What is relapsing MS?

Understanding the details can help

MS is a progressive disease that causes damage to the central nervous system (CNS), manifested in outward and silent symptoms. Although there is no cure for MS, many treatments are available that can help slow progression of the disease.

Find out how MS affects the body

Learn about relapsing MS signs and symptoms

Discover different relapsing MS treatment options

Get to know common MS terms in our MS glossary

How MS affects the body

Relapsing MS is thought to be an autoimmune disease, which means that instead of defending the body against harmful invaders (such as viruses or bacteria), the immune system attacks the body itself.

Healthy nerve vs. damaged nerve in CNS
Healthy nerve vs. damaged nerve in CNS
Healthy nerve vs. damaged nerve in CNS
Healthy nerve vs. damaged nerve in CNS

Specifically, MS affects the cells of the CNS. Your brain contains nerve cells called neurons, and the nerve fibers are protected and insulated by what is called the myelin sheath. The myelin helps neurons send electrical signals to and from the brain, telling the body what to do.

With MS, immune cells cross the blood-brain barrier, cause inflammation within the CNS, and attack the myelin sheath. This is thought to interfere with the ability of neurons to send signals between the brain and the body. When your brain cannot communicate with the nerves and muscles the way it’s supposed to, various symptoms of MS (such as vision problems and difficulty with muscle movement, coordination, and balance) can occur.

What causes relapsing MS?

MS is thought to affect more than 2 million people across the globe. About 85% of those are diagnosed with relapsing-remitting MS, the most common form of the disease. It is about 2-3 times more common in women than in men. An MS diagnosis generally occurs between 20 and 50 years of age, but it can also happen when you’re younger or older.

Nobody knows exactly what causes MS, but research is being conducted to investigate:

  • Environmental elements
  • Infectious agents (such as bacteria or a virus)
  • Genetic predisposition (a family history of MS)
  • Ethnicity: although anyone can get relapsing MS, a large percentage are of Northern European descent

Understanding MS relapses, symptoms, disability progression, and lesions

As your disease progresses, existing symptoms may worsen, or new symptoms may appear during a flare-up. If you have any questions about relapsing MS symptoms, the best source of information is your healthcare provider.

TYSABRI is indicated for the treatment of patients with relapsing forms of MS. TYSABRI is not indicated to treat the individual symptoms of relapsing MS, including those listed below.

Some of the common symptoms* of relapsing MS include:

  • Bladder and bowel problems
  • Difficulties with attention, learning, and memory
  • Mood changes
  • Fatigue
  • Muscle rigidity or stiffness
  • Weakness or poor coordination
  • Numbness and tingling
  • Pain in arms and legs
  • Visual disturbances

To learn more about the symptoms of relapsing MS, talk with your healthcare provider.

*Currently, there are no disease-modifying therapies (DMTs) indicated to treat the symptoms listed, including TYSABRI.


Relapses, also known as flare-ups or exacerbations, are new symptoms or a worsening of existing symptoms. Their severity and duration are often unpredictable. If you think that you might be having a relapse, be sure to talk with your healthcare provider.

Flare-ups may vary in severity and can last from a few days to several months. Even infrequent or mild flare-ups can cause permanent damage to the CNS and may lead to future disability.

MS causes brain lesions that can be detected by MRI

MS causes brain lesions that can be visualized with magnetic resonance imaging (MRI). MRIs are able to show both recent lesion development and previous lesion damage. Some common types of lesions that can be visualized with MRIs include:

  • Gd+ enhanced lesions: Lesions that show active inflammation using a dye containing gadolinium
  • Lesions: Some lesions show the long-term impact of inflammation on your brain, while others show active inflammation

The exact relationship between MRI findings and your overall health is not clear. However, MRIs are commonly used to help you and your healthcare provider monitor disease activity in your body.

Healthcare providers can’t say for sure if there is a link between brain lesions and the progression of physical disability. But it’s important to talk with your neurologist about each one of your MRIs because that may help with working out a treatment plan.

Finding the right MS treatment option for you

You may be experiencing some MS symptoms that you can feel on a daily basis. But whether you are or not, underlying MS activity could be damaging your CNS. So even if you’re feeling fine, your MS may be worsening and you might experience new symptoms later on.

Many studies have shown that permanent nerve damage can happen during relapses. These relapses may contribute to physical disability progression. To help slow this progression, talk with your healthcare provider about starting treatment with an FDA-approved medication as soon as you are diagnosed.

There are different types of MS treatments

Do your research. Look at the ways that different treatment options work. Find out about their clinical studies, side effects, and effectiveness. Bring up specific concerns about safety and side effects with your healthcare provider. Learning all you can empowers you to make a confident decision with your healthcare provider.

Some different treatment options include:

  • Injections
  • Infusions
  • Oral pills

Treatment options from Biogen

Biogen offers a number of treatment options for relapsing MS. Find out which could be right for you.

See treatment options