthritis or diabetes mellitus).

See the figure What Is Referred Pain?

Pain is sometimes felt in one area of the body when the problem causing it is located in another area. This type of pain is called referred pain. For example, pain due to infection and inflammation in the gallbladder may be felt in the shoulder. Referred pain happens because messages from several areas of the body often travel along the same nerves going to the spinal cord and brain.

For additional detail on this topic, see Nociceptive, Neuropathic, and Psychogenic Pain.

Symptoms and Diagnosis

Pain is described in many different ways: aching, throbbing, squeezing, burning, shooting, and stabbing. Pain can range in severity from mild or annoying to severe or excruciating.

Because pain is so common, many doctors routinely question people about it regardless of the reason for their office visit. Neither examinations nor tests can prove that a person is in pain. Instead, the doctor asks a series of questions. The person's answers can indicate whether the pain is acute or chronic and possibly help identify any causes of the pain.

Questions the doctor might ask can include the following:

• When and how did the pain start? Did it begin suddenly or gradually? Was there a specific event that seemed to trigger the pain?
• What is the pain like? Is there a pattern (for example, steadily worsening, always present, comes and goes, only after meals, or never disrupts sleep)?
• How intense is the pain?
• Where is the pain?
• What makes the pain worse? What makes the pain better?
• Does pain affect the ability to carry out daily activities? How are sleep, appetite, and bowel and bladder function affected?
• Does pain affect mood and sense of well-being? Is the pain accompanied by feelings of depression or anxiety?

Questions also focus on past and present medical problems that might have a role in causing or worsening the pain. Questions are also posed about current and prior drug use, including pain relievers (analgesics).

Other kinds of questions help the doctor gather more information. For example, the person may be asked to rate the intensity of the pain on a scale of 1 to 10, with 1 representing a very small amount of pain and 10 representing the worst pain imaginable. Some doctors ask people to respond to a set of questions developed by experts (a pain assessment tool).

Sometimes obtaining information by asking questions is difficult or even impossible. For example, an older person who has had a stroke may be unable to answer because of damage to parts of the brain that control speech. The person may be able to answer "yes" or "no" by making sounds, blinking, or raising a finger or hand. The doctor may show the person a series of pictures depicting faces a person might make when experiencing different amounts of pain. The person can then point to the face that best represents the amount of pain experienced.

In some cases, a person cannot understand questions about pain and cannot describe the pain, even with a tool that uses pictures. For example, a person with dementia or someone who has had a massive stroke may have no way to understand the questions or to communicate. The doctor may have to rely on observations from caregivers. A caregiver may have noticed a change in behavior (for example, a normally outgoing person who withdraws or a calm person who becomes disruptive or aggressive). Changes in sleep patterns or a decrease in appetite may also indicate pain.

A physical examination can provide useful information. Facial expressions can suggest or hint at pain—for example, when a person frowns frequently or seems frightened. Grimacing, tight wrinkling of the forehead, and rapid blinking or eye closing may suggest pain. The person may hold his body rigid or seem to withdraw or guard a painful area when the doctor tries to examine it.

See the figure Quantifying Pain.

Pale skin, sweating, and a fast heart rate may indicate acute pain. The doctor feels for trigger points, which produce pain when touched. Joints are checked for swelling and inflammation. The doctor also moves the person's arms and legs through their normal range of motion to see if these motions produce pain. The skin may be touched with a variety of objects (for example, soft objects versus sharp objects), to check for abnormal nerve activity.

Treatment

Often, pain goes away by itself. When pain worsens or persists, people usually seek relief.

Treatment begins with a discussion between the person, if able, and the doctor. The discussion is an opportunity to review goals of treatment, expectations, and possible benefits as well as risks and side effects of each treatment choice.

Pain is most often treated with drugs, but there are many effective nondrug treatments. Drugs combined with nondrug treatment can result in better pain control than either method used alone.

Nondrug treatments: Muscle and joint pain may respond to gentle stretching of muscles and movement of joints through their normal range of motion. Massaging painful muscles may also be helpful.

Applying ice, a cold pack, or cold compresses to a painful area may help reduce discomfort that accompanies swelling and inflammation when muscles, ligaments, or tendons are injured. Cold therapy also helps relieve discomfort due to muscle spasms.

