Pediatric emergency medicine trisk 830

Medial extravasation of contrast is often seen with UPJ ruptures and no
contrast will be seen in the distal ureter on delayed images of complete UPJ
avulsion. Historically, diagnosis of UPJ injuries was delayed in 50% of cases but
routine evaluation of trauma with CT, especially when delayed images are
obtained, has increased the initial detection rate to almost 90%.
Ultrasound
The focused assessment by sonography for trauma (FAST) is often used to
evaluate trauma patients for abdominal injuries and intra-abdominal fluid
collections. Despite the availability and low risk nature of sonography, this
modality has a low sensitivity (48%) for detecting renal injuries and often
overlooks significant damages.
The use of contrast-enhanced ultrasound has recently been reported to increase
the sensitivity to 69%, which is still inferior to the >90% sensitivity of CT.
Extravasation is also more difficult to visualize on ultrasound. Currently used
contrast preparations are not well excreted into the collecting system, limiting
evaluation in the trauma setting. This study is being utilized more often for
follow-up of parenchymal injuries, especially in stable patients.
Intravenous Urography
Although almost completely replaced by CT for evaluating stable trauma patients,
the intravenous urogram or pyelogram still maintains a role in evaluating the
unstable trauma patient taken directly to the operating room. The main utility of
this modality is to verify the presence of a functioning contralateral kidney. The
one-shot urogram is performed by giving a 2 mL/kg body weight contrast bolus
followed by plain film 10 minutes later. Identifying a functional contralateral
kidney is important first because every possible attempt should be made to save
the injured kidney if it is the only one. The injured kidney may lack contrast
uptake if there is a major vascular injury or demonstrate a delayed nephrogram
due to significant compression from a contained hematoma. An abnormal renal
outline, displacement of the bowel or ureter, and loss of the psoas margin are all
suggestive of renal injury and hematoma. Distinctive patterns of contrast
extravasation that raise concern of a possible UPJ injury include extravasation

medial or circumferential (circumferential urinoma) to the kidney. Also, with a
complete UPJ disruption, the ipsilateral ureter will lack intraluminal contrast. The
study is not particularly sensitive for picking up ureteral injuries.


FIGURE 108.3 Renal fracture. Computed tomography section of the abdomen shows fracture
of the left kidney with moderate subcapsular hematoma.

Angiography
Angiography has been largely replaced by noninvasive modalities, especially in
the pediatric patients in whom technical problems with vascular access result in a
higher complication rate than in adults. Arteriography does not add useful
information to contrast CT scanning and may increase diagnostic delay during the
preoperative workup.
It is however quite useful in patients who require therapeutic embolization of
an active bleeding site (generally segmental artery or more distal) and may be
considered as first-line therapy in such cases.
Nuclear Medicine Imaging and MRI
Currently, there is no role for radionuclide imaging (DMSA, MAG3) or magnetic
resonance imaging (MRI) in the acute setting for children with suspected renal
trauma although there is a role in the follow-up evaluation of renal injury and
long-term renal function.

Clinical Indications for Discharge or Admission


In cases of blunt trauma, children with grade I renal injuries (contusions) can be
discharged home without further imaging and followed with serial urinalyses.
Patients are instructed to limit daily activity until the urinalysis is within normal
limits. Outpatient radiographic evaluation is necessary if microscopic hematuria

persists for more than 30 days.
Grade II and III renal injuries warrant admission to the hospital for a minimum
of 24 hours when the risk of bleeding is highest. Expectant treatment includes
supportive care with bed rest, hydration, antibiotics, and serial hematocrits,
although the evidence supporting these therapies is relatively low. Once the gross
hematuria resolves, these children may be discharged home with limited activity
until microscopic hematuria resolves and repeat imaging demonstrates total
healing.
Management of the remaining patients (with grade IV and V injuries) evokes
significant controversy. The shift from early operative intervention to a more
expectant approach for most solid organ injuries has been increasingly applied to
high-grade renal injuries. Advocates of early surgical exploration argue that this
approach results in decreases in morbidity, hospital stay, and complications
without a significant increase in the risk for nephrectomy. Opponents believe that
nonoperative management of selected patients does not lead to negative
consequences, may result in a higher renal salvage rate, and cuts down the
morbidity associated with surgical exploration.
Nonoperative management requires admission to the hospital, serial
examinations, and hematocrits. Debate continues regarding the necessity of repeat
CT scan at 36 to 72 for conservatively managed renal injuries. According to
expert opinion, repeat imaging is not required for grade I and II injuries and grade
III injuries without hemodynamic instability or devitalized fragments. Some
authors are now beginning to advocate against routine repeat imaging for grade
IV or V renal injuries when there is no clinical indication (e.g., sepsis, decrease in
hematocrit, unstable blood pressure, increasing hematuria or oliguria), arguing
that repeat scans rarely change the management of this population and that
kidneys with stable or improved appearance on repeat CT still have a delayed
complication rate of 25%.
Patients who demonstrate hemodynamic instability require surgical
intervention or angiographic embolization of renal vessels. Angioembolization

should be performed only in those children who have a definable segmental artery
injury. Persistent urinary extravasation can be managed with percutaneous
drainage or internal ureteral stenting. These procedures, as well as embolization,
should be limited to institutions that can provide appropriate resources.


Operative exploration is required in 5% to 10% of cases. Absolute indications
for renal exploration are life-threatening hemorrhage believed to be from renal
injury, renal pedicle avulsion and expanding, pulsatile or uncontained
retroperitoneal hematoma. Relative indications include incomplete radiographic
staging with concurrent traumatic injuries that require repair/exploration,
extensive devitalized renal parenchyma, vascular injury, and significant urinary
extravasation. Attempts to preserve the kidney are more likely to succeed in
patients with grade IV injuries. Children with grade V injuries frequently require
nephrectomy. In patients with vascular injuries, chances of renal salvage are
improved if renal parenchyma is minimally disrupted and revascularization is
achieved within a few hours of the injury.
Penetrating renal injuries have traditionally been managed with operative
intervention. Compared with blunt trauma, far less literature is available in
support of nonoperative treatment after penetrating trauma. In addition, many
recommendations are extrapolated from data on adult patient populations. Careful
selection of hemodynamically stable patients who can tolerate CT staging may
identify a cohort of children who can be safely treated conservatively. Indications
for renal exploration are similar to those for injuries caused by blunt trauma.
Patients with penetrating trauma have a higher need for surgical intervention.
Short-term complications of renal trauma include delayed hemorrhage, urinary
extravasation, abscess formation, and ureteral obstruction secondary to clot
formation. Drainage with a ureteral stent or percutaneous nephrostomy may be
considered in cases of ongoing urinary extravasation.
Long-term complications include compromised renal function, hypertension,

and arteriovenous fistula. Chronic hypertension develops in a period ranging from
2 days to 32 years, which is why patients with a history of renal trauma should
undergo long-term yearly blood pressure monitoring.

URETER
Goal of Treatment
Ureteral injuries are uncommon in children and are often missed on initial
evaluation. As the ureters are well protected in the retroperitoneum, significant
concomitant injuries are usually present. The goal of emergency evaluation is to
recognize the clinical scenarios in which ureteral trauma is possible so as to allow
high suspicion for these injuries and prompt operative intervention. These injuries
occur in less than 1% of all genitourinary traumas.