Skip to Content

Myasthenia Gravis


What is myasthenia gravis?

Myasthenia gravis, or MG, is a long-term disease that causes severe muscle weakness. It happens when your nerve endings fail to interact properly with your muscles. MG usually affects muscles of the eyes, face, neck, arms, and legs. MG is most common in young women 20 to 30 years of age, and in men 60 to 70 years of age.

What causes myasthenia gravis?

MG is most often caused by an autoimmune disease. This happens when immune cells produce abnormal antibodies that attack your own body's cells. Problems in the thymus (a gland in your chest) may cause MG. Your risk for MG is higher if you have a family member with MG.

What are the signs and symptoms of myasthenia gravis?

  • 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 myasthenia gravis diagnosed?

  • Blood tests: These are done to check for abnormal antibodies caused by autoimmune MG.
  • Tensilon test: This is a test used to help diagnose MG. IV medicine is given to see if your symptoms improve.
  • Ice test: This is a test that checks for improvement in eyelid drooping after covering your eyelids with ice packs.
  • An electromyography (EMG) test measures the electrical activity of your muscles at rest and with movement.
  • CT scan: This test is also called a CAT scan. An x-ray machine uses a computer to take pictures of your chest. It is done to check for an enlarged thymus gland. You may be given dye before the pictures are taken to help healthcare providers see the pictures better. Tell the healthcare provider if you have ever had an allergic reaction to contrast dye.
  • MRI: This scan uses powerful magnets and a computer to take pictures of your chest. This test is also used to check for an enlarged thymus gland. You may be given dye to help the pictures show up better. Tell the healthcare provider if you have ever had an allergic reaction to contrast dye. 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 myasthenia gravis treated?

  • Medicines:
    • Anticholinesterase medicine: This medicine helps improve energy and strength.
    • Immunosuppressives: Steroid medicine or other immunosuppressive medicine may be given to slow down your immune system and slow the progression of MG.
    • Immune globulins: This is given as a shot or an IV infusion to help your immune system. Each infusion can take 2 to 5 hours.
  • Plasmapheresis: This procedure removes abnormal antibodies from the blood.
  • Surgery: This may be done to remove your thymus gland. This may reduce or prevent future symptoms of MG.

What are the risks of myasthenia gravis?

If left untreated, your MG symptoms can worsen and make it difficult for you to swallow or breath. This is called a myasthenic crisis. It is a serious condition that may become life-threatening.

When should I contact my healthcare provider?

  • 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.

When should I seek immediate care or call 911?

  • You have severe breathing problems.

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:

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.

Ā© Copyright IBM Corporation 2020 Information is for End User's use only and may not be sold, redistributed or otherwise used for commercial purposes. All illustrations and images included in CareNotesĀ® are the copyrighted property of A.D.A.M., Inc. or IBM Watson Health

Learn more about Myasthenia Gravis

Associated drugs

Symptoms and treatments

Mayo Clinic Reference

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.