by EBSCO Medical Review Board

Multiple sclerosis (MS) is a disease of the nervous system. It causes inflammation, harm, and scarring of the nerve sheath that covers the brain and spine. There can also be harm to the nerve itself.

Nerve cells (neurons) showing normal and damaged myelin sheaths
nucleus image
Copyright © Nucleus Medical Media, Inc.

There are many types:

  • Relapsing-remitting—Problems return for few months or years, last for a few weeks or months, and then go away. They may get worse each time.
  • Primary progressive—Problems slowly worsen after they first show up. They do not go away and come back.
  • Secondary progressive—After years of going away and coming back, problems start to get worse.
  • Progressive relapsing—Problems slowly worsen after they first happen. One or more relapses may also happen.

A problem with the body's immune system seems to be the cause. It is not known why this happens. The system protects the body from infection and disease. With MS, it starts attacking the body instead. These health problems may lead to MS:

  • Viral or other infection
  • Genes
  • Environmental causes
What are the risk factors for multiple sclerosis?What are the symptoms of multiple sclerosis?How is multiple sclerosis diagnosed?What are the treatments for multiple sclerosis?Are there screening tests for multiple sclerosis?How can I reduce my risk of multiple sclerosis?What questions should I ask my doctor?Where can I get more information about multiple sclerosis?


Multiple sclerosis (MS). EBSCO DynaMed website. Available at: Accessed March 16, 2022.

NINDS multiple sclerosis information page. National Institute of Neurological Disorders and Stroke website. Available at: Accessed March 16, 2022.

What is MS? National Multiple Sclerosis Society website. Available at: Accessed March 16, 2022.

Revision Information

  • Reviewer: EBSCO Medical Review Board Rimas Lukas, MD
  • Review Date: 11/2021