Current management of infants with fetal renal pelvis dilation: a survey by French-speaking pediatric nephrologists and urologists

Radiological and surgical correlation of pelviureteric junction obstruction in positional anomalies of the kidney in children

Pelviureteric junction obstruction, also known as ureteropelvic junction obstruction, is a congenital narrowing of the urinary excretory tract at the junction between the renal pelvis and the ureter and is a common cause of congenital pelvicalyceal dilatation. The outcome is variable, from spontaneous resolution to renal parenchymal function loss in cases of untreated high-grade obstruction. Abnormalities in renal ascent, rotation and vascularity can be associated with pelviureteric junction obstruction and easily overlooked radiologically. In this pictorial review, we explore the anatomical, radiological and surgical correlations of pelviureteric junction obstruction in the context of a normal kidney and a spectrum of renal abnormalities, including hyper-rotation (also known as renal malrotation), failed renal ascent, fusion anomalies and accessory crossing renal vessels. For each scenario, we provide technical tips on how to identify the altered anatomy at the first ultrasound assessment and correlation with scintigraphic, cross-sectional and postoperative imaging where appropriate. A detailed ultrasound protocol specifically to assess and characterise pelviureteric junction obstruction in paediatric patients is also offered.

Postnatal management of children with antenatal hydronephrosis

Background

Postnatal management of infants with antenatal hydronephrosis (ANH) is still one of the most controversial issues. The majority of infants with ANH are asymptomatic with only few children who develop renal insufficiency. Thus, the biggest challenge for pediatric urologists is to distinguish children who will require further investigations and possible intervention prior to the development of symptoms, complications or renal damage in a cost effective manner without exposing them to the hazards of unnecessary investigations.

Main body

In this review article, literature on ANH were reviewed to present the current suggestions, recommendations, guidelines and their rational for postnatal management of ANH. It is agreed that a large portion of infants with ANH will improve; thus, the protocol of management is based mainly on observation and follow-up by ultrasound to detect either resolution, stabilization or worsening of hydronephrosis. The first 2 years of life are critical for this follow-up as the final picture is mostly reached during that period. Advanced imaging using voiding cystourethrography or renal scintigraphy are required for children at risk. Then, surgical intervention is selected only for a subgroup of these infants who showed worsening of hydronephrosis or renal function.

Conclusions

The protocol of management is based mainly on observation and follow-up by US to detect either resolution, stabilization or worsening of hydronephrosis. Postnatal evaluation should be performed for any neonate with a history ANH at any stage during pregnancy even if it was resolved during third trimester. Exclusion of UTI should be performed by urinalysis for all cases followed by urine culture if indicated. Serum creatinine should be performed especially in patients with bilateral ANH. US is the initial standard diagnostic imaging technique. Other imaging modalities like VCUG and nuclear renal scans may be required according to the results of the US evaluation. The most important items in decision making are the presence of bilateral or unilateral hydronephrosis, presence or absence of hydroureter, presence of lower urinary tract obstruction and degree of hydronephrosis on the initial postnatal US. Then an intervention is selected only for a subgroup of these patients who showed deterioration in renal function or degree of hydronephrosis or were complicated by UTIs. All these recommendations are based on the available literature. However, management of ANH is still a controversial issue due to lack of high evidence-based recommendations. Randomised controlled studies are still needed to provide a high level evidence for different aspects of management.

Clinical Outcome of Children With Antenatally Diagnosed Hydronephrosis

Fetal renal pelvis dilation is a common condition, which is observed in 1-4. 5% of pregnancies. In many cases, this finding resolves spontaneously. However, sometimes it may be a signal of significant urinary tract pathologies. The main abnormalities found after birth are uretero-pelvic junction stenosis, primary vesicoureteral reflux, megaureter, duplex kidneys, and posterior urethral valves, with uretero-pelvic junction stenosis and primary vesicoureteral reflux accounting for most of the cases. Diagnosis, management, and prognosis at short and longer term of these conditions will be reviewed in this article.

Nuclear Medicine in Pediatric Nephro-Urology: An Overview

In the context of ante-natally diagnosed hydronephrosis, the vast majority of children with a dilated renal pelvis do not need any surgical treatment, as the dilatation resolves spontaneously with time. Slow drainage demonstrated at Tc-99m-mercaptoacetyltriglycine (MAG3) renography does not necessarily mean obstruction. Obstruction is defined as resistance to urinary outflow with urinary stasis at the level of the pelvic-ureteric junction (PUJ) which, if left untreated, will damage the kidney. Unfortunately this definition is retrospective and not clinically helpful. Therefore, the identification of the kidney at risk of losing function in an asymptomatic patient is a major research goal. In the context of renovascular hypertension a DMSA scan can be useful before and after revascularisation procedures (angioplasty or surgery) to assess for gain in kidney function. Renal calculi are increasingly frequent in children. Whilst the vast majority of patients with renal stones do not need functional imaging, DMSA scans with SPECT and a low dose limited CT can be very helpful in the case of complex renal calculi. Congenital renal anomalies such as duplex kidneys, horseshoe kidneys, crossed-fused kidneys and multi-cystic dysplastic kidneys greatly benefit from functional imaging to identify regional parenchymal function, thus directing further management. Positron emission tomography (PET) is being actively tested in genito-urinary malignancies. Encouraging initial reports suggest that F-18-fluorodeoxyglucose (FDG) PET is more sensitive than CT in the assessment of lymph nodal metastases in patients with genito-urinary sarcomas; an increased sensitivity in comparison to isotope bone scans for skeletal metastatic disease has also been reported. Further evaluation is necessary, especially with the promising advent of PET/MRI scanners. Nuclear Medicine in paediatric nephro-urology has stood the test of time and is opening up to new exciting developments.

