Ten percent of all combat casualties in current U.S. conflicts have GU injuries, which may be blunt, penetrating, or combined. The extensive use of improvised explosive devices (IED) resulted in a substantial number of penetrating injuries that include GU organs as part of a complex wounding pattern with trauma to the abdomen, pelvis, perineum, and extremities.5-11 A significant reduction in kidney injuries has been noted in combat casualties wearing body armor.12 Given the mechanism of injury, the most commonly injured GU structures are the external genitalia and lower urinary tract (bladder and urethra).8,13,14 Because most patients with GU injuries are severely injured, as mentioned above, a thorough initial trauma evaluation and treatment following proper Tactical Combat Casualty Care (TCCC) and Advanced Trauma Life Support (ATLS) and damage control resuscitation principles is critical.

INITIAL EVALUATION

Severely injured patients typically warrant bladder drainage via catheter placement to facilitate urinary drainage and assist with hemodynamic monitoring via hourly assessment of urine output (Figure 1). A urethral injury should be suspected in the setting of blood at the urethral meatus or a high-riding prostate on the initial rectal exam. In these situations, or if there is any difficulty with initial catheter placement, urethral integrity must be evaluated via retrograde urethrography. 6, 15 The inability to safely pass a catheter should prompt suprapubic catheter placement.

- A urinalysis should be obtained after successful catheter placement, and any gross hematuria should be immediately noted. Evaluation for renal or bladder injury is necessary for patients with:
- Gross hematuria
- Microscopic hematuria AND an initial systolic BP < 90 mmHg (after they become hemodynamically stable)

A mechanism of injury or physical examination findings suggestive of renal injury (i.e. rapid deceleration, rib fracture(s), flank ecchymosis, pelvic fracture, or a penetrating injury to the abdomen, flank, or lower chest).15

The patient's hemodynamic stability, the operational environment, and the capabilities of the medical treatment facility will dictate which radiographic and surgical evaluation resources are available at each echelon of care. The preferred imaging test to evaluate renal and ureteral injury is an intravenous (IV) contrast-enhanced computed tomography (CT) with arterial and delayed phase imaging.15 During the initial evaluation of patients with hematuria, it is essential to note that the severity of hematuria (gross or microscopic) does not necessarily correlate to the severity of the injury.14 For example, it is possible to have minimal hematuria despite high-grade renal damage such as disruption of the ureteropelvic junction, pedicle injuries, and segmental arterial thrombosis.13 Conversely, low-grade renal injury can result in ongoing gross hematuria. Thus, proper injury staging, and a high index of suspicion are critical regardless of hematuria severity. In cases of blunt renal trauma, most injuries can be managed conservatively. The grading scale is listed in the Renal Injury table section in Appendix A: Urological Diagnosis and Treatments.