Does every patient with prenatal hydronephrosis need voiding cystourethrography?

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.

Role of antibiotic prophylaxis in antenatal hydronephrosis: A systematic review from the European Association of Urology/European Society for Paediatric Urology Guidelines Panel

BACKGROUND

The benefits and harms of continuous antibiotic prophylaxis (CAP) versus observation in patients with antenatal hydronephrosis (ANH) are controversial.

OBJECTIVE

The aim was to determine the effectiveness of CAP for ANH, and if beneficial to determine the best type and regimen of antibiotic and the most harmful to provide guidance for clinical practice.

METHODS

A systematic literature search was performed in databases including Medline, Embase, and Cochrane in June 2015. The protocol was prospectively registered to PROSPERO (CRD42015024775). The search started from 1980, when maternal ultrasound was first introduced into clinical practice. Eligible studies were critically evaluated for risk of bias using Revman software. The outcomes included reduction in urinary tract infections (UTI), drug-related adverse events and kidney functions.

RESULTS

Of 797 articles identified, 57 full text articles and six abstracts were eligible for inclusion (2 randomized controlled trials, 11 non-randomized comparative studies, and 50 case series). It remains unclear whether CAP is superior to observation in decreasing UTIs. No conclusion could be drawn for drug-related adverse events and kidney function because of lack of data. Children who were not circumcised, with ureteral dilatation, and high-grade hydronephrosis may be more likely to develop UTI, and CAP may be warranted for these subgroups of patients. A majority of the studies had low-to-moderate quality of evidence and with high risk of bias.

CONCLUSIONS

The benefits of CAP in a heterogeneous group of children with ANH involving different etiologies remains unproven. However, the evidence in the form of prospective and retrospective observational studies has shown that it reduces febrile UTI in particular subgroups.

Urinary tract infections in children with prenatal hydronephrosis: A risk assessment from the Society for Fetal Urology Hydronephrosis Registry

INTRODUCTION

Risk factors for urinary tract infection (UTI) in children with prenatal hydronephrosis (PNH) are not clearly defined. Our study aim was to describe incidence and identify factors associated with UTI among a cohort of children diagnosed with PNH.

MATERIAL AND METHODS

Patients with confirmed PNH from four medical centers were prospectively enrolled in the Society for Fetal Urology (SFU) hydronephrosis registry between 9/2008 and 10/2015. Exclusion criteria included enrollment because of UTI, associated congenital anomalies, and less than 1-month follow-up. Univariate analysis was performed using Fisher's Exact test or Mann-Whitney U. Probability for UTI was determined by Kaplan-Meier curve.

RESULTS

Median follow-up was 12 (IQR 4-20) months in 213 patients prenatally diagnosed with hydronephrosis. The majority of the cohort was male (72%), Caucasian (77%), and 26% had high grade (SFU 3 or 4) hydronephrosis. Circumcision was performed in 116/147 (79%) with known status, 19% had vesicoureteral reflux (VUR), and 11% had ureteral dilatation. UTI developed in 8% (n = 18), 89% during their first year of life. Univariate analysis found UTI developed more frequently in females (p < 0.001), uncircumcised males (p < 0.01), and the presence of parenchymal renal cyst (p < 0.05). Logistic regression found renal cyst to no longer be significant, but female gender a significant risk factor for development of UTI (p < 0.001). Regression analysis stratified by gender found neither hydronephrosis grade nor parenchymal renal cyst to be significant risk factors for UTI development among females. However, hydronephrosis grade and circumcision status were significant risk factors for development of UTI among males (p < 0.05 and p < 0.01, respectively).

CONCLUSION

Identification of factors associated with UTI in patients with PNH is still progressing; however, several observational studies have identified groups that may be at increased risk of UTI. Use of prophylactic antibiotics (PA), degree of kidney dilation, gender, and circumcision status all have been reported to have some degree of impact on UTI. A previous study identified risk factors for UTI as female gender, uncircumcised status, hydroureteronephrosis, and VUR, and reported that prophylaxis provided a protective effect on prevention of UTI. Our data mirror those in some respect, identifying an association of UTI with female gender and, among males, uncircumcised status, and high grade hydronephrosis. However, we were unable to demonstrate an association between UTI and the use of PA, presence of VUR, dilated ureter, or renal duplication in this observational registry.

