Fulminant Eosinophilic Myocarditis in a Young Adult: Successful Recovery After Extracorporeal Membrane Oxygenation (ECMO) Support and Multisystem Complications

Eosinophilic myocarditis (EM) is a rare inflammatory cardiomyopathy with a highly variable clinical presentation, ranging from mild symptoms to fulminant cardiogenic shock. Its diagnosis is challenging due to non-specific clinical findings and requires a high index of suspicion, with endomyocardial biopsy (EMB) serving as the gold standard. Early initiation of immunosuppressive therapy and, in severe cases, mechanical circulatory support (MCS) are essential to improve outcomes. We report the case of a 21-year-old male who presented with progressive dyspnea, chest pain, and hypoxemia. Echocardiography revealed severe left ventricular dysfunction. Coronary angiography excluded obstructive disease, while EMB confirmed EM. Due to cardiogenic shock, veno-arterial extracorporeal membrane oxygenation (ECMO) was implanted on the day of admission. High-dose corticosteroids and azathioprine were initiated, leading to gradual improvement of ventricular function and subsequent ECMO explantation. The course was complicated by left ventricular thrombus formation, which resolved under systemic anticoagulation, and by ischemic colitis requiring right hemicolectomy with ileostomy. Following tracheostomy and prolonged weaning, the patient achieved functional recovery and was discharged on immunosuppressive and anticoagulant therapy. Six months later, surgical restoration of bowel continuity was performed without complications. Follow-up echocardiography demonstrated recovery of left ventricular ejection fraction (LVEF) to 50%, with no evidence of thrombus recurrence. This case highlights the diagnostic and therapeutic challenges of EM, including its fulminant presentation, life-threatening complications, and the critical role of multidisciplinary management. Prompt recognition, biopsy-guided diagnosis, early immunosuppression, MCS when indicated, and careful monitoring for systemic complications can lead to favorable outcomes, even in complex and prolonged clinical courses.