Pediatric ureteropelvic junction disruption with renal laceration: organ-saving management through delayed diagnosis and surgical repair

Abstract

This case highlights a rare occurrence of ureteropelvic junction (UPJ) disruption combined with a deep renal laceration involving the collecting system, following blunt trauma in an 11-year-old male. The patient was initially diagnosed with Grade IV renal trauma. Despite conservative management, a growing urinoma was noted, prompting the patient to present to our hospital. Retrograde pyelography confirmed the diagnosis of UPJ disruption. Subsequent surgery involved ureteropelvic anastomosis and calyceal-ureteral anastomosis, with stenting. The case emphasizes the importance of comprehensive imaging and timely intervention in preserving kidney function in trauma cases involving renal laceration and UPJ disruption.

1. Introduction

Renal injuries are the most common type of urinary tract injury in children, accounting for approximately 10 %–20 % of abdominal trauma in pediatric patients.¹ Ureteral injuries in children are relatively rare, constituting less than 1 % of pediatric urogenital trauma, with the most common injury being ureteropelvic junction (UPJ) disruption.² In the latest classification of renal injuries by the American Association for the Surgery of Trauma (AAST), UPJ disruption is categorized as a Grade IV renal injury.³ However, due to its nonspecific symptoms, it is often underdiagnosed, potentially leading to renal function loss if not promptly recognized.^2,4

This case report discusses a rare presentation of a pediatric patient with UPJ disruption combined with renal laceration extending through the main renal cortex, medulla and collecting system. The patient presented to our hospital three months post-injury. After performing retrograde pyelography, a diagnosis of UPJ disruption was made. Despite the delayed surgical repair, the kidney was preserved, and no complications were observed.

2. Case report

An 11-year-old boy presented to the local hospital after falling from a great height while playing outside by himself. On presentation, he had severe abdominal pain and was curled up in a fetal position. Initial computed tomography (CT) revealed a right kidney laceration and intra-abdominal bleeding. He was diagnosed with Grade IV renal trauma. After approximately 20 days of conservative management—including bed rest, hydration, serial hematocrit monitoring, antibiotic administration, and blood transfusions—his abdominal pain improved. He was discharged after follow-up laboratory investigations indicated without active bleeding. However, a routine follow-up ultrasound revealed a growing cystic mass in the right renal area, and the patient began experiencing respiratory difficulty and right-sided chest and flank pain, which led to presentation at our institution.

Upon examination, the patient appeared to have a swollen right chest, with decreased breath sounds on the right side and a raised right lung base. Abdominal palpation revealed a large, non-tender mass on the right side with dull percussion sounds over the mass area. Imaging studies, including contrast-enhanced CT and ultrasound, revealed a large cystic mass (approximately 26.3 × 14.5 × 16.0 cm) in the right perirenal region, confirmed as a urinoma, likely secondary to renal rupture (Fig. 1). The CT scan also showed reduced enhancement in parts of the renal parenchyma and compression of renal vasculature. A diagnosis of right kidney rupture with massive urinoma formation was made. Given the extent of the injury and the complications, a decision was made to perform a percutaneous drainage of the urinoma under local anesthesia, followed by ongoing drainage of about 3000 mL of fluid. After drainage, an intravenous pyelogram (IVP) was performed. It demonstrated clear contrast in the left renal pelvis and ureter, with no visible contrast in the right ureter (Fig. 2).

Fig. 1.

Contrast enhanced CT scan before drainage of perinephric urinoma.

(a)The CT scan displays a cystic mass (approximately 26.3 × 14.5 × 16.0 cm) in the right kidney region. (b)Excretory-phase CT scan shows contrast material in the cyst, indicating the presence of a continuous urine leak. (c)CT scan shows reduced enhancement in parts of the renal parenchyma (arrow).

Fig. 2.

Intravenous pyelogram (IVP) before operation.

The IVP demonstrates a clear contrast of left renal pelvis and left ureter and no visible contrast material in the right ureter.

The patient underwent further surgical intervention, including a cystoscopy and retrograde pyelography, which revealed a UPJ disruption. A subsequent surgery involved ureteropelvic anastomosis and calyceal-ureteral anastomosis (Fig. 3), with intraoperative placement of a ureteral stent. Postoperatively, the patient developed hypertension, requiring medication and close monitoring, but his condition gradually improved. Gastrointestinal symptoms such as nausea and vomiting were attributed to duodenal compression by the surrounding mass. After several days of gastrointestinal decompression and nutritional support, the child's condition stabilized, and his blood pressure was better controlled. The patient's postoperative progress was satisfactory and he was discharged on the 15th day.

Fig. 3.

Intraoperative photograph of pyeloureteroplasty and calyceal-ureteral anastomosis.

White arrows show the two parts of the kidney. Black arrow shows the calyceal-ureteral anastomosis.

