Steroid myopathy in connective tissue disease.

In eight women with polymyositis (three patients), systemic lupus erythematosus (SLE) (three patients), rheumatoid arthritis (one patient) and shoulder-hand syndrome (one patient), weakness developed during high dose prednisone therapy. These women were studied using serial functional and manual muscle tests, determination of serum glutamic oxaloacetic transminase (SGOT), creatine phosphokinase (CPK) and serum aldolase levels, and urinary excretion of creatine. Insidious onset of weakness was characteristic. Myalgias were seen in five patients and unusual sudden weakness in two. Weakness was always most severe in the pelvic girdle muscles; there was a lesser involvement of shoulder girdle and distal muscles. Serum muscle enzyme levels were normal in all cases, but urinary creatine excretion was invariably increased and proved to be the most sensitive laboratory indicator for clinical diagnosis and for monitoring patient improvement. Serial urinary creatine excretion and serum enzyme studies were of value in differenting steroid myopathy from a flare of myositis in patients with connective tissue disease. Diagnosis and effective management were achieved by the use of readily available laboratory and clinical procedures without resorting to muscle biopsy.