CD-ROM Today 1996 January/CD-ROM Today 1996 January.iso/dp/0402/04026.txt

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$Unique_ID{BRK04026}
$Pretitle{}
$Title{Myasthenia Gravis}
$Subject{Myasthenia Gravis ERB Goldflam Disease Myasthenia Gravis
Pseudoparalytica MG Familial Infantile Myasthenia Gravis Transitory Neonatal
Myasthenia Gravis }
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Copyright (C) 1985, 1986, 1988, 1990, 1992 National Organization for Rare
Disorders, Inc.

50:
Myasthenia Gravis

** IMPORTANT **
It is possible that the main title of the article (Myasthenia Gravis) is
not the name you expected.  Please check the SYNONYM list to find the
alternate names and disorder subdivisions covered by this article.

Synonyms

     ERB
     Goldflam Disease
     Myasthenia Gravis Pseudoparalytica
     MG
     Familial Infantile Myasthenia Gravis
     Transitory Neonatal Myasthenia Gravis
     Congenital Myasthenia Gravis
     Generalized Myasthenia Gravis

General Discussion

** REMINDER **
The information contained in the Rare Disease Database is provided for
educational purposes only.  It should not be used for diagnostic or treatment
purposes.  If you wish to obtain more information about this disorder, please
contact your personal physician and/or the agencies listed in the "Resources"
section of this report.


Myasthenia Gravis (MG) is a chronic neuromuscular disease characterized
by weakness and abnormally rapid fatigue of the voluntary muscles, with
improvement following rest.  Any group of muscles may be affected, but those
around the eyes and the muscles used for swallowing are the most commonly
involved.  They also are the most resistant to therapy.

Symptoms

The onset of Myasthenia Gravis may be sudden with severe generalized
weakness, but more often the symptoms in early stages are subtle and the
progression so gradual that the disease is not readily identified.

Symptoms vary depending upon which muscles are affected.  The muscles
most frequently involved in the early stages are those used in talking,
swallowing, and chewing.  The patients's voice tends to become nasal and
during conversation may fade until almost unintelligible.  Muscle weakness in
the throat and neck area represents a significant danger gravis since food
can accidentally become trapped in the trachea.

Weakness of the eye muscles, resulting in drooping eyelids (ptosis) and
diplopia is also an early sign.  The condition becomes worse in the afternoon
or evening and improves in the morning or after rest.  Similarly, weakness of
the limbs is a frequent characteristic of myasthenia gravis, and is most
pronounced after exercise and at the end of the day.

In the majority of cases, the course of the disease is punctuated with
periods of greater and lesser weakness.  Short term aggravation of symptoms
can be provoked by a host of factors, including excessive physical activity,
emotional upset, menstruation, and pregnancy.  Complete spontaneous
disappearance of symptoms has been reported in rare instances.

The most feared complication of the myasthenia gravis patient is a
"crisis".  The term is applied to sudden, severe muscle weakness and
especially a weakness of muscles involved in respiration.  Myasthenic crisis
is considered to be a sudden increase in severity of the basic disease that
may occur during menstruation, infection (such as flu), excessive physical
activity, emotional upset, and pregnancy.  Cholinergic crisis, which has
similar symptoms, is caused by over-dosage of anticholinesterase agents.

Infants of mothers with myasthenia gravis sometimes have a transient form
of the disease.  Weakness is present at birth and lasts from 18 to 50 days
with return of normal function.

Causes

Recent scientific evidence indicates that Myasthenia Gravis may be caused by
an autoimmune reaction involving binding of antibodies to a membrane protein
which obstructs nerve transmission in the muscles.  This obstruction causes
the muscles to become weaker with repetitive use.  Autoimmune disorders occur
when the body's natural defenses against invading organisms (antibodies), for
unknown reasons, suddenly begin to attack perfectly tissue.

Affected Population

Approximately 100,000 people in the United States have myasthenia gravis.

Myasthenia gravis can strike any individual at any age at any time.  Symptoms
generally appear earlier in females, with a peak age of onset between 15 and
35 years, compared with 40 to 70 years in males.  Generalized myasthenia
gravis is more common in younger females and conversely, symptoms limited to
the eye muscles are more frequent in older males.  However, any form can
appear at any age and in either sex.

Therapies:  Standard

For nearly 40 years the anticholinesterase drugs, especially pyridostigmine
and neostigmine, have been the mainstays of symptomatic relief.  A patient's
condition may worsen temporarily before improving.

