Source:http://linkedlifedata.com/resource/umls/id/C0022972
MSH: An autoimmune disease characterized by weakness and fatigability of proximal muscles, particularly of the pelvic girdle, lower extremities, trunk, and shoulder girdle. There is relative sparing of extraocular and bulbar muscles. CARCINOMA, SMALL CELL of the lung is a frequently associated condition, although other malignancies and autoimmune diseases may be associated. Muscular weakness results from impaired impulse transmission at the NEUROMUSCULAR JUNCTION. Presynaptic calcium channel dysfunction leads to a reduced amount of acetylcholine being released in response to stimulation of the nerve. (From Adams et al., Principles of Neurology, 6th ed, pp 1471),NCI: A rare autoimmune presynaptic disorder characterized by impairment of the impulse transmission at the neuromuscular junction. It affects predominantly the proximal muscles of the lower extremities, resulting in muscle weakness and fatigability. It has been associated with small cell lung carcinoma.