Overview of Multiple Sclerosis

Multiple sclerosis (MS) is an autoimmune disorder in which the body's immune system attacks and eventually destroys myelin, the fatty substance that surrounds and protects nerve fibers in the brain and spinal cord (central nervous system). The inflammatory process that destroys myelin is called demyelinization. Scarring (sclerosis) develops at sites where myelin is destroyed. The disease is characterized by recurrent attacks that are followed by periods of partial or complete recovery.

The age of onset for MS is typically between 28 and 35, but people can be affected at any age. It is more common in women than men. The effects of MS range from minor physical annoyances to major disabilities. About 25 percent of MS patients become wheelchair-bound and more than 70 percent eventually have limited capacity. However, people with multiple sclerosis usually have a normal life span. Several agents, including immune system disorders and genetic and environmental factors, are suspected contributory causes of multiple sclerosis, but there is no scientific consensus about what causes the disorder.

Demyelinization impairs the transmission of signals from the brain to the muscles and organs of the body, causing the following physical symptoms:

  • Abnormal sensations such as "pins and needles"
  • Bladder and bowel dysfunction
  • Difficulty walking
  • Numbness
  • Paralysis
  • Tremor
  • Vision loss

Depression is common in people with MS and may be a direct, physiological result of demyelinization or a psychological response to chronic illness and physical disability.

Initial attacks may be brief and are sometimes mild enough to go unrecognized. Because myelin can heal itself in the disease's initial phases, symptoms may come and go. For many patients, multiple sclerosis results in a chronic, recurrent, symptom pattern at first. Generally, the first full-fledged bout lasts weeks or months and subsequent attacks are sporadic.

Diagnosis of multiple sclerosis is based on symptoms and the results of imaging procedures, such as MRI (magnetic resonance imaging), that reveal plaques.

Treatment for MS includes drugs, such as corticosteroids, to curtail attacks and reduce inflammation, as well as immune therapies and medical treatments for specific symptoms as they arise. MS patients usually are advised to adopt an appropriate exercise program in order to maintain as much strength, coordination, and flexibility as possible.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 01 Jan 2001

Last Modified: 25 Sep 2015