Postnatal management of antenatally detected hydronephrosis

With the increasing use of ultrasonography, congenital anomalies are often picked in utero. Antenatally detected hydronephrosis is amongst the most commonly detected abnormality. The management of this condition has raised considerable debate amongst clinicians dealing with it. This article is written with an idea to provide comprehensive information regarding the postnatal management of antenatally detected hydronephrosis. A detailed review of the current literature on this topic is provided. Also, guidelines have been given to facilitate the management of this condition.

Fetal hydronephrosis: natural history and risk factors for postnatal surgery

BACKGROUND

The objective of this study was to assess the ability of prenatal ultrasound to predict an unfavorable outcome and the need for postnatal surgery in cases of fetal hydronephrosis (HY).

METHODS

Antenatal HY was classified according to the renal pelvis anteroposterior (AP) diameter in the third trimester. Postnatal outcome was considered favorable in the presence of spontaneous resolution or postnatal diagnosis of HY <20 mm, and unfavorable in the presence of postnatal diagnosis of >20 mm HY or urinary tract pathologies.

RESULTS

Prenatal diagnosis of HY was made in 120 fetuses (for a total of 161 abnormal renal units). The rates of postnatal urinary tract pathology were 14, 27 and 53% for antenatal HY of ≤7, 8-15 and >15 mm, respectively. An AP diameter ≥7 mm in the third trimester had a sensitivity of 100% and a specificity of 23% to predict unfavorable outcome. A formula inclusive of AP diameter and presence or absence of urinary tract anomalies can predict the need for postnatal surgery.

CONCLUSIONS

The majority of infants with congenital HY have a favorable postnatal outcome. Risk of unfavorable outcome increases with the degree of dilatation of the renal pelvis and the presence of urinary tract anomalies. An AP diameter ≥7 mm in the third trimester warrants postnatal follow-up.

Prenatal anteroposterior pelvic diameter cutoffs for postnatal referral for isolated pyelectasis and hydronephrosis: more is not always better

PURPOSE

Congenital hydronephrosis and isolated pyelectasis are frequently diagnosed by prenatal ultrasound. About 80% of cases resolve spontaneously in early childhood. Currently there is no agreed on protocol for prenatal followup. Most clinicians use a renal pelvis anteroposterior diameter of greater than 4 mm as a threshold for identifying isolated pyelectasis and hydronephrosis at 33 weeks of gestation or anteroposterior diameter greater than 7 mm at 40 weeks of gestation. We sought to determine a fetal renal pelvis diameter cutoff at 20 and 30 weeks of gestation that would be able to predict significant nephron uropathy requiring surgery.

MATERIALS AND METHODS

Our protocol included 2 prenatal ultrasounds at 20 and 30 weeks of gestation and 3 postnatal ultrasounds at ages 1, 6 and 12 months. Between January 2009 and December 2011 we evaluated 149 prenatal cases (130 males, 19 females) of isolated pyelectasis and 41 cases (28 males, 13 females) of hydronephrosis with a renal pelvis anteroposterior diameter of greater than 4 mm at 20 weeks of gestation.

RESULTS

For isolated pyelectasis we identified cutoffs of 6 mm at 20 weeks of gestation (100% sensitivity, 84.3% specificity) and 10 mm at 30 weeks of gestation (100% sensitivity, 91.9% specificity). For hydronephrosis we identified cutoffs of 10 mm at 20 weeks of gestation (100% sensitivity, 86.1% specificity) and 12 mm at 30 weeks of gestation (100% sensitivity, 66.7% specificity).

CONCLUSIONS

Using these thresholds, we could avoid a significant number of followup ultrasounds in the prenatal and postnatal periods, as well as invasive postnatal tests (ie voiding cystourethrography and mercaptoacetyltriglycine scintigraphy) without missing even a single case of obstructive nephropathy requiring surgery.

Antenatally diagnosed hydronephrosis: current postnatal management

The issue of antenatal hydronephrosis has become a routine component for the care of a pregnant woman despite limited evidence of a clinical benefit. The genitourinary tract represents the most commonly detected organ system with identified abnormalities, with antenatal hydronephrosis (ANH), being the most notable and common finding. ANH represents a spectrum, with most cases being a trivial and inconsequential finding on maternal fetal ultrasound. However, there is a correlation with increased grades of ANH being associated with increased severity of urinary tract pathology. Most patients can be managed expectantly with appropriate evaluation commenced postnatally based on severity of ANH and proper parental counseling and education. The purpose of this review was to assess current literature and guidelines pertaining to ANH and incorporate our practical interpretations of their significance.

