Idiopathic acute eosinophilic pneumonia.

Idiopathic acute eosinophilic pneumonia (IAEP) is a rare disease but of clinical importance because of its good prognosis if treated promptly and appropriately. The etiology remains unknown and the temporal relationship between IAEP and a history of resent onset of cigarette smoking has been described. We report a typical case of a 21-year-old male with recent onset of smoking, who presented with acute febrile hypoxemic respiratory failure. High-resolution chest computed tomography scan revealed patchy ground glass opacity and ill-defined nodules, diffuse interlobar and interlobular septal thickening, and bilateral small amount of pleural effusion, which mimicked congestive heart failure except that the heart size was within normal limits. Bronchoalveolar lavage (BAL) was performed soon after the patient was admitted and remarkable eosinophilia was noted in BAL fluid. Clinical condition and chest radiographs improved dramatically after corticosteroid treatment. Because effective treatment and prompt institution of therapy can obviate unnecessary morbidity and mortality, IAEP should be kept in mind when treating patients presenting with diffuse parenchymal lung disease and acute respiratory failure. In that case, BAL is valuable and should be performed as soon as possible.