Case Report

Urologia

Received: October 18, 2013 Accepted after revision: March 6, 2014 Published online: August 7, 2014

Urol Int 2015;95:246–248 DOI: 10.1159/000362094

Internationalis

Urinoma following Kidney Biopsy: A Case Report Sorawan Limwattana a Pornpimol Rianthavorn b  

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Department of Pediatrics, Faculty of Medicine, Prince of Songkla University, Hat Yai, and b Division of Nephrology, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand  

 

Key Words Kidney biopsy complications · Percutaneous kidney biopsy · Urinoma

Abstract Major complications of a percutaneous kidney biopsy are infrequent but warrant early detection and appropriate treatment. We herein report a patient who developed urinoma following kidney biopsy in the effort to emphasize the paramount importance for practitioners to recognize this complication. Prompt diagnosis and proper management of urinoma following kidney biopsy is prudent as delayed treatment may lead to abscess formation, hydronephrosis, obstructive uropathy and chronic kidney failure.

Case Report A 10-year-old girl underwent a PKB for further evaluation of asymptomatic persistent proteinuria and microscopic hematuria. Urinalysis revealed 20–30 red blood cells (RBC)/high power field (HPF) and 3+ proteinuria. Antinuclear antibody and complement levels were within normal limits. The PKB was done at the left lower pole of an 8-cm kidney under real-time ultrasound (US) guidance. A 16 gauge × 16 cm automated biopsy device with a fixed penetration depth of 22 mm was used. Routine post-PKB US

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Introduction

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Fig. 1. US after PKB showed a 2-cm hypoechogenic fluid collection at the left lower pole (arrowheads).

Pornpimol Rianthavorn, MD Division of Nephrology, Department of Pediatrics Faculty of Medicine, Chulalongkorn University 1873 King Rama 4 Road, Pathumwan, Bangkok 10330 (Thailand) E-Mail pornpimol.r @ chula.ac.th

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Urinoma is a collection of extravasated urine from a rupture of the urinary tract at any level from renal calyces to the urethra. It could complicate many surgical procedures, including percutaneous kidney biopsy (PKB). We herein report a patient who developed urinoma following PKB in order to emphasize the importance of this complication.

showed a 2-cm hypoechogenic fluid collection at the puncture site, suggestive of a perirenal hematoma (fig. 1). One day after PKB, the patient developed a temperature of 39 ° C and severe generalized abdominal tenderness. She had a stable hemoglobin concentration and normal levels of serum electrolytes, creatinine, lipase and amylase. Urinalysis showed 30–50 RBC/HPF and 1–2 white blood cells/HPF. Plain abdominal radiography revealed generalized bowel ileus without free air. Subsequent kidney US showed similar findings to the previous study without sonographic features indicating abscess formation. After blood and urine collection for culture, a daily dose of intravenous ceftriaxone 75 mg/kg was administered. Two days after PKB, the patient continued to have fever and abdominal pain. Serum sodium was decreased to 133 mmol/l and serum creatinine was increased from the baseline of 0.6 to 1 mg/ dl. Urinoma was suspected, thus abdominal computerized tomography (CT) was performed. The CT showed clear fluid in the peri 

 

renal space with an increased attenuation of the fluid after intravenous contrast administration, confirming the diagnosis of urinoma (fig. 2). After a 24-hour period of conservative management, the patient underwent percutaneous urinoma drainage with catheter placement under US guidance due to clinical deterioration. A 1-liter initial drainage with a creatinine level of 29 mg/dl was aspirated. The subsequent daily output was gradually decreasing. The catheter was removed on post-PKB day 7 after the kidney US confirmed the resolution of urinoma. Culture results of blood, urine and aspirated fluid were negative. The patient received a 7-day course of intravenous ceftriaxone and was discharged on postPKB day 9. PKB yielded adequate tissue for histopathological evaluation, which revealed normal glomeruli by light microscopy and immunofluorescence. Electron microscopy showed an attenuation of the glomerular basement membrane consistent with thin basement membrane disease or early Alport syndrome. She was treated with oral enalapril. At the 6-month follow-up, no abnormalities were reported. Urinalysis showed persistent microscopic hematuria and improving proteinuria. The kidney function test was within normal limits.

