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Understanding Multiple Sclerosis

The National Multiple Sclerosis Society is the go-to source for accurate, actionable information about multiple sclerosis. We are here to answer your questions.

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Multiple sclerosis FAQs

If you or someone you love has been diagnosed with multiple sclerosis, you probably have lots of questions. Learn the basic facts about MS here, including what researchers believe causes MS, who develops it and the types of MS.

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What is multiple sclerosis?

MS is a chronic, unpredictable disease of the central nervous system, which is made up of the brain, spinal cord and optic nerves. MS is thought to be an immune-mediated disorder. This means that the immune system mistakenly attacks your own healthy tissue in the central nervous system.

The resulting damage to the central nervous system interferes with the transmission of nerve signals between the brain and spinal cord and other parts of the body. This causes the symptoms of MS.

Read more about MS.

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Is MS an autoimmune disease?

Multiple sclerosis is considered to be an immune-mediated disease. This means that in MS, the body's immune system attacks the central nervous system. Most MS experts believe it to be an autoimmune disease although no specific antigens (proteins that stimulate the immune system) have been identified in MS.

Doctors have identified more than 80 types of autoimmune diseases. Some examples include:

  • Psoriasis
  • Crohn’s disease
  • Hashimoto's thyroiditis
  • Rheumatoid arthritis
  • Systemic lupus erythematosus
  • Insulin-dependent (type 1) diabetes mellitus

In MS, the immune system attacks and damages certain structures and cells within the central nervous system, including:

  • Myelin (the fatty sheath that surrounds and protects nerve fibers)
  • Oligodendrocytes (cells that produce myelin)
  • Nerve fibers underlying myelin

Read more about immune-mediated diseases.

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Who develops MS?

Anyone may develop MS, but there are some patterns. For instance, three times as many women as men develop MS.

MS occurs in most ethnic groups. Researchers used to believe that MS mostly affected white people, particularly those of European descent. Recent studies, however, indicate that more Black people have the disease than previously thought. In fact, the rate among Black Americans is consistent with the rate of MS in white Americans. Doctors are also seeing increased rates of MS in the Hispanic/Latinx community.

Studies suggest that genetic factors increase the risk of developing MS, but there is no evidence that MS is directly inherited. Environmental factors, such as low vitamin D and cigarette smoking have also been shown to increase the risk of MS.

Read more about who develops MS.

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How many people have MS?

Nearly 1 million people are living with MS in the United States, according to our 2019 prevalence initiative, a four-year study that used millions of health records to get a more accurate count. This number is more than twice the one previously reported in a 1975 national study and subsequent updates. Worldwide, more than 2.8 million people have an MS diagnosis.

The Centers for Disease Control and Prevention (CDC) has received federal funding to implement a neurological disease surveillance system, and they are actively working on the development of that system. The scientific community will be able to learn more about MS with such a system in place.

Read about how many people live with MS.

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What are the different types of MS?

While there is no way to predict with any certainty how MS will progress, 4 basic disease courses have been defined:

  • Clinically isolated syndrome (CIS) refers to a first episode of neurologic symptoms caused by inflammation and demyelination in the central nervous system.
  • Relapsing-remitting MS (RRMS) is characterized by clearly defined attacks of new or increasing neurologic symptoms. These attacks are followed by periods of partial or complete recovery or remission.
  • Secondary progressive MS (SPMS) follows relapsing-remitting MS in some people and is characterized by a more progressive course, with or without relapses or new lesions on MRI.
  • Primary progressive MS (PPMS) is characterized by a gradual but steady progression of disability from the onset of symptoms, with few or no relapses or remissions.

Read more about the types of MS.

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What are the typical symptoms of MS?

Symptoms of MS are unpredictable and vary in type and severity from one person to another and in the same person over time. Symptoms may disappear completely or they may persist and worsen over time.

Common symptoms of MS include:

  • Depression and emotional changes
  • Fatigue
  • MS hug (dysesthesia), a squeezing sensation around the torso that feels like a tightening blood pressure cuff
  • Numbness or tingling of the face, body or extremities (arms and legs)
  • Pain and itching
  • Problems with memory and concentration
  • Spasticity
  • Vision problems, including optic neuritis, blurred vision, poor contrast or color vision and pain on eye movement 
  • Walking difficulties
  • Weakness

MS symptoms from A to Z” talks about how to manage symptoms, and “6 less-common symptoms of MS” delves into some of the lesser-known challenges of MS.

