Multiple sclerosis (MS) is a chronic disease of the central nervous system that affects an estimated 2.5 million people worldwide and is the most common disabling neurological condition among young adults. Therapy has made great strides in the past 15 years when the first disease-modifying medicines were introduced. There is still no known cause or cure, but advances in clinical research are increasing the understanding of MS and effective ways to manage this debilitating disease.
MS is a chronic, progressive disease of the central nervous system in which mylin—the insulating sheath that surrounds nerve fibers in the brain and spinal cord—is damaged. The mylin sheath protects nerve fibers in much the same way that insulation protects an electric cord from short circuiting. When the mylin sheath is damaged, the flow of electrical impulses in the brain and spinal cord is disrupted, causing a wide range of symptoms that vary from person to person—and from time to time in the same person.
MS is an unpredictable disease. Symptoms include extreme fatigue, tremors, numbness, blurred vision, loss of strength, coordination and balance, and incontinence. MS is difficult to diagnose, since symptoms are similar to many other conditions. Symptoms depend on which of the central nervous system’s thousands of nerve pathways are damaged—no two MS patients have exactly the same symptoms. Symptoms may be permanent, or they may come and go.
The cause of MS is unknown, but researchers believe that a disturbance in the immune system causes the body’s immune cells to attack and destroy mylin. MS is categorized as an autoimmune disease, with conditions like arthritis and lupus. Environmental factors may play a role, since cases of MS increase with distance from the equator. For example, there are roughly twice as many cases of MS in North Dakota as in Florida.
Anyone may develop MS, but it is more common in women than in men and in Caucasians than in other ethnic groups. Most patients experience relatively mild and manageable symptoms. But as MS progresses, it can become seriously disabling and, in extreme cases, life-threatening. Numerous support groups—including the National Multiple Sclerosis Society and the Multiple Sclerosis Foundation — offer help to improve life with MS.