Revised guidelines on management of antenatal hydronephrosis

Widespread antenatal screening has resulted in increased detection of anomalies of the kidneys and urinary tract. The present guidelines update the recommendations published in 2000. Antenatal hydronephrosis (ANH) is transient and resolves by the third trimester in almost one-half cases. The presence of oligohydramnios and additional renal or extrarenal anomalies suggests significant pathology. All patients with ANH should undergo postnatal ultrasonography; the intensity of subsequent evaluation depends on anteroposterior diameter (APD) of the renal pelvis and/or Society for Fetal Urology (SFU) grading. Patients with postnatal APD exceeding 10 mm and/or SFU grade 3-4 should be screened for upper or lower urinary tract obstruction and vesicoureteric reflux (VUR). Infants with VUR should receive antibiotic prophylaxis through the first year of life, and their parents counseled regarding the risk of urinary tract infections. The management of patients with pelviureteric junction or vesicoureteric junction obstruction depends on clinical features and results of sequential ultrasonography and radionuclide renography. Surgery is considered in patients with increasing renal pelvic APD and/or an obstructed renogram with differential renal function <35-40% or its subsequent decline. Further studies are necessary to clarify the role of prenatal intervention, frequency of follow-up investigations and indications for surgery in these patients.

Diagnostic accuracy of renal pelvic dilatation for detecting surgically managed ureteropelvic junction obstruction

PURPOSE

In this study we evaluate the diagnostic accuracy of renal pelvic dilatation for detecting infants with prenatal hydronephrosis who will need surgical intervention for ureteropelvic junction obstruction during followup.

MATERIALS AND METHODS

Between 1999 and 2010, 371 newborns diagnosed with isolated prenatal hydronephrosis were prospectively followed. The main event of interest was the need for pyeloplasty. Diagnostic odds ratio, sensitivity, specificity and diagnostic accuracy (assessed by AUC) of fetal renal pelvic dilatation and postnatal renal pelvic dilatation were evaluated.

RESULTS

A total of 312 patients were included in the analysis and 25 (7.5%) infants underwent pyeloplasty. The diagnostic performance for detecting the need for pyeloplasty was excellent for all ultrasonography measurements. The AUC was 0.96 (95% CI 0.92-0.98) for fetal renal pelvic dilatation, 0.97 (95% CI 0.95-0.98) for postnatal renal pelvic dilatation and 0.95 (95% CI 0.92-0.97) for the Society for Fetal Urology grading system. A cutoff of 18 mm for fetal renal pelvic dilatation and a cutoff of 16 mm for postnatal renal pelvic dilatation had the best diagnostic odds ratio to identify infants who needed pyeloplasty. Considering a diagnosis to be positive only if fetal renal pelvic dilatation was greater than 18 mm and postnatal dilatation was greater than 16 mm, sensitivity was 100% and specificity was 86% (95% CI 80.7-89.9).

CONCLUSIONS

Our findings suggest that the combination of fetal and postnatal renal pelvic dilatation is able to increase the diagnostic accuracy for detecting infants who need a more comprehensive postnatal investigation for upper urinary tract obstruction.

Current management of antenatal hydronephrosis

The strategy for the management of children with urinary tract anomalies has changed considerably as a result of the development of ultrasound equipment and techniques that allow for detailed fetal evaluation. Hydronephrosis is the most common urogenital anomaly detected, suggesting that an obstructive process may be potentially present. The goal of postnatal management is to identify and treat those patients whose renal function is at risk, while leaving alone the high percentage of patients who are at no risk of renal damage. This management involves a spectrum of radiological, medical, and surgical interventions for diagnosis, surveillance, and treatment. In this article, we review our current understanding of the natural history of antenatal hydronephrosis and its management.

Antibiotic prophylaxis for urinary tract infections in antenatal hydronephrosis

BACKGROUND AND OBJECTIVE

Continuous antibiotic prophylaxis (CAP) is recommended to prevent urinary tract infections (UTIs) in newborns with antenatal hydronephrosis (HN). However, there is a paucity of high-level evidence supporting this practice. The goal of this study was to conduct a systematic evaluation to determine the value of CAP in reducing the rate of UTIs in this patient population.

METHODS

Pertinent articles and abstracts from 4 electronic databases and gray literature, spanning publication dates between 1990 and 2010, were included. Eligibility criteria included studies of children <2 years old with antenatal HN, receiving either CAP or not, and reporting on development of UTIs, capturing information on voiding cystourethrogram (VCUG) result and HN grade. Full-text screening and quality appraisal were conducted by 2 independent reviewers.

