Co-occurrence of Polymyositis and systemic lupus erythematosus: Polymyositis-systemic lupus erythematosus overlap syndrome: a case report from Ethiopia

Abstract

IntroductionThe term overlap syndrome includes a large group of conditions characterized by the coexistence of signs, symptoms, and immunological features of two or more connective tissue diseases occurring simultaneously in the same patient.1 It is very rare to see an overlap of inflammatory myositis and SLE and it has not been well studied.2 With variable epidemiological data, most often diagnosed concurrently with SLE.3 In contrast to myalgia which can affect nearly half of patients with SLE, true myositis is relatively rare as shown by some studies.11Myositis can occur before, after SLE, or sporadically both diseases can be present simultaneously.10Myositis associated with overlap syndromes is usually of paroxysmal variety and has been associated with one or another of connective tissue disorders.1 Raised serum creatine kinase is found to correspond with underlying myositis in patients with SLE.12 Furthermore, the presence of myositis-specific antibodies such as anti-U1RNP, anti-Ro/SSA, anti-La/SSB, anti-Sm or anti-PM-Scl is suggestive of an overlap myositis.13,12