Bilateral spontaneous urinary extravasation shown by computed tomography urography in a patient with benign prostatic hyperplasia.

Spontaneous extravasation of urine (SUE) is a rare urologic manifestation. Predisposing conditions of SUE include ureteric calculus, retrograde pyelography, pregnancy, abdominal aorta aneurysm, tumors, or enlargement of the prostate gland. Usually, SUE is a self-limiting condition that mandates differentiaton from other catastrophic conditions of pelviureteric ruptures. Most reported cases of SUE based on urograms are unilateral in presentation. Herein, we report a case of bilateral SUE evident on computed tomography urography in a patient with benign prostatic hyperplasia. We also review the literature briefly.

Introduction

Spontaneous extravasation of urine (SUE) is a relatively rare urologic condition evident in only 0.08%-1% of urograms [1]. It was defined first by Schwartz et al. in 1966 [2]. Until now, most reported cases have had a unilateral presentation. There has been only one case of bilateral SUE, reported by Niggemann et al. [3], but that patient had undergone stent placement for an infrarenal aortic stenosis.

Often, SUE is a self-limiting condition with a favorable prognosis on conservative treatment. Rarely, surgery is indicated because of the repeated urinary extravasation that induces secondary retroperitoneal fibrosis, which leads to compression of the ureters or urinoma formation [4], [5], [6].

Herein, we report bilateral SUE in a patient with benign prostatic hyperplasia (BPH) that was imaged by computed tomography urography (CTU). Also, a brief review of the literature is described.

Case report

A 67-year-old man with previously diagnosed BPH presented to our hospital complaining of dysuria, colicky abdominal pain, and abdominal distension of 3-hour duration. He did not have any other symptoms, and medical history was uneventful.

Physical examination did not reveal any abnormality. There was slight fullness in the suprapubic region that was mildly tender on palpation. All laboratory investigations (including renal function) were normal except for microscopic hematuria. Ultrasonography revealed an enlarged prostate gland measuring 4.3 × 6.2 × 2.8 cm3 with ≈691 mL of retained urine.

CTU demonstrated bilateral moderate hydronephrosis and hydroureter with pre-renal thickened (Fig. 1). Extravasation of urine and contrast medium was evident in the bilateral renal hilum, anterior renal and periureteric spaces, and with evidence of an obstructed bladder and prostatic hyperplasia (Figs. 2 and 3).

Fig. 1

In the renal medulla, spontaneous urinary extravasation (large white arrow) in the anterior pararenal space and bilateral hydronephrosis (small white arrow) can be observed.

Fig. 2

Pyelography demonstrates the right pyelosinus backflow (white arrow) and bilateral pyelotubular backflow (black arrows) of urine.

Fig. 3

Coronal maximum intensity projection image demonstrates the possible position of clefts (black arrows), and extravasation of contrast from bilateral renal collecting systems (white arrows).

The patient was administered conservative treatment (antibiotics and antispasmodic agents) for 2 days. However, abdominal distension worsened. Urethral catheterization with drainage of ≈2200 mL urine resulted in immediate disappearance of abdominal distension and symptom alleviation. Follow-up CT (Fig. 4) carried out 2-weeks later demonstrated complete absorption of urine and contrast medium from the bilateral renal hilum, periureteric space, and retroperitoneal spaces.

Fig. 4

Follow-up computed tomography after 14 days of conservative treatment shows extravasated urine and contrast medium completely absorbed.

Discussion

In SUE, for the extravasation to be considered “spontaneous,” 6 main criteria must be fulfilled, that is, absence of (1) ureteric instrumentation during the past 3 weeks; (2) previous surgery on the kidney, upper ureter, or in the immediate vicinity of either; (3) external trauma; (4) destructive kidney lesions; (5) external compression; and (6) cleft produced in the ureter or pelvis by pressure necrosis of the stone [1]. Pyelorenal backflows have been categorized into pyelovenous, pyelolymphatic, pyelotubular, pyelointerstitial, or pyelosinus types [6].

In acute ureteral obstruction, cortical hypoperfusion occurs as a manifestation of decreased renal blood flow and glomerular filtration rate (GFR). Increased tubular reabsorption is a compensatory mechanism that overcomes increased intratubular pressure and which maintains the GFR. Pyelotubular outflow is considered to be a normal physiological phenomenon [7].

Ureteric calculi are the most common predisposing factor for SUE [8]. Other conditions include retrograde pyelography, pregnancy, abdominal aorta aneurysm, tumors or, as in our case, enlargement of the prostate gland [9], [10]. All cases reported so far have involved unilateral involvement with a right-sided predilection, whereas the bilateral involvement observed in our patient using CTU has not been described [11].

The differential diagnosis of SUE can pose a problem because of other causes of acute abdomen such as pyelonephritis, ureteral colic due to stones, cholelithiasis, appendicitis, or gynecologic or obstetric causes [12]. Recognition of SUE has considerable clinical implications for overall management. Various radiologic patterns help to distinguish SUE from leakage from a cleft in the pelvis or ureters. Contrast material specifically around a calyx and visualization of ureters favors the diagnosis of SUE. In addition, follow-up examination after the onset of SUE will demonstrate marked absorption, whereas the appearance remains unchanged if a perforation is present [13]. CT has been reported to better demonstrate the extent of urine collection than urography alone [14].

Only certain cases with complications such as urinoma formation or associated significant retroperitoneal fibrosis due to repeated extravasation require surgical intervention [4]. CTU can have a pivotal role in the overall management of SUE by identification of symptoms and signs, recognition of the extent of urine collection, and close follow-up.