Myasthenia Gravis

Abstract

Myasthenia gravis, first described in 1672 by Sir Thomas Willis and named by Jolly in 1895, is clinically characterized by muscular weakness relieved by rest. The incidence rate is about 4/million/year, the prevalence in Norway is about 100/million. Anticholinesterase drugs, introduced by Mary Walker in 1934, are still the primary therapeutics. Since about 1960 the disease has been recognized as autoimmune. Circulating antibodies to the acetylcholine receptor of the neuromuscular synapse are detectable in greater than or equal to 85% of the patients. Hence thymectomy, plasmapheresis and immunosuppressant drugs are useful. The thymus is recognizably pathological in 75-80% of the cases. The thymic hormone thymopoietin stimulates thymocytes and T-cells, and directly blocks the acetylcholine receptor.