Chapter 27: Genitourinary Trauma

• Perform a urinalysis on all major trauma patients as well as those suspected of having isolated genitourinary (GU) injury.

• Penetrating trauma between the nipples and perineum requires resuscitation efforts and careful evaluation for intra-abdominal and renal trauma.

• Renal trauma can lead to acute tubular necrosis with renal failure, delayed bleeding, infection, or abscess secondary to urinary extravasation.

• Consider bladder rupture in children who present with abdominal trauma with gross hematuria, blood at the urethral meatus, inability to void, or little urine upon urinary catheter placement.

• Genital injuries in a child must always be concerning for abuse.

Genitourinary (GU) tract injuries occur in 10% of abdominal trauma patients. The kidney is the most commonly injured organ in the urinary tract, followed by the bladder, urethra, and ureter.^1,2 Renal injury occurs from trauma to the back, flank, lower thorax, or upper abdomen. Compared with adults, the pediatric kidney is more vulnerable to injury because there is less protection afforded by the pliable rib cage, weaker abdominal muscles, the relatively larger size of the kidneys in proportion to the rest of the child's body, less perirenal fat, and congenital abnormalities. Preexisting renal abnormalities, for example, ureteropelvic junction (UPJ) obstruction, hydroureteronephrosis, horseshoe kidney, are three- to fivefold more common in children undergoing a screening CT scan for trauma than in adults.³ Patients with a preexisting congenital renal abnormality present with a history of hematuria disproportionate to the severity of trauma.³ Blunt trauma accounts for 80% to 95% of all renal injuries and the most common cause of blunt trauma is motor vehicle collisions.^1,4–8 Other common causes are sports activities. Penetrating trauma accounts for approximately 10% of all renal injuries.^1,4

Hemodynamically stable patients with hematuria and suspected urinary system injury are best evaluated by a contrast-enhanced CT scan. If CT scanning is not available, an intravenous pyelogram (IVP) is an alternative. Cystography and urethrography remain useful techniques in the initial evaluation and follow-up of urinary bladder and urethral injuries.⁹ Sexual and physical abuse should be considered in patients with perineal injuries, for example, burns, inconsistent mechanism of injury, previous injury, child's history, etc.

As in all major traumas, management of GU injuries begins with the basics of advanced trauma life support. After stabilizing the patient, specific organ systems are evaluated. The kidneys may be sources for major bleeding in patients with hypovolemic shock; however, shock due to an isolated renal fracture is uncommon since the kidneys are surrounded by a tight fascia which limits parenchymal bleeding to 25% or less of total blood volume. The vast majority of urologic injuries are not life-threatening; however, failure to diagnose them and any delay in treatment can lead to significant morbidity. Table 27-1 shows the initial assessment and management of GU injuries. A urine dipstick analysis is an initial screening test for hematuria; if positive for blood, perform a microscopic urinalysis. Hematuria may be absent in GU injuries. Table 27-2 lists indications for further GU evaluation. The signs of GU trauma as seen in an anteroposterior pelvic plain film are as follows: (1) loss of the psoas shadow indicates retroperitoneal blood, (2) scoliosis with concavity to the side of injury, and (3) lower rib or transverse process fractures. Monitor urinary output (see Table 27-3).

Blunt GU injuries occur most commonly with rapid deceleration. The kidneys are crushed against the ribs or vertebral column from their relatively fixed position within Gerota's fascia. This can result in a contusion or a parenchymal laceration. The vascular pedicle can be stretched, injuring the renal artery or vein with subsequent thrombosis.

Hematuria is present in more than 75% to 95% of cases of renal trauma.⁵ However, UPJ injuries, for example, renal pedicle injury, can occur without hematuria in 25% to 50% of patients.¹⁰ In penetrating trauma, renal vessels or the ureter may be severed without hematuria.¹¹ Contusions, hematomas, or ecchymoses to the back or flank should lead one to suspect renal injury, requiring a CT scan or an IVP. Hemodynamically unstable patients may require immediate surgery. Other indications for evaluating the urinary tract are gross or microscopic hematuria (>20 RBCs/HPF) with: (1) penetrating abdominal trauma; (2) hypotension with a systolic blood pressure less than 90 mm Hg; (3) other intra-abdominal injuries from blunt trauma; or (4) rapid deceleration injury (i.e., high-speed motor vehicle collisions, fall from a height).

