Blunt genitourinary trauma: Initial evaluation and management

INTRODUCTION — Timely identification and management of blunt genitourinary (GU) injuries minimize associated morbidity, which may include impairment of urinary continence and sexual function. Prompt injury identification depends upon a systematic evaluation with consideration of the mechanism of injury, pertinent physical examination findings, analysis of the urine, and appropriate diagnostic imaging, performed in the correct sequence.

Except in the rare instance of a shattered kidney or major renal vascular laceration with significant hemorrhage, GU injuries seldom pose a threat to life. Once life-threatening conditions are stabilized, investigation for GU injury is conducted in a retrograde fashion beginning with evaluation of the external genitalia and urethra prior to that of the bladder. The ureters and kidneys are evaluated after lower tract injury is excluded, or after initiation of appropriate initial management for an identified lower tract injury.

This topic review will discuss the diagnosis and management of GU injury sustained through blunt trauma. Discussions of general trauma management and other specific injuries are provided separately. (See "Initial management of trauma in adults" and "Initial evaluation and management of blunt abdominal trauma in adults" and "Pelvic trauma: Initial evaluation and management".)

EPIDEMIOLOGY — Approximately 10 percent of patients suffering injuries severe enough to require admission to a trauma service sustain injury to the GU tract. The majority of these injuries (approximately 80 percent) result from blunt trauma. Common mechanisms of injury include motor vehicle collisions (MVC), falls from height, and direct blows to the torso or external genitalia. Injuries to the female genitalia are often associated with pelvic fractures.

Other important mechanisms include physical or sexual assault, consensual intercourse, and penetrating injuries. In the adult patient, isolated blunt injury to the vulva is unusual and should prompt screening for interpersonal violence. In men, up to 85 percent of testicular injuries result from blunt trauma. Resultant injuries include hematoma, rupture, displacement, and torsion. Penile fracture is an uncommon injury resulting from rupture of the tunica albuginea, with concomitant urethral injury occurring in up to 20 percent of cases [1-4]. Overall, urethral disruption accompanies pelvic fracture in approximately five percent of cases in women and up to 25 percent in men; risk varies with the extent of the fracture [5,6]. Blunt injury accounts for the majority of bladder trauma and a pelvic fracture accompanies most cases of bladder rupture [4,7,8]. (See "Pelvic trauma: Initial evaluation and management".)

The kidney is the most commonly injured GU organ. Due to the significant forces required, associated intraabdominal injuries occur commonly [9]. Most kidney injuries result from blunt trauma and tend to be less severe overall, with a lower nephrectomy rate than those seen with penetrating injuries [7]. Ureteral injury is rare, comprising less than one percent of all GU injuries [10].

ANATOMY, PHYSIOLOGY, AND MECHANISM — Anatomically, the GU system is divided into the upper and lower tracts (figure 1 and figure 2 and figure 3). Specific mechanisms lead to injury in different parts of the system. The lower GU tract consists of the external genitalia, urethra, and bladder (figure 4). The upper tract consists of the ureters and the kidneys.

●External genitalia – The male external genitalia consist of the penis, scrotum, testicles, and the ejaculatory complex (figure 4 and picture 1 and figure 5). The female external genitalia consist of the vulva and vagina and includes the labia majora, labia minora, and the clitoris (figure 6 and figure 7). Injuries to the external genitalia may occur by blunt mechanisms such as a direct blow, a fall from height, or a straddle injury. (See "Straddle injuries in children: Evaluation and management".)

Injury may also occur by circulatory compromise inflicted by constricting objects applied either accidentally (eg, hair tourniquet) or intentionally to enhance sexual performance and pleasure. Penile fracture occurs when the erect penis is bent suddenly and forcefully, rupturing the tunica albuginea of one or both of the corpora cavernosa. This occurs most commonly during sexual intercourse when the penis slips out of the vagina and strikes the partner's pubis or perineum, but may also occur during masturbation [1,3,11]. Significant injury to the external genitalia may accompany pelvic fractures.

●Urethra – The male urethra is divided into the anterior (bulbous and pendulous) and posterior (prostatic and membranous) urethra. Traditionally, this division was described at the level of the urogenital diaphragm; however, some researchers have questioned the existence of this anatomic structure [6,12,13]. Regardless, the weakest point of the posterior urethra is the bulbomembranous junction, where the majority of posterior urethral disruptions occur [6]. Anterior urethra injuries may be inflicted by direct blows, straddle injuries, instrumentation, or in conjunction with a penile fracture. By contrast, posterior urethral injuries usually occur in the setting of significant pelvic fractures, often caused by motor vehicle collisions (MVC). Urethral injuries are much less common in women because the urethra is short, relatively mobile, and lacks significant attachment to the pubis.

