MULTIPLE SCLEROSIS

DEFINITION

Multiple sclerosis (MS; pronounced multiple skluh-RO-siss) is a chronic autoimmune disorder (see autoimmune disorders entry) that affects the nerves. "Chronic" means that it develops slowly over time; "autoimmune" means that the body's immune system becomes confused about some part of the body it is designed to protect. It attacks that part of the body as if it were a foreign invader. MS affects a person's ability to move, to feel, and to control his or her body functions.

DESCRIPTION

Nerve messages consist of electrical impulses that travel through the body by means of nerve cells. Nerve cells are also called neurons. Neurons are covered by a thin layer of tissue known as myelin (pronounced MY-uh-lin) that acts as an insulator. It prevents the electrical currents that pass through neurons from leaking away.

MS occurs when the myelin that surrounds neurons in the brain and spinal cord is destroyed. The loss of myelin causes electrical impulses to pass through neurons more slowly. Over time, scar tissue forms around the damaged myelin. This scar tissue, called plaque (pronounced PLAK), also reduces the neurons' ability to function normally.

Damage to myelin can cause a variety of symptoms. A person may lose the ability to use his or her senses, such as touch and vision. Loss of muscular control also occurs because movement of muscles is controlled by nerves. A person with MS may have problems with balance, strength, and coordination.

MS affects more than 250,000 people in the United States. Most people experience their first symptoms between the ages of twenty and forty. Symptoms rarely begin before the age of fifteen or after sixty. Women are twice as likely to get MS as men, especially in their early years. MS is more common among some ethnic groups than others. For example, the disease is more common in North America and northern Europe than in other parts of the world. MS is very rare among Asians, Indians of North and South America, and Eskimos.

CAUSES

Multiple sclerosis is an autoimmune disease in which the immune system begins to attack myelin. It "decides" that the myelin is a foreign substance that threatens the body and must be destroyed. Researchers do not know why this happens.

As myelin is destroyed, neurons no longer function normally. Brain neurons cannot receive and process information from the outside world. Neurons in the brain and the spinal cord cannot send messages to other parts of the body. Normal muscular functions, such as standing, walking, lifting, and turning, become difficult or impossible.

The progress of MS seems to depend on the appearance of new plaques. These plaques slow down nerve messages and worsen the symptoms of the disease. Scientists do not understand how, where, and why plaques develop. For that reason, they cannot predict how the disease will progress in any one person over time.

Finding the reason for a body's autoimmune reaction to myelin is a major field of research. So far, no final answer has been found. Some possible factors leading to this condition are a person's heredity (his or her genes), environmental factors, viruses, or a combination of these factors.

An MRI scan showing legions, which are often an indicator of MS, in the left lobe of the brain. (Reproduced by permission of

Custom Medical Stock Photo

)

The reason that heredity is considered a possible factor is that MS seems to run in some families. A person who has a family member with MS is more likely to develop the disease than someone whose family has no history of MS. In addition, the tendency of some ethnic groups to contract (get) the disease suggests a hereditary factor.

Support for environmental factors comes from data on migration. Migration is the process of moving from one part of the world to another part. Studies have been done on people who move from a low-risk part of the world (such as Asia) to a high-risk part (such as the United States). Young people who make such moves have a higher risk of developing MS than those of the same age who remained at home. Older people do not experience an increased risk. These data suggest that environmental conditions in the new location might be responsible for MS.

One possible environmental factor is viruses. There are some kinds of viruses that attack the body very slowly. HIV, the virus that causes AIDS (see AIDS entry), is one such virus. Some researchers think that a slow-acting virus may be responsible for MS. But no data supporting this theory have yet been produced.

SYMPTOMS

Multiple sclerosis can develop in one of three patterns. The most common pattern is called "relapsing-remitting." In this pattern, symptoms appear and then disappear. A person may feel fine for a while and then experience the symptoms of MS for a period of twenty-four hours or more. Then the symptoms disappear again for a span of time. That span may be as long as a year or more at the beginning of the disease. But the span grows shorter as the person becomes older. This pattern is especially common in younger people with MS.

"Primary progressive" is a second pattern. In this pattern, the disease simply gets worse over time. A person may have brief periods when the disease does not get worse, but these are rare. The primary progressive pattern is more common in older people.

The "secondary progressive" pattern is a combination of the first two patterns. A patient first goes through a period of relapsing and remitting. Eventually, however, the disease just continues to get worse, as in the primary progressive pattern.

Between 10 percent and 20 percent of MS patients have a benign form of MS. Benign means that the symptoms do not change very much throughout a person's life.

