Miliary Pneumonia as a Complication of BCG Instillation

A 55-year-old man presented with a 4-month history of progressive exertional dyspnea. He denied having a cough, but reported occasional night sweats. There were no cardiological abnormalities; lung function was unremarkable; laboratory tests showed a slightly elevated CRP concentration. Thoracic computed tomography carried out to exclude lung structure changes revealed a miliary distribution pattern (Figure a). Bronchoscopy then reinforced the suspicion by demonstrating necrotizing granulomas (Figure b) and Mycobacterium tuberculosis complex (PCR). The patient had previously received bacille Calmette–Guérin (BCG; M. bovis) instillation therapy to prevent the recurrence of non-invasive high-grade urothelial carcinoma. The QuantiFERON-TB-Gold-Plus test (M. tuberculosis) was negative, confirming that the pneumonia was caused by BCG. The instillation therapy had to be briefly interrupted after the induction phase owing to BCG prostatitis, with no demonstration of mycobacteria at that time, and maintenance therapy had been started 4 months before the patient presented to us. It can be stated that the cause of his exertional dyspnea was disseminated pulmonary infection with M. bovis. Systemic BCG infections can occur as complications of BCG instillation into the bladder (incidence 1–10:1000). The BCG instillations were discontinued and triple antitubercular treatment (isoniazid, rifampicin, ethambutol) was started.

Figure.

a) Axial MIP (maximum intensity projection) with 7 mm slice thickness in lung window reconstruction from plain thoracic computed tomography, showing miliary distribution of nodules (arrows).

b) Transbronchial biopsy from segments 8–10 of the right lung, showing a centrally necrotic granuloma (*) with histiocytic margin and occasional multinucleate giant cells (arrows) in the alveolar parenchyma.