●Bladder – When empty, the bladder lies along the floor of the pelvis where it remains relatively protected, unless the force of injury fractures the bony pelvis. When distended by urine, the bladder may extend up to the level of the umbilicus where it is vulnerable to blunt trauma inflicted upon the lower abdomen. The weakest and most mobile area of the bladder is at the peritoneal surface of the dome.

Blunt force bladder injuries are seen with lower abdominal trauma and in conjunction with pelvic fractures, often resulting from a MVC. They are classified as a contusion, intraperitoneal rupture, or extraperitoneal rupture. Most bladder ruptures are extraperitoneal (60 percent), followed by intraperitoneal (30 percent) and mixed injuries (10 percent) [14]. Contusions are partial thickness injuries to the bladder wall without rupture. Intraperitoneal rupture occurs from a blunt force injury to the lower abdomen in a patient with a full bladder, resulting in rupture at the bladder dome followed by extravasation of urine into the peritoneal cavity. Extraperitoneal rupture most often occurs in association with a pelvic fracture. The injuring force causes rupture at the anterior or anterolateral wall. In other cases, bone fragments from a pelvic fracture impale the bladder causing extraperitoneal rupture.

●Kidneys and ureters – The kidneys lie in the retroperitoneal space and are protected by the lower ribs, the back musculature, and the perinephric fat. The right kidney extends lower than the left due to the presence of the liver. Significant force is required to injure the kidney. MVCs, falls, direct blows, and lower rib fractures are common mechanisms. Significant decelerating forces may cause avulsion of the renal pedicle or renal artery dissection. In children, bicycle accidents represent a prominent mechanism of kidney trauma [15].

The ureters course distally along the psoas muscles and enter the bladder posteriorly and inferiorly at the trigone. The adjacent musculature and the bony pelvis provide the ureters a degree of protection from injury. The majority (75 percent) of ureteral injuries are iatrogenic, with most occurring during gynecologic, general surgical, or urologic operative or ureteroscopic procedures. Of the remaining injuries, approximately one-third are inflicted by blunt trauma [10]. The most common blunt mechanism is a significant deceleration force with avulsion at the ureteropelvic junction, resulting from a MVC or fall from height. This injury is more common in children due to the increased mobility of the vertebral column [7].

PREHOSPITAL MANAGEMENT — The prehospital management of the patient with blunt GU trauma should focus on identification and stabilization of any potential life threats. Suspected open-book pelvic fractures should be stabilized with an external compression device, which may be as simple as a tightly wrapped sheet (picture 2 and picture 3). (See "Pelvic trauma: Initial evaluation and management", section on 'Initial stabilization and approach'.)

CLINICAL FEATURES — When possible, obtain a focused history of the injury from the patient, prehospital personnel, and available bystanders. Important information relevant to GU injury includes the mechanism of injury, prehospital care provided, and any previous history of GU injury or disease. As the GU tract is seldom injured in isolation, a meticulous physical examination is crucial to avoid missing occult injuries.

●External genitalia injury – Blunt scrotal trauma may result in superficial ecchymosis and swelling or testicular rupture, torsion, or displacement. In testicular rupture, the tunica albuginea is disrupted. Even in the absence of testicular rupture, blood or fluid may accumulate between the tunica albuginea and tunica vaginalis resulting in a hematocele or hydrocele. Testicular torsion disrupts the vascular supply and causes ischemia. Testicular displacement occurs when the testicle is forced from the scrotum, usually into the peritoneal cavity. With these injuries, physical examination may be limited by pain and swelling.

Penile fracture is often accompanied by an audible snap or cracking sound and followed immediately by severe pain, detumescence, swelling, and ecchymosis. The corpus spongiosum is involved in 20 to 30 percent of cases and urethral injury occurs in 10 to 20 percent. If Buck's fascia remains intact, the swelling and ecchymosis are confined to the penile shaft. If not, blood and urine may dissect into the scrotum, perineum, and suprapubic spaces [1,16].

In the presence of a pelvic fracture or blood at the introitus, the clinician must perform meticulous vaginal and rectal examinations. The complications of missed vaginal injuries include infection, fistula formation, and significant hemorrhage [17,18]. In one small case series, 25 percent of women sustaining injury of the external genitalia required red cell transfusion due to blood loss from genital injury alone [17]. If a pelvic fracture is present or suspected, the examiner should take care to avoid penetrating injury to the examining hand from bone edges or fragments when performing a vaginal or rectal examination.

Trauma to the lower genital tract in women, including injuries sustained from sexual assault, is reviewed in greater detail separately. Genital injuries in children sustained via sexual abuse are also reviewed separately. (See "Evaluation and management of female lower genital tract trauma", section on 'Etiology' and "Evaluation and management of female lower genital tract trauma", section on 'Physical examination' and "Evaluation and management of adult and adolescent sexual assault victims in the emergency department" and "Evaluation of sexual abuse in children and adolescents".)