CT scanning is the best initial imaging study for patients suspected of having renal injury. It describes (1) the extent of damaged parenchymal tissue and perirenal hemorrhage or hematomas, (2) extravasation of urine, (3) renal pedicle or vascular injuries, and (4) injuries to other intra-abdominal structures. The focused assessment sonography for trauma (FAST) scan cannot differentiate between blood, extravasated urine, and other types of free fluid with regard to GU trauma. Thus, ultrasonography is less sensitive, compared with CT scan, for identifying renal injuries.^12,13

Ninety-five percent of blunt renal injuries can be treated nonoperatively.¹⁴ Children who are initially hemodynamically unstable from blunt renal trauma and respond to rapid crystalloid fluid resuscitation require admission to the intensive care unit for continuous monitoring. Major penetrating injuries to the kidneys with extravasation and hemodynamic instability usually require surgery. Upper tract injuries are rare and include thrombosis of the renal artery and disruption of the renal pedicle secondary to deceleration. They usually present with severe abdominal pain. Hematuria may be absent in these cases. IVP, CT scan, or renal arteriograms are the diagnostic studies of choice.

The classification of renal injuries with its recent revisions is shown in Figure 27-1.¹⁵ The grading system of the American Association for the Surgery of Trauma takes into account depth of injury, vascular involvement, and presence of urinary extravasation.^16,17 Grade I injuries occur in approximately 80% of all renal injuries.⁸ Subcapsular hematoma is less common than perinephric hematoma in blunt trauma.¹⁸ The hallmark of grade IV injuries is extravasation of opacified urine into the perirenal space on CT scan.¹⁹ The revised grade IV classification includes all collecting system, renal pelvis injuries, and segmental arterial and/or venous injuries.¹⁵ Urinary extravasation resolves spontaneously in approximately 80% of cases.²⁰ Grade IV segmental infarctions often resolve with conservative treatment.⁸ In the revised grade IV injuries, the hallmark of complete avulsion of the UPJ injury is noted by the absence of opacification of the distal ureter. The revised grade V classification is limited to main renal artery and/or vein injuries, including laceration, avulsion, and thrombosis.¹⁵ Most children with grades IV and V renal injury following blunt trauma can be managed nonoperatively, exceptions include complete UPJ disruption or a hemodynamically unstable patient.^15,21

Renal pedicle injuries occur in up to 5% of all renal traumas.²² Hematuria may be absent. The most common vascular pedicle injury from blunt trauma is renal artery occlusion. Traumatic renal infarction can occur at any time, even long after the initial renal trauma. Isolated renal vein injuries are infrequent.²³ Renal vein thrombosis from trauma almost always occurs with an arterial or parenchymal injury.²⁴ A devascularized kidney will show no enhancement on CT scan.

Complications of renal trauma are urinary extravasation, urinoma, infected urinoma, secondary hemorrhage, perinephric abscess, pseudoaneurysm, hypertension, arteriovenous fistula, pulmonary complications, acute tubular necrosis with renal failure, chronic pyelonephritis, hydronephrosis, chronic calculi, and pseudocyst. These occur in 3% to 33% of patients with renal trauma.⁸ Urinary extravasation is the most common complication.²⁵ This is present in grade IV parenchymal injury and avulsion of the UPJ. Urinoma is a urine collection that may occur in 1% to 7% of all renal trauma patients.²⁶ Intraperitoneal urine extravasation is usually due to a penetrating injury.²⁷ Secondary hemorrhage is common in grade V injuries and in penetrating trauma is managed conservatively.⁸ Secondary hemorrhage is often caused by a traumatic pseudoaneurysm or an arteriovenous fistula. Posttraumatic renovascular hypertension may occur weeks to decades later, with an average of 34 months after renal trauma.¹⁶ Anomalous kidneys (hydronephrosis, tumor, horseshoe kidney, or polycystic kidney disease) are more easily injured with minor trauma and can present with hematuria of varying degrees.

