Multiple sclerosis (MS) is a chronic, disabling disease of the central nervous system. The disease causes inflammation, destruction, and scarring of the sheath that covers nerve fibers, called myelin, in the brain and spinal cord. As a result, electrical signals from the brain are slowed or blocked from reaching the eyes, muscles, and other parts of the body.
Nerve Fiber (Neuron)
© 2009 Nucleus Medical Art, Inc.
There are several types of MS:
- Relapsing-remitting MS—Symptoms suddenly reappear every few years, last for a few weeks or months, then go back into remission. Symptoms sometimes worsen with each occurrence.
- Primary progressive MS—Symptoms gradually worsen after symptoms first appear. Relapses and remissions usually do not occur.
- Secondary progressive MS—After years of relapses and remissions, symptoms suddenly begin to progressively worsen.
- Progressive relapsing MS—Symptoms gradually worsen after symptoms first appear. One or more relapses may also occur.