Macroscopic hematuria caused by running‐induced traumatic bladder mucosal contusions

INTRODUCTION: To clarify the mechanisms responsible for running‐induced asymptomatic gross hematuria. CASE PRESENTATION: We identified 12 patients who visited our outpatient clinic with hematuria after running as a chief complaint. In 9 of 12 patients (75%), cystoscopic findings revealed mucosal contusions at the center of the posterior wall. Our examination including cystoscopy and magnetic resonance imaging revealed that this bladder contusion development was caused by the repeated contact of the bladder posterior wall against the fixed bladder neck by vertical motion in the empty bladder lumen during running. All patients with bladder contusion were male because the bladder neck is more firmly fixed to the pelvic floor by the protruding prostate in men than women. Gross hematuria in all patients quickly resolved without treatment after running cessation. CONCLUSION: This is the first report in which cystoscopic findings showed that running‐induced macroscopic hematuria can be frequently caused by traumatic bladder contusion.