●Urethra and bladder injury – The signs and symptoms of urethral injury include blood at the urethral meatus, gross hematuria, inability to void, an absent or abnormally positioned prostate on digital rectal examination, or ecchymosis or hematoma involving the penis, scrotum, or perineum. Unfortunately, these classic findings may be absent in up to 57 percent of urethral injuries [19].

With pelvic fractures, the risk of urethral injury varies with fracture type [6,19-23]. High risk injuries include concomitant fractures of all four pubic rami or fractures of both ipsilateral rami accompanied by massive posterior disruption through the sacrum, sacroiliac joint, or ilium. Low risk injuries include single ramus fractures and ipsilateral rami fractures without posterior ring disruption. The risk of urethral injury approaches zero with isolated fractures of the acetabulum, ilium, and sacrum [6]. Posterior urethral disruption occurs when a significant pelvic fracture causes upward displacement of the bladder and prostate. Avulsion of the puboprostatic ligament is followed by stretching of the membranous urethra resulting in a partial or complete disruption at the anatomic weak point, the bulbomembranous junction [6]. (See 'Anatomy, physiology, and mechanism' above and "Pelvic trauma: Initial evaluation and management".)

Greater than two thirds of blunt bladder injuries present with gross hematuria, with or without pelvic fracture. Microhematuria, defined here as ≥25 red blood cells (RBC)/high-powered field (HPF), is present in nearly all remaining cases; fewer than 1 percent of all blunt bladder injuries present with a urinalysis containing <25 RBCs/HPF [24-26]. Bladder injury may occur with any pelvic fracture, but is more likely with fractures of the anterior arch or when all four pubic rami are fractured. Additional signs and symptoms include lower abdominal pain or tenderness and inability to void.

●Upper GU tract injury – The clinical clues to a potential kidney injury are nonspecific, but include: bruising, pain, or tenderness to the flank or abdomen; posterior rib or spine fractures; gross hematuria; other organ injury; microhematuria, defined as ≥3 to 5 RBCs/HPF; and shock, defined as a systolic blood pressure ≤90 mmHg. Hematuria (gross or microscopic) is not a sensitive predictor of ureteral injury, as the urinalysis is normal approximately 25 percent of the time [27]. Ureteral injury is frequently missed during the initial evaluation as the signs and symptoms are minimal and nonspecific. Delayed findings include fever, flank pain, and a palpable flank mass (urinoma).

PRIMARY EVALUATION AND MANAGEMENT

Initial assessment — As with any emergency department patient, the initial assessment of the patient with blunt GU trauma should focus on the rapid identification and stabilization of life-threatening injuries. GU trauma is rarely life-threatening, although a shattered kidney, major renal vascular laceration with significant hemorrhage, and renal artery dissection or avulsion of the pedicle from significant deceleration can pose a threat to life or to the kidney itself. (See "Initial management of trauma in adults".)

In the multiply injured or unstable patient, evaluation for GU injury is deferred until potentially life-threatening injuries are excluded and the patient is stabilized. Findings that may herald GU injury, such as gross hematuria or pelvic fracture, are noted so appropriate investigation may be undertaken once immediate life threats have been addressed.

Standard trauma management should be implemented. Apply dressings to open wounds and control any ongoing hemorrhage with direct pressure. Place a pelvic stabilization device (prefabricated pelvic binder, or a bed sheet tied tightly around the pelvis) on any potentially unstable pelvic fracture that may be contributing to hemodynamic instability. This is particularly important with "open-book" type pelvic fractures (image 1). Administer intravenous fluids, blood products, analgesics, and tetanus immunization as needed. Give the patient nothing by mouth until the need for operative intervention has been excluded.

History, examination, and approach to testing — Classic teaching holds that the digital rectal examination provides useful clinical information in the blunt trauma patient with an associated pelvic fracture or suspected urethral injury. The rectal examination includes evaluation for an absent or "high riding" prostate, which may be associated with a posterior urethral disruption and suggests the need for a prompt investigation of urethral integrity. However, multiple retrospective and observational studies suggest that the digital rectal examination is not useful for detecting urethral injuries, and that its accuracy may be particularly limited when performed on a supine or obese patient [28-31]. In such circumstances, the prostate may not be palpable due to inherent limitations of the examination rather than the presence of urethral injury.

In addition, in most instances of urologic injury, other clinical indicators are present, such as a scrotal or perineal hematoma or blood at the urethral meatus. Therefore, when deciding to evaluate for urethral injury, the clinician should consider all clinical features, including the mechanism of injury and the presence and type of any pelvic fracture, and not rely solely on the findings of the digital rectal examination. (See "Pelvic trauma: Initial evaluation and management".)

