Myasthenia Gravis is an autoimmune disorder which causes multiple muscle groups to weaken. Myasthenia Gravis is caused by a decreased number of receptors of a neurotransmitter called acetylcholine. The body begins to produce antibodies that destroy the acetylcholine receptors; the cause is not know, but in some cases it can be related to the thymus gland. In approximately 15% of Myasthenia Gravis patients are diagnosed with a thymoma (a tumor of the thymus gland); a thymoma is usually a non-cancerous tumor, but the thymus is usually removed as a result. Myasthenia Gravis is a chronic condition that can cause muscle to tire or weaken easily; there can be periods of worsening (exacerbation) and improvement (remission).
The most commonly affected muscles are those that control eye and eyelid movement resulting in drooping or blurred vision. Other commonly affected muscles are those that help with chewing, swallowing, smiling, shrugging, lifting arms, grip strength, rising from a seated position and walking up stairs.
There is no cure for Myasthenia Gravis, but there are medications that can help decrease the amount of anti-acetylcholine antibodies produced.