Overview and Facts
Multiple sclerosis (MS) is a potentially debilitating disease in which your body's immune system eats away at the protective sheath that covers your nerves. This interferes with the communication between your brain and the rest of your body. Ultimately, this may result in deterioration of the nerves themselves, a process that's not reversible.
MS is caused by damage to the myelin sheath, the protective covering that surrounds nerve cells. When this nerve covering is damaged, nerve impulses are slowed down or stopped.
MS is a progressive disease, meaning the nerve damage (neurodegeneration) gets worse over time. How quickly MS gets worse varies from person to person.
The nerve damage is caused by inflammation. Inflammation occurs when the body's own immune cells attack the nervous system. Repeated episodes of inflammation can occur along any area of the brain and spinal cord. Researchers are not sure what triggers the inflammation. The most common theories point to a virus or genetic defect, or a combination of both.