Read more about the symptoms of MS.

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What are common first signs of MS?

While MS symptoms vary from person to person and any symptom can be a first symptom, there are some common initial symptoms. These are the signs that lead many people to first see a healthcare provider. They are caused by inflammation in the optic nerve and/or the spinal cord.

  • Optic nerve inflammation causes blurred vision, pain with eye movements and headache.
  • Spinal cord inflammation causes numbness and/or weakness in the arms, legs or trunk, bladder and/or bowel problems and difficulty walking.

If you are experiencing any of these symptoms, see your healthcare provider. An MS Navigator can help you locate one if you don’t have one already.

Read more about the symptoms of MS.

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Why is MS so difficult to diagnose?

Diagnosing MS can be a challenging process. In early MS, symptoms may be non-specific and suggestive of several disorders of the nervous system. People may ignore early symptoms that come and go. While no single laboratory test is yet available to prove or rule out MS, magnetic resonance imaging (MRI) data and spinal fluid analysis greatly help in reaching a definitive diagnosis.

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What causes MS symptoms?

Symptoms of MS occur because of damage within the central nervous system, which includes the brain, spinal cord and optic nerves. In MS, the immune system mistakenly attacks healthy tissue in the central nervous system leading to inflammation. Central nervous system inflammation then leads to the damage of:

  • Myelin (the protective insulation surrounding nerve fibers)
  • Oligodendrocytes (cells that make nervous system myelin)
  • Underlying nerve fibers

Symptoms may be temporary or permanent and may worsen over time.

Read more about what causes MS.

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Does MS always cause paralysis?

No. Moreover, the majority of people with MS do not develop severe disability. Two-thirds of people who have MS remain able to walk, though many may need an aid, such as a cane or crutches, and some will use a scooter or wheelchair because of fatigue, weakness or balance problems, or to conserve energy.

Read more about the symptoms of MS.

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Is MS fatal?

The life expectancy of people diagnosed with MS has increased over time, likely due to treatment breakthroughs, improved healthcare and lifestyle changes. Research indicates that the average life expectancy of people with MS is about 7 years less than the general population because of disease complications or other medical conditions. However, many of these complications are preventable or manageable. Attention to overall health and wellness can help reduce the risk of other medical conditions, such as heart disease and stroke, that can contribute to a shortened life expectancy. In very rare instances, MS can progress rapidly from disease onset and can be fatal.

Read about living well with MS.

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Can MS be cured?

The U.S. Food and Drug Administration (FDA) has approved medications shown to modify the course of MS by limiting new areas of damage in the central nervous system, reducing the number of relapses and delaying progression of disability. In addition, therapeutic and technological advances are providing more effective symptom management. Advances in treating and understanding MS are made every year, hopefully moving research closer to identifying a cure.

Read about our efforts to cure MS.

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What can be done about MS now?

You can start treatment with an FDA-approved disease-modifying drug. These medications reduce the frequency of MS relapses and the number of new lesions in the central nervous system, and may also slow the progression of disability. These medications are approved for relapsing forms of MS, which include clinically isolated syndrome (CIS), relapsing-remitting MS (RRMS) and active secondary progressive MS (SPMS) with relapses.

In addition to medications that address the disease process, there are many medications and other strategies to manage MS symptoms. Research shows that a healthy diet, exercise, not smoking, ongoing preventive care and management of other medical conditions can also impact your MS progression and lifespan. Consult a knowledgeable MS care provider to develop a comprehensive plan to manage your MS.

Understand the MS treatments that are available.

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Why is early treatment important?

Early damage in the central nervous system can occur even before you experience any symptoms. Studies show that the best chance for reducing long-term disability is during the early, relapsing phase of the disease. This phase is characterized by inflammation, which does much of the damage. The medications currently available all primarily target inflammation. Early and ongoing treatment helps to minimize this inflammation and also reduces damage to nerve fibers (axons) and loss of brain tissue.

Learn more about available MS treatments.


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