Abstract 10819: Eosinophilic Myocarditis Due to Idiopathic Hypereosinophilic Syndrome

Abstract

Background: Idiopathic Hypereosinophilic Syndrome (iHES) is a rare disease with varied clinical presentations including acute heart failure. Case: A 44-year-old man who had been treated for asthma 9 months ago was admitted with worsening exertional dyspnea. EKG demonstrated sinus tachycardia with anterolateral ST depressions. Labs revealed troponin-I 44.95 ng/ml, BNP 405 pg/mL, and white blood cell count 21.2k with 50% eosinophils. Transthoracic echocardiogram showed normal left ventricular size with globally reduced ejection fraction (30-35%). Coronary angiography found normal coronary arteries. An extensive infectious and auto-immune workup was unrevealing, and bone marrow biopsy was negative for monoclonal proliferation (Fig 1A). He received 1 gram of IV methylprednisolone for 2 days lowering eosinophil count to zero and was discharged on heart failure GDMT. Two weeks later, he was readmitted from clinic for ventricular tachycardia (VT) near 120bpm (Fig 1B). Cardiac MRI and endomyocardial biopsy confirmed active eosinophilic myocarditis (Fig 1C/D). Patient was diagnosed with iHES and treated with IV methylprednisolone (500mg BID x 3 days) with an oral prednisone taper. Amiodarone and lidocaine infusions were temporarily needed to suppress his VT and an ICD was placed. After clinical stabilization and immunology consultation, an interleukin-5 inhibitor was used for further treatment of iHES. Discussion: Only 6% of patients with iHES present with cardiac symptoms, however one in five eventually develop cardiac manifestations that are often rapidly progressive. Prompt treatment with glucocorticoids is indicated for severe presentations, and subsequent use of targeted therapies can dramatically reduce morbidity and mortality. Recognition of severe peripheral eosinophilia should prompt a broad hematologic, infectious, and auto-immune workup to guide treatment and prevent end-organ damage.