Heating pads, warm compresses, hot packs, infrared heat, and hydrotherapy (whirlpool with warm water) can relieve pain on or just below the skin. Heat generated with electrical current (diathermy) or high-frequency sound waves (ultrasound) relieves pain in deeper tissues. Applying heat to painful strained muscles may reduce discomfort. Heat also helps relieve pain in stiff joints affected by arthritis and pain due to sprained ligaments.

Transcutaneous electrical nerve stimulation (TENS) can help relieve pain by applying a gentle electrical current through electrodes placed on the skin's surface. TENS seems to work best when combined with drugs that relieve pain (analgesics).

Acupuncture, which involves inserting hair-thin needles into specific areas of the body, may help relieve pain in some people. Chiropractic therapy may relieve some types of discomfort, such as low back pain.

Cognitive therapy attempts to improve the person's ability to cope with pain and works best when combined with other types of treatment. Types of cognitive therapy include relaxation training, biofeedback, and hypnosis.

Psychologic support can be very helpful for people who live with chronic pain that is not completely relieved.

Drug therapy: Many drugs to relieve pain (analgesics) are available. Unfortunately, older people are more likely than younger people to experience side effects of some analgesics. Doctors "start low and go slow" when deciding how big a dose to start with and how often to increase the dose. In other words, doctors use the lowest dose that provides relief and change doses slowly and cautiously. This approach usually enables older people to safely obtain relief from pain.

Generally, chronic pain is best treated with long-acting or sustained-release drugs that provide steady relief over many hours. Short-acting drugs, which work quickly, may be used while waiting for a long-acting drug to take effect. Relying solely on short-acting drugs may result in peaks of relief alternating with valleys when the pain is poorly controlled.

Under most circumstances, analgesics are taken by mouth. Certain analgesics can be taken under the tongue, as skin patches, or as suppositories inserted into the rectum. Such dosage forms are helpful for people who have trouble swallowing. When rapid action is needed, some opioid analgesics (such as morphine) can be injected directly into a vein (intravenously). If a doctor prescribes patient-controlled analgesia (PCA), the person has some control over the timing and dose of intravenous opioid analgesics.

Analgesics can be divided into three main categories: nonopioids, opioids, and adjuvants (auxiliary drugs).

Nonopioids include nonsteroidal anti-inflammatory drugs (NSAIDs) and acetaminophen. NSAIDs and acetaminophen are equally effective for relieving pain and are commonly used to treat headaches and muscle and joint pain. Unlike acetaminophen, NSAIDs also reduce inflammation. Reducing inflammation often directly treats the cause of pain, thus providing a cure or control rather than simply relief of pain. Some NSAIDs, such as aspirin and low doses of ibuprofen, are available without a prescription.

Aspirin, one type of NSAID, is a tried and true pain reliever. It is relatively safe, although it can irritate the stomach and increase the risk of bleeding. Taking an antacid along with the aspirin (as in buffered aspirin) decreases the likelihood of stomach irritation. Aspirin increases the risk of bleeding because it interferes with the function of platelets, cell-like microscopic particles in the blood that help the blood clot. Taken regularly and at high doses, aspirin may interfere with breathing or produce ringing or other abnormal noises in the ear (tinnitus).

NSAIDs other than aspirin, such as ibuprofen and naproxen, are about equal to aspirin for pain relief. Which NSAID will relieve pain most effectively is impossible to predict. Like aspirin, ibuprofen and naproxen can irritate the stomach and cause bleeding. The risk of side effects, especially the risk of bleeding in the digestive tract, is very high among older people.

Taking NSAIDs with food or liquids reduces the risk of bleeding. Taking other drugs that help protect the digestive tract at the same time, such as misoprostol, histamine-2 (H₂) receptor blockers, and proton pump inhibitors, can also reduce the risk of bleeding.

Coxibs, or COX-2 inhibitors, are another type of NSAID. Compared with other NSAIDs, coxibs provide similar pain relief and are less likely to irritate the stomach or cause bleeding in the digestive tract. However, one of the coxibs, rofecoxib (withdrawn from the market), appears to increase the risk of heart attack and stroke after long-term use. The risk with other coxibs is being studied. Because one recent study has shown a 2.5-fold increase in cardiovascular problems with another coxib, 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.