While most multiply injured patients receive a digital rectal examination, the vaginal examination is often erroneously omitted. To avoid missing occult injuries that may result in significant hemorrhage and infection, clinicians should perform a meticulous vaginal examination in all injured women with pelvic fractures to assess for lacerations or bone fragments. This is especially critical in patients with displaced fractures of the anterior pelvic ring, but less so in those with an isolated, unilateral pubic ramus fracture. Clinicians should take care to avoid penetrating injury to the examining hand from bone fragments.

The diagnosis of injuries to external genitalia is largely based on the mechanism of injury and the physical examination. Unexplained penile or clitoral swelling necessitates a careful search for a hair tourniquet, especially in infants and young children. Consider concomitant urethral injury and perform a retrograde urethrogram to assess urethral integrity in any patient with blood at the urethral meatus, gross hematuria, or ecchymosis or hematoma involving the external genitalia. Plain films revealing a pelvic fracture should prompt a careful examination for occult colorectal or vaginal injury.

In cases of suspected urethral injury, perform a retrograde urethrogram prior to attempting placement of a Foley (ie, bladder or urinary) catheter. Prompt urinary drainage is recommended for patients with a pelvic fracture associated urethral injury, preferably via open or percutaneous suprapubic tube placement. If a partial urethra injury is identified, it is reasonable for an experienced clinician to make one attempt at passing a bladder (Foley) catheter [32,33]. Placement and management of urinary catheters is discussed separately. (See "Placement and management of urinary bladder catheters in adults".)

If a bladder (Foley) catheter has been placed, evaluate all patients with gross hematuria, and those with a pelvic ring fracture and microscopic hematuria (defined here as ≥25 red blood cells (RBC)/high-powered field (HPF)), for bladder rupture. This is accomplished by retrograde cystography or retrograde computed tomography (CT) cystography. Retrograde urethrography or cystography should be deferred, however, when significant pelvic vascular injury is suspected as extravasated contrast dye from the retrograde urethrogram or cystogram may obscure computed tomography and angiography images thereby interfering with study interpretation and subsequent embolization attempts [34].

Kidney imaging is indicated in blunt injuries in the presence of gross hematuria or microscopic hematuria (≥3 to 5 RBCs/HPF) with shock (defined as systolic blood pressure less than 90 mmHg). Additional relative indications include a trauma mechanism involving rapid deceleration, such as a high speed MVC or a fall from height, significant blow to the flank, rib fracture, or clinical features suggestive of kidney injury, including flank bruising or tenderness [9,35]. The imaging study of choice is CT scanning with intravenous contrast [35]. Delayed CT images are indicated in cases of suspected renal collecting system injury.

The diagnosis of ureteral injury is elusive. Intravenous pyelography has long been the test of choice, although the reported sensitivity ranges from 25 to 100 percent [27]. CT imaging is often performed for identification of related injuries. Additional delayed CT images of the renal collecting system (obtained 10 minutes after contrast injection) are indicated when the initial images are nondiagnostic in a patient with suspected injury to the renal collecting system. The delay allows time for the intravenous contrast to be excreted by the kidneys. If operative exploration is indicated, the ureters may be directly evaluated in the surgical suite. When the diagnosis remains in doubt, retrograde pyelography may be of use.

Trauma to the lower genital tract in women, including injuries sustained from sexual assault, is reviewed in greater detail separately. Genital injuries in children sustained via sexual abuse are also reviewed separately. A complete examination of the traumatized lower GU tract of an infant or child may need to be performed by a clinician with suitable expertise under general anesthesia. (See "Evaluation and management of female lower genital tract trauma", section on 'Etiology' and "Evaluation and management of female lower genital tract trauma", section on 'Physical examination' and "Evaluation of sexual abuse in children and adolescents".)

Diagnostic tests

Urinalysis — Hematuria is an important marker for potential injury to the GU tract. When possible, inspect the initial urine output to avoid missing transient hematuria that may clear with ongoing fluid resuscitation. A spontaneously voided specimen is ideal, but is frequently impractical in the multiply injured patient.

Gross hematuria is defined as urine that is any color other than clear or yellow. This necessarily conservative definition is clinically important as the degree of gross hematuria does not correlate with the severity of injury: a relatively minor urethral injury may result in impressive hemorrhage while major vascular disruption may present with only slightly discolored urine. False positives may result from many factors including ingestion of certain food products or dyes, select medications, or the presence of free myoglobin due to rhabdomyolysis.

Microscopic hematuria is generally defined as ≥3 to 5 red blood cells per high powered field (RBCs/HPF) or a positive dipstick evaluation. The significance of gross versus microscopic hematuria varies with the age of the patient and with the location (kidney, ureter, bladder, or urethra) and mechanism of injury (blunt versus penetrating). Thus different thresholds for microscopic hematuria are used to determine management according to clinical circumstance.

