Multiple sclerosis (MS) is a chronic autoimmune disorder affecting movement,sensation, and bodily functions. It is caused by destruction of the myelin insulation covering nerve fibers (neurons) in the central nervous system (brainand spinal cord). This insulation, called myelin, helps electrical signals pass quickly and smoothly between the brain and the rest of the body. When themyelin is destroyed, nerve messages are sent more slowly and less efficiently. Patches of scar tissue, called plaques, form over the affected areas, further disrupting nerve communication. The symptoms of MS occur when the brain and spinal cord nerves no longer communicate properly with other parts of thebody. Because there appears to be no pattern in the appearance of new plaques, the progression of MS can be unpredictable.
Multiple sclerosis affects more than a quarter of a million people in the United States. Most people have their first symptoms between the ages of 20 and40; symptoms rarely begin before 15 or after 60. Women are almost twice as likely to get MS as men, especially in their early years. Despite considerableresearch, the trigger for this autoimmune destruction is still unknown. At various times, evidence has pointed to genes, environmental factors, viruses, or a combination of these.
- The symptoms of multiple sclerosis may occur in one of three patterns:
- The most common pattern is the "relapsing-remitting" pattern, in which thereare clearly defined symptomatic attacks lasting 24 hours or more, followed by complete or almost complete improvement. The period between attacks may bea year or more at the beginning of the disease, but may shrink to several months later on. This pattern is especially common in younger people who developMS.
- In the "primary progressive" pattern, the disease progresses without remission or with occasional plateaus or slight improvements. This pattern is more common in older people.
- In the "secondary progressive" pattern, the person with MS begins with relapses and remissions, followed by more steady progression of symptoms.
Between 10-20% of people have a benign type of MS, meaning their symptoms progress very little over the course of their lives.
- Because plaques may form in any part of the central nervous system, the symptoms of MS vary widely from person-to-person and from stage-to-stage of the disease. Initial symptoms often include:
- Muscle weakness, causing difficulty walking
- Loss of coordination or balance
- Numbness, "pins and needles," or other abnormal sensations
- Visual disturbances, including nystagmus (eye tremor), and blurred or double vision.
- Later symptoms may include:
- Muscle spasticity and stiffness
- Speech or swallowing difficulty
- Loss of bowel and bladder control
- Incontinence, constipation
- Sexual dysfunction
- Cognitive changes, especially depression.
Symptoms of MS may be worsened by heat or increased body temperature, including fever, intense physical activity, or exposure to sun, hot baths, or showers.
As of 1997, there are three drugs approved for the treatment of multiple sclerosis which have been shown to affect the course of the disease. None of these drugs is a cure, but they can slow disease progression in many patients.
Avonex and Betaseron are forms of the immune system protein beta interferon,while Copaxone is glatiramer acetate (formerly called copolymer-1). All threehave been shown to reduce the rate of relapses in the relapsing-remitting form of MS. Different measurements from tests of each have demonstrated other benefits as well: Avonex may slow the progress of physical impairment, Betaseron may reduce the severity of symptoms, and Copaxone may decrease disability.All three drugs are administered by injection--Copaxone daily, Betaseron every other day, and Avonex weekly. Betaseron, at least, has led to the development of neutralizing antibodies, which reduce the effectiveness of treatment.
Immunosuppressant drugs have been used for many years to treat acute exacerbations (relapses). Drugs used include corticosteroids such as prednisone and methylprednisone; the hormone adrenocorticotropic hormone (ACTH); and azathioprine. Recent studies indicate that several days of intravenous methylprednisone may be more effective than other immunosuppressant treatments for acute symptoms. This treatment may require hospitalization.
MS causes a large variety of symptoms, and the treatments for these are equally diverse. Most symptoms can be treated and complications avoided with goodcare and attention from medical professionals. Good health and nutrition remain important preventive measures. Vaccination against influenza can prevent respiratory complications, and contrary to earlier concerns, is not associatedwith worsening of symptoms. Preventing complications such as pneumonia, bedsores, injuries from falls, or urinary infection requires attention to the primary problems which may cause them. Shortened life spans with MS are almostalways due to complications rather than primary symptoms themselves.
Physical therapy helps the person with MS to strengthen and retrain affectedmuscles; to maintain range of motion to prevent muscle stiffening; to learn to use assistive devices such as canes and walkers; and to learn safer and more energy-efficient ways of moving, sitting, and transferring. Exercise and stretching programs are usually designed by the physical therapist and taught to the patient and caregivers for use at home. Exercise is an important part of maintaining function for the person with MS. Swimming is often recommended,not only for its low-impact workout, but also because it allows strenuous activity without overheating.
Occupational therapy helps the person with MS adapt to her environment and adapt the environment to her. The occupational therapist suggests alternate strategies and assistive devices for activities of daily living, such as dressing, feeding, and washing, and evaluates the home and work environment for safety and efficiency improvements that may be made.
Training in bowel and bladder care may be needed to prevent or compensate forincontinence. If the urge to urinate becomes great before the bladder is full, some drugs may be helpful, including propantheline bromide (Probanthine),oxybutynin chloride (Ditropan), or imipramine (Tofranil). Baclofen (Lioresal)may relax the sphincter muscle, allowing full emptying. Intermittent catheterization is effective in controlling bladder dysfunction. In this technique,a catheter is used to periodically empty the bladder.
Spasticity can be treated with oral medications, including baclofen and diazepam (Valium), or by injection with botulinum toxin (Botox). Spasticity reliefmay also bring relief from chronic pain. Other more acute types of pain mayrespond to carbamazepine (Tegretol) or diphenylhydantoin (Dilantin). Low backpain is common from increased use of the back muscles to compensate for weakened legs. Physical therapy and over-the-counter pain relievers may help.
Fatigue may be partially avoidable with changes in the daily routine to allowmore frequent rests. Amantadine (Symmetrel) and pemoline (Cylert) may improve alertness and lessen fatigue. Visual disturbances often respond to corticosteroids. Other symptoms that may be treated with drugs include seizures, vertigo, and tremor.
It is difficult to predict how multiple sclerosis will progress in any one person. Most people with MS will be able to continue to walk and function at their work for many years after their diagnosis. The factors associated with the mildest course of MS are being female, having the relapsing-remitting form,having the first symptoms at a younger age, having longer periods of remission between relapses, and initial symptoms of decreased sensation or vision rather than of weakness or incoordination.
Less than 5% of people with MS have a severe progressive form, leading to death from complications within five years. At the other extreme, 10-20% have abenign form, with a very slow or no progression of their symptoms. The most recent studies show that about seven out of 10 people with MS are still alive25 years after their diagnosis, compared to about nine out of 10 people of similar age without disease. On average, MS shortens the lives of affected women by about six years, and men by 11 years. Suicide is a significant cause ofdeath in MS, especially in younger patients.
The degree of disability a person experiences five years after onset is, on average, about three-quarters of the expected disability at 10-15 years. A benign course for the first five years usually indicates the disease will not cause marked disability.