With all NSAIDs, including coxibs, there is a risk of kidney damage. NSAIDs can also cause the body to retain salt (sodium), which may in turn lead to swelling (especially in the feet and ankles) and sometimes an increase in blood pressure. Someone who has had bleeding in the digestive tract or kidney damage should not use NSAIDs.

Acetaminophen, available in several forms and dosages, is a nonprescription drug. Although safer than most other analgesics, acetaminophen can cause dangerous side effects when it is used in large amounts or for a long time. For example, more than 12 regular-strength or 8 extra-strength tablets taken in a single day may damage the liver. In some cases, the damage can cause death. A person with liver disease should not use acetaminophen. More than 12 regular-strength or 8 extra-strength tablets taken daily or almost daily for many years can damage the kidneys.

Opioids are the most powerful analgesics. They are used most often for severe acute pain (such as pain after surgery) and for chronic pain that occurs with cancer. The ability to relieve pain varies widely among different opioids.

With prolonged use of opioids, some people need higher doses because the body sometimes adapts to and responds less well to the drug—a phenomenon called tolerance. People who take opioids for a long time may become dependent on them; that is, they experience symptoms of withdrawal if the drug is discontinued abruptly. These symptoms may include confusion, sweating, and nausea. When opioids are discontinued after long-term use, doctors slowly and steadily reduce the dose to minimize the risk of withdrawal symptoms.

Opioids have many side effects. Many people who take opioids for acute pain become drowsy at first. For some people, this drowsiness may not be a side effect. Rather, it may represent the ability to finally rest as pain is relieved. Many people find the drowsiness a welcome respite; others do not. When opioids are taken regularly, most people stop feeling drowsy. Similarly, many other undesirable side effects diminish. Constipation is an exception.

Almost every older person who takes opioids becomes constipated. Constipation continues to be a problem as long as the opioid is taken. Consequently, some people who take opioids regularly must prevent constipation by increasing their activity, increasing their intake of fluids, and taking laxatives. Laxatives that stimulate the large intestine, such as bisacodyl, cascara, and senna, are often used to treat the constipation caused by opioids. Others such as lactulose or sorbitol may be used over a longer period of time without damaging the digestive tract.

Opioids can cause confusion, especially in older people. This side effect may diminish, but often the amount of the drug or the frequency at which it is taken must be decreased. If confusion persists, some people may need to be switched to a different drug.

Opioids can also make urination (voiding) more difficult, causing urine to remain in the bladder after urinating. One way a person can try to overcome this problem is by urinating again almost immediately after urinating (double voiding).

Opioids can sometimes affect appetite. They may also cause nausea—a particularly troubling problem when a person is already experiencing nausea as a result of the pain. Antiemetic drugs (such as metoclopramide, hydroxyzine, ondansetron, and prochlorperazine) can help prevent or relieve nausea.

Taking too much of an opioid can cause a dangerous slowing of breathing, coma, and even death. These effects can be reversed with naloxone, an antidote given intravenously.

See the table Opioid Analgesics.

Adjuvants are drugs that are not usually given to treat pain but that may relieve pain in certain circumstances. Antidepressants, anticonvulsants, and oral and topical local anesthetics are adjuvants. When used to relieve pain, adjuvants are usually combined with other analgesics or nondrug pain treatments.

Antidepressants can help relieve pain in people who do not have depression. Tricyclic antidepressants (such as nortriptyline) have been used for many years for this purpose. Selective serotonin reuptake inhibitors (SSRIs), another type of antidepressant that includes fluoxetine and sertraline, can be used.

Anticonvulsants can be used to help relieve pain caused by abnormal nerve activity (neuropathic pain). Gabapentin is commonly used, but others (such as carbamazepine) may be tried.

Anesthetics are sometimes injected directly in or near a sore area or trigger point to help reduce pain. Occasionally, severe long-lasting pain related to nerve injury can be treated by injecting a chemical into the nerve to destroy it.

Some anesthetic drugs can be applied to the skin as a lotion or ointment or in a patch to control pain resulting from problems on or just below the skin. For example, a lidocaine patch can be used to relieve the pain that sometimes follows shingles (postherpetic neuralgia).

A cream containing capsaicin, a substance found in hot peppers, sometimes helps reduce the pain caused by such disorders as shingles and osteoarthritis. This cream must be applied several times a day.