Myasthenia Gravis


Myasthenia Gravis is characterized by rapid fatigue of your voluntary muscles as a result of poor communication between nerves and muscles.

There is no current cure for this condition, but treatment has been shown to relieve signs and symptoms. Myasthenia Gravis is most common in women under 40 and men over 60, but can affect anyone of any age.


After the onset of Myasthenia Gravis, the disease tends to progress with the severity of symptoms peaking a few years after the onset of the disease. The main symptom associated with Myasthenia Gravis is muscle weakness. As muscles are used repeatedly, weakness and fatigue will worsen.

Image Courtesy of John Hopkins Medicine

Image Courtesy of John Hopkins Medicine

This condition can affect any voluntary muscle, but certain muscle groups are more likely to experience symptoms:

  • Eye muscles
    • Drooping of one or both eyelids
    • Double vision
  • Face and throat muscles
    • Difficulty swallowing
    • Problems chewing
    • Altered speaking

If you experience trouble breathing, seeing, swallowing or walking, see your doctor immediately.

Causes & Risk Factors

The thymus gland, a gland which is located underneath the breastbone, is thought to be responsible for producing antibodies that block or destroy the neurotransmitters that bring messages from your nerves to you muscles.

In individuals with Myasthenia Gravis, the thymus gland is abnormally large causing an overproduction of the antibodies that block neurotransmitters. This overproduction causes your voluntary muscles to receive fewer nerve signals, resulting in weakness.

Furthermore, a small percentage of patients suffer from a tumor of the thymus, causing their Myasthenia Gravis. These tumors are usually noncancerous.


The telltale sign that leads to the indication of Myasthenia Gravis is muscle weakness that tends to become less severe with rest. Tests that will help your doctor arrive at a diagnosis include:

  • Edrophonium test
  • Blood analysis
  • Repetitive nerve stimulation
  • Single-fiber electromoygraphy
  • Imaging scans to search for a tumor or abnormality of the thymus


Conventional treatment options include:

  • Medication
  • Therapy


For the 15 percent of patients who have Myasthenia Gravis as a result of a tumor on their thymus, the thymus is usually removed in order to resume normal muscular functioning. It remains unclear whether the removal of the thymus is beneficial for those without a tumor.

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