RESULTS

Of 1681 citations, 21 were included in the final analysis (N = 3876 infants). Of these, 76% were of moderate or low quality. Pooled UTI rates in patients with low-grade HN were similar regardless of CAP status: 2.2% on prophylaxis versus 2.8% not receiving prophylaxis. In children with high-grade HN, patients receiving CAP had a significantly lower UTI rate versus those not receiving CAP (14.6% [95% confidence interval: 9.3-22.0] vs 28.9% [95% confidence interval: 24.6-33.6], P < .01). The estimated number needed to treat to prevent 1 UTI in patients with high-grade HN was 7.

CONCLUSIONS

This systematic review suggests value in offering CAP to infants with high-grade HN, however the impact of important variables (eg, gender, reflux, circumcision status) could not be assessed. The overall level of evidence of available data is unfortunately moderate to low.

Natural history of bilateral mild isolated antenatal hydronephrosis conservatively managed

BACKGROUND

The purpose of this study was to assess the prevalence and outcome of newborns with bilateral mild isolated antenatal hydronephrosis managed with neither antibiotic prophylaxis nor voiding cystourethrography (VCUG).

METHODS

Inclusion criteria were ultrasonographic evidence of an anterior-posterior pelvic diameter (APPD) of 5-15 mm at the third trimester of gestation and on the first postnatal ultrasound sonogram. Exclusion criteria were an APPD >15 mm, calyectasis, hydroureteronephrosis, or renal or bladder abnormalities. Ultrasound follow-up was performed. Parents were familiarized with the signs of urinary tract infection (UTI). If UTI was confirmed, VCUG was performed. The outcome was assessed as intrauterine resolution of hydronephrosis, total or partial resolution, stability, or progression.

RESULTS

Hydronephrosis was bilateral in 98 of the 236 newborns (196 hydronephrotic kidneys) with mild isolated antenatal hydronephrosis enrolled in this study. Nine patients had UTI, and none showed reflux. After a mean follow-up of 15 months, 74 kidneys showed intrauterine resolution (38%), 82 (42%) showed total resolution, 13 showed partial resolution, 24 were stable, and 3 showed progression. Bilateral cases represented 42% of mild isolated antenatal hydronephrosis. During the first year of life, 80% of the kidneys showed total hydronephrosis resolution, 9% of patients had UTI, and none of the patients showed reflux.

CONCLUSIONS

Antibiotic prophylaxis and VCUG are not mandatory in newborns with bilateral mild isolated antenatal hydronephrosis, but clinical and ultrasound follow-up are recommended during the first year of life.

Feasibility of measuring 3-dimensional renal parenchymal volume to predict postnatal renal function in near-term fetuses with congenital hydronephrosis: a preliminary study

OBJECTIVES

The purposes of this study were to evaluate the feasibility of predicting kidney function using the fetal renal parenchymal volume as determined by prenatal 3-dimensional (3D) sonography and to determine the association among the prenatal renal pelvic diameter, renal parenchymal volume, and postnatal renal function in near-term fetuses with unilateral hydronephrosis.

METHODS

This retrospective study included 42 kidneys (21 normal and 21 hydronephrotic) from 21 fetuses between 30 and 39 weeks' gestation. We used the extended imaging virtual organ computer-aided analysis (XI VOCAL; 10 planes) technique for the prenatal volumetric measurements, and postnatal renal function was estimated using renal scintigraphy. An independent-samples Student ttest, Spearman's rank correlation, and simple linear regression were used for the statistical analyses. Reproducibility was confirmed with a paired Student t test and intraclass correlation coefficients.

RESULTS

The renal pelvic diameter correlated well with the renal parenchymal volume Spearman ρ = 0.765; P < .001). The postnatal renal function correlated with the adjusted 3D renal parenchymal volume (Spearman ρ = -0.321; P = .043) but did not correlate with the prenatal renal pelvic diameter (Spearman ρ = -0.291; P = .062).

CONCLUSIONS

This preliminary study showed that 3D renal parenchymal volume could be a coparameter for predicting postnatal renal function with the renal pelvic diameter. Further studies in a larger population are required to obtain robust results.

Short-term outcome of mild isolated antenatal hydronephrosis conservatively managed

OBJECTIVES

To assess the outcome of newborns with mild isolated antenatal hydronephrosis (MIAHN) managed with neither antibiotic prophylaxis nor voiding cystourethrography (VCUG).

INCLUSION CRITERIA

anterior-posterior pelvic diameter 5-15 mm at third trimester of gestation, confirmed by first postnatal ultrasound.

EXCLUSION CRITERIA

pelvic diameter > 15 mm, calyectasis, hydroureteronephrosis, renal or bladder abnormalities. Clinical and ultrasound follow-up was performed. Parents were familiarized with urinary tract infection (UTI) signs. If UTI was confirmed, VCUG was performed. Hydronephrosis outcome was assessed as intrauterine resolution, total or partial resolution, stability or progression.