Management of blunt renal trauma can be executed based on clinical features, CT imaging, and staging of renal injuries. The goal of management of blunt renal trauma in children is nonoperative renal preservation in stable patients with a vascularized kidney.²⁸ The methods of achieving this goal have not been well established in current literature. Surgical intervention is needed for associated abdominal organ injuries and renal vascular injuries.²¹ However, there is no prospective data addressing management of pediatric blunt renal trauma.²⁸

Traumatic ureteral injuries are rare, occurring in less than 1% of all GU traumas.^29,30 The proximal ureter is protected by the psoas muscle and vertebrae; the distal ureter is protected by the bony pelvis. Penetrating trauma is the most common mechanism of injury. However, in blunt trauma, avulsion of the ureter occurs more commonly in children than in adults. The ureter can be stretched by sudden extreme flexion of the trunk. Approximately 56% of patients with ureteral injuries are hypotensive.²⁹ Gross or microscopic hematuria is present in approximately 75% to 85% of these patients.^29,31 If there is complete ureteral transection or an adynamic segment of ureter, hematuria may not be present. CT scan with contrast is the best initial imaging study and is highly sensitive at detecting urine extravasation. It is important that, after initial scanning of the abdomen and pelvis, a second scan—approximately 10 minutes after contrast injection—is done to fully evaluate the collecting system and to assess urinary extravasation.³² Ureteral transection is treated with ureteropyelostomy.

Bladder injuries are uncommon because of protection by the bony pelvis. However, children with pelvic fractures have a concomitant bladder injury approximately 10% of the time.³³ In young children, the bladder has an abdominal position and is more vulnerable to rupture when full. Bladder rupture requires surgical consultation for possible exploration, repair, debridement, and drainage. It is associated with a high mortality rate and that rate increases with delay in diagnosis. It should be considered in patients who have gross hematuria, blood at the urethral meatus, inability to void, or little to no urine flow on catheterization. These findings are indications for cystography.^34,35 Multidetector computed tomography (MDCT) is rapidly becoming the most recommended study for evaluation of the bladder for suspected trauma.³⁶

Traumatic urethral injuries occur in approximately 10% of patients with pelvic fractures.³⁷ The mechanism of injury for urethral injuries is usually blunt trauma. These injuries are less common in children due to a more flexible pelvis. Urethral injuries are rare in females due to the hypermobility of the urethra and lack of bony attachments. Concomitant bladder injuries occur in 10% to 29% of patients with urethral injuries.³⁸ Examples of causes of urethral injuries are pelvic fracture, straddle injury, and urethral manipulation. Indications for a retrograde urethrogram before inserting a urinary catheter are as follows:

1. Gross hematuria

2. Blood at the urethral meatus

3. Inability to urinate

4. Perineal or scrotal swelling and ecchymosis. A perineal “butterfly hematoma” is a classic finding.

5. An absent or high-riding, floating, or boggy prostrate on digital rectal examination

6. Inability to insert a urethral catheter

7. Unstable pelvic fracture

Urethral disruptions may require insertion of a suprapubic catheter.

A rectal examination can reveal a high-riding prostate indicating urethral disruption. Blood at the urethral meatus and hematuria may be better screening tests than the digital rectal examination in blunt urethral injuries.³⁹

Anterior pelvic fractures usually accompany urethral injuries. Urethral disruptions are divided into those above (posterior) or below (anterior) the urogenital diaphragm. Posterior urethral injuries usually coincide with multisystem injuries and pelvic fractures. Penetrating anterior urethral and perineal injuries can occur due to straddle injuries such as falls on a fence, and may be an isolated injury. Suspect a urethral tear when (1) there is blood at the urethral meatus or (2) ecchymoses or hematoma of the scrotum or perineum. Early urologic consultation is necessary.