Plain radiographs — After the initial assessment and stabilization, and depending on the specific mechanism of injury, plain radiographs may provide information about associated injuries that may be markers for potential GU trauma. Such injuries include: low posterior rib fractures on chest radiograph, vertebral and transverse process fractures on spine or chest radiographs, and pelvic fractures.

Retrograde urethrogram — In cases of suspected urethral injury, the integrity of the urethra is investigated by retrograde urethrogram (image 2). However, the procedure is deferred if significant pelvic vascular injury is suspected or when pelvic angiography is indicated for any reason. This is because assessment for potentially life-threatening injuries takes precedence and because the contrast used to perform a retrograde urethrogram may interfere with the interpretation of a pelvic angiogram or CT scan. (See 'History, examination, and approach to testing' above.)

The procedure is performed as follows. Keep the patient supine and still to avoid potentially disrupting a stable pelvic hematoma. Obtain a baseline abdominal radiograph (KUB) and ensure the film captures the entire course of the urethra and bladder. Retract the foreskin, if present, and control the shaft of the penis with a 4 by 4 inch gauze pad to prevent slippage. Stretch the penis obliquely over the thigh to promote unfolding and visualization of the entire urethra. Fill a 60 mL syringe with 10 percent water-soluble contrast (diluted in sterile saline) and attach a Christmas tree adaptor. Insert the adaptor snugly into the urethral meatus ensuring a tight fit as leaking contrast will result in a spurious study.

Alternatively, insert a Foley (ie, bladder or urinary) catheter a few centimeters into the urethra and partially inflate the balloon to ensure a snug fit within the fossa navicularis. Attach a catheter-tip syringe filled with contrast as above. Inject 50 to 60 mL (0.6 mL/kg in children) of contrast and obtain a KUB during infusion of the final 10 mL. Lack of urethral extravasation with contrast entering the bladder defines a normal study. A partial disruption is demonstrated by urethral extravasation accompanied by contrast entering the bladder. A complete disruption results in urethral extravasation with no contrast entering the bladder.

Retrograde cystogram — Once urethral injury is excluded and/or a Foley (ie, bladder or urinary) catheter has been placed, evaluate all stable patients with gross hematuria or pelvic fracture for bladder rupture using retrograde cystography or retrograde CT cystography.

As with the retrograde urethrogram, keep the patient supine and still to avoid potentially disrupting a stable pelvic hematoma and take care to avoid contrast spillage which will result in a spurious study. Obtain a baseline abdominal radiograph (KUB). Remove the central piston from a 60 mL catheter-tip syringe and attach it to the Foley catheter. Hold the syringe upright above the level of the bladder and instill 400 mL of 10 percent water-soluble contrast (diluted in sterile saline) by gravity. In patients younger than 11 years, calculate the appropriate amount of contrast in mL using the formula: (age in years + 2) x 30.

If the bladder contracts prior to instillation of 400 mL (as demonstrated by the contrast level rising in the barrel of the syringe), wait for the contraction to pass and refill the bladder to the point of contraction, then forcefully inject another 50 mL of contrast. The goal is to distend the bladder adequately to ensure extravasation when rupture is present. The most common reason for false-negative cystography is failure to instill sufficient contrast.

After filling the bladder, clamp the catheter and obtain a KUB. After ensuring adequacy of the contrast study, unclamp the catheter, allow the bladder to drain, and obtain a postevacuation film. Extraperitoneal rupture appears as flame-like areas of contrast confined to the pelvis, often extending lateral to the bladder (image 3). Intraperitoneal rupture appears as contrast outlining bowel and other structures in the peritoneal cavity. Using the baseline film for comparison, carefully scrutinize the postevacuation study for any subtle areas of extravasation not seen on the contrast-distended view.

For retrograde CT cystography, the bladder is filled in an identical manner (image 4 and image 5 and image 6). Do not simply clamp the Foley catheter and rely on passive filling of the bladder by intravenously administered contrast for CT cystography. Multiple studies have demonstrated missed injuries using this approach [8,9,36,37]. A postevacuation film is not necessary with retrograde CT cystography.

CT scanning — CT scanning with intravenous contrast enhancement is the modality of choice for the identification and staging of kidney trauma in the hemodynamically stable patient (image 7) [35]. The initial CT images will frequently miss injuries to the renal pelvis and ureters as sufficient contrast may not yet be present in the collecting system. Additional delayed images are needed to assess for contrast extravasation when these injuries are suspected (image 8) [7,9]. In patients undergoing CT scanning of other organ systems, suspected bladder injuries may be investigated with CT cystography after retrograde filling of the bladder, as described above. (See 'Retrograde cystogram' above.)

