Objective: Bacille Calmette-Guèrin (BCG) intravesical instillation is a valid therapy for patients with non-muscle invasive bladder cancer. Although it is almost safe, uncommon cases of systemic dissemination have been reported.

Case presentation: A 70-years-old patient with a recurrent bladder carcinoma was treated with transurethral resection of bladder tumor and BCG intravesical instillation. After the last instillation, he developed high fever, cough, nausea and vomiting, associated with shortness of breath. The patient was admitted to the Infectious Diseases Unit with a 2-point-qSOFA score. Imaging revealed interstitial infiltrates in both lungs along with hepatosplenomegaly and abdominal lymphadenopathies. Laboratory examinations showed pancytopenia and numerous acid-fast bacilli in urine whereas bone marrow biopsy showed epithelioid cells without caseous necrosis. Antituberculous treatment was started with isoniazid, rifampicin, ethambutol and moxifloxacin as well as intravenous prednisolone. The patient was discharged after 30 days with recommendation to extend 3-drugs therapy for as long as 30 days followed by a further 4 months with 2-drugs.

Discussion: Mild complications to intravesical BCG treatment are self-limiting. On suspicion of BCG dissemination, antituberculous therapy should be promptly started. There are no official guidelines regarding treatment, however a regimen that includes isoniazid, rifampicin, ethambutol and fluoroquinolone, is usually administered for at least 6 months.

Conclusions: Although negative smears and cultures, early recognition and prompt treatment of patients with disseminated BCG infection are essential.