RESULTS

MIAHN was detected in 193 newborns (109 unilateral, 84 bilateral; 277 renal units); 23 (12%) had UTI and 2 of them showed low-grade reflux. After a mean follow-up of 15 months, 91 renal units showed intrauterine resolution (33%), 111 (40%) total resolution, 20 (7%) partial resolution, 52 (19%) stability and 3 (1%) progression.

CONCLUSION

Total resolution of hydronephrosis was observed in 73% of renal units during the first year. Routine antibiotic prophylaxis and VCUG might not be necessary in all infants with MIAHN, clinical and ultrasound follow-up being advisable during the first year of life.

Clinical course of 822 children with prenatally detected nephrouropathies

BACKGROUND AND OBJECTIVES

With the advent of fetal screening ultrasonography, the detection of congenital anomalies of the kidney and urinary tract (CAKUT) in utero has permitted early management of these conditions. This study aims to describe the clinical course of a large cohort of patients with prenatally detected nephrouropathies.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In this retrospective cohort study, 822 patients were prenatally diagnosed with CAKUT and systematically followed up at a tertiary Renal Unit for a median time of 43 months. Variables included in the analysis were sex, laterality, fetal ultrasonography (isolated versus associated hydronephrosis), and presence/absence of nephrouropathies. The events of interest were urinary tract infection, surgical interventions, hypertension, CKD, and death. Survival analyses were performed to evaluate time until occurrence of the events of interest.

RESULTS

Urinary tract infection occurred in 245 (29.8%) children, with higher risk in females (hazard ratio=1.30, 95% confidence interval=1.02-1.70, P=0.05); 22 patients (2.7%) had hypertension, and 49 (6%) patients developed CKD. The risk of CKD was greater in patients with associated hydronephrosis (hazard ratio=5.20, 95% confidence interval=2.90-9.30, P<0.001). Twelve patients (1.5%) died during follow-up. Death was significantly associated with being born during the first period of the study (hazard ratio=6.00, 95% confidence interval=1.60-22.50, P<0.001), associated hydronephrosis (hazard ratio=9.30, 95% confidence interval=2.90-29.30, P<0.001), and CKD (hazard ratio=170.00, 95% confidence interval=41.00-228.00, P<0.001).

CONCLUSIONS

In our series, the clinical course of prenatally detected CAKUT was heterogeneous, and those infants with associated hydronephrosis at baseline were identified as a high-risk subgroup.

Probability of urinary tract infection in infants with ureteropelvic junction obstruction: is antibacterial prophylaxis really needed?

In infants with ureteropelvic junction obstruction (UPJO), the risk of urinary tract infection (UTI) is unknown, and there is a lack of prospective studies showing definitive evidence regarding the benefits and necessity of antibiotic prophylaxis. The aim of this study was to assess the risk of UTI in infants with UPJO and to determine whether the risk varies according to the degree of hydronephrosis. Infants with hydronephrosis detected prenatally or within the postnatal 28th day and who had no previous history of UTI were followed prospectively without antibacterial prophylaxis. Imaging studies were performed according to our Pediatric Uro-Nephrology Study Group protocol. Dimercaptosuccinate (DMSA) scintigraphy was performed in all infants at the end of 1 year of follow-up. Eighty-four infants (56 boys, 28 girls) were included in the study. The distribution of patients in each hydronephrosis grading group was incidentally similar. Within a median follow-up period of 18 (12-24) months, none of the patients had UTI. Furthermore, no pyelonephritic scar was found on DMSA scans in any patient. We conclude that prophylactic antibiotic usage is not indicated in infants with UPJO, regardless of the severity of hydronephrosis, as the risk of UTI is minimal in this population.

[Postnatal evaluation and management of fetal pyelectasis on prenatal ultrasound]

Fetal pyelectasis is the most frequently encountered anomaly on prenatal ultrasound. The ultrasound diagnostic criteria are well established: nature of dilated structures, degree of dilatation, ultrasound appearance of the kidneys, volume of amniotic fluid. Ultrasound can also determine if the anomaly is isolated or not, which is important for the management and prognosis of the pregnancy. Ultrasound is the initial postnatal study to evaluate the urinary tract. Further management will be based on suspected diagnosis. In cases of suspected vesico-ureteral reflux, VCUG is performed. In cases of obstructive uropathy or complex malformation (duplications), MRI is performed at 6 months of age to further define the anatomy of the urinary tract. Radionuclide renogram, performed in most cases, allows evaluation of split renal function. Follow-up ultrasound is important to monitor renal development, urinary tract dilatation and appearance of the renal parenchyma. Functional follow-up is assured by radionucline renography. This comprehensive follow-up is recommended to prevent complications and progressive loss of renal function.

Placebo-controlled trials in pediatric urology: a cautionary view from an ethical perspective

The ethical dispute regarding placebo-controlled trials is discussed in this review. Important issues, such as clinical equipoise, fiduciary obligation and middle ground theory, are examined in the context of pediatric urology clinical research. After reviewing the literature, the authors summarize specific indications for placebo-controlled trials in pediatric urology, and emphasize that physicians have ethical and moral obligations to patients, in the sense that one should carefully plan and conduct such trials in order to gain clinically important information without exposing children to undue risks.