Intravenous pyelography (IVP) — CT has largely supplanted IVP as the imaging modality of choice for suspected kidney trauma (image 9), but IVP may be useful in select cases, such as suspected ureteral injury when delayed CT images are nondiagnostic. The so-called "single shot IVP" is rarely indicated in the emergency department evaluation of suspected blunt kidney trauma but may be used at the discretion of the consulting urologist. The main indication is to confirm the presence of a functioning contralateral kidney in a patient deemed too unstable for transport to the CT scanner. However, this study should never delay transfer to the operating suite in such cases. The procedure is performed by injecting 2 mL/kg of intravenous contrast material and then taking an abdominal radiograph (KUB) 10 minutes later [9,38].

Retrograde pyelography — In select cases, such as suspected ureteral injury when other imaging modalities are nondiagnostic, the operating urologist may elect to perform cystoscopy with retrograde pyelography.

Ultrasound — Ultrasound is used to evaluate testicular blood flow in cases of suspected torsion (using color and pulsed Doppler) and to supplement the physical examination in cases of testicular trauma [39]. Sonographic findings of testicular rupture include disruption of the tunica albuginea, abnormal testicular contour, heterogenous appearance of the testicle, and extrusion of testicular tissue through a defect in the tunica [40]. Scrotal pain unrelated to trauma, including testicular torsion (a urologic emergency) and surgical assessment of scrotal trauma are reviewed separately. (See "Traumatic injury to the male anterior urethra, scrotum, and penis" and "Acute scrotal pain in adults".)

While the reported test characteristics of ultrasound for the diagnosis of testicular rupture vary, in a retrospective review of 65 patients presenting to a single emergency department with blunt scrotal trauma, the combination of heterogenous echo texture and loss of the normal testicular contour demonstrated a sensitivity and specificity of 100 and 93.5 percent, respectively [41]. Penile ultrasound may be informative in patients with equivocal signs and symptoms of fracture but is not indicated when the diagnosis is clear [42].

Ultrasound examination of the bladder may reveal free abdominal fluid in the case of an intraperitoneal bladder injury, but ultrasound cannot differentiate urine from blood. For this reason, the focused assessment with sonography for trauma (FAST) examination is less reliable in patients at high risk for bladder injury [43]. Ultrasound lacks sensitivity for kidney trauma and should not be relied upon to exclude significant injury [9]. (See "Emergency ultrasound in adults with abdominal and thoracic trauma".)

PEDIATRIC CONSIDERATIONS — Kidney injuries are more common in children than adults. This is because the child’s kidney is larger relative to the abdomen and pelvis, and because the surrounding ribcage, musculature, and relatively scant perinephric fat provide less protection [44].

Contrary to prior guidelines that recommended imaging for children with microhematuria, the American Urological Association endorses using the same imaging criteria for suspected kidney trauma in both children and adults. As such, kidney imaging is indicated for children with blunt injuries in the presence of gross hematuria or microscopic hematuria (≥3 to 5 RBCs/HPF) with shock [35,45].

As with adults, relative indications for imaging include a significant decelerating mechanism, such as a high speed MVC or a fall from height, or clinical features suggestive of kidney injury, including flank bruising or tenderness. While the guidelines do not define pediatric shock, they note that children may not manifest hypotension with kidney injury as often as do adults. Unlike adults, the guidelines acknowledge that ultrasound may be used to image suspected pediatric kidney trauma, though computed tomography (CT) remains the preferred modality.

SUBSEQUENT MANAGEMENT — Remove any genital-constricting devices promptly. This is accomplished by unwinding a hair tourniquet, cutting a tight-fitting constricting ring or band, or by wrapping a Penrose drain or string around the entire portion of the penis that lies distal to a constricting object to decrease swelling and facilitate removal. Liberal use of a water based lubricant may be beneficial. After significant underlying injury has been excluded, superficial lacerations to the scrotum or penis are copiously irrigated and closed with absorbable suture.

In patients with a low risk pelvic fracture and no evidence of urethral injury on physical examination, it is reasonable to make one attempt at passage of a Foley (ie, bladder or urinary) catheter. Placement and management of urinary catheters is discussed separately. (See "Placement and management of urinary bladder catheters in adults".)

Low risk fractures include single ramus fractures and ipsilateral rami fractures without posterior ring disruption. The risk of urethral injury approaches zero with isolated fractures of the acetabulum, ilium, and sacrum. If resistance is met during this single attempt, remove the catheter and obtain a retrograde urethrogram. If the urethra is intact, insert a Foley and inspect the initial output for evidence of hematuria. (See 'Retrograde urethrogram' above.)

