抗MDA-5抗體陽性之皮肌炎患者發生氣胸與氣縱膈之報告

Spontaneous Pneumothorax and Pneumomediastinum in Anti- MDA5 antibody-positive Dermatomyositis

Dermatomyositis (DM) is a systemic autoimmunedisease with increased association with cancerand interstitial lung diseases (ILD). Among thedisease spectrum of DM, clinically amyopathicdermatomyositis (CADM) could be associatedwith rapidly progressive ILD that requiresaggressive treatment with high-dose corticosteroidand immunosuppressants. Spontaneouspneumothorax and pneumomediastinum is anunusual but severe and potentially fatal complicationof DM. If left untreated, patients with DM/CADM showed an inferior 5-year survival ratethan patients with polymyositis due to lethalpulmonary complications. Recently, myositisspecificantibodies had been widely used for thediagnosis and treatment of DM. Anti-melanomadifferentiation-associated protein 5 (MDA5)antibody was shown to be associated with CADMand ILD [5,6]. However, spontaneous pneumothoraxin MDA5-positive DM patient has never beenreported in the literature. 抗MDA-5抗體與無肌肉病變之皮肌炎有關，常發生在亞洲病患，這一類患者可能發生快速進展之間質性肺病，且需要大劑量類固醇與及時的免疫抑制治療。我們在此報導一位51歲女性抗MDA-5抗體陽性之無肌肉病變皮肌炎患者，手掌與皮膚出現紅色疼痛之結節，肺部電腦斷層檢查為非特異性間質性肺病（NSIP），在診斷後四個月，病患發生急性胸痛，影像學檢查發現氣胸、氣縱膈與皮下氣腫，經氧氣治療與類固醇、tacrolimus 及mycophenolate治療，氣胸於九日後緩解。此一病例顯示抗MDA-5抗體陽性之皮肌炎患者除了快速進展之間質性肺病外，更可能引起自發性氣胸與氣縱膈，早期診斷與即時免疫治療或可改善這一類疾病患者之預後。