[Pulmonary involvement, pleural effusion, and electrocardiographic abnormality in hypereosinophilic syndrome].

A 47-year-old man was admitted to our hospital with complaints of cough and shortness of breath. Chest radiography showed infiltration of the right lung and left pleural effusion, the eosinophil count increased notably in the peripheral blood, sputum, and pleural effusion. Transbronchial lung biopsy revealed the invasion of eosinophils like eosinophilic pneumonia. Heart failure easily developed in this patient after the intravenous infusion. Myocardial involvement was suspected, and hypereosinophilic syndrome was diagnosed. After prednisolone was administered, the peripheral blood eosinophil count normalized rapidly, and subsequently, the pleural effusion and infiltration shadows in the lung disappeared.