Multiple sclerosis is a chronic degenerative disease of the nervous system, the cause of which is unknown. It usually begins between the ages of 20 and 40. It is more common among whites than among blacks and seems to be more frequent in Europe, particularly in the Scandinavian countries, than in the United States. It is relatively rare in Africa and Asia. Occasionally, multiple sclerosis is seen in families, but there is no evidence that it is a genetic disorder. A variety of theories have been advanced to explain its cause, including infection by a virus or spirochete, deficiency of certain minerals or enzymes, and poisonings, but none has been proven.
Multiple sclerosis is characterized by the de-' velopment of multiple lesions in the brain and spinal cord due to loss of myelin, a fatty substance that sheathes the nerve fibers. Symptoms depend on the areas of the brain or spinal cord affected.
Initially multiple sclerosis may have any of a wide variety of symptoms. There may be brief loss of vision in one eye, double vision, or a bizarre jerky movement of one or both eyes known as nystagmus. Sometimes there is difficulty with speech. Tremors, numbness, or a feeling of pins-and-needles may occur in one or more limbs, one arm or leg may be weak or hard to use, the gait may be unsteady, or there may even be loss of control of a limb.
In most cases, multiple sclerosis is slowly progressive over a period of years. The chronic relapsing form of the disease, which is the most common, often begins with one or a group of symptoms that usually disappear for a period of years until the same or frequently other symptoms appear. These too may subside after a few days or even a few hours, to be followed by another remission period with no symptoms. As time goes on, however, symptoms tend to occur more frequently and fail to subside.
In acute forms of the disease, which may run for a course of months or even weeks, symptoms develop rapidly and may remit only partially or, if completely, may be followed by a relapse in a relatively short time. In acute forms the onset is often marked by headache, vomiting, or delirium. Multiple sclerosis may also cause mental changes and convulsions. Sphincter muscles controlling bladder and bowel function are also frequently affected. Eventually there is paraplegia and increasing disability. The prognosis is variable, with some patients deteriorating rapidly but the majority living 20 or 30 years or longer before succumbing to the disease.
There is no known treatment for multiple sclerosis. It is important that the patient be given good psychological support since many become severely depressed when they are told the nature of their disease, and many of the symptoms may actually be due to psychological factors.