Trauma

Traumatic injuries to the genitourinary tract represent about 10% of all injuries seen in the emergency room. The urgency of the patient’s overall clinical condition will dictate how a diagnosis will be made. Care must be taken not to overlook significant urologic injuries during the commotion of a major trauma emergency. The initial assessment of major trauma will focus on control of hemorrhage and shock. Resuscitative efforts will usually require placement of intravenous (IV) lines and a Foley catheter. This early urologic intervention will be the first problem faced. Careful examination of the urethral meatus for the presence of blood is essential before Foley placement. Blood at the meatus indicates urethral injury. A retrograde urethrogram can be performed to assess the extent of urethral injury before catheterization. The second urologic challenge will be to assess for renal injury in any major blunt abdominal trauma or penetrating trauma to the upper abdomen. This is best accomplished by contrast-enhanced computed tomography (CT) scan. Obtain urologic consultation before opening the abdomen.

INITIAL UROLOGIC ASSESSMENT

Physical Examination

Injury to the bladder or urethra would be suggested by evidence of a pelvic fracture, blood at the urethral meatus, or superior displacement of the prostate on digital rectal examination. Examination of the abdomen, chest, and back must be performed. The presence of a flank hematoma, abdominal or
flank tenderness, rib fractures, and penetrating injuries to the low thorax or flank indicate possible renal injury:

Urinalysis
Retrograde urethrogram if blood at the meatus or pelvic fracture
CT scan with IV contrast
Double-dose (150 mL) bolus intravenous urogram (IVU) (if CT unavailable)

RENAL INJURY

The kidney is the organ most commonly involved in urinary system trauma. Microscopic [>5 red blood cells (RBCs)/high power field (hpf)] or gross hematuria indicates injury to the urinary system. However, 10% to 25% of significant renal injuries will present without hematuria, and these are most often major injuries of the renal pedicle. Renal injuries are properly separated into two major groups for diagnostic purposes: those caused by penetrating trauma (20%) and those caused by blunt trauma (80%).

Penetrating Renal Trauma

Penetrating trauma often results in surgical exploration because of other significant injuries (e.g., liver, small bowel, stomach, colon, and spleen). Gunshot and stab injuries are the most common causes. Renal injury can often be overlooked in the face of more urgent problems. Absence of hematuria does not rule out renal injury. A CT scan with IV contrast should be obtained before going to the operating room whenever possible. Radiographic evidence of unilateral nonfunction, extravasation, suspected laceration, or large perirenal hematoma may require renal arteriography. Unfortunately, renal exploration of penetrating trauma often results in partial or total nephrectomy. An intraoperative single-shot IVU (10 minutes after injection of contrast) may be helpful to prove the presence of a functioning contralateral kidney when forced to do surgery without adequate imaging.

Blunt Renal Trauma

Blunt trauma requires considerable diagnostic effort to fully assess the extent of injury and determine proper management. Most blunt renal injuries result from rapid deceleration as in
a motor vehicle accident or a fall. Hematuria will usually be present, but its absence does not rule out renal injury. Patients with gross hematuria or microscopic hematuria (>5 RBCs/hpf) with shock should undergo imaging studies, usually a CT with IV contrast. Fracture of a lumbar transverse process or lower rib should raise suspicion of renal injury.

Classification of Renal Injury

Staging of renal trauma should begin with a double-dose (150 mL) IVU if the patient is hemodynamically unstable. This will effectively stage 85% of renal injuries. A CT scan with IV contrast is preferred if the patient is stable. Nonvisualization requires immediate renal arteriography without delay to evaluate for renal pedicle injury.

Minor Renal Trauma	Major Renal Trauma
Grade I—Renal contusion or subcapsular hematoma	Grade III—Cortical lacerations >1 cm without collecting system injury
Grade II—Nonexpanding perirenal hematoma or laceration <1 cm	Grade IV—Major lacerations of cortex; collecting system injury
	Grade V—Renal pedicle injury; shattered kidney