Concentric macro EMG role in electrodiagnostic evaluation of inflammatory myopathies

Inflammatory Myopathies (IM) encompass a diverse group of systemic autoimmune muscle disorders, not easy to diagnose. Concentric-macro EMG is supposed to reflect electrical activity of the entire motor unit. It could help in electrophysiological characterization of inflammatory myopathies and recognizing earlier myopathic changes. Conventional EMG in our IM patients showed myopathic changes in all the cases, so it could be a golden tool for diagnosis. The degree of abnormalities was variable in different muscles in concentric macro EMG. Myopathic changes using concentric macro EMG was not so advanced as those seen in chronic stable relapsing phase. Pooling up the results of the conventional EMG, muscle enzyme tests, muscle ultrasound , and Con-Mac will give optimal results for diagnosis and could help in follow up of patients with IM.