A Case of Idiopathic Eosinophilic Myocarditis Recovered Spontaneously without Corticosteroids Therapy

Case: A 22-year-old woman was referred to our institute because of chest pain, dyspnea, and syncope. White blood cell count (WBC) was high (16,670/µl) with marked elevation of eosinophils (10,418/µl, 62.5% of WBC). Troponin I and BNP levels were elevated to 561.3 pg/ml and 298.2 pg/ml respectively, whereas vital signs and physical examination showed no remarkable findings. ECG showed negative T-wave in precordial leads and echocardiography showed moderate pericardial effusion with preserved left ventricular ejection fraction. Endomyocardial biopsy revealed eosinophilic infiltration of the myocardium. Secondary causes of hyper-eosinophilia such as allergy, parasitic infections, vasculitis, and hematologic disorders were excluded by medical history, antibody of blood samples, and bone marrow aspiration biopsy. Four weeks after conservative treatment, the eosinophilia was normalized and her signs and symptoms including pericardial effusion disappeared spontaneously. Corticosteroid was not used throughout the clinical course. Conclusion: Eosinophilic myocarditis is relatively rare myocardial disease, and there are only little systematic evidences supporting the use of corticosteroid for all cases. We are reporting this case because this is an interesting case of idiopathic eosinophilic myocarditis which recovered spontaneously without corticosteroids treatment.