Myasthenia gravis is a rare, auto-immune neuromuscular junction disorder. 
Prevalence rates is about 50/1,000000. The disease results from circulating 
auto-antibody attacks against post-synaptic targets (acetylcholine receptor 
[AChR] in 80% cases) on the endplate region of the postsynaptic membrane. The 
diagnosis is supported clinically by transient weakness, increased by activity 
that can affect eye movements, swallowing, speech, upper and lower limbs, and 
trunk. There are generalized or focalized forms (as ocular myasthenia). The 
course is variable and evolved either with attacks or more chronically. Helpful 
tests for diagnosis are serologic antibodies detection against AChR, decrement 
of muscle action potential after repetitive nerve stimulations, identification 
of thymus gland abnormality (frequently associated with myasthenia) by chest 
computed tomography. Myasthenia gravis treatment is based on oral form of 
cholinesterase inhibitors, corticosteroids and other immunosuppressive drugs in 
severe forms. During myasthenia crisis, intraveinous immune globulines or plasma 
exchanges can be used. Thymectomy is proposed in case of thymus abnormality.