Trauma to the Genitourinary Tract

Published on 27/03/2015 by admin

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Chapter 540 Trauma to the Genitourinary Tract

Etiology

Injuries to the genitourinary tract in children usually result from blunt trauma during falls, athletic activities, or motor vehicle accidents (Chapter 66). Children are at greater risk of blunt renal injury than are adults, because they have less body fat and because the kidneys are not located directly behind the ribs. Children with a pre-existing renal anomaly such as hydronephrosis secondary to a ureteropelvic junction obstruction, horseshoe kidney, or renal ectopia also are at increased risk for renal injury. Blunt abdominal or flank trauma often causes a renal injury. Falling can cause a deceleration injury that results in an injury to the renal pedicle, interrupting blood flow to the kidney. If the bladder is full, blunt lower abdominal trauma can cause a bladder rupture. Rupture of the membranous urethra occurs in 5% of pelvic fractures. Straddle injuries usually are associated with trauma to the bulbous urethra.

Symptoms and signs of urinary tract injury include gross or microscopic hematuria, bleeding from the urethral meatus, abdominal or flank pain, a flank mass, fractured lower ribs or lumbar transverse processes, and a perineal or scrotal hematoma.

In >50% of cases there also are major injuries to the brain, spinal cord, skeleton, lungs, or abdominal organs.

Diagnosis

Evaluation of the patient begins after an adequate airway has been established and the patient is hemodynamically stable (Chapter 62). With significant abdominal injury, gross hematuria or >50 red blood cells (RBCs) per high-power field (HPF), or suspicion of renal injury (deceleration injury, flank pain or bruise), renal imaging is indicated. The bladder should be catheterized unless blood is dripping from the urethral meatus, which is an indication of potential urethral injury. Passing the catheter in the presence of a urethral injury can increase the extent of the damage and convert a partial membranous urethral tear into a total disruption. In these patients, a retrograde urethrogram should be performed by injecting radiopaque contrast medium into the urethral meatus under fluoroscopy. Oblique radiographs demonstrate the extent of the injury and whether urethral continuity is preserved or has been disrupted.

A 3-phase spiral CT scan should be performed to evaluate the kidneys, ureters, and bladder. The delayed images are important to detect renal extravasation of blood or urine. Prompt function of both kidneys without extravasation usually excludes significant renal injury. Renal injuries are classified according to the grading scale presented in Table 540-1. Minor renal injuries are most common; these include contusion of the renal parenchyma and shallow cortical lacerations not involving the collecting system. Major renal injuries include deep lacerations involving the collecting system, the shattered kidney, and renal pedicle injuries (Fig. 540-1). Complete absence of function of 1 kidney without contralateral compensatory hypertrophy (indicating congenital absence) should be regarded as an indication of major injury to the renal pedicle. Renal angiography, once used for further evaluation of renal injuries, particularly if a renal pedicle injury is suspected, now is rarely used because such patients are often hemodynamically unstable, and management is not significantly affected by the findings. In some cases, a pre-existing renal anomaly is demonstrated on the study. A ruptured ureteropelvic junction obstruction may be apparent if the kidney is intact but the distal ureter is not visualized.

Table 540-1 GRADING OF RENAL INJURIES

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GRADE DESCRIPTION
1 Renal contusion or subcapsular hematoma
2 Nonexpanding perirenal hematoma, <1 cm parenchymal laceration, no urinary extravasation; all renal fragments viable; confined to renal retroperitoneum
3 Nonexpanding perirenal hematoma, >1 cm parenchymal laceration, no urinary extravasation; renal fragments may be viable or devitalized
4