Injuries to the external male genitalia result from the testis being forced against the pubic ramus. A common mechanism of injury is a straddle injury from a bicycle. Problems caused by scrotal trauma include testicular or appendage torsions, testicular dislocation, epididymitis, hematocele, hematoma, pyocele, hydrocele, and testicular rupture. Evaluate significant straddle injuries with a pelvic radiography to assess for fracture of the pubic ramus. Doppler ultrasound should be immediately available to evaluate the testes for hematoma, rupture, dislocation, or blood flow and torsion.⁴⁰ Obtain urologic consultation early as delay of 4 to 6 hours may result in the loss of the testis. If these conditions are ruled out, the patient may be discharged to home with urologic follow-up. Scrotal support and cold packs may help.

Testicular or epididymal rupture results from direct trauma when the testis is forced against the pubic ramus, which leads to tearing of the inelastic tunica albuginea with extrusion of the seminiferous tissue. This is rare in children. Suspect testicular or epididymal rupture when there is a recurrence of pain and delayed onset of scrotal swelling from hours to 3 days after the injury. Early surgical exploration is recommended. Complications include epididymoorchitis with localized redness, warmth, swelling, and fever.

Testicular dislocation occurs when the testis is forcibly displaced from the scrotum into the inguinal, acetabular, crural, perineal, penile, or abdominal region or extruded through a scrotal laceration. Testicular dislocations are rare. Consider this diagnosis when there is an empty hemiscrotum after trauma. Symptoms include scrotal pain, nausea, and vomiting. Obtain urologic consultation.

The most common cause of penile injuries is from complications of circumcision. Other mechanisms of injury are direct blows from toilet seats, falls, and sports injuries; zipper entrapment of the foreskin; and tourniquet injuries. Most injuries are minor and can be treated conservatively. However, associated GU injury may occur with major trauma. Urinalysis is recommended in significant penile injury. Retrograde urethrography is recommended as urethral injuries occur in up to 50% of patients with penile injury.^41,42 Superficial lacerations of the penis can be repaired as in any other laceration. Treatment of zipper injuries to the foreskin includes using bone cutters or similar device to cut the bridge of the sliding piece of the zipper. Scrotal exploration is recommended with the presence of a large hematocele or rupture of the tunica albuginea.⁴³

Penile fracture, or corpus cavernosal rupture, from blunt trauma to an erect penis is uncommon. The most common mechanism of injury for a fractured penis is when an erect penis is forced against a solid object, for example, the pubis, during sexual intercourse. The patient hears a “crack” or “pop” followed by pain, swelling, ecchymosis, deformity of the penis, and occasionally a palpated corporal defect. Urologic consultation is recommended. Consider a scrotal ultrasound or cavernosography as an adjunct to the physical examination in these cases.^44,45 Penile fractures can be treated conservatively except when penile deformity or urethral involvement is present. One study suggests that patients with high suspicion of penile fractures be treated surgically.⁴⁶ Urethral injuries occur in approximately one-third of patients with penile fractures.⁴⁷ Thus, indications for a retrograde urethrogram in patients with penile fractures are gross hematuria, blood at the meatus, and the inability to void.

Tourniquet injuries in an infant may present as balanitis, paraphimosis, or cellulitis of the penis. This may occur when hair surrounds the coronal groove and cuts into the shaft of the penis. Treatment usually involves removal of the band of hair and treating any infection. Follow-up with a urologist if deeper injury is suspected.

Vaginal lacerations may occur from bony fragments from pelvic fracture(s). Confirm an intact urethra with a retrograde urethrogram before inserting a urinary catheter in cases such as gross hematuria; blood at the urethral meatus; inability to urinate; perineal swelling and ecchymosis; inability to insert a urethral catheter; and unstable pelvic fracture. A disrupted urethra may require a suprapubic tube placement. Perineal trauma in females often results from blunt trauma, for example, straddle injuries.