If a urethral injury is suspected subsequent to successful placement of a Foley catheter, do not remove the catheter. A retrograde urethrogram may be obtained by inserting a small feeding tube alongside the catheter and proceeding as above. Urologic consultation is indicated for management of patients with an abnormal urethrogram or in cases of suspected urethral injury when a urethrogram cannot be performed. In females, suspected urethral injury mandates urologic consultation; urethrography is not indicated in the emergency department.

With bladder injuries, the primary goal is to keep the bladder completely decompressed, which facilitates healing by minimizing bladder wall tension. If urethral injury is excluded, place a Foley catheter and irrigate the bladder as needed to clear any clots and ensure adequate drainage. Because bladder injuries are frequently associated with intraabdominal trauma, a diligent search for additional injuries should be undertaken in all patients with an abnormal cystogram. When undertaking this search, keep in mind that ultrasound cannot distinguish between blood and urine. (See 'Retrograde cystogram' above and 'CT scanning' above and 'Ultrasound' above.)

With upper tract injuries, identification and urologic consultation are the priorities of emergency management.

Patients with microscopic hematuria, but without apparent significant GU injury, should be referred for routine outpatient urology follow-up within a few of weeks.

PITFALLS OF MANAGEMENT

●Delaying transfer to definitive care to obtain imaging studies in the hemodynamically unstable patient.

●Relying on ultrasound to exclude significant injury in the setting of a grossly abnormal testicle on physical examination.

●Missing significant injuries due to failure to perform rectal and vaginal examinations in patients with pelvic fractures.

●Missing significant bladder injuries by clamping the Foley (ie, bladder or urinary) catheter and relying on passive filling of the bladder by intravenously administered contrast prior to computed tomography (CT) cystography. An adequate study requires retrograde filling to distend the bladder.

DISPOSITION AND DEFINITIVE MANAGEMENT — Most patients with significant GU injuries require immediate or urgent urologic consultation in the emergency department. Many such patients have associated nonurologic injuries that mandate intervention by trauma or general surgeons. In the event that appropriate specialists are unavailable, expeditious transfer to a referral center is necessary following initial assessment and stabilization. Transfer should not be delayed to obtain more detailed imaging in an unstable patient or a patient at risk of decompensating.

Definitive management of GU injuries is discussed in detail separately. Limited guidance for emergency department management is provided below. (See "Overview of traumatic lower genitourinary tract injury" and "Overview of traumatic upper genitourinary tract injuries in adults" and "Traumatic injury to the male anterior urethra, scrotum, and penis" and "Management of blunt and penetrating renal trauma".)

Some hemodynamically stable patients with minor GU trauma and no other significant injury may be discharged from the emergency department after a discussion with the urologist assuming responsibility for follow-up care. Such cases include minor lacerations and zipper injuries not requiring formal wound exploration, and isolated, partial, anterior urethral injuries with a functioning Foley (ie, bladder or urinary) catheter in place. Counsel these patients on the signs and symptoms of infection and Foley catheter dysfunction and ask them to return to the emergency department if they develop these or any other concerning symptoms. Ensure that they understand the importance of complying with the scheduled follow-up plan. (See "Management of zipper entrapment injuries" and "Overview of traumatic lower genitourinary tract injury".)

Traumatic testicular torsion and displacement are treated surgically. Early (within 72 hours) operative intervention maximizes the rate of testicular salvage in cases of testicular rupture. Likewise, prompt surgical exploration and repair of penile fractures reduces the risk of the late complications of penile curvature, erectile dysfunction, and dyspareunia. Reimplantation of an amputated penis should be performed as expeditiously as possible, but has been successful after 16 hours of cold ischemia and six hours of warm ischemia [46]. The majority of women with vaginal injuries will require operative repair or washout to prevent significant morbidity and mortality. (See "Traumatic injury to the male anterior urethra, scrotum, and penis" and "Evaluation and management of female lower genital tract trauma".)

Optimal definitive management of urethral injuries depends on several factors, including: location (anterior or posterior), severity (partial or complete), and the preference and expertise of the consulting urologist [35]. Options vary from placement of a Foley catheter to facilitate healing by secondary intention (for some partial anterior urethral injuries) to early endoscopic realignment or delayed urethroplasty (for posterior urethral injuries). Often, placement of a suprapubic cystostomy tube will be required to promote decompression of the bladder and divert urine from the healing urethral injury or anastomosis. Regardless of the approach, the ultimate goal is the maintenance of urinary continence and sexual function. (See "Posterior urethral injuries and management" and "Traumatic injury to the male anterior urethra, scrotum, and penis".)

Operative repair is the rule for most intraperitoneal bladder ruptures. By contrast, the majority of extraperitoneal ruptures can be managed nonoperatively with catheter drainage alone. Exceptions include injuries involving the bladder neck, associated rectal or vaginal injury, and those patients requiring laparotomy for other indications. (See "Traumatic and iatrogenic bladder injury".)

