MYOPATHY IN CUSHING'S SYNDROME

Abstract

The myopathy seen in Cushing''s syndrome has been associated with pathological changes in muscle. A study was made of 6 patients, 1 having no paresis and the others having weakness primarily of the proximal muscles of the lower limbs. None of the patients had muscular pain, tenderness, fasciculations or evidence of atrophy. The electromyographs showed no sign of a gross reduction in the number of motor units or signs of increased muscular irritability or denervation. Individual potentials were altered in the 5 patients showing paresis in that there was a general reduction in size and duration and an increased proportion of polyphasic units. Muscle biopsies in 4 of the patients with weakness revealed pathological signs of degenerated fibers, hypertrophic fibers and fiber replacement by connective tissue and fat. Since no neurogenic lesion existed, the true myopathy has been related to metabolic disturbances in muscle involving an increased production of corticoids.