Variation among pediatric urologists and across 2 continents in antibiotic prophylaxis and evaluation for prenatally detected hydronephrosis: a survey of American and European pediatric urologists

PURPOSE

No clear practice guidelines exist to evaluate prenatally diagnosed hydronephrosis or recommend antibiotic prophylaxis. We hypothesized that among pediatric urologists there is significant variability in prenatal hydronephrosis evaluation and management.

MATERIALS AND METHODS

We created a survey questionnaire to answer certain questions, including 1) what prenatal parameters trigger postnatal evaluation, 2) how pediatric urologists manage prenatal hydronephrosis and 3) what are their recommendations for antibiotic prophylaxis. Survey questions included demographics and practice patterns, and influences concerning radiographic tests and prophylactic antibiotics. A Web based survey link was sent to members of the Urology Section, American Academy of Pediatrics and the European Society for Pediatric Urology. We received 156 responses. We also compared practices based in Europe in 60 respondents and in the United States in 70.

RESULTS

There was significant response variability to all questions answered with no question achieving a consensus of more than 50%. European and American respondents were equally distributed in regard to years in practice and number of patients per month. Radiographic factors influenced the decision to perform further imaging or provide prophylactic antibiotics in around 50% of respondents. There was wide variability in parameters triggering intervention and in prophylactic antibiotics. Pediatric urologists in practice more than 15 years were less likely to prescribe antibiotic prophylaxis at birth than those in practice less than 15 years. Variation also existed by geographic region with American physicians more likely to prescribe antibiotics for any prenatal hydronephrosis compared to their European counterparts (77% vs 40%, p <0.005) and European physicians more likely to be influenced by prenatal pelvic diameter when obtaining postnatal imaging (unilateral 70% vs 47%, p = 0.009 and bilateral 55% vs 36%, p = 0.03, respectively). European pediatric urologists were also more likely to order renal scans than their American counterparts. These differences were less significant for high grade hydronephrosis.

CONCLUSIONS

Even among pediatric urologists there is considerable variation in radiographic resource and prophylactic antibiotics use when managing prenatal hydronephrosis. Some variation may be explained by regional differences but it is most probably due to absent clear guidelines based on prospective, randomized, controlled trials.

Obstructive diseases of the urinary tract in children: lessons from the last 15 years

Imaging urinary tract obstruction is a common query in paediatric uroradiology. With the advent of a more conservative treatment approach, the task of imaging today is to distinguish as early as possible those kidneys that do not require surgery, from those that will deteriorate and lose function and/or growth potential and thus benefit from surgery. At present, in spite of significant advancements in imaging and the introduction of diuretic paediatric MR-urography, there is still no reliable a-priori pro-futuro assessment. Thus, repeated follow-up imaging is often necessary for monitoring. Imaging usually starts with US; the major additional complementary and more function-oriented tools are diuretic renal scintigraphy and MR-urography. The frequency and timing as well as the detailed protocol vary within institutions, partly because of differences in the criteria that are used for indicating surgery. Intra-venous urography (IVU) for obstruction has practically vanished apart from for a few exceptions, and the "Whitaker" test is today seldom performed, being reserved for complicated cases.

Management in children of mild postnatal renal dilatation but without vesicoureteral reflux

Infants with mild postnatal renal dilatation but without vesicoureteral reflux pose a challenge. For how long and in what way should they be followed? From May 1989 to December 2006, we prospectively followed 1,795 pregnancies in which the foetal renal pelvis measured 4 mm or greater. Voiding cystourethrography (VCUG) and renal ultrasound were performed on 1,315 infants at 6 weeks of age. Our study group comprised 208 (167 male) infants with normal VCUG findings who had a renal pelvis of 6-11 mm. We followed them for 1-17 years (mean 11 years). Medical and radiological records were reviewed to determine any urinary symptoms and final outcome. They underwent, on average, four further imaging tests. The renal dilatation had resolved by 24 months in approximately 70%. Urinary tract infection (UTI) developed in 16 (8%). Calyceal dilatation was more likely in those developing UTI (P=0.02). Twenty-two (10.6%) had a radiologically demonstrated urinary tract abnormality. Of the five who had renal scarring or severe obstruction, four became symptomatic. Most infants with mild postnatal renal dilatation can be investigated with only one further sonogram at 24 months of age. Mild postnatal renal dilatation is associated with subsequent UTI or renal tract abnormality in 18%. Severe renal abnormality occurred in 2.4%.

The long-term outcome of antenatal hydronephrosis up to 15 millimetres justifies a noninvasive postnatal follow-up

AIM

To assess the incidence of urinary tract infections (UTIs) and surgery in infants with different grades of antenatal hydronephrosis (ANH) and to evaluate incidence, severity and course of underlying vesicoureteral reflux (VUR).

METHODS

Retrospective data of 125 infants with ANH were collected. The patients were divided into two groups according to the anterior-posterior pelvis diameter: group I, 5-14 mm and group II, > or =15 mm.

