[A case of interstitial pneumonitis caused by intravesical bacillus Calmette-Guérin instillation].

A 61-year-old man was referred to our hospital due to positive urine cytology. He underwent multiple cold punch biopsies of the bladder and the histopathological finding was transitional cell carcinoma (TCC), carcinoma in situ (CIS), grade 3. He was treated with 121.5 mg of bacillus Calmette-Guérin (BCG) (Connaught strain) suspended in 50 ml of saline instilled into the bladder at weekly intervals. After the third instillation he developed a fever up to 39 degrees C, pain on urination and an elevation of liver enzymes. Antituberculous drugs were administered and he was re-admitted for further evaluation. The chest radiograph showed diffuse extensive bilateral lung densities. His chest computed tomographic (CT) scan showed bilateral interstitial pneumonitis. All cultures from his blood, urine, sputum, and bronchoalveolar lavage remained negative for mycobacteria. He was diagnosed as having a hypersensitivity reaction of bilateral lung after immunotherapy with BCG. Pulse steroid therapy was done. The chest radiograph, findings improved and he was clinically asymptomatic after steroid therapy.