[Drug-induced pneumonitis caused by sulfamethoxazole-trimethoprim].

A 33-year-old man was treated with sulfamethoxazole-trimethoprim (SMT-TMP) for an infection in the cervical vertebrae by methicillin-resistant Staphylococcus aureus (MRSA). Two weeks later a fever of 39 degrees C appeared, and a productive cough, hemosputum, and dyspnea developed a further three weeks later. Chest radiographs showed bilateral ground-glass opacity. Cell differentiation of bronchoalveolar lavage fluid (BALF) revealed increases of lymphocytes and eosinophils, and the CD4/CD8 ratio of the BALF lymphocytes was decreased. A thoracoscopic lung biopsy specimen showed fibroedematous thickening of the alveolar walls, hypertrophic alveolar cells, and cell infiltration with neutrophils and lymphocytes. The pathological diagnosis was nonspecific interstitial pneumonia, group II. The fever resolved 6 days after discontinuance of SMX-TMP. The lymphocyte stimulation test for SMX-TMP gave a positive result. Administration of glucocorticoid improved both the symptoms and the laboratory data.