RESULTS

UTIs developed in 4 of 106 infants from group I and 5 of 19 infants from group II. Surgical interventions were performed on 1 of 106 patients of group I and 7 of 19 patients of group II. These differences were statistically significant (p-values 0.004 and <0.001, respectively). In group I, 6 of 106 patients had VUR; none of them required surgical intervention and only two developed a UTI (one of whom also had contralateral ureteropelvic junction obstruction). Five of 19 infants in group II had underlying VUR, four of them with associated anomalies, 1 infant required surgical correction and 4 developed UTIs.

CONCLUSION

Infants with ANH up to 15 mm have a low incidence of UTIs and surgery and a low incidence and benign course of underlying VUR. Therefore, noninvasive postnatal follow-up is justified and standard voiding cystourethrography should not be performed, but only in cases of ureteric dilatation.

Management of fetal hydronephrosis

Prenatally detected hydronephrosis has become a common diagnosis for both pediatric nephrologists and urologists. Hydronephrosis is most commonly assessed by the Society for Fetal Urology grading system or anterior-posterior diameter of the renal pelvis in the transverse plane. Some cases of bilateral obstruction, most commonly from posterior urethral valves, can be life-threatening and require close monitoring or, occasionally, fetal intervention. The majority are unilateral and of no threat to the growing fetus. The crux of postnatal management is the separation of the minority of patients whose renal function is at risk from the majority who will suffer no renal consequences. This management involves a regimen of ultrasounds, voiding cystourethrograms, and nuclear renograms for diagnosis and surveillance. Recent literature has been aimed at the timing and necessity of these studies in order to minimize extraneous studies without compromising renal function.

Outcome of isolated antenatal hydronephrosis: a prospective cohort study

The purpose of this study was to report the outcome of infants with antenatal hydronephrosis. Between May 1999 and June 2006, all patients diagnosed with isolated fetal renal pelvic dilatation (RPD) were prospectively followed. The events of interest were: presence of uropathy, need for surgical intervention, RPD resolution, urinary tract infection (UTI), and hypertension. RPD was classified as mild (5-9.9 mm), moderate (10-14.9 mm) or severe (>or=15 mm). A total of 192 patients was included in the analysis; 114 were assigned to the group of non-significant findings (59.4%) and 78 to the group of significant uropathy (40.6%). Of 89 patients with mild dilatation, 16 (18%) presented uropathy. Median follow-up time was 24 months. Twenty-seven patients (15%) required surgical intervention. During follow-up, UTI occurred in 27 (14%) children. Of 89 patients with mild dilatation, seven (7.8%) presented UTI during follow-up. Renal function, blood pressure, and somatic growth were within normal range at last visit. The majority of patients with mild fetal RPD have no significant findings during infancy. Nevertheless, our prospective study has shown that 18% of these patients presented uropathy and 7.8% had UTI during a medium-term follow-up time. Our findings suggested that, in contrast to patients with moderate/severe RPD, infants with mild RPD do not require invasive diagnostic procedures but need strict clinical surveillance for UTI and progression of RPD.

Antenatally detected hydronephrosis

The strategy of management of children with hydronephrosis has considerably changed as a result of the development of ultrasound techniques, allowing a prenatal detection. Hydronephrosis is defined as a dilation of the renal collecting system, and several entirely different clinical entities can be considered this general heading, whereas early detection may have a different impact depending on the entity considered. The present work aims to describe a certain number of these clinical entities, to discuss the strategic options of management that are proposed, and to evaluate the role of medical imaging, in particular the radionuclide approach. Congenital ureteropelvic junction anomaly, vesicoureteral reflux, posterior urethral valves, and duplex kidney will be successively considered. Multicystic dysplastic kidney disease, although not classified as hydronephrosis, will be mentioned because it may be mistaken for hydronephrosis.

Postnatal management of isolated mild pelvic dilatation detected in antenatal period

AIM

Mild antenatal renal pelvic dilatation (ARPD) revealed by prenatal ultrasound (US) raises the question whether or not screening for vesicoureteral reflux (VUR) is mandatory. The aim of our study was to suggest guidelines for postnatal management of infants with mild ARPD defined as an antero-posterior (AP) dilatation >5 and <10 mm.

METHOD

Therefore we assessed the value of postnatal US at day 30 to predict VUR, the incidence of VUR at day 30 and the rate of spontaneous resolution at 1 year. Two hundred (200) infants with ARPD were included and had renal US and voiding cystourethrography (VCUG) at day 30. If VUR was present, VCUG was repeated 1 year later.

RESULTS

Incidence of VUR was 10% (20/200) at day 30 after birth and only 3% (6/200) 1 year later. VUR at day 30 was twice as frequent in children with postnatal dilatation (11%) than in nondilated kidneys (6%).

CONCLUSIONS

Considering the low incidence of VUR at 1 year, screening for VUR in mild ARDP seems not to be justified. However follow-up by US to detect increase in dilatation and clinical monitoring for signs of urinary infection is required.