Medical providers must evaluate the risk of child sexual abuse in all cases of genital trauma. The publication by the American Academy of Pediatrics (AAP) Committee on Child Abuse and Neglect includes a report on evaluation, reviews the definition and presentation, an outline for history taking, suggestions on performing the physical examination, discussion of indicated laboratory specimens, guidelines for reporting suspected cases, treatment, follow-up, and legal issues.⁴⁸ Child abuse should be considered when the history or reported mechanism does not match the injuries. All developmentally capable patients with suspected sexual abuse should be referred for formal forensic interview in a timely manner. Trained forensic interviewers can be from child advocacy centers, the police department, or child protective services (CPS). Children who are suspected to have been sexually abused warrant a screening examination.

Reasons for emergency examinations include, but are not limited to, the following:

1. Complaints of pain in the genital area

2. Evidence or complaint of genital bleeding or injury

3. The alleged assault may have occurred within the previous 72 hours, depending on the state law; transfer of biologic materials may occur for forensic analysis

4. Medical intervention is needed emergently for the health and safety of the child

5. Significant behavioral or emotional problems, for example, suicidal ideation/plan

The physical examination includes the following:

1. Placing the patient in a frog-leg position

2. Gentle traction on the labia majora, tugging toward the examiner with lateral traction, to examine the genitals including labia minora, vestibule, hymen, and vaginal opening

3. Considering examination in the knee–chest position

4. Consulting a specialist if the examination is inadequate or if abnormalities are present

5. Avoiding a speculum examination in prepubertal children

6. Visual identification and/or photos of the genital anatomy before a speculum examination in adolescents

The majority of patients, who have disclosed sexual abuse or sexual assault, have normal examination results.⁴⁹ The absence of genital findings does not exclude sexual abuse. The Centers for Disease Control and Prevention (CDC) and the AAP have published guidelines for evaluating sexually transmitted infections in sexually abused children.^50,51 Each state has its own standards for forensic evidence collection. The AAP recommends that forensic evidence collection be considered when the victim presents within 72 hours of the assault.⁵² Recommendations for interpretation of physical and laboratory findings are from the AAP Committee on Child Abuse and Neglect, the Ray E. Helfer Society (an honorary society for physician specialists in child abuse diagnosis and treatment), and Cornell University Special Interest Group in Child Abuse.^48,52 The CDC (www.cdc.gov) and AAP have published medication dosing guidelines for sexually transmitted disease prophylaxis.^50,51 A progestin-only regimen, that is, plan B (levonorgestrel), has been shown to be the most efficacious and least toxic of the postexposure prophylaxis to prevent pregnancy when started within 5 days of the sexual contact.⁵³ Patients with a specific concern for sexual abuse based on caretaker history or disclosure by the patient should have CPS involvement.

Accidental genital trauma may be confused with sexual abuse findings. Accidental genital trauma can present in the pediatric emergency department, most of which are due to straddle injuries.^54,55 Typical findings in straddle injuries are lysis of labial adhesions, lacerations in the gutter between the labia minora and the labia majora, labial contusions or hematomas, and injuries to the skin overlying the perineal body. Lysis of adhesions and small abrasions may also result from sexual abuse.⁵⁶ Injuries to the hymen or vagina are unusual.⁵⁷

Approximately 3% to 10% of trauma patients have injury to the GU tract.^58,2 Figures 27-2, 27-3 and 27-4 summarize diagnostic studies in GU injuries. Hematuria is the hallmark of GU trauma. A urinalysis should be performed on all major trauma patients and those with minor GU injury (Figs. 27-2, 27-3 and 27-4). CT scan with contrast is the best initial imaging study to provide accurate American Association for the Surgery of Trauma grading by demonstrating the depth of injury and involvement of vessels or the collecting system. Delayed images are important in diagnosing urinary extravasation. Patients with pelvic injuries and gross hematuria should have a cystography. Consider urethral injuries in patients with pelvic fractures. The GU tract has an amazing ability to heal itself. If the flow of urine can be maintained without obstruction, healing is likely to occur. The majority of renal injuries can be managed conservatively. Those with grade IV injuries, grade V injuries, or coexisting organ injuries more often require intervention or surgery.

The author thanks Hannes Schweiger, PhD, for his assistance with the diagrams in the manuscript.