Renal injury in sport.

Hematuria is the most common presenting sign of renal injury. Its presence in athletes may indicate a benign entity such as exercise-induced hematuria or a more serious injury in the presence of trauma. Exercise-induced hematuria can originate in the kidney, bladder, urethra, or prostate. The type of activity, as well as activity duration and intensity, contributes to its development. A wide differential diagnosis must be considered if hematuria persists longer than 24 to 72 hours. Trauma to the kidney can occur from a direct blow or deceleration; contact and collision sports are most commonly involved. Fortunately, most sports-related renal trauma is mild, and can be managed expectantly. A sporting injury rarely results in nephrectomy. Determining return to play for the athlete with a single kidney remains a controversial issue that requires patient education and an individualized approach.