A Man With Recurrent Pneumonitis: A Rare Case of Interstitial Lung Disease Associated With Anti-Mi-2 Beta-Specific Dermatomyositis

Abstract

Dermatomyositis (DM) and polymyositis (PM) are idiopathic inflammatory myopathies. Interstitial lung disease (ILD) develops in most patients with DM and PM directly related to morbidity and mortality. Diagnosis requires a myositis panel and high-resolution computed tomography (HRCT). Prognosis depends on specific myositis-specific antibodies and the pattern of the interstitial lung changes. Anti-Mi-2 antibody-specific dermatomyositis has a lower prevalence of interstitial lung disease and has a favorable prognosis, responding well to steroids. Our patient is a 72-year old male who presented with recurrent episodes of pneumonitis, and ILD was found to have anti-Mi-2 beta-specific dermatomyositis and SLE overlap disease. He was responding well to high-dose steroids but was rebounding to similar symptoms whenever steroid weaning was attempted. He was started on azathioprine, but unfortunately, his disease rapidly progressed, and he died within a few months. This manuscript enhances the temporal relationship between dermatomyositis and ILD.

Myositis interstitial lung disease and autoantibodies

“…A longitudinal study of anti-Mi-2 patients in the United States found only 3 patients out of 58 developed features of ILD ( 70 ). Literature search revealed a case report from the United States of a patient with persistent dry cough and dyspnea who was found to have bibasilar infiltrates on CXR and bilateral patchy ground glass infiltrates on HRCT, with serial imaging revealing of organizing pneumonia, in addition to the development of progressive proximal myopathy in the presence of anti-Mi-2 antibody positivity ( 74 ).…”