Bacillus Calmette-Guérin (BCG)-Induced Pneumonitis: A Case Report.

Bladder cancer is the second most common genitourinary (GU) malignancy worldwide. Treatment involves early cystectomy and intravesical Bacillus Calmette-Guérin (BCG), which is effective for T1 high-grade tumors and carcinoma in situ (CIS) but can cause significant side effects, including chemical and bacterial cystitis, hematuria, incontinence, pneumonitis, malaise, fever, and sepsis. We present the case of a 47-year-old male with transitional cell carcinoma (TCC, G3 pTa) treated with transurethral resection of bladder tumor (TURBT) who developed a fever and non-productive cough after BCG injections. Initially discharged, he returned with worsened symptoms. His vital signs showed a fever of 38.2°C, a heart rate of 104 beats per minute (bpm), and a saturation of 93% on room air. Blood tests indicated inflammation and liver dysfunction. Imaging revealed lung micronodularity, and further CT imaging showed bilateral miliary nodules indicative of BCG pneumonitis. MRI ruled out disseminated tuberculosis, identifying a hepatic cyst. Cultures from blood, urine, sputum, and broncho-alveolar lavage were negative, but granulomatous inflammation was confirmed on liver biopsy. The patient was treated with oral glucocorticoids and anti-tuberculosis medications (rifampicin, isoniazid, and ethambutol), and clinical improvement was shown. The patient was discharged, and a follow-up at the respiratory clinic was scheduled. BCG pneumonitis, a severe BCG therapy complication, necessitates early diagnosis and management to reduce morbidity and mortality.