“…Myasthenic reactions in the myopathies Polymyositis, dermatomyositis and carcinomatous myopathy may simulate myasthenia gravis clinically, pharmacologically and electromyographically (Benedek, 1944;Christensen and Levison, 1950;Ragan, 1950;Eaton and Lambert, 1957;Walton and Adams, 1958;Brain and Henson, 1958). There may be an abnormal fatiguability of the affected muscles and at first some response to the administration of anticholinesterase drugs.…”