Urinoma Mimicking Pancreatic Pseudocyst: A Case Report by Dragana Zivkovi´c in Journal of Clinical Case Reports Medical Images and Health Sciences

 Urinoma Mimicking Pancreatic Pseudocyst: A Case Report by Dragana Zivkovi´c in Journal of Clinical Case Reports Medical Images and Health Sciences 

Abstract 

Urinomas in pediatric patients, stemming from traumatic injuries to the genitourinary system, pose diagnostic and therapeutic challenges. We present a case of a boy with a penetrating injury of the abdomen in whom a ureteric injury was missed, highlighting the complexities in diagnosing and managing these cases and emphasizing the need for a comprehensive approach. Traumatic urinomas demand astute clinical assessment and advanced imaging for accurate diagnosis. Our exploration underscores the intricate diagnostic path and therapeutic nuances, advocating for multidisciplinary strategies to optimize outcomes in pediatric patients with traumatic urinomas.

Introduction

 Urinoma, a rare yet significant clinical entity, represents an encapsulated collection of extravasated urine, often arising from trauma, obstructive urinary pathologies, or iatrogenic injuries [1, 2, 3, 4]. While typically associated with trauma or surgical complications, the manifestation of urinoma presenting as a pseudocyst following abdominal injury is exceedingly rare. Although relatively uncommon, urinomas present diagnostic challenges due to their varied etiologies and clinical presentations. Identifying a urinoma requires a comprehensive understanding of its varied origins often necessitating a multidisciplinary diagnostic approach involving imaging modalities and biochemical analyses. Imaging modalities, notably ultrasonography, aid in the initial assessment by detecting free fluid collections, whereas CT and MRI offer superior delineation of the urinoma’s extent, localization, and potential complications, aiding in differential diagnoses. Treatment strategies for urinomas revolve around addressing the underlying cause, mitigating potential complications, and promoting urinary tract healing [5, 6]. This case report delineates an atypical scenario where a patient initially misdiagnosed with a pancreatic pseudocyst after abdominal trauma subsequently developed a urinoma with intricate consequences, necessitating multiple interventions and highlighting diagnostic challenges.

Case report presentation 

The 17-year-old patient was admitted with a stab wound to the abdomen and displayed stable vital signs: a pulse rate of 89/min, blood pressure at 120/85 mmHg, and arterial oxygen saturation of 100 percent. A clinical assessment revealed a penetrating wound in the left hypochondrium with a protruding omentum, which was confirmed by abdominal ultrasonography revealing the presence of free fluid. An immediate exploratory laparotomy uncovered two abdominal wall wounds, including a minor splenic vessel injury and a 7mm colonic perforation. They were surgically closed with the suture and the abdominal drain was placed. The postoperative phase was uneventful, the drain was removed 4 days later the patient was discharged on the 12th postoperative day. One week after the discharge the patient returned due to abdominal pain and fever. Subsequent ultrasound imaging revealed dense free fluid in the pelvic area and a distinct formation (132x60mm) in the upper left abdomen near the left kidney. Control ultrasound imaging revealed an encapsulated oval-shaped fluid collection (140x80mm) surrounding the pancreas tail and another collection compressing the left kidney’s pelvicalyceal system. The decision was to do the relaparotomy. During an exploratory procedure, a tense bursa omentalis was observed, leading to the identification of a pseudocyst (15x10cm) containing 400ml of clear, yellowish fluid, sampled for bacteriological and biochemical analysis. Hyperemic pancreatic tissue made the posterior wall of the pseudocyst without visible pancreatic lesion sites. Abdominal drains were placed in the Duglas’ space, bursa omentalis, and pseudocyst. The pseudocyst was considered to be a pancreatic cyst. During post-operative care, there was a suspiciously large amount of clear fluid on drains so a CT scan was indicated. The CT scan correctly diagnosed a left-sided urinoma, causing a perirenal abscess and consequent grade III hydronephrosis. The diagnosis was confirmed through cystoscopy and retrograde pyelography, revealing the lesion on the left ureter in the proximal third of the ureter. The urinary catheter was placed. Follow-up CT imaging showed ongoing communication between the proximal left ureter and the urinoma (94x49x67mm) adjacent to the left kidney, prompting the placement of a percutaneous nephrostomy. The patient was discharged stable, without any symptoms with a working nephrostomy after one month of hospitalization. Two months after he was admitted to the hospital for further analyses. Intravenous urography was done highlighting a slight narrowing of the left ureter below the ureteropelvic junction without impeding contrast flow. Placement of the JJ stent through the nephrostomy was done. Three months later J-J stent was removed as well as nephrostomy. The postinterventional course was uneventful, with complete resolution of all intraabdominal collections, without pelvic system dilatation.

