Sometimes, it is not possible to establish an obvious distinction between the muscular manifestations due to infectious diseases and the idiopathic myositis. In fact, in some situations it is believed there is a causal relationship between those diseases. We describe the case of a patient with clinical and laboratorial features of polymyositis who had developed leptospirosis previously. The hypothesis of the infectious agent acting as a "trigger" to the muscular disease is discussed.
polymyositis; leptospirosis; rhabdomyolysis; anti-Jo-1