Hypereosinophilic syndrome associated with acute necrotizing myocarditis and cardiomyopathy

We report the rare case of a 55-year-old female with massive eosinophilic myocarditis and severe, however reversible, impairment of left ventricular function. The patient presented with reduced physical condition, progressive dyspnea on exertion and peripheral edema. The white blood count revealed a leukocytosis and markedly elevated peripheral blood eosinophilics (48.8%). An endomyocardial biopsy demonstrated massive myocardial infiltration with eosinophilic granulocytes and necrosis. The symptoms and laboratory parameters indicate the presence of a hypereosinophilic syndrome. The differential diagnosis of a Churg-Strauss syndrome is discussed. Medical heart failure treatment according to international guidelines and an immunosuppressive treatment with prednisolone (Decortin H) 1.5 mg/kgBW) were initiated. This therapy led to a dramatic reduction of the eosinophilic granulocyte count and normalization of the peripheral blood count, which correlated with a significant improvement of clinical symptoms. Consistently, an increase of left-ventricular function was observed. Upon successive dose reduction to a maintenance dosage of 10 mg prednisolone, the patient's clinical status and peripheral blood count remained stable.