What is myasthenia gravis?
Myasthenia gravis is an autoimmune disease. This means that the body's defenses against infection attack the body's own tissue. Myasthenia gravis makes your muscles very weak.
How does it occur?
When you have myasthenia gravis, your immune system attacks your muscles. Antibodies made by your body block the action of chemicals that normally transmit signals from the nerves to the muscles. This makes it hard for you to use your muscles.
The cause of this disease is not well understood. It sometimes happens with other immune system disorders. It may begin at any age, but most often it starts between the ages of 20 and 40.
Rarely, this disease is caused by tumors of the thymus gland (a tissue of the immune system).
What are the symptoms?
Symptoms may include:
- muscle weakness that gets worse with activity and gets better with rest
- eye problems such as double vision or droopy eyelids
- weakness in the muscles of the face, throat, and neck, which may cause trouble speaking, chewing, and swallowing
- trouble performing activities that use the muscles of the arms or legs, such as climbing stairs or combing hair
- trouble breathing because of weakness in the respiratory muscles.
Weakness, which gets worse over time, can vary from day to day. Stress, infection, or other factors can make symptoms worse. You may have symptom-free periods (remissions) followed by recurrences of symptoms (relapses). When this disease causes trouble breathing, it can be life-threatening.
How is it diagnosed?
Your health care provider will take your medical history and examine you. You may have tests such as:
- Tensilon test. This test involves giving you a drug called Tensilon. The drug temporarily restores strength to the muscles by supplying the chemicals blocked by the disease. A good response to this drug helps confirm the diagnosis.
- Electromyography (EMG), which tests the function of nerves and muscles.
- Blood tests to check for antibodies.
What is the treatment?
Treatments may include:
- medicines that temporarily improve muscle strength by helping the muscles to receive impulses from the nerves
- taking steroids or other drugs that suppress your body's immune response
- exchanging your plasma, the fluid part of your blood that contains antibodies, with plasma that does not have these antibodies
- removal of the thymus gland, or removal of a tumor on the thymus gland.
How long will effects last?
With treatment, you can expect to lead a nearly normal life. Sometimes muscle weakness may go away for a time. There is no cure, except in rare instances when the disease is caused by a tumor of the thymus gland and the tumor or gland is surgically removed.
How can I take care of myself?
If you are on drug therapy, it is very important to take your medicine on an exact schedule. Any delay in taking medicine may leave you unable to swallow or breathe. You may want to set an alarm clock to remind you to take your medicine. These medicines should generally be taken with milk and crackers or other nonacid food.
Sedatives (tranquilizers or sleeping pills) and narcotic analgesics (pain medicines) can cause severe breathing problems. Wear a bracelet or necklace that states that you have myasthenia gravis. If you have trouble swallowing or breathing, get emergency treatment right away.
Since physical exertion may make your symptoms worse, you may have to change your activity somewhat.
You may also want to:
- Join a support group.
- Look for ways to help reduce stress.
- Wear an eye patch to relieve double vision.
More information is available from:
Myasthenia Gravis Foundation of America
Phone: (800) 541-5454
Web site: http://www.myasthenia.org.
National Institute of Neurological Disorders and Stroke
Phone: (800) 352-9424
Web site: http://www.ninds.nih.gov.