Beware of 'normal' creatine kinase levels in HIV-associated polymyositis

Abstract

Generalised weakness may be a common complaint of persons infected with HIV, but the development of significant proximal weakness requires specific attention. Polymyositis may occur in HIV infection and is readily treatable with prednisone. Elevated creatine kinase (CK) levels have been regarded as an important criterion for diagnosing polymyositis. A study of HIV-associated polymyositis reported similarly elevated CK levels to those observed in non-HIV settings. However, muscle inflammation can be associated with normal or near-normal CK levels. We report 4 cases of HIV-associated polymyositis in which the diagnosis was almost missed owing to the absence of raised CK levels.