Corticosteroid-responsive skeletal muscle disease associated with partial carnitine deficiency: studies of liver and metabolic alterations.

A patient with progressive skeletal muscle weakness had lipid-containing vacuoles in type I muscle fibers and partial carnitine deficiency of skeletal muscle. Results of certain liver function tests were abnormal, marked morphologic abnormalities of liver were detected, and a reduced cyclic adenosine 3',5'-monophosphate response to glucagon was present. After the oral administration of prednisone the patient exhibited gradual but striking clinical improvement, skeletal muscle fiber vacuoles could no longer be demonstrated, and the glucagon-provoked cyclic AMP response reverted to normal, but liver abnormalities persisted. At the same time utilization by skeletal muscle of long-chain fatty acids, pyruvate and beta-hydroxybutyrate was depressed. It is possible that the involvement of skeletal muscles was due to an inability of carnitine to attach to or to penetrate the sarcolemmal membrane. Some of the derangement, perhaps related to liver malfunction, was apparently corrected by the oral administration of prednisone although skeletal muscle metabolism remained impaired.