A Case of Polymyositis with Normal Creatine Kinase

Proximal muscle weakness can be induced by many diseases, such as muscular dystrophies, inflammatory muscle diseases, and polymyalgia rheumatica. Differential diagnosis of these diseases is important. The patient had proximal muscle weakness with a normal creatine kinase (CK) level. Our initial diagnosis was polymyalgia rheumatica because the CK level was normal. The patient was treated with low-dose corticosteroid. However, the muscle weakness did not improve. The diagnosis of polymyositis was confirmed by a muscle biopsy. We suggest that if the patient has typical symptoms with normal CK, then evaluations for inflammatory muscle diseases are essential.

Creatine kinase 증가가 없었던 다발성근염 1예

환자는 CK의 상승 없이 상, 하지 근무력감을 주소로 내원하여 초기에는 류마티스 다발성 근통으로 진단하였으나 추후 증상 호전을 보이지 않아 근육 조직 검사를 통하여 다발성 근염으로 진단되었다. CK 등의 근육 수치의 증가가 없더라도 임상적으로 염증성 근염이 의심되는 경우에는 근육 조직 검사를 포함한 자기공명검사, 근전도 검사 등의 적극적인 검사를 통하여 염증성 근염 여부를 반드시 감별할 필요가 있겠다.