[Pranoprofen-induced lung injury manifesting as acute eosinophilic pneumonia]

A 48-year-old man was admitted to our hospital complaining of fever, dyspnea, and cough. He had been treated with pranoprofen and antibiotics by an outpatient clinic for the preceding 4 days. Chest X-ray films revealed Kerley B lines, perivascular cuffing, and hilar haze with pleural effusion in both lungs. Chest computed tomographic films showed non-segmental patchy infiltrates, and thickening of bronchovascular bundles and interlobular septa. Laboratory data showed eosinophilia in peripheral blood (28%) and severe hypoxemia (PaO2:60 torr). Bronchoalveolar lavage fluid disclosed an increased total cell count, eosinophils (39%), and CD 4/CD 8 ratio (2.1). Microscopic examination of transbronchial lung biopsy specimens showed infiltration of eosinophils and mononuclear cells into alveolar wall's and spaces. Acute eosinophilic pneumonia was suspected on the basis of Allen's diagnostic criteria (N Engl J Med: 1989). After discontinuation of pranoprofen, the patient's clinical symptoms, laboratory data, and chest X-ray findings improved rapidly without steroid therapy. A leukocyte migration test (LMT) for pranoprofen was positive and a challenge test for smoking was negative. An environmental provocation test in the patient's home gave negative results. A challenge test for pranoprofen was not performed due to the lack of informed consent. Based on these findings, our diagnosis was pranoprofen-induced lung injury manifesting as acute eosinophilic pneumonia.