Discussion

 Genitourinary (GU) trauma is often overlooked in the setting of acute trauma due to life-threatening injuries taking precedence, but accounts for roughly 10 percent of all injuries seen in the emergency room. Ureteral trauma is uncommon, accounting for less than 1 percent of all urologic trauma [7, 8]. In diagnosing ureteral injuries from trauma, the most important factor is a high index of suspicion [7]. In our case initially, it was decided to perform laparotomy due to evidence of intraabdominal leason on the ultrasound, the presence of an increased amount of intraabdominal fluid as well as blood loss. Even though laparotomy has shown splenic and colonic lacerations, the ureteric injury was missed. Unfortunately, there is no imaging modality best suited to diagnose acute ureteral injury. The use of ultrasound has gained widespread use in trauma but has proven unreliable in evaluating ureteral injuries, particularly because of their small caliber and retroperitoneal location. According to the European Association of Urology guidelines, computed tomography (CT) and an intraoperative single-shot intravenous pyelogram (IVP) are the most useful diagnostic tools [7]. When unexplained free intraperitoneal fluid is identified on a CT scan in a hemodynamically stable patient after trauma, management options include observation, diagnostic peritoneal lavage, diagnostic laparoscopy, and exploratory laparotomy. A new era was marked with the advent of laparoscopy, enabling the surgeon to diagnose or rule out intra-abdominal injuries in a minimally invasive way [9]. Benefits of diagnostic laparoscopy compared with peritoneal lavage include accurate visualization of the source and extent of bleeding as well as the potential for therapeutic repair of an enterotomy [9] In our case GU injury was not suspected, therefore no further diagnostic procedures were indicated and the patient was discharged. However genitourinary trauma can manifest itself later in the course [8]. Urinoma can form as a result of the collecting system disruption at any level from calyces to the urethra [3]. Perinephric urinomas can be asymptomatic but a collection of urine surrounding the kidney can lead to various complications. These include a risk of infection, adynamic ileus, and abdominal and flank pain as well as electrolyte imbalance [10]. Sterile urine in contact with the retroperitoneum can trigger an inflammatory response, whereas infected urine may lead to acute abdomen, retroperitoneal abscess formation, and retroperitoneal fibrosis in later stages [3]. In our case, as it was described boy returned to the hospital due to a high temperature and pains, so the re-laparotomy was done as well as further diagnostic protocols. A CT scan clearly showed a urinoma. As Ogreden et al. suggested CT is adequate for definitive diagnosis of urinoma [3], but CECT is the preferred modality, as extravasated contrast can be used to identify urinary leaks [5, 11, 12, 8]. Renal scintigraphy, on the other hand, is also used in patients with compromised renal function as it can diagnose preserved function in the residual renal parenchyma, identify the nature of the peri-nephric collection, and establish the communication of this collection with PCS. This provides a low radiation alternative to serial CECTs in follow-up [5]. According to the literature, ultrasound-guided percutaneous aspiration can confirm the diagnosis, if fluid shows elevated levels of creatinine and decreased levels of glucose relative to serum. [11, 12]. Once we had a correct diagnosis of post-traumatic urinoma, the treatment strategy was to place firstly drains and later as needed percutaneous nephrostomy. Many urinomas are small and resolve spontaneously, but large and expanding urinomas often require intervention management of these injuries is to maintain drainage of urine from the kidney [7]. The American Urological Association Urotrauma Guidelines recommend urinary drainage via a ureteral stent, percutaneous nephrostomy tube, or both [13, 14, 12, 15]. In comparison with percutaneous nephrostomy, ureteral stents may be advantageous in improving patient comfort, avoiding additional catheter and urinary bag care, and limiting the risk of dislodgment in the pediatric population [10]. As Cheng et al. suggest firstly we only placed a ureteral stent but later a nephrostomy was needed. 

Conclusion 

The uniqueness of this case lies in the initial misinterpretation of a urinoma as a pancreatic pseudocyst, elucidating the diagnostic challenges associated with rare presentations. This atypical manifestation underscores the importance of differential diagnosis, especially in complex post-traumatic scenarios. Imaging modalities, despite their precision, failed to distinguish the entity accurately initially, emphasizing the need for nuanced interpretations and comprehensive evaluations. The management of this urinoma involved multiple interventions, including exploratory laparotomies, drainage procedures, and urological interventions. Imaging follow-ups illustrated persistent urinoma-related complications necessitating a tailored approach, ultimately resulting in the successful resolution of the condition. 

Acknowledgment:

 This research was supported by the Science Fund of the Republic of Serbia, 7295, Development of portable device for continence preservation - Conti4All 

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