CASE 12304 Published on 24.11.2014

Iatrogenic Urinoma, mini-invasive percutaneous treatment


Interventional radiology

Case Type

Clinical Cases


Spinelli A, D'Onofrio S, Loreni G, Tosti D, Claroni G, Croce G, Simonetti G

Viale Oxford 81, 00133, Rome, Italy

50 years, male

Area of Interest Abdomen ; Imaging Technique CT-Angiography, Fluoroscopy, Image manipulation / Reconstruction
Clinical History
A 50 year-old male, treated 7 days before in another institution with urethrocystoscopy and laser for perinephric renal cysts, came to our emergency department with acute abdomen and renal indexes increases. The contrast-enhanced CT showed fluid-filled mass with compression of the left kidney.
Imaging Findings
The massive urinoma compresses the left kidney which presented reduced nephrographic renal effect and peri-renal tissue suffering; the urinoma is capsulated (Fig 1).
CT delayed phase (5–20 minutes after contrast medium administration) shows no contrast extravasation (Fig.2). The urinoma was punctured with a Chiba needle under ultrasonographic guidance and nephrostomy a catheter of 8 French was placed (Flexima Regular 8Fr, Boston Scientific) (Fig.3). The urinoma was drained with minimum residual and subsequently placed a 8 French double-J stent (Flexima Regular 8Fr, Boston Scientific) to facilitate urinary flow (Fig.4). At the end of the procedure another diversionary nephrostomy catheter of 8 French was placed in the renal pelvis (Fig.4). There was no evidence of intra- and postoperative complications. The two nephrostomy were removed before the dismissal and the Double-J stent was removed 4 weeks later. The angio-TC control, performed at 3 months, showed a complete resolution of urinoma and no renal sequelae.
Urinoma is a mass formed by encapsulation of extravasated urine. It may follow closed renal injury, surgical operation including percutaneous kidney biopsy, or arise spontaneously in the presence of obstruction [1].
First cases were described in 1856 by Diaz and Buenrostro [2]. Usually, a collecting system rupture is monolateral, but Niggeman et al. [3] described a case of bilateral spontaneous fornices rupture. The fornix is the most common site of rupture followed by the upper ureter, when pressure exceeds a critical level reported from 20 to 75 mmHg. Urinoma could be confined, be encapsulated as in our case, or may manifest as free fluid. Most urinomas involve the perirenal space within the Gerota fascia, but if extensive they can cross the midline. Urinomas may cause sensations of pressure or pain due to their mass-effect; if the urinoma is large enough or positioned in a critical spot it can cause obstruction of adjacent structures, such as ureters. Usually, symptomatology could not be differentiated from a renal colic but sometimes, could mime an acute abdomen [4]. In some cases it could be very difficult due to lack of symptoms. Differential diagnosis includes diverticulitis, cholecystitis, appendicitis, and others. Computed tomography is the technique of choice in the diagnosis of urinary collecting system leaks and urinomas [4]. Delayed acquisitions (5–20 minutes after contrast medium administration) are mandatory to identify the attenuation increase of the urinoma, which can range from 0 to 20 HU before intravenous contrast administration and then enhance up to 200HU after contrast administration [5, 6]. Imaging alone is not always able to distinguish between a urinoma and other types of fluid collections. Aspirations of the fluid can make that distinction by allowing measurement of the creatinine level in the fluid and comparing it to the serum creatinine [9]. Treatment options included surgery or interventional radiology [7 –8] and should be individualized in each case, but the surgical approach is often invasive. In this case, a minimally invasive procedure can consist of percutaneous urinoma drainage using a nephrostomy catheter, with a double-J stent placement. Catheters can usually drain the urinoma more completely. In addition, catheter placement maintains access to the collection until culture and fluid analysis as been completed [9]. Output from the drain should be monitored and the catheter removed when output is consistently below 20 cc/day. In our experience, the interventional approach is effective and safe.
Differential Diagnosis List
Left Kidney Urinoma
renal colic
Final Diagnosis
Left Kidney Urinoma
Case information
DOI: 10.1594/EURORAD/CASE.12304
ISSN: 1563-4086