What are the causes of Myasthenia gravis?
Circulating antibodies to the nicotinic acetylcholine receptors on muscles and a reduction in the number of receptors are the defects responsible for the findings in myasthenia gravis. The thymus is always abnormal, with 70% of the cases showing hyperplasia and 15% harboring a thymoma (tumor of thymus). It may also occur in patients receiving D-pencillamine. What are the types of myasthenia? To facilitate the treatment and staging the disease, the following classification is used: I. Ocular myasthenia (15-20%) II. A. Mild generalized myasthenia with slow progression; drug responsive (30%). B. Moderately severe generalized myasthenia; severe skeletal and bulbar involvement but no crises; drug response less than satisfactory (25%) III. Acute fulminating myasthenia; rapid progression of severe symptoms with respiratory crises and poor drug response; high mortality (15%) IV. Late severe myasthenia; symptoms as above, but resulting from steady progression over 2 years from class I to class
