Myasthenia Gravis
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What is Myasthenia Gravis?Is there any treatment?What is the prognosis?What research is being done?OrganizationsPublicaciones en Español
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What is Myasthenia Gravis?
Myasthenia gravis is a chronic autoimmune neuromuscular disease characterized by varying degrees of weakness of the skeletal
(voluntary) muscles of the body. The hallmark of myasthenia gravis is muscle weakness that increases during periods of activity
and improves after periods of rest. Muscles that control eye and eyelid movements, facial expression, chewing, talking, and
swallowing are often, but not always, involved. The muscles that control breathing and neck and limb movements may also be
affected. Myasthenia gravis is caused by a defect in the transmission of nerve impulses to muscles. Normally when impulses
travel down the nerve, the nerve endings release a neurotransmitter substance called acetylcholine. In myasthenia gravis,
antibodies produced by the body's own immune system block, alter, or destroy the receptors for acetylcholine. The first noticeable
symptoms of myasthenia gravis may be weakness of the eye muscles, difficulty in swallowing, or slurred speech. Symptoms vary
in type and severity. Myasthenia gravis is not directly inherited nor is it contagious. The first steps in diagnosing myasthenia
gravis include a review of the individual's medical history and physical and neurological examinations. If the doctor suspects
myasthenia gravis, several diagnostic tests are available to confirm the diagnosis, including a special blood test that can
detect the presence of immune molecules or acetylcholine receptor antibodies.
Is there any treatment?
Myasthenia gravis can be controlled. Some medications improve neuromuscular transmission and increase muscle strength, and
some suppress the production of abnormal antibodies. These medications must be used with careful medical followup because
they may cause major side effects. Thymectomy, the surgical removal of the thymus gland (which often is abnormal in myasthenia
gravis patients), improves symptoms in certain patients and may cure some individuals, possibly by re-balancing the immune
system. Other therapies include plasmapheresis, a procedure in which abnormal antibodies are removed from the blood, and high-dose
intravenous immune globulin, which temporarily modifies the immune system and provides the body with normal antibodies from
donated blood.
What is the prognosis?
With treatment, the outlook for most patients with myasthenia is bright: they can expect to lead normal or nearly normal lives.
Some case of myasthenia gravis may go into remission temporarily, and muscle weakness may disappear so that medications can
be discontinued. In a few cases, the severe weakness of myasthenia gravis may cause respiratory failure, which requires immediate
emergency medical care.
What research is being done?
Scientists are evaluating new and improving current treatments for myasthenia gravis. One study is testing the efficacy of
intravenous immune globulin, and another study seeks to understand the molecular basis of synaptic transmission in the nervous
system.
Select this link
to view a list of studies currently seeking patients.
Organizations
Publicaciones en Español
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Las Miastenia GravisInformación de la Miastenia Gravis/Spanish-language information on La Miastenia Gravis compiled by the National Institute
of Neurological Disorders and Stroke (NINDS).
Prepared by:
Office of Communications and Public Liaison
National Institute of Neurological Disorders and Stroke
National Institutes of Health
Bethesda, MD 20892
NINDS health-related material is provided for information purposes only and does not necessarily represent endorsement by
or an official position of the National Institute of Neurological Disorders and Stroke or any other Federal agency. Advice
on the treatment or care of an individual patient should be obtained through consultation with a physician who has examined
that patient or is familiar with that patient's medical history.
All NINDS-prepared information is in the public domain and may be freely copied. Credit to the NINDS or the NIH is appreciated.
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Last updated February 14, 2007