Should prenatal hydronephrosis that resolves before birth be followed postnatally? Analysis and comparison to persistent prenatal hydronephrosis

BACKGROUND

Prenatal ultrasonography has greatly enhanced detection of congenital genitourinary abnormalities. However, although persistent prenatal hydronephrosis (PPH) is typically imaged and followed postnatally, it remains unclear if prenatal hydronephrosis that resolves in utero (RPH) should be similarly managed. We determined postnatal abnormalities associated with RPH and compared these to those associated with PPH.

METHODS

We performed a retrospective review of all consecutive patients evaluated for prenatal hydronephrosis over 24 months. Patients were followed prenatally with serial ultrasounds and postnatally with ultrasonography and a voiding cystourethrogram.

RESULTS

Of the consecutive 165 patients enrolled in the study, 72 had RPH. The average prenatal anterior-posterior renal pelvis length was significantly longer in patients with PPH (5.5 mm) than in those with RPH (4.9 mm) (p = 0.01). Recurrent postnatal hydronephrosis occurred in 44% of patients with RPH, with eventual resolution in 34% of those affected. In comparison, 29% of PPH cases resolved postnatally. Mean time to resolution was statistically shorter for PPH (116 days) than for RPH (175 days) (p = 0.01). Seven PPH patients required surgery, while no RPH patients needed intervention (difference was statistically significant).

CONCLUSIONS

A significant number of RPH children had postnatal hydronephrosis. Despite a slower resolution time, no children with RPH required intervention. Although RPH may recur postnatally, the significantly lower chance of intervention being required suggests that these children may not require postnatal imaging.

Risk factors for febrile urinary tract infection in children with prenatal hydronephrosis: a prospective study

PURPOSE

We prospectively investigated the impact of risk factors for febrile urinary tract infection in infants with postnatally confirmed prenatal hydronephrosis.

MATERIALS AND METHODS

Patients seen for prenatal hydronephrosis from 2010 to 2013 were prospectively followed. Those with ectopic ureters and ureteroceles, posterior urethral valves and neuropathic bladders were excluded. The primary outcome was febrile catheter specimen urinary tract infection. We performed univariate analysis of 7 a priori risk factors, including age, hydronephrosis grade (low-I or II vs high-III or IV), type (isolated hydronephrosis vs hydroureteronephrosis), continuous antibiotic prophylaxis, vesicoureteral reflux grade, gender and circumcision status. Time to febrile urinary tract infection curves analyzed by Cox proportional regression were generated to adjust for confounders.

RESULTS

We collected data on 334 patients, of whom 78% were male. A febrile urinary tract infection developed in 65 patients (19%) at a median of 4 months (range 1 to 31). High grade hydronephrosis was present in 192 infants (57%). Continuous antibiotic prophylaxis was prescribed in 96 cases (29%). Of patients on continuous antibiotic prophylaxis 69% had high grade hydronephrosis. Vesicoureteral reflux was identified in 57 of 238 patients in whom voiding cystourethrogram was done. Reflux was grade I to III in 14 cases and grade IV or V in 43. Two-thirds of the patients with reflux were on continuous antibiotic prophylaxis. Circumcision was performed in 95 males (36%). Cox proportional regression identified female gender (HR 3.3, p = 0.02), uncircumcised males (HR 3.2, p = 0.02), hydroureteronephrosis (HR 10.9, p <0.01), vesicoureteral reflux (HR 20.8, p <0.01) and lack of continuous antibiotic prophylaxis (HR 5.2, p <0.01) as risk factors for febrile urinary tract infection. Subgroup analysis excluding vesicoureteral reflux showed that high grade prenatal hydronephrosis was also a significant risk factor (HR 3.0, p = 0.04).

CONCLUSIONS

After patients with vesicoureteral reflux were excluded from the study, females and uncircumcised males with high grade hydroureteronephrosis had significantly higher febrile urinary tract infection rates. Therefore, those patients may benefit from continuous antibiotic prophylaxis.

Urinary tract infection and vesicoureteral reflux in children with mild antenatal hydronephrosis

OBJECTIVE

The postnatal management of mild antenatal hydronephrosis (ANH) remains controversial. The purpose of this study was to evaluate the incidence of UTI and VUR in children with mild ANH in order to determine the necessity of antibiotic prophylaxis (ABP) and VCUG.

