Myasthenia Gravis

General Illness Information

Medical Term: Myasthenia Gravis

Common Name: None Specified

Description: Autoimmune disorder, characterized by progressive muscle fatigue and weakness, and improved by drugs which inhibit the enzyme choline-esterase. Usually involves muscles around the eyes, mouth, throat and limbs. Usually presents between ages 20-40, and is more common in women

Causes: This is an autoimmune disorder. The body produces antibodies to a receptor (acetyl-choline) at the level of the microscopic nerve cells and synapses (junction) in the muscles, and leads to a defect in neuro-muscular transmission.  Underlying cause is unknown.

In newborns, may be caused by a tumor of the thymus gland.

Prevention: Cannot be prevented at present.

Signs & Symptoms

  • Drooping eyelids.
  • Loss of normal facial expression
  • Double vision.
  • Swallowing difficulty.
  • Weakness of the arms and legs especially after exertion.
  • Difficulty speaking clearly.
  • Breathing difficulty.
  • Most symptoms appear after a brief period of normal muscle function, and worsen as the muscle is used
  • Life-threatening respiratory muscle involvement occurs in 10% of cases.

Risk Factors

  • Medical history of other auto-immune diseases.
  • Family history of autoimmune disease.
  • Some cancers, especially thymus and lung cancer.
  • Newborns and infants of mothers with myasthenia gravis. They show symptoms in 2 to 3 weeks.

Diagnosis & Treatment

Diagnosis is made by complete history and physical examination. Tests include laboratory studies of antibodies in the blood, electromyography (electrical muscle test), X-rays of the chest, and a therapeutic trial of anticholinesterase drugs (under close medical supervision).

General Measures:

  • Treatment is directed towards controlling symptoms.
  • Surgical removal of the thymus gland (thymectomy) (only in certain cases).
  • Plasmapheresis.
  • Acute flare-ups may require emergency care for respiratory distress.

Medications:

  • Anti-cholinesterase drugs to restore normal muscle function. Excessive doses may cause weakness.
  • Cortisone drugs.
  • Immunosuppressive medications.

Activity:

Plan activities to make the most of energy peaks. Frequent rest periods are important. Day-to-day fluctuations in symptoms are common. Avoid strenuous activities and needless exposure to the sun or to cold weather.

Diet:

No special diet. Soft diet may be necessary if chewing and swallowing are difficult.

Possible Complications :

  • Choking from swallowing difficulty.
  • Respiratory infections and respiratory paralysis.

Prognosis

This condition is currently considered incurable. However, symptoms can be relieved or controlled. Worsening may be followed by improvement. Life expectancy is reduced but patients usually live many years with the disease.

Other

Nothing Specified.

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