Recently, scientists at the National Institute of Neurological and
Disorders and Stroke are employing a new treatment for Myasthenia Gravis -
long-term use of a high-single-dose, alternate-day oral prednisone regimen.
This has proven extremely beneficial over long periods in a majority of
patients treated.  Patients over age 40, especially males, appear to respond
best to this treatment.

A surgical procedure for removing the thymus ("thymectomy") has benefited
a number of myasthenia gravis patients, many of whom were severely affected.
Recent studies have led a number of physicians to believe that thymectomy
should be performed routinely in most myasthenia gravis patients.

Certain drugs can provoke worsening of symptoms in the myasthenic patient
and should be avoided.  These include curare, quinidine and quinine.
Occasionally quinine may be unknowingly self-administered in the form of
tonic water from a gin and tonic.  Other drugs that may aggravate MG symptoms
are some of the antibiotics.

Therapies:  Investigational

The National Institute of Neurological Disorders and Stroke (NINDS) has
studied plasmapheresis as a treatment for Myasthenia Gravis.  Plasmapheresis
(plasma exchange) is a method for removing unwanted elements (toxins,
metabolic substances, and plasma parts affected by disease) from the blood.
It is performed by removing blood, separating the plasma from the other blood
products, and replacing the plasma with clean human plasma.

In Myasthenia Gravis, the immune system appears to attack the transmitter
nerves at the muscle and nerve junctions, nerve pathways and certain nerve
endings (acetylcholine receptors).  Plasmapheresis has been used successfully
to strengthen patients before surgical removal of the thymus gland
(thymectomy), and during the postoperative period.  It can also be valuable
in lessening symptoms during immune suppression drug treatment and during
acute crisis attacks.  However, more research is needed before plasmapheresis
becomes a standard therapy, particularly because side effects of this
treatment have not been fully evaluated.  The effects of plasmapheresis are
temporary, and it is not commonly used for routine treatment because of high
cost and the effects tend to wear off after a short period of time.

Cyclosporine, a potent drug that suppresses the immune system, is being
tested as a treatment for Myasthenia Gravis.  Some patients have shown gains
in strength after using this drug.  However, more research is necessary
before cyclosporine can be used as a standard treatment for this disorder.

Studies are being conducted in the use of Sandoglobulin and the
immunosuppressant drug azathioprine as treatments for Myasthenia Gravis.
Further investigation is needed to determine it's safety and effectiveness.

In 1990 the Office of Orphan Drug Product Development awarded a New Grant
Award to Dr. Donald B. Sanders of Duke University of Duke University,
Durham, NC for his work in the use of 3,4-DAP in the treatment of Myasthenia
Gravis and Lambert-Eaton Syndrome.

Intravenous gamma globulin is being tested for treatment of Myasthenia
Gravis; however, so far the effects are temporary.

This disease entry is based upon medical information available through
April 1990.  Since NORD's resources are limited, it is not possible to keep
every entry in the Rare Disease Database completely current and accurate.
Please check with the agencies listed in the Resources section for the most
current information about this disorder.

Resources

For more information on Myasthenia Gravis, please contact:

     National Organization for Rare Disorders (NORD)
     P.O. Box 8923
     New Fairfield, CT  06812-1783
     [phone]

     Myasthenia Gravis Foundation, Inc.
     53 W. Jackson Blvd., Suite 660
     Chicago, IL  60604
     [phone]
     [phone]

     NIH/National Institute of Neurological Disorders & Stroke (NINDS)
     9000 Rockville Pike
     Bethesda, MD  20892
     [phone]
     [phone]

     Muscular Dystrophy Association, National Office
     3300 E. Sunrise Dr.
     Tucson, AZ  85718
     [phone]

For more information on genetics and genetic counseling referrals, please
contact:

     March of Dimes Birth Defects Foundation
     1275 Mamaroneck Avenue
     White Plains, NY  10605
     [phone]

     Alliance of Genetic Support Groups
     35 Wisconsin Circle, Suite 440
     Chevy Chase, MD  20815
     (800) 336-GENE
     [phone]

References

THE MERCK MANUAL 15th ed:  R. Berkow, et al:  eds; Merck, Sharp & Dohme
Research Laboratories, 1987.  P. 1449.

CECIL TEXTBOOK OF MEDICINE, 18th ed.:  James B. Wyngaarden, and Lloyd H.
Smith, Jr., Eds.:  W. B. Saunders Co., 1988.  Pp. 2285-7.