Clinical features:
(1) presence of hematuria following a long-distance run (marathon, etc)
(2) noticed in the first urine passed after the run
(3) may be profuse with small blood clots
(4) usually clears within 24 hours
(5) absence of hematuria at other times
(6) cystoscopy shows bladder mucosal contusions between the ureteral orifices, around the ureters and along the posterior wall of the internal urethral meatus
Risk factors:
(1) little or no urine in the bladder during the race (urine cushions the mucosa)
(2) aspirin or other drug associated with bleeding
(3) history of runner's hematuria in the past
Differential diagnosis:
(1) myoglobinuria
(2) hemoglobinuria (secondary to runner's hemolysis, see above)
(3) bleeding from a kidney or renal pelvis