Depending upon the degree and location of ureteral disruption, management options include cystoscopic stent placement or surgical repair over a stent. (See "Overview of traumatic and iatrogenic ureteral injury".)

The need for operative repair of kidney trauma depends on the severity of injury, as classified by the American Association for the Surgery of Trauma (AAST) organ injury severity scale for the kidney (table 1 and figure 8). Many grade I and II injuries can be managed nonoperatively while grade V injuries frequently require nephrectomy, which in the rare case of exsanguinating hemorrhage from a renal vascular injury may be lifesaving. (See "Management of blunt and penetrating renal trauma".)

The definitive management of renovascular injuries is a subject of debate among the surgeons who care for these patients. Treatment options vary, depending on hemodynamic stability and associated injuries, and include operative revascularization, nephrectomy, or observation [47]. Immediate intervention is recommended for hemodynamically unstable patients with a large perirenal hematoma (>4 cm) or when there is evidence of active contrast extravasation in a patient with a high-grade kidney laceration. Endovascular stenting may be used to restore arterial flow in cases of renal artery dissection. In cases of major renal vascular disruption, emergency angiography with selective embolization can be both diagnostic and therapeutic. Angiography requires significant time, expertise, and specialized equipment, which is not available in all medical centers. (See "Management of blunt and penetrating renal trauma", section on 'Vascular injury'.)

OUTCOMES — Timely recognition and appropriate treatment of GU trauma are paramount to minimizing associated morbidity. Early complications include bleeding, infection, abscess formation, urinary extravasation and fistulas, and urinoma formation. Delayed complications are discussed in greater detail separately, but in summary may include bleeding, hydronephrosis, calculus formation, chronic pyelonephritis, hypertension, arteriovenous fistulas, pseudoaneurysms, urethral strictures, urinary incontinence, and sexual dysfunction. Acute kidney failure may occur, most commonly in the multiply injured patient with hemodynamic instability. A subset of patients will require short term hemodialysis, but the vast majority will regain sufficient kidney function to avoid long term dialysis treatment. (See "Overview of traumatic upper genitourinary tract injuries in adults" and "Overview of traumatic lower genitourinary tract injury" and "Management of blunt and penetrating renal trauma".)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: General issues of trauma management in adults" and "Society guideline links: Genitourinary tract trauma in adults" and "Society guideline links: Thoracic and lumbar spine injury in adults".)

SUMMARY AND RECOMMENDATIONS

●Anatomy and injury patterns – Timely identification and management of genitourinary (GU) injuries minimizes associated morbidity, which may include compromised kidney function and impairment of urinary and sexual function. Significant force is required to injure the kidney and associated intraabdominal injuries are common. The GU tract is seldom injured in isolation. The relevant anatomy and the mechanisms and clinical features of specific injuries are described in the text. (See 'Anatomy, physiology, and mechanism' above and 'Clinical features' above and "Initial evaluation and management of blunt abdominal trauma in adults".)

●Evaluation – Injury identification depends upon a systematic evaluation with consideration of the mechanism of injury, pertinent physical examination findings, analysis of the urine for blood, and appropriate diagnostic imaging performed in the correct sequence. Perform a careful physical examination to avoid missing occult injuries. (See 'Primary evaluation and management' above.)

●Imaging: approach and lower GU tract – Investigate for GU injury in a retrograde fashion beginning with evaluation of the external genitalia and urethra prior to that of the bladder. When urethral injury is suspected, perform a retrograde urethrogram. In cases of gross hematuria or high-risk pelvic fracture, obtain a retrograde cystogram or retrograde computed tomography (CT) cystogram to evaluate for bladder injury. Defer such studies when pelvic angiography is indicated for the diagnosis or management of pelvic hemorrhage, which may be life threatening. (See 'Primary evaluation and management' above and 'Disposition and definitive management' above.)

●Assessment and imaging of upper GU tract – Evaluate the upper GU tract (ureters and kidneys) after lower tract (urethra, bladder) injury is excluded, or after initiation of appropriate emergency management for an identified lower tract injury. Suspect upper tract injury and obtain an IV contrast enhanced CT scan in patients with gross hematuria or microscopic hematuria (≥3 to 5 RBCs/HPF) associated with shock. Obtain additional, delayed CT images (10 minutes after contrast injection) when the initial images are nondiagnostic in cases of suspected collecting system involvement. (See 'Primary evaluation and management' above.)

●Consultation and transfer – Most patients with significant GU injuries require immediate or urgent urologic consultation. Many patients will have associated nonurologic injuries that mandate surgical consultation. In the event that appropriate specialists are unavailable, expeditious transfer to a referral center is indicated after the initial assessment and stabilization. Do not delay transfer to obtain imaging studies in a patient who is hemodynamically unstable or at risk of decompensation. (See 'Disposition and definitive management' above.)