[A case of polymyositis associated with unusual CPK isoenzyme pattern and myocardial imaging]

A case of polymyositis (PM) associated with abnormal creatinine phosphokinase (CPK) isoenzyme pattern and Thallium-201 (Tl-201) myocardial imaging was reported. No such case has ever been reported in Japan. A 44-year-old female was admitted for evaluation of muscular weakness of proximal limbs and polyarthralgia. On laboratory examinations, the serum levels of CPK, aldolase and transaminase were markedly elevated. The electromyograms revealed a typical myogenic pattern. On the pathological findings, the principal changes in muscle tissue consisted of inflammatory cell infiltration. Based on those findings, she was diagnosed as having polymyositis. In our patient, there were three characteristics as following; (1) CPK-MB of CPK isoenzyme showed persistent high levels, (2) macro CPK in Electrophoresis of CPK was observed, (3) Tl-201 myocardial imaging revealed multifocal perfusion defects and localized defect in left ventricular inferior wall. She was started on therapy with prednisolone (30 mg/day). The clinical and laboratory manifestations were improved. Abnormal CPK isoenzyme pattern and myocardial imaging were also improved parallel with disease activity of PM. Thus, this case indicated the relation of the damage of skeletal muscle and cardial involvement in PM to unusual CPK isoenzyme pattern. Then wer reported this case.