Adult-onset Still’s disease presenting as fulminant myocarditis and refractory shock rescued by ECMO: a case report

Adult-onset Still’s disease (AOSD) is a rare systemic autoinflammatory disorder of unknown etiology. While cardiac involvement such as pericarditis can occur, fulminant myocarditis is an exceedingly rare and life-threatening complication. Herein, we report a rare case of AOSD-induced fulminant myocarditis and cardiogenic shock successfully rescued using veno-arterial extracorporeal membrane oxygenation (VA-ECMO) combined with intensive immunotherapy. A 32-year-old male presented with persistent high fevers, a characteristic salmon-pink rash, pharyngitis, and marked hyperferritinemia (54342 ng/mL), fulfilling the Yamaguchi criteria for AOSD. During hospitalization, he suddenly developed refractory cardiogenic shock, pulmonary edema, significantly elevated myocardial injury biomarkers, and a severely depressed left ventricular ejection fraction (LVEF of 35%). Cardiac magnetic resonance (CMR) confirmed acute myocarditis. Given the critical hemodynamic instability, VA-ECMO was immediately deployed. Concurrently, aggressive corticosteroid therapy and intensive immunotherapy were administered. The patient’s cardiac function progressively recovered, allowing successful weaning from VA-ECMO on day 29, with LVEF improving to 55%. At the 2-year follow-up under maintenance therapy with prednisone, tacrolimus, and tocilizumab, the patient remained asymptomatic with complete normalization of all laboratory parameters and cardiac function. Fulminant myocarditis is a catastrophic yet rare complication of AOSD. This case highlights that early recognition, timely VA-ECMO circulatory support, and a comprehensive corticosteroid-centered multidisciplinary strategy are crucial for successfully rescuing patients from fatal cardiogenic shock and achieving excellent long-term outcomes.