Covert muscle injury in aged patients admitted to hospital following falls.

Ten patients (mean age 85 years) had elevation of serum creatine kinase and other enzyme levels when admitted to hospital after falling at home and lying on the floor. No patient had definite clinical evidence of muscle injury but isoenzyme studies showed that the creatine kinase originated from skeletal muscle. A high ratio of peak creatine kinase to aspartate transaminase levels also helped distinguish skeletal from cardiac muscle damage. Several patients had minor disturbance of renal function and one developed acute renal failure.