Impact of prenatal urinomas in patients with posterior urethral valves and postnatal renal function

Fetal ascites in cloacal malformations-a red flag

INTRODUCTION

Cloacal malformation is a rare anomaly that remains a diagnostic challenge prenatally, despite the current advances in ultrasonography and MRI. This condition can in some, present with isolated ascites or with other findings, such as a pelvic cyst or upper urinary tract dilatation. In a minority, the ascites may be progressive, questioning the role of antenatal intervention.

METHODS

We report on ten patients that have been identified from our Cloaca database between 2010 and 2022.

RESULTS

The presence of ascites was associated with extensive bowel adhesions and matting, leading to a challenging initial laparotomy and peri-operative course.

CONCLUSIONS

Antenatal finding of ascites in newborns with cloacal malformations should raise a red flag. The surgeon and anaesthetist should be prepared for the operative difficulties secondary to bowel adhesions and the higher risk of haemodynamic instability at the initial surgery. An experienced team at initial laparotomy in such patients is vital.

LEVEL OF EVIDENCE

II.

Neonatal urinoma associated with ascites in a newborn with a solitary kidney

Fetal urinomas are often diagnosed in prenatal ultrasonography. The etiology is usually an obstructive uropathy leading to hydronephrosis and increased intrarenal pressure putting future kidney function at risk. Rupture of pyelocaliceal system in such cases may lead to retroperitoneal urinoma or urinary ascites, sepsis, uraemia, and acute renal failure. On the other hand, this may serve as "pop-off valve" mechanism decreasing intrarenal pressure and protecting from definitive kidney function loss. We present a case of a newborn girl with a retroperitoneal urinoma, ascites, uraemia, and obstruction of a solitary right kidney, which was successfully treated minimally invasively through peritoneal and retroperitoneal drainage and intubation of the right ureter with a DJ stent shortly after birth.

Prenatal extravasation of urine seems to preserve renal function in boys with posterior urethral valves

INTRODUCTION

A posterior urethral valve (PUV) may lead to extravasation of urine, resulting in prenatal ascites and/or perirenal urinoma. Extravasation has been presumed to act as a pop-off mechanism, preserving renal function, but previous reports addressing this presumption have been inconclusive.

AIM OF STUDY

The present study compares renal function in patients with PUV with and without extravasation.

MATERIAL AND METHODS

Sixty boys with a confirmed diagnosis of PUV as neonates (gestational age [GA]<44 weeks) throughout 2001-2016 were included. Clinical data were collected from medical records. Renal function was assessed by nadir plasma creatinine, creatinine at the last follow-up, and glomerular filtration rate (GFR) at the last follow-up. The GFR was estimated using the Schwartz formula. Renal function was classified according to the kidney disease: improving global outcomes (KDIGO) guidelines' grades of chronic kidney disease (CKD). Glomerular filtration rate > 90 ml/min/1.73m² at the last follow-up was classified as normal renal function.

RESULTS

Twelve patients (20%) had ascites and/or urinoma, and 48 (80%) did not. GA and birth weight were not different in patients with and without extravasation. PUV was suspected from prenatal ultrasound findings in 66.7% of the patients in both groups. Median nadir creatinine was 21 (range, 11-33) μmol/L in boys with ascites/urinoma, and all values were within the age-adjusted reference values. Nadir creatinine was 23 (14-199) μmol/L in boys without extravasation, and it was above the normal range in 14 boys. The incidence of elevated nadir creatinine was significantly different in the two groups (p < 0.025). One of the 12 patients with extravasation developed chronic renal failure (CKD 3). In the group of 48 patients without extravasation, 20 (42%) had chronic renal failure grade 2-5, and among these, 5 patients have had a renal transplant (CKD grade 5). The prevalence of CKD grade 2-5 was statistically different in the two groups (p = 0.03). These findings are presented in the summary figure.

CONCLUSION

Extravasation of urine was found in 12 of 60 (20%) boys with PUV. These patients had significantly lower prevalence of CKD at the last follow-up than patients without extravasation. This finding is important in prenatal counseling. It also indicates that prenatal decompression of the bladder and upper tract is beneficial in patients with PUV, which is relevant to the discussion of prenatal intervention in these fetuses.

Neonate with urinary ascites but no hydronephrosis: unusual presentation of posterior urethral valves

Posterior urethral valves (PUV) are an important cause of paediatric obstructive uropathy. PUV are usually diagnosed by prenatal ultrasonography (US) revealing hydronephrosis and bladder distention. We describe a 17-day-old male infant with abdominal distention who had no hydronephrosis on prenatal US. Laboratory investigations showed serum creatinine of 12 mg/dL, hyperkalaemia and metabolic acidosis. Abdominal US showed large amount of ascites, normal-sized kidneys without hydronephrosis and incompletely distended bladder. Paracentesis revealed clear, yellow ascitic fluid with creatinine level of 27 mg/dL compatible with urinary ascites. Voiding cystourethrogram (VCUG) demonstrated PUV with a dilated posterior urethra, grade 5 right vesicoureteral reflux and a ruptured kidney fornix with peritoneal extravasation of contrast. Foley decompression resulted in normalisation of creatinine within 72 hours. Transurethral resection of PUV was performed, and a repeat VCUG showed recovery of forniceal rupture. This case illustrates an unusual presentation of a potentially life-threatening but treatable cause of urinary tract obstruction.

