Emerging concepts and spectrum of renal injury following Intravesical BCG for non-muscle invasive bladder cancer

BACKGROUND: Intravesical Bacilli Calmette-Guerin (IVBCG) therapy for non-muscle invasive bladder cancer (NMIBC) has long been in use successfully. Albeit rarely, we still face with its safety concerns more than 25 years on since its approval by US Food and Drug Agency in 1990. Local and systemic infection following intravesical BCG is widely reported as compared to immune mediated local or systemic hypersensitivity reactions involving kidneys; acute kidney injury (AKI) and other renal manifestations are well reported but not of chronic kidney disease (CKD). CASE: An interesting case of a female was referred to nephrologists in advanced stages of CKD at an eGFR of 10 ml/min/1.73(2) following IVBCG for NMIBC. Our patient’s renal function plateaued when IVBCG was held; and worsened again when reinstilled. It introduces the concept of ‘repetitive’ immune mediated renal injury presenting as progressive CKD rather than AKI, as is generally reported. Although response was poor, corticosteroids stopped CKD progression to end stage renal disease. CONCLUSIONS: We highlight the need for increased awareness and early recognition of IVBCG renal complications by both urologists and nephrologists in order to prevent progressive and irreversible renal damage. Low incidence of IVBCG renal complications may also be due to under recognition in the era prior to CKD Staging and AKI Network (and AKI e-alerts) that defined AKI as a rise in serum creatinine of ≥26umol/L; hence an unmet need for urgent prospective studies. Major literature review focuses on emerging spectrum of histopathological IVBCG related renal complications and their outcomes.