METHOD

The data of 1511 patients with various grades of ANH who were referred to Department of Urology, Boston Children's Hospital between January 1998 and January 2010 were reviewed and 760 patients who had mild ANH were identified. The inclusion criteria were: 1) A confirmed report of ANH or actual prenatal ultrasound (US) images. 2) Postnatal evaluation and management conducted at the hospital. 3) Persistent mild hydronephrosis on the first US done between two weeks and three months of age. 4) No other US findings such as ureteral dilatation, duplication anomalies or bladder abnormalities. 5) At least one three-month follow up. Univariate statistical analysis was performed using a Student's t test.

RESULTS

Of the 760 patients who were identified, 608 (80%) were males, and 225 (30%) had bilateral mild hydronephrosis. Of these, 475 patients (63%) underwent an initial screening VCUG. VUR was identified in 13 patients (1.7%) with grades varying from 1 to 5. At follow up, hydronephrosis resolved in 67% of the renal units and worsened in 3.3%. Among the 692 patients with available follow-up data, 23 (3.3%) had a documented UTI. Twelve of these children had an initial screening VCUG that was negative for VUR. Of these 12 patients, seven underwent a subsequent RNC with none having VUR; five of the 12 patients did not undergo a repeat evaluation for VUR (four had a UTI after the screening VCUG and one had an afebrile UTI). Eleven of the 23 children with mild ANH did not have an initial screening VCUG, and all underwent a subsequent VCUG/RNC. Only two children were then found to have VUR Grade 4-5.

CONCLUSION

The incidence of UTI and VUR in children with mild ANH is low. Consequently, routine VCUG screening for VUR and the use of long-term ABP is not necessary for all patients with asymptomatic mild AHN. Evaluation for VUR in children with mild ANH should be reserved for those who subsequently present with a UTI.

Variations in management of mild prenatal hydronephrosis among maternal-fetal medicine obstetricians, and pediatric urologists and radiologists

PURPOSE

There are no current guidelines for diagnosing and managing mild prenatal hydronephrosis. Variations in physician approach make it difficult to analyze outcomes and establish optimal management. We determined the variability of diagnostic approach and management regarding prenatal hydronephrosis among maternal-fetal medicine obstetricians, pediatric urologists and pediatric radiologists.

MATERIALS AND METHODS

Online surveys were sent to mailing lists for national societies for each specialty. Participants were surveyed regarding criteria for diagnosing mild prenatal hydronephrosis and recommendations for postnatal management, including use of antibiotic prophylaxis, followup scheduling and type of followup imaging.

RESULTS

A total of 308 maternal-fetal medicine obstetricians, 126 pediatric urologists and 112 pediatric radiologists responded. Pediatric urologists and radiologists were divided between Society for Fetal Urology criteria and use of anteroposterior pelvic diameter for diagnosis, while maternal-fetal medicine obstetricians preferred using the latter. For postnatal evaluation radiologists preferred using personal criteria, while urologists preferred using anteroposterior pelvic diameter or Society for Fetal Urology grading system. There was wide variation in the use of antibiotic prophylaxis among pediatric urologists. Regarding the use of voiding cystourethrography/radionuclide cystography in patients with prenatal hydronephrosis, neither urologists nor radiologists were consistent in their recommendations. Finally, there was no agreement on length of followup for mild prenatal hydronephrosis.

CONCLUSIONS

We observed a lack of uniformity regarding grading criteria in diagnosing hydronephrosis prenatally and postnatally among maternal-fetal medicine obstetricians, pediatric urologists and pediatric radiologists. There was also a lack of agreement on the management of mild intermittent prenatal hydronephrosis, resulting in these cases being managed inconsistently. A unified set of guidelines for diagnosis, evaluation and management of mild intermittent prenatal hydronephrosis would allow more effective evaluation of outcomes.

Do infants with mild prenatal hydronephrosis benefit from screening for vesicoureteral reflux?

PURPOSE

Screening for vesicoureteral reflux in asymptomatic infants with low grade hydronephrosis is unjustified if this condition is benign. We present a cohort with prenatally detected hydronephrosis, some observed without voiding cystourethrography, and compare outcomes to a classic, screened group.

MATERIALS AND METHODS

A total of 206 consecutive children presenting with postnatally confirmed prenatally detected hydronephrosis (47% bilateral) were included in the study. Cases with associated renal or bladder anomalies were excluded. Children with low grade hydronephrosis either underwent screening voiding cystourethrography or did not, largely based on whether care was managed by a urologist or a nephrologist. Patients with high grade hydronephrosis routinely underwent voiding cystourethrography. Primary outcome was a symptomatic or febrile urinary tract infection. We used Mantel-Haenszel analysis to determine urinary tract infection risk factors during the first 2 years of life.

