Myographic evidence of polymyositis and dermatomyositis in COVID-19 patients

Abstract

Idiopathic inflammatory myopathies, commonly known as myositis, are a diverse group of disorders defined clinically by persistent muscle weakness and reduced muscle endurance, as well as inflammatory cell infiltrates inside the muscle tissue. Myositis as a complication of coronavirus disease 2019 (COVID-19) has been described in an increasing number of reports. An analytical and cross-sectional study was undertaken in Basrah to analyze nerve conduction studies (NCS) and electromyographic (EMG) data in a COVID-19-affected patient. During the evaluation of 2240 patients, three cases of myositis were reported among the COVID-19 population, two of them with new clinical and EMG evidence of inflammatory myositis after the onset of COVID-19 infection, and one patient had a history of polymyositis before the COVID-19 pandemic, but a relapse was triggered by COVID-19, resulting in respiratory failure and death. The study found that the prevalence of myositis among the COVID-19 population was equal to 0.22%, which is 44 times higher than the prevalence of myositis (0.005%) worldwide before the onset of COVID-19 (P < 0.001).