Myasthenia Gravis (MG) is a disorder in which the muscles become weak due to decreased signals reaching the muscles (from the nerves) due to a defect in the receptors. The defect in the receptors due to autoantibodies (antibodies to self).
Typically the weakness is in the muscles that control the eyes, throat and the limb muscles but sometimes very unusual presentations are seen. A characteristic feature of the weakness in myasthenic patients is that the symptoms wax and wane - being more severe after exercise, exhaustion and by the end of the day. Many patients are nearly normal in the mornings. Because of this waxing and waning myasthenia is often mistaken for easy fatigability and hence the diagnosis is delayed.
Sometimes the disease is just confined to the eye muscles alone - in that case it is termed occular myasthenia, which is a very benign illness.
MG is one of the very gratifying illnesses to treat and excellent outcomes are quite common - of course the initial part of the illness requires a lot of investigations and sometimes surgery as well.
Patients with MG need to follow their neurologists advice very carefully as sometimes minor deviations lead to major complications. There are several medications that patients with MG need to avoid.
Here are few links of interest: