Myasthenia gravis is a common autoimmune disorder characterized by the presence 
of pathogenic antibodies directed against the acetylcholine receptor. Patients 
present with variable degrees and distribution of fluctuating weakness at times 
life threatening. Clinical manifestations, establishment of diagnosis, the 
natural history of myasthenia gravis, and therapeutic options are herein 
reviewed. Far less common is Lambert-Eaton syndrome (the myasthenic syndrome), 
another autoimmune disorder due to the presence of antibodies directed against 
the PQ-type voltage-gated calcium channels. Clinical features and treatment 
options are summarized.