[Myasthenia gravis]

Myasthenia gravis is an autoimmune disease, which leads to load-dependent weakness of voluntary skeletal muscles with recovery of function after resting. The disease is caused by autoantibodies directed against the postsynaptic nicotinic acetylcholine receptors (AChR) leading to a reduction of neuromuscular transmission. Muscles and nerves are not affected. Disorders of the thymus play a role in the pathogenesis of AChR antibody-positive myasthenia. The clinical symptoms include exercise-induced fatigue either of the ocular muscles alone (ocular myasthenia) or striated skeletal muscle and the ocular, facial and bulbar musculature (generalized myasthenia). Treatment of myasthenia gravis involves administration of acetylcholine esterase inhibitors and immunosuppressive drugs. A myasthenic crisis is characterized by life-threatening complications with severe weakness, swallowing difficulties and respiratory failure, which requires intensive care treatment.