Multiple Sclerosis (MS)

Reviewed/Revised Jan 2024
VIEW PROFESSIONAL VERSION
Get the full details

What is multiple sclerosis (MS)?

Multiple sclerosis is a disease that causes multiple scars on nerves in your brain and spinal cord. These scars keep the nerves from working properly.

  • You may have vision problems, strange sensations, weak or clumsy movements, or trouble thinking clearly

  • You'll have different symptoms at different times

  • Symptoms usually come and go, and you may feel fine between episodes of symptoms

  • MS tends to get worse over time

  • Diagnosis is based on MRI (magnetic resonance imaging) of the brain and spinal cord.

  • Several different medicines can help, but there's no cure

  • MS can cause disability, but most people have a normal life span

What causes MS?

Doctors don’t know what causes MS. But most doctors believe that your immune system attacks your body’s own tissues as if they don't belong to you. This is called an autoimmune reaction. In MS, the immune system attacks and damages nerves in your brain and spinal cord.

What are the symptoms of MS?

Because MS attacks different nerves, symptoms are different for different people. And the pattern of how symptoms come and go is different.

Usually, MS symptoms appear suddenly (called a flare) and then go away (called remission). Usually, you're in good health between flares. Most people have flares only every year or two, but you may have more. Each flare may affect a different part of your body. Flares can last a few days to a few months.

As time goes on, your symptoms may not go away completely between flares. In some people, symptoms never go away. Whatever your symptom pattern is, MS tends to slowly get worse.

Common early symptoms of MS include:

  • Tingling or numbness in parts of your arms, legs, chest, back, or face

  • Weakness, clumsiness, or stiffness in your arms or legs

  • Blind spots, blurry vision, or pain when moving one eye

Other early symptoms include:

  • Double vision (seeing two of one thing)

  • Sudden burning or electric shock-like pains down your back, legs, or arm that may come on their own, when something touches you, or when you bend your neck

Later symptoms of MS may include:

  • Shaky, irregular movements

  • Being unable to move a part or all of your body

  • Painful muscle cramps and muscle weakness

  • Balance and walking difficulty

  • Feeling tired and weak

  • Slow, slurred speech

  • Depression or mood swings

  • Difficulty thinking, remembering things, paying attention, or making decisions

  • Dizziness

  • Problems controlling urination (peeing) or bowel movements (pooping)

Symptoms may become worse if you're hot, such as on a hot day or during a fever.

How can doctors tell if I have MS?

It can be hard to tell if you have MS. Doctors diagnose MS based on your symptoms and usually with:

How do doctors treat MS?

To treat symptom flares, doctors use:

  • Medicines called corticosteroids

If corticosteroids don't help, doctors may try a blood treatment called plasma exchange.

To help prevent flares of symptoms, doctors use various different medicines that help keep your immune system from attacking your nerves.

Doctors may use other medicines to treat specific symptoms, such as muscle tightness, tingling sensations, tiredness, and depression.

You can make life with MS easier and help prevent disability by:

  • Staying active

  • Doing physical therapy

  • Walking on your own for as long as possible

  • Avoiding heat, such as taking hot baths or showers

  • Not smoking

  • Taking supplements

Where can I find more information on MS?

Drugs Mentioned In This Article

quizzes_lightbulb_red
Test your KnowledgeTake a Quiz!
Download the free Merck Manual App iOS ANDROID
Download the free Merck Manual App iOS ANDROID
Download the free Merck Manual App iOS ANDROID