Discussion

Urinoma following PKB is rare, and only 3 reports have been published in the medical literature previously [1–3]. When taking the number of PKB performed into account, the incidence of urinoma following PKB is higher in children than in adults as 3 of 4 patients were aged ≤21 years [2, 3]. A recent study focusing on predictive factors of PKB-related complications has shown that patient size is an important factor when selecting biopsy needle gauge and penetration depth in children [4]. With a similar penetration depth, the device would puncture relatively deeper into the renal parenchyma of small than large kidneys. Thus, the likelihood of the renal pelvis being perforated would be higher in children than in adults. Prompt diagnosis of urinoma following PKB is crucial as delayed treatment may lead to sepsis, hydronephrosis and kidney failure [2, 5]. In addition to infected hematoma and perforation of internal organs, the differential diagnosis of patients with fever and abdominal pain following PKB should include urinoma, especially when hyponatremia and impaired kidney function are present. A contrast-enhanced abdominal CT is the diagnostic study of choice. Delayed CT images demonstrate an increased attenuation of the fluid collection 5–20 min after intravenous contrast administration [6]. If the CT is contraindicated or unavailable, renal scintigraphy is another confirmatory imaging study. The US study could not differentiate between urinoma and hematoma as findings of perirenal hypoechogenic fluid collection were observed in both conditions but measurement of creatinine and glucose levels in the aspirated fluid can confirm the diagnosis [6]. The treatment guidelines for urinoma following PKB have not been established due to the rarity of cases. Three

Fig. 2. Abdominal CT at the level of the kidneys. a Plain CT showed a clear fluid col-

Urinoma following Kidney Biopsy

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Urol Int 2015;95:246–248 DOI: 10.1159/000362094

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lection in the left perirenal space (asterisk). b Contrast-enhanced CT showed a leak of contrast-enhanced urine from the collecting system into the dependent portion of the left perirenal space (arrow), consistent with the diagnosis of urinoma.

Disclosure Statement The authors have no conflicts to declare.

1 River GL, Dovenbarger WV, Nikolai TF, Moffat NA: Unusual complications of kidney biopsy. J Urol 1970;103:15–17. 2 Trehan A, Takhtani D, Singh S, Kumar L: Urinoma – an unusual complication following kidney biopsy. Indian J Pediatr 1998;65:911– 913. 3 Ham YR, Moon KR, Bae HJ, Ju HJ, Jang WI, Choi DE, Na KR, Lee KW, Shin YT: A case of urine leakage: an unusual complication after renal biopsy. Chonnam Med J 2011; 47: 181– 184.

References

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healing. Double J-stent placement is the preferable option if there is a concomitant ureteral injury. Urinoma following PKB was resolved by double-J stent placement in the case reported by Ham et al. [3]. Percutaneous nephrostomy alone can divert the urine and decompress the collecting system but may not be enough to allow urinary leakage to heal [6]. In conclusion, urinoma following PKB is rare and requires a high index of suspicion to reach the diagnosis. When clinical deterioration is observed during conservative management, percutaneous drainage is a reasonable first-step treatment if the pattern of spread of urinoma allows and should be done promptly. Selection of the biopsy needle gauge and penetration depth should be tailored to the patient size to prevent this complication.

Urol Int 2015;95:246–248 DOI: 10.1159/000362094

4 Rianthavorn P, Kerr SJ, Chiengthong K: Safety of paediatric percutaneous native kidney biopsy and factors predicting bleeding complications. Nephrology (Carlton) 2014; 19: 143–148. 5 Alsikafi NF, McAninch JW, Elliott SP, Garcia M: Nonoperative management outcomes of isolated urinary extravasation following renal lacerations due to external trauma. J Urol 2006;176:2494–2497. 6 Titton RL, Gervais DA, Hahn PF, Harisinghani MG, Arellano RS, Mueller PR: Urine leaks and urinomas: diagnosis and imagingguided intervention. Radiographics 2003; 23: 1133–1147.

Limwattana /Rianthavorn  

 

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of the 4 patients required surgical drainage [2, 3]. Indications for drainage include large size, refractoriness to conservative treatment, and urinoma complicated by infection, hydronephrosis or kidney failure [6]. Surgical options, which could be performed in isolation or in combination, include percutaneous urinoma drainage, double-J catheter placement and percutaneous nephrostomy. The intervention of choice depends on the pattern of spread of urinoma, concomitant ureteral injury, center feasibility and surgeon preference [6]. In our patient, the superficial location and the extent of the urinoma made percutaneous drainage a suitable choice. Percutaneous drainage has several advantages. The procedure is less invasive when compared with double-J catheter placement. Percutaneous drainage can be performed under local anesthesia with imaging guidance by urologists or intervention radiologists. Urinoma pressure is rapidly relieved and the aspirated fluid can be biochemically tested. If urinary leakage continues despite percutaneous drainage, diversion of urine with double-J catheter placement or nephrostomy can facilitate the