Antenatal hydronephrosis as a predictor of postnatal outcome: a meta-analysis

OBJECTIVE

Antenatal hydronephrosis is diagnosed in 1% to 5% of all pregnancies; however, the antenatal and postnatal management of hydronephrosis varies widely. No previous studies define the risk of postnatal pathology in infants with antenatal hydronephrosis. Our objective was to review the current literature to determine whether the degree of antenatal hydronephrosis and related antenatal ultrasound findings are associated with postnatal outcome.

METHODS

We searched Medline (1966-2005), Embase (1991-2004), and the Cochrane Library databases for articles on antenatal hydronephrosis. We required studies to have subjects selected on the basis of documented measurements of antenatal hydronephrosis and followed to a postnatal diagnosis. We excluded case reports, review articles, and editorials. Two independent investigators extracted data.

RESULTS

We screened 1645 citations, of which 17 studies met inclusion criteria. We created a data set of 1308 subjects. The risk of any postnatal pathology per degree of antenatal hydronephrosis was 11.9% for mild, 45.1% for moderate, and 88.3% for severe. There was a significant increase in risk per increasing degree of hydronephrosis. The risk of vesicoureteral reflux was similar for all degrees of antenatal hydronephrosis.

CONCLUSIONS

The findings of this meta-analysis can potentially be used for prenatal counseling and may alter current postnatal management of children with antenatal hydronephrosis. Overall, children with any degree of antenatal hydronephrosis are at greater risk of postnatal pathology as compared with the normal population. Moderate and severe antenatal hydronephrosis have a significant risk of postnatal pathology, indicating that comprehensive postnatal diagnostic management should be performed. Mild antenatal hydronephrosis may carry a risk for postnatal pathology, but additional prospective studies are needed to determine the optimal management of these children. A well-defined prospective analysis is needed to further define the risk of pathology and the appropriate management protocols.

Evolution of fetal ultrasonography

The authors wish to highlight the evolution that has occurred in fetal ultrasound in recent years. A first significant evolution lies in the increasing contribution of first trimester ultrasound for the detection of fetal anomalies. Malformations of several organs and systems have been diagnosed during the first trimester. Furthermore the systematic measurement of the fetal neck translucency has led to increasing rate of detection of aneuploidies and heart malformations. For several years now, three-dimensional (3D) and 4D ultrasound (US) have been used as a complementary tool to 2D US for the evaluation of fetal morphology. This brings an improved morphologic assessment of the fetus. Applications of the techniques are increasing, especially for the fetal face, heart and extremities. The third field where fetal US is continuously providing important information is the knowledge of the natural history of diseases. This has brought significant improvement in the postnatal management of several diseases, especially urinary tract dilatation and broncho-pulmonary malformation.

Outcome of isolated antenatal hydronephrosis: a systematic review and meta-analysis

Idiopathic antenatal hydronephrosis (IAHN), defined as antenatal hydronephrosis not associated with other morphologic renal tract abnormalities, is the most common abnormality detected by antenatal ultrasound. We performed a systematic review and meta-analysis to determine the outcome of IAHN. We screened three databases and bibliographies to identify English-language original peer-reviewed papers that reported serial postnatal renal ultrasonography in children with IAHN. Patients who stabilized and/or improved were extracted and pooled according to the individual grading systems used by each study. A systematic analysis of data extracted from 25 articles revealed overall resolution of pelviectasis in milder cases of IAHN (Society of Fetal Urology [SFU] grade 1-2; anterior posterior pelvic diameter [APPD]<12 mm). In contrast, IAHN of higher severity (grades 3-4; APPD>12 mm) resolved with a lower frequency. Meta-analysis of data extracted from seven papers showed stabilization of pelviectasis in 98% of patients with grades 1-2 (95% confidence interval [CI] 0.93-1.0; p =0.0008) and in 51% of patients with grades 3-4 (95% CI 0.34-0.68; p <0.00001). Grades 1-2 pelviectasis was five times more likely to stabilize than grades 3-4 pelviectasis (odds ratio [OR] 4.69; 95% CI 1.73-12.76; p =0.002). We conclude that in patients with IAHN and lesser degrees of pelvic dilatation, pelvic diameter decreases to the normal range or does not worsen with the vast majority of patients. Further studies are needed to define outcomes, particularly in more severe forms of IAHN.

Insights into the pathogenesis and natural history of fetuses with renal pelvis dilatation

Fetal renal pelvis dilatation is a frequent abnormality that has been observed in 4.5% of pregnancies. The majority of these cases have a tendency to resolve during infancy. Nevertheless, fetal renal pelvis dilatation may be due to significant structural abnormalities such as pelvi-ureteric junction stenosis or vesico-ureteral reflux that may adversely affect renal function or cause urinary infection or sepsis. This review article aims to summarize the data regarding fetal renal pelvis dilatation and to analyze controversial attitudes in the light of the various lines of practice, and to present rational antenatal and postnatal investigation strategy.