Ultrasound follow-up of an unusual giant urinoma in a newborn

Urinoma, defined as an encapsulation of urine caused by urine extravasation into the perirenal space either through rupture of a calyceal fornix or a tear in the renal parenchyma, is an uncommon finding in prenatal diagnosis and the neonatal period. Urinoma can be associated with any urinary tract obstruction, or, as reported in several published cases, related to vesicoureteral reflux, kidney dysplasia, or complication arising during amniocentesis. We report on a newborn with a perinatal urinoma, with initial slight corpusculated fluid associated with nonobstructive and nonrefluxing megaureter, and no signs of kidney dysplasia. Close sonography follow-up of the urinoma allowed complex differential diagnoses, including cystic, septated, and solid perirenal masses, due to dissimilar and peculiar ultrasound images during urinoma evolution stages.

The fetal urinoma revisited

The fetal urinoma is a rare but important diagnosis, as it indicates substantial underlying obstruction with implications for the functionality of the affected kidney. This case series describes a single center's experience with the diagnosis and management of fetal urinomas. All 25 cases were diagnosed or referred to our medical center over an 11-year period. Most cases were secondary to either posterior urethral valves or ureteropelvic junction obstruction. Fetal interventions, including percutaneous drainage of the urinoma and cystoscopic alleviation of bladder outlet obstruction, were performed in 4 cases.

Fetal obstructive uropathy complicated by urinary ascites: outcome and prognostic value of fetal serum β-2-microglobulin

OBJECTIVES

To determine whether the prognostic value of fetal serum β-2-microglobulin is altered and whether the occurrence of fetal urinary ascites prevents kidney damage in cases of fetal obstructive uropathy with urinary ascites.

METHODS

This was a retrospective study of cases of fetal bilateral obstructive uropathy that occurred between 2006 and 2010, for which both fetal serum and ascites samples were sent to our laboratory for analysis. β-2-microglobulin was assayed in both fetal serum and the corresponding ascites. Renal outcome was analyzed. Histological features of the kidney in cases of termination of pregnancy and renal function of liveborn infants were recorded.

RESULTS

Fourteen cases with analysis of fetal serum and fetal ascites in a context of urinary obstruction were included. Renal outcome was unfavorable in eight cases (57%) and favorable in six (43%). When fetal serum β-2-microglobulin was < 5 mg/L, renal outcome was favorable in all cases (4/4). When fetal serum β-2-microglobulin was ≥ 5 mg/L, 8/10 cases (80%) had an unfavorable renal outcome (sensitivity, 100%; specificity, 66%).

CONCLUSION

Fetal serum β-2-microglobulin reliably predicts postnatal renal outcome in obstructive uropathy complicated by urinary ascites. Moreover, urine extravasation does not seem to protect fetal renal function.

The impact of perinatal urinoma formation on renal function: our experience and review of the literature

INTRODUCTION

A urinoma is a fluid mass consisting of extravasated urine in the perirenal space. Its impact on renal function was analysed.

METHODS

All cases of prenatal and neonatal urinoma reported in the literature were analysed as well as two cases recently observed in our department.

RESULTS

A review of all prenatally diagnosed urinomas revealed 25 cases, for a total of 30 renal units. The cause of obstruction was: lower urinary tract (LUT) obstruction in 16 cases (62.5%), upper urinary tract (UUT) obstruction in seven cases (29.5%) and unknown in two cases (8%). A preserved renal function was found in only 30% of all cases. Furthermore, prognosis for renal function was better in posterior urethral valve (PUV) patients than in uretero-pelvic junction obstruction (UPJO) patients. In addition, we analysed 35 published cases of urinoma with a neonatal onset, without prenatal diagnosis, and secondary to LUT obstruction in 27 cases (77%), UUT obstruction in seven cases (20%), while the underlying cause was unknown in one cases (3%). A preserved renal function was observed in 84% of cases with UUT obstruction and in 80% of cases presenting a LUT obstruction.

CONCLUSIONS

Prognosis concerning renal function seems to be mainly related to two factors: age at presentation and underlying diagnosis. Decompression of the urinary tract by urine extravasation produces the best results in terms of preservation of the renal function in LUT obstruction (75% in prenatal and 84% in postnatal cases); UUT obstruction however is associated with a good prognosis in the neonatal period (80% of preserved renal function) but with a severe impairment (only 20% of preserved renal function) in prenatally detected cases.

