Inflammatory myopathies in Nigerians: case series and literature review

Abstract

Background: Idiopathic Inflammatory myopathies(IIM) are rare connective tissue diseases and have been rarely reported among Nigerians. Objective: To study the clinical, laboratory and electromyographic characteristics of Nigerian patients with polymyositis and dermatomyositis. Method: In a retrospective study, patients attending a private practice rheumatology clinic in Lagos and fulfilling the Bohan and Peter's criteria for polymyositis and dermatomyositis were examined and common causes of proximal muscle weakness were excluded. Haematological, biochemical, serological and electromyographic studies were carried out. Patients were treated with standard drugs. Results: Fourteen patients (F-13, M-1) were diagnosed with Polymyositis(PM) and Dermatomyositis(DM). Seven had probable PM, 4 with possible PM and 3 with probable DM. Mean age was 35 years (range 22-54) ESR was markedly raised mean 105/min (26-150). Muscle and liver enzymes were raised in all patients. Creatinine kinase median 1134(29-10,166); lactic dehydrogenase median 477(209-787); ALT 43(19-233); AST 136(25-725). Serology for ANF was positive in eight patients; Anti Jo 1 in 1 out of 9 while Anti Mi2 was negative in all tested. EMG in 6 tested showed myopathic pattern. Conclusion: Inflammatory myopathies are rare among Nigerians but a heightened awareness is needed for diagnosis and management.