The ureteral stent was removed 2.5 months after surgery. After stent removal, the child experienced fever and urinary tract discomfort, which was diagnosed as a urinary tract infection. Treatment with antibiotics was initiated, and symptoms resolved within days. A follow-up CT scan performed 8 months postoperatively showed mild structural changes in the right kidney, including scar tissue through the mid pole of the right kidney dividing the kidney into two parts and reduced vascular supply to the lower pole, but the overall renal function was preserved (Fig. 4). Follow-up renal ultrasonography and IVP showed no evidence of ureteropelvic junction obstruction (Fig. 5). The patient was advised to have annual follow-up investigations. The prognosis remains favorable at two years postoperatively, with no significant complications noted at the latest follow-up.

Fig. 4.

Contrast-enhanced CT image after operation.

(a)Coronal section shows scar tissue through the mid pole of the right kidney dividing the kidney into two parts. (b)Enhancing right kidney (both parts) indicates proper function after the procedure.

Fig. 5.

IVP after operation.

The image highlights the anatomical repair of pyeloureteroplasty and calyceal-ureteral anastomosis, with normal contrast excretion through the kidney and ureter.

3. Discussion

Ureteral trauma is the least common type of genitourinary trauma due to the ureter's small size, mobility, and relatively well-protected location.⁴ The most common cause of ureteral injuries is iatrogenic trauma.^5,6 Blunt and penetrating trauma account for less than 25 % of all ureteral injuries.⁷ UPJ disruption is a kind of ureteral trauma. Most cases occur in children involved in motor vehicle collisions or falls from a height of 20 feet.⁸

UPJ disruption rarely occurs as an isolated injury, and the management of associated life-threatening injuries should be prioritized. A diagnostic delay of 36 hours or longer has been observed in over 50 % of patients.⁹ As in this case, the laceration involving the collecting system caused urinary extravasation, leading to a missed diagnosis at the local hospital. UPJ disruption lacks specific clinical manifestations. Due to ureteral peristaltic dysfunction after ureteral disruption, hematuria may be absent. A single-center study of 57 cases of ureteral injury reported hematuria in only 17 % of pediatric patients.¹⁰ Pereira et al. reviewed 77 literatures on ureteral injuries involving 1021 patients, showing hematuria in 43 %.¹¹ Therefore, in patients with obvious perirenal urinary extravasation but no hematuria, UPJ disruption should be suspected.

Children with delayed diagnosis often present with abdominal mass, abdominal pain, nausea and vomiting after their condition stabilized. Re-examination of urinary CT may reveal perirenal urinoma and/or hydronephrosis. The surgical difficulty of delayed diagnosed UPJ disruption is relatively high. Delayed diagnosis can even lead to loss of renal function. Studies have reported that the nephrectomy rate in cases of delayed diagnosis can reach about 40 %.¹²

The delayed phase (or excretory phase) of enhanced CT of the urinary system is helpful for early diagnosis of UPJ disruption. In this phase, the visualization of the ureter can be observed through the excretion of contrast agent. The typical CT finding is contrast extravasation at the renal hilum, combined with non-visualization of the distal ureter, and generally no renal parenchymal laceration. However, in this case, a deep renal parenchymal laceration extending through the cortex, medulla, and collecting system was present, contributing to the delayed diagnosis. For children with the above manifestations, further retrograde pyelography should be performed to confirm the diagnosis after their general condition stabilizes.

Once UPJ disruption is confirmed, surgical repair should be performed as early as possible. Experienced surgeons may attempt primary repair within 2 weeks after injury. If primary repair is not feasible, nephrostomy should be chosen instead of mere perirenal urinoma drainage. After urinoma drainage, the proximal ureter may gradually become occluded, resulting in irreversible renal function loss. Drainage volume may gradually decrease or even cease, which may be mistakenly interpreted as spontaneous healing. Early diagnosis and prompt treatment are crucial for salvaging the function of the affected kidney. On the other hand, the risk of nephrectomy was consistently decreased in children with high-grade renal trauma managed conservatively regardless of injury characteristics.¹³ Thus, in cases similar to the one presented here, to preserve as much functional renal tissue as possible, a nephrostomy can be performed first to avoid partial or complete loss of the kidney due to massive bleeding during primary repair.

For patients who did not undergo primary repair but only received nephrostomy, UPJ repair surgery should be performed half a year after the injury when the scar tissue has softened. Ureteropelvic anastomosis with stenting and temporary proximal diversion is the preferred treatment for UPJ disruption and can be successfully performed in most cases. Calyceal-ureteral anastomosis or ureter replacement operation (ureteral replacement using intestinal segments or the appendix) can be performed if the gap between the pelvis and the ureter is too great to allow a tension-free anastomosis.

4. Conclusions

UPJ disruptions are frequently missed due to haemodynamic instability and other concurrent injuries. UPJ disruption should be suspected if the delayed phase of enhanced CT shows contrast extravasation at the renal hilum combined with non-visualization of the distal ureter. Retrograde pyelography should be performed to confirm the diagnosis.

CRediT authorship contribution statement

Yu-si Wang: Writing – original draft, Project administration. Hong-cheng Song: Writing – review & editing, Supervision. Ning Li: Writing – review & editing, Resources, Project administration.

Ethics declarations

Informed consent was taken from the patient's parents for publication of this case report and the associated images.

Funding

This work was supported by The Science and Technology Planning Program of Beijing Municipal Science & Technology Commission and Administrative Commission of Zhongguancun Science Park (grant numbers Z231100004823034).