RESULTS

No urinary tract infection was observed in patients with grade I hydronephrosis. Urinary tract infections in low grade hydronephrosis were only seen in the voiding cystourethrogram group (7 patients), including 1 infection following voiding cystourethrogram. Urinary tract infection rate was 3.52 infections per 100 patient-years in children with low grade hydronephrosis and 11.1 infections per 100 patient-years in those with high grade hydronephrosis (p = 0.02). This increased risk of urinary tract infection in high grade hydronephrosis persisted after correcting for gender and circumcision status (IRR 3.17, p = 0.01). The association remained strong (IRR 2.48, 95% CI 0.96-6.44) but was not statistically significant (p = 0.053) after additionally correcting for vesicoureteral reflux status.

CONCLUSIONS

Our data suggest that children with low grade hydronephrosis and otherwise normal kidneys and bladder do not benefit from voiding cystourethrographic screening. Interestingly high grade hydronephrosis appears to carry a threefold greater risk of urinary tract infection compared to low grade hydronephrosis.

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.

The necessity of voiding cystourethrography in children with prenatally diagnosed hydronephrosis

The postnatal persistence of fetal hydronephrosis requires further evaluation to establish whether pathological abnormalities are present. This study determined the necessity for voiding cystourethrography (VCUG) to identify vesicoureteral reflux (VUR) in children (n = 195) with prenatally diagnosed hydronephrosis. Among the study population, the prevalence of VUR was 17.4% (24 males, 10 females). There was a poor correlation between the severity of hydronephrosis, ureteral dilatation, presence of bilateral hydronephrosis and presence of VUR. Except for the frequency of urinary tract infections and the presence of renal damage on (99m)Tc-dimercaptosuccinic acid scans, VCUG was the only reliable method for confirming VUR in this study. The diagnosis of VUR is important for the early detection of renal damage. Further information is needed to develop the optimal approach to the evaluation of prenatal hydronephrosis, with reliable parameters that avoid invasive procedures such as VCUG.

[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.

The Society for Fetal Urology consensus statement on the evaluation and management of antenatal hydronephrosis

The evaluation and management of fetuses/children with antenatal hydronephrosis (ANH) poses a significant dilemma for the practitioner. Which patients require evaluation, intervention or observation? Though the literature is quite extensive, it is plagued with bias and conflicting data, creating much confusion as to the optimal care of patients with ANH. In this article, we summarized the literature and proposed recommendations for the evaluation and management of ANH.

Vesicoureteral reflux and urinary tract infection in children with a history of prenatal hydronephrosis--should voiding cystourethrography be performed in cases of postnatally persistent grade II hydronephrosis?

PURPOSE

The clinical relevance of prenatal hydronephrosis is not well-defined. We determined the risk of febrile urinary tract infection in the absence of screening for vesicoureteral reflux, and whether postnatal voiding cystourethrography should be performed in patients with a history of prenatal hydronephrosis and postnatally persistent Society for Fetal Urology grade II hydronephrosis.

MATERIALS AND METHODS

From a longitudinal database of patients with prenatal hydronephrosis maintained since 1998 we identified those with postnatally persistent grade II hydronephrosis. This cohort was divided into patients who were and were not screened with an initial voiding cystourethrogram. The rates of vesicoureteral reflux and development of febrile urinary tract infection were determined.

RESULTS

Of 2,076 patients with prenatal hydronephrosis 1,514 had grade II hydronephrosis. Of the patients 76% underwent an initial voiding cystourethrogram and vesicoureteral reflux was found in 28%. There was no relation between laterality of hydronephrosis and incidence of vesicoureteral reflux. There was no difference between nonscreened and screened patients with respect to gender and laterality of hydronephrosis. Urinary tract infection developed in 1.3% of the patients who were screened and did not have vesicoureteral reflux and, therefore, were not receiving antibiotics. Of the screened patients with vesicoureteral reflux who were receiving prophylactic antibiotics urinary tract infection developed in 1.6% at a mean age of 9.4 months. In 363 patients who did not undergo an initial voiding cystourethrogram we estimated (based on the screened population) that 101 would have vesicoureteral reflux and 5 would have a urinary tract infection. However, a febrile urinary tract infection developed in 16 patients (4.4% overall, p <0.0001) at a mean age of 9.3 months. Voiding cystourethrogram performed in these 16 patients revealed vesicoureteral reflux in 12. Of all the patients with a urinary tract infection who were ultimately observed to have vesicoureteral reflux (including those initially screened and those discovered to have reflux after a urinary tract infection) the laterality of hydronephrosis, grade of reflux and laterality of reflux were comparable.

