Report of a case of Crohn's disease associated with hyper-creatine phosphokinase-emia.

A young male patient with myositis associated with Crohn's disease is reported. His serum creatine phosphokinase (CPK) level was markedly elevated, but he had no muscle symptoms. The serum CPK level was not correlated with the activity of Crohn's disease. Muscle biopsy showed myositis with only degeneration of the muscle fibers and infiltration of inflammatory cells. The etiology of myositis in this case was not clear. Diagnosis of myositis based on a muscle biopsy in patients with Crohn's disease showing an elevated serum CPK level without any discernible cause has not been reported previously. Careful attention to the serum CPK and muscle symptoms in patients with Crohn's disease is suggested.