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Myasthenia Gravis

Medically reviewed by Last updated on Oct 1, 2023.

What is myasthenia gravis (MG)?

MG is a long-term disease that causes severe muscle weakness. It happens when nerves cannot send signals to your muscles properly. MG usually affects muscles of the eyes, face, neck, arms, and legs.

What causes or increases my risk for MG?

MG can happen at any age. It is most common in women aged 20 to 40 years and in men aged 60 to 80 years. Any of the following may increase your risk:

  • An autoimmune disease that causes antibodies to attack your body's own cells
  • Problems in the thymus (a gland in your chest)
  • A family history of MG
  • Certain medicines, such as malaria medicine and calcium channel blockers
  • Surgery

What are the signs and symptoms of MG?

  • Painless, worsening muscle weakness usually seen at the end of the day or after exercise
  • Blurred or double vision
  • Drooping eyelids and facial muscles
  • Slurred speech
  • Fast heartbeats
  • Shortness of breath or trouble breathing
  • Trouble chewing and swallowing food

How is MG diagnosed?

  • Blood tests are used to check for abnormal antibodies caused by autoimmune MG.
  • A Tensilon test means IV medicine is given to see if your muscles get stronger after you get the medicine.
  • An ice test checks for improvement in eyelid drooping after your eyelids are covered with ice packs.
  • An electromyography (EMG) test measures the electrical activity of your muscles at rest and with movement.
  • An MRI or CT scan may be used to check for an enlarged thymus gland. You may be given contrast liquid before the pictures are taken to help your thymus show up better in pictures. Tell the healthcare provider if you have ever had an allergic reaction to contrast liquid. Do not enter the MRI room with anything metal. Metal can cause serious injury. Tell the healthcare provider if you have any metal in or on your body.

How is MG treated?

Symptoms of MG can become severe if they are not treated. You may develop trouble swallowing or breathing. This is a serious condition called a myasthenic crisis that can become life-threatening. The following may be used to treat MG:

  • Medicines may be given to improve energy and strength or to slow your immune system.
  • Plasmapheresis is a procedure to remove abnormal antibodies from the blood.
  • Surgery may be done to remove your thymus gland. This may reduce or prevent future symptoms of MG.

Treatment options

The following list of medications are in some way related to or used in the treatment of this condition.

View more treatment options

Where can I find support and more information?

  • Myasthenia Gravis Foundation of America, Inc.
    355 Lexington Avenue, 15th Floor
    New York , NY 10017
    Phone: 1- 800 - 541-5454
    Web Address:

Call your local emergency number (911 in the US) or have someone call if:

  • You have severe breathing problems.

When should I call my doctor?

  • You have a fever.
  • You have diarrhea.
  • You have more weakness than usual.
  • You are having problems swallowing.
  • You are depressed and feel that you cannot cope with your illness.
  • You have questions or concerns about your condition or care.

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your healthcare providers to decide what care you want to receive. You always have the right to refuse treatment. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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Learn more about Myasthenia Gravis

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Further information

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