CONCLUSIONS

In patients with a history of prenatal hydronephrosis who are observed to have postnatally persistent grade II hydronephrosis identification of vesicoureteral reflux and use of prophylactic antibiotics significantly reduce the risk of febrile urinary tract infection. Therefore, we recommend that patients with a history of prenatal hydronephrosis and postnatally persistent hydronephrosis be screened with voiding cystourethrography early in life, and be placed on prophylactic antibiotics until the screening results are known.

Antenatal hydronephrosis: infants with minor postnatal dilatation do not need prophylaxis

The aim of this study was to determine the occurrence of urinary tract infection (UTI) in infants with antenatal renal pelvis dilatation (ARPD). Consecutive ultrasound (US) screening of 14,000 pregnant women detected ARPD >or=5 mm in 106 foetuses. After birth, two US examinations were performed: on the fifth to seventh day and during the third week of life. The findings were considered normal when renal pelvis dilatation (RPD) was <or=7 mm on both examinations and no other signs of abnormality were present. Voiding cystourethrography (VCUG) was done in all infants 6-8 weeks after birth. One hundred and three infants were followed for 2 years. Antibacterial prophylaxis (trimethoprim 1 mg/kg per day) was given to those with RPD >or=15 mm, vesicoureteric reflux (VUR) grades III-V and suspected obstruction. In 53/103 babies, both US examinations were normal, three had VUR grade I. Two girls had UTI at 18 and 24 months of age, respectively. Among the 50 infants with abnormal initial US, six had VUR, of which four were high grade (IV-V). All four developed UTI. We conclude that UTI is uncommon in infants with two normal postnatal US examinations. Routine use of antibacterial prophylaxis in these infants therefore cannot be recommended.

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.

Antenatal hydronephrosis and the risk of pyelonephritis hospitalization during the first year of life

OBJECTIVES

To assess the risk of hospitalization for pyelonephritis within the first year of life among infants with and without antenatal hydronephrosis.

METHODS

A retrospective cohort analysis was performed using linked birth-hospital discharge records from Washington State for 1987 to 2002 to evaluate the risk of hospitalization in the first year of life for pyelonephritis among infants with and without hydronephrosis. Eligible infants had mothers who had prenatal ultrasound screening. A total of 522 singleton infants with antenatal hydronephrosis (International Classification of Diseases, Ninth Revision code 753.2) at the birth hospitalization were identified. For comparison, 2610 singletons without hydronephrosis were selected. We screened hospital discharge records for 1 year after delivery to identify hospitalizations for pyelonephritis and estimate the relative risk (RR) among infants with and without hydronephrosis.

RESULTS

Five percent of infants with antenatal hydronephrosis and 1% of those without had pyelonephritis-related hospitalizations in their first year (RR 11.8, 95% confidence interval [CI] 6.8 to 20.5). Among girls the RR was 36.3 (95% CI 10.6 to 124.0); among boys it was 5.3 (95% CI 2.2 to 13.1). In infants with hydronephrosis, girls were more likely to be hospitalized with pyelonephritis (odds ratio 2.9, 95% CI 1.2 to 6.9).

CONCLUSIONS

Infants with antenatal hydronephrosis are nearly 12 times more likely to have pyelonephritis-related hospitalizations in the first year of life. This association is stronger in girls. Parents and healthcare providers of infants with this diagnosis should be vigilant for the signs and symptoms of urinary tract infections.

Current diagnosis and management of fetal genitourinary abnormalities

Prenatal assessment with ultrasonography provides excellent imaging of fluid-filled structures (eg, hydronephrosis, renal cysts, and dilated bladder) and renal parenchyma. This information allows for the generation of a differential diagnosis, identification of associated anomalies, and assessment of the prenatal and postnatal risks of a given anomaly. This enhances parental education and prenatal and postnatal planning. This article discusses the current methods of diagnosis and management of fetal genitourinary anomalies, and also the postnatal evaluation and treatment of these conditions.

Antenatal renal pelvic dilatation; the long-term outlook

AIM

The purpose of this study was twofold: first to provide data for more accurate counselling of parents with regard to prognosis, and second, to ensure that by following a policy of selective micturating cystourethography (MCUG), significant pathology is not missed, in particular vesicoