Carbamazepine-Induced Lymphocytic Interstitial Pneumonitis

A twenty-seven-year-old male was admitted with cough, sputum production, dyspnea and weight loss. Postero-anterior chest x-ray showed bilateral, diffuse reticulonoduler infiltration. He had received tuberculosis treatment in the past and he had been on carbamazepine for 8 years for a seizure disorder. Three sputum smear examinations for acid-fast bacilli were negative. Pulmonary function tests revealed FVC of 2.35L (51 %), FEV1 of 2.12 L (54 %), FEV1/FVC of 90 %, DLCO of 39 % and DLCO/VA of 75 %. Fiberoptic bronchoscopy was normal. Transbronchial lung biopsy and bronchial washing were nondiagnostic. Right mini-thoracotomy and open lung biopsy were performed. Pathologic examination revealed diagnosis of lymphocytic interstitial pneumonitis. Carbamazepine was withdrawn after neurological consultation. The patient was clinically and functionally well two months later. Computed tomography of the thorax was completely normal. The patient was consideredto be compatible with carbamazepine-induced lymphocytic interstitial pneumonitis.