A bladder matter: redefining the grading system for pediatric hemorrhagic cystitis.

INTRODUCTION: Pediatric hemorrhagic cystitis (HC) is a morbid, understudied condition ranging from microscopic hematuria to life-threatening hemorrhage. Existing grading systems, based on adult populations, fail to account for pediatric-specific factors and lack predictive value. This study aimed to identify risk factors for severe HC and propose a modernized, predictive grading scale. METHODS: We retrospectively reviewed patients ≤ 18 years with gross hematuria due to HC at our institution (2014-2024). Bladder toxic exposures, treatments, and outcomes were analyzed. Existing grading systems were applied to assess utility. Chi-square, Mann-Whitney, and logistic regression identified predictors of surgical intervention (p < 0.05). RESULTS: Ninety-three patients were included. The strongest predictors of surgical intervention were male sex (p = 0.023), history of bone marrow transplantation (BMT) (p = 0.031), busulfan exposure (p = 0.011), graft versus host disease (GVHD) (p = 0.027), BK virus (p = 0.01), AML (p = 0.043), and clot volume of >/= 10% of estimated bladder capacity (OR 34.8, p < 0.0001). CONCLUSION: We propose an updated grading system incorporating ultrasound findings to guide management. This revised scale improves risk stratification, guides timely urologic consultation, and standardizes clinical decision-making. Prospective validation is warranted.