The actual symptoms of MS vary considerably from person to person. The reason for this is that plaques form in different places and at different times in different individuals. Some initial symptoms of the disease include:

• Muscle weakness, causing difficulty in walking
• Loss of coordination or balance
• Numbness, feelings of "pins and needles," or other abnormal sensations
• Problems with vision, including blurred or double vision

As the disease develops, other symptoms may appear. These include:

• Fatigue
• Muscle stiffness
• Tremors (shaking)
• Paralysis
• Pain
• Vertigo (dizziness, light-headedness)
• Difficulty with speech and/or swallowing
• Loss of bowel or bladder control
• Constipation
• Sexual problems
• Changes in one's ability to think clearly

Weakness in one or both legs is common. It is often the first symptom noticed by a person with MS. Excessive tightness of muscles is also common. It may actually cause more problems than muscular weakness.

Damage to myelin in the optical (eye) nerves can cause visual problems, such as blurred vision, changes in color vision, and even blindness. The condition may affect one or both eyes.

More than half of all people with MS have pain during the course of their disease. Many experience pain nearly all the time, often because of muscle spasticity (stiffness). The pain is often a sharp, stabbing pain, especially in the face, neck, or back. Numbness and weakness in the face are also common.

Some mental changes that can occur include loss of memory, depression, and personality changes. Some of these changes may result from damage to neurons. Others may be a side effect caused by the patient's despair about the disease. In less common cases, a person with MS may actually feel happier than usual.

The symptoms of MS can be affected by environmental conditions. Heat; increased body temperature; vigorous physical activity; or exposure to sun, hot baths, or showers can make symptoms worse.

DIAGNOSIS

Sometimes a doctor can make a reliable diagnosis of MS fairly easily and quickly. The distribution of symptoms is important since MS affects many different areas of the body over a period of time. The pattern of symptoms is also important. A case of relapsing-remitting MS can often be diagnosed because of the way the symptoms come and go.

Since the symptoms of MS are similar to those of other diseases, diagnosis can often be difficult and complicated. Many tests and extended observation may be necessary to decide what is causing the patient's symptoms.

The usual medical procedures used to make a diagnosis include a medical history, a standard neurological (nervous system) examination, and several laboratory tests. Among the tests most commonly used to confirm or rule out a diagnosis of MS are:

• Magnetic resonance imaging (MRI) can show plaques on the brain and spinal cord. But plaques are present with other disorders as well. For example, the plaques caused by MS are sometimes difficult to distinguish from those caused by strokes (see stroke entry) or the simple process of aging.
• A lumbar puncture (spinal tap) is a process in which cerebrospinal fluid (CSF) is removed from the patient's spine with a long, thin needle. The CSF is then studied. The presence of white blood cells and other substances may be a clue to the presence of MS.
• Evoked potential tests (EPT) are tests that measure how quickly an electrical current passes through neurons. Scientists know the normal rate at which currents pass. If they move more slowly than normal, plaques may be present. An EPT can be conducted in various ways. One method is to apply a small electrical charge to the skin. A light can also be shined into a person's eyes. Or a tone can be sounded near his or her ears.

The neurologist (nerve specialist) conducting these tests may decide the patient is in one of three categories: "definite MS," "probable MS," or "possible MS." These three categories represent decreasing confidence in the accuracy of the diagnosis.

TREATMENT

Treatment of MS takes two forms. First, although there are no drugs that will actually cure the disease, there are drugs that can slow down the course of MS. Second, a variety of treatments can be used to ease the symptoms of multiple sclerosis.

As of 1997, three drugs had been approved for use with multiple sclerosis: Avonex, Betaseron, and Copaxone. All three reduce the rate of relapses in the relapsing-remitting form of MS. Each has other benefits as well. Avonex may slow the progress of physical damage; Betaseron may reduce the severity of symptoms; and Copaxone may decrease disability. All three drugs are administered by injection.

Immunosuppressant drugs have also been used to treat severe relapses. These drugs act on the immune system directly, causing it to work less effectively. The drugs carry some risks, so a patient may have to be hospitalized during treatment.

MS causes a large variety of symptoms. For that reason, many different treatments may be necessary to relieve those symptoms. A person should be vaccinated against influenza (see influenza entry). The vaccination can help protect against respiratory (breathing) problems, thus reducing the symptoms of MS. Preventing complications from MS is also important. Such complications include pneumonia (see pneumonia entry), bed sores, injuries from falls, or urinary infections. These complications lead to death more often than does MS.

Physical therapy is important in treating MS. It helps the patient strengthen and retrain affected muscles, maintain range of motion to prevent muscle stiffening, learn to use assistive devices such as canes and walkers, and learn safer and more energy-efficient ways of moving and sitting.

A program of physical therapy usually includes exercise and stretching. These activities can be taught and practiced at home. Swimming is often recommended. It provides a way for a patient to get exercise without becoming overheated.

Treatment programs usually include occupational therapy as well. People with MS are taught how to deal with daily activities, such as dressing, feeding, and washing. The occupational therapist can make suggestions for arranging the home and work environment so that an MS patient can function more safely and efficiently.

An MS patient may need training in bowel and bladder control. Drugs are sometimes used to deal with these problems. They help the patient to empty his or her bowel and bladder on a more normal schedule.

Spasticity can be treated with drugs as well. Baclofen (pronounced BAK-lo-fen) and diazepam (pronounced di-AZE-uh-pam, trade name Valium) are given by mouth, while botulin toxin (Botox) is given by injection. These drugs can help relieve the pain caused by spasticity. Back pain can be treated with over-the-counter pain relievers, such as aspirin or acetaminophen (pronounced uh-see-tuh-MIN-uh-fuhn, trade name Tylenol), or with physical therapy.

Fatigue can be treated by having the patient plan and follow a regular daily routine. The routine should allow for frequent rest periods. Drugs such as amantadine (pronounced uh-MANT-uh-deen, trade name Symmetrel) and pemoline (pronounced PEM-uh-leen, trade name Cylert) can help improve alertness and lessen fatigue. Corticosteroids are used to treat visual problems. Other types of drugs can be used to treat seizures, vertigo, and tremor.

Alternative Treatment

A variety of alternative treatments have been recommended for multiple sclerosis. So far, there are few scientific data to support most of these claims. For example, bee venom has been suggested as a treatment for MS. But studies have not supported this claim. Marijuana has been recommended for the relief of certain symptoms of MS, including tremor, pain, and spasticity. But the drug has side effects of its own. It is not widely recommended in the United States for the treatment of MS.

Some practitioners suggest that high doses of vitamins, minerals, and other dietary supplements can help slow the progress of MS. Specific nutrients recommended include linoleic (pronounced lin-uh-LEE-ik) acids, selenium, vitamin E, and a diet low in saturated fats.

Lane Phalen, a multiple sclerosis sufferer, with her service dog. The dog helps her with daily activities that have become difficult because of MS. (Reproduced by permission of

AP/Wide World Photos

)

PROGNOSIS

The prognosis for MS differs markedly from person to person. Most people with the disease can continue walking and functioning at home and work for many years after their diagnosis. Some conditions that favor a promising diagnosis include being female, having the relapsing-remitting form of the disease, having the first symptoms at an early age, having long periods of remission between relapses, and having vision and touch symptoms rather than muscular problems.

Less than 5 percent of people with MS have a severe progressive form of the disease that leads to death within five years. At the other extreme, 10 percent to 20 percent have a benign (relatively harmless) form with very slow or no progression of symptoms. On average, MS shortens the lives of women with the disease by about six years and men by about eleven years. Suicide is a significant cause of death in people with MS, especially among younger patients.

Most people experience the severest disabilities of MS within five years of diagnosis. After that point, disabilities do not continue to worsen significantly. If no disabilities appear within the first five years, they are unlikely to occur at all.

PREVENTION

There is no known way to prevent multiple sclerosis. Until the cause of the disease is discovered, that will continue to be the case. The symptoms of the disease can be reduced, however, by good nutrition; adequate rest; avoidance of stress, heat, and extreme physical exercise; and good bladder hygiene.

FOR MORE INFORMATION

Books

Holland, Nancy T., Jock Murray, and Stephen Reingold. Multiple Sclerosis: A Guide for the Newly Diagnosed. New York: Demos Vermande, 1996.

Kalb, Rosalind C., ed. Multiple Sclerosis: A Guide for Families. New York: Demos Vermande, 1997.

Matthews, Bryan. Multiple Sclerosis: The Facts. New York: Oxford University Press, 1993.

Swank, R. L., and M. H. Pullen. The Multiple Sclerosis Diet Book. Garden City, NH: Doubleday, 1997.

Organizations

Multiple Sclerosis Association of America. 706 Haddonfield Road, Cherry Hill, NJ 08002-2652. (800) LEARN-MS; (609) 488-4500. http://www.msaa.com.

The National Multiple Sclerosis Society. 733 Third Avenue, New York, NY 10017. (800) FIGHT-MS. http://www.nmss.org.