VURD Syndrome in a Female

VURD syndrome has been repeatedly described as unilateral reflux into a nonfunctioning renal moiety. This syndrome is considered a pop-off mechanism dissipating pressure in lower urinary tract obstruction: it may be found in association with other protective mechanisms occurring in utero, such as ascites and/or urinomas, and has been exclusively described in male patients. A premature female baby with signs and symptoms of outflow obstruction underwent diagnostic workup revealing congenital urethral hypoplasia with unilateral reflux into a dysplastic kidney. Obstetrical history was positive for early onset, serologically negative ascites without cardiomegaly, which required serial aspirations. Reconstructive surgery was carried out with good results: ascites and VURD syndrome were both deemed to be perinatal protective mechanism against excess pressure in the urinary tract. Although rare, lower urinary tract obstruction in the female can lead to the same protective mechanisms seen in male fetuses/newborns. VURD syndrome and ascites should be interpreted as such and require perinatal specialist counselling.

Endoscopic management of a type IV syringocele causing massive perirenal urinoma in an infant

The finding of a urinoma in the fetal and neonatal period is almost always related to an obstruction distal to the collection itself. Syringocele is a congenital or acquired dilation of a bulbourethral Cowper's gland. An exceedingly rare case of neonatal anterior urethral obstruction caused by a syringocele and manifesting itself with a dramatic clinical onset is presented. Clinical and radiologic findings are discussed and minimally invasive therapeutic strategies emphasized.

[Impact of fetal urinary ascites on serum beta2 microglobuline in obstructive uropathies: a case report]

We report a posterior urethral valves case diagnosed at 33 week's gestation on a fetus presenting with anamnios and urinary ascites. In this fetus, the serum beta2 microglobuline rate was high, suggesting a very poor renal prognosis. At 1-year-old, the creatinine rate is nearly normal. In case of urinary ascites, the serum beta2 microglobuline rate could be improved in relation with the transperitoneal reabsorption of this protein.

Urinomas protect renal function in posterior urethral valves--a population based study

BACKGROUND/PURPOSE

Urinomas have been thought to protect renal function in boys with posterior urethral valves (PUVs), although recent reports have disputed this. This study tested the hypothesis that urinomas protect global renal function in boys with PUV.

METHODS

A retrospective analysis of all boys with PUV presenting to a tertiary unit derived from a region with an estimated population of 5.5 million was performed. Comparisons of the initial nadir creatinine, current creatinine, and renal status score (RSS) were made between those with and without urinomas. The RSS was derived from nephrology assessment of current renal status (0 = normal to 4 = end-stage renal failure or transplantation). Results were given as median (range), except for RSS, which was given as mean +/- SEM. P < or = .05 was regarded as significant.

RESULTS

During 1989-2009, 9 of 89 PUV boys were diagnosed with urinomas. Initial nadir creatinine was statistically lower in boys with urinomas (31 [18-44] vs 45 [20-574] mumol/L, P < .01). Length of follow-up was similar (5.1 [2.2-17.3] vs 5.9 [1.8-19.7] years, P = .59). Follow-up creatinine was significantly lower in urinoma boys (44 [25-77] vs 61 [29-1227] micromol/L, P < .05), as was the RSS (0.14 +/- 0.14 vs 0.91 +/- 0.14, P < .01). No urinoma boys progressed to end-stage renal failure or required transplant.

CONCLUSION

This population-based study of PUV boys demonstrates that urinomas reduce nadir creatinine and significantly protect long-term global renal function.

Urinomas associated with posterior urethral valves

PURPOSE

We evaluated the incidence and clinical implications of urinomas in boys with posterior urethral valves. Our secondary aim was to evaluate the treatment modalities of urinomas.

MATERIALS AND METHODS

We retrospectively reviewed the hospital data of 200 patients with posterior urethral valves treated between 1953 and 2003. Documentation was sufficient in 196 cases to evaluate the presence of urinomas. A group of 69 patients with posterior urethral valves without urinoma served as controls.

RESULTS

Of 196 patients 17 (9%) had urinoma. However, the incidence of urinoma increased to 15% after ultrasonography came into standard clinical use. Nine patients had perirenal urine collection, 6 had urinary ascites and 2 had urinothorax. At presentation median serum creatinine values were similar in patients with urinoma (145 mumol/l, range 54 to 431) and controls (126 mumol/l, 19 to 593, p = 0.547). Creatinine decreased similarly in patients with and without urinoma after the obstruction was relieved. Vesicoureteral reflux was detected in 69% of the patients with urinoma and in 76% of the controls. Median split function on the side of the urinoma was 51% (range 38% to 70%) on (99m)technetium diethylenetetramine pentaacetic acid scintigraphy. During childhood end-stage renal failure developed in 4 of the 16 patients (25%) with urinoma and in 16 of the 69 controls (23%).

CONCLUSIONS

The true incidence of urinomas is probably close to 15% in patients with posterior urethral valves. Renal function is similar in patients with posterior urethral valves with and without urinoma. In asymptomatic cases urinomas apparently do not require any specific treatment.