Disseminated Mycobacterium bovis Infection: A Rare Complication of Bacillus Calmette-Guérin Immunotherapy

Intravesical instillation of bacillus Calmette-Guérin (BCG) is a crucial adjunctive therapy in the treatment of bladder carcinoma. Its systemic complications are rare but include disseminated Mycobacterium bovis (M. bovis) infections, the diagnosis of which is a challenging task that requires keen clinical awareness. We report the case of an adult male treated with BCG who presented with fever, nonspecific constitutional symptoms, hepatic cytolysis, and cholestasis. After a detailed workup, the diagnosis was made of disseminated M. bovis infection with hepatic, pulmonary, renal, and ureteral involvement. Prompt anti-tuberculosis treatment resulted in clinical and analytical improvement. This case highlights the importance of early recognition of this serious complication in patients with BCG exposure, as well as the difficulty in confirming the diagnosis for proper treatment.