In multiple sclerosis (MS), nerve cells in the brain and spinal cord become progressively damaged, causing problems with a wide range of body functions.
Electrical signals pass between the brain and body along the nerves. Healthy nerves are covered by a protective sheath of a substance called myelin, which facilitates the passage of nerve signals.
MS involves progressive destruction of the myelin sheaths, disrupting the transmission of signals. MS is an autoimmune disease, in which the body’s immune system attacks the myelin sheaths. The underlying cause is unknown, although genetic and environmental factors may play a role.
Typically, symptoms first appear between the ages of about 20 and 40. They may include problems with speech, balance, and coordination; numbness; tingling; weakness; muscle spasms; pain; fatigue incontinence; and mood changes. In some people, symptoms come and go, while in others they get progressively worse.
There is no cure, but medication may relieve symptoms.