Corticosteroid myopathy.

Abstract

Corticosteroid myopathy was measured electromyographically, using the mean potential duration of the deltoid muscle as the parameter of measurement. The normal range was defined by examination of 33 healthy persons of various ages. Eight patients with myopathy were examined to confirm that MPD [maximum permissible dose] was lowered in this condition. Twelve patients suffering from rheumatoid arthritis, with or without evidence of disease in the shoulder joint or shoulder girdle, had the MPD measured on the deltoid muscle. Since all fell within the normal range it seems that local joint disease does not lower MPD. Fifty patients with rheumatoid arthritis and one with ankylosing spondy-litis, all taking corticosteroids (prednisolone), were examined; their hypercorticism was classified clinically into 3 degrees as mild, moderate, or severe. The MPD was lowest in the group of patients with the severest degree of hypercorticism. Dosage levels and the duration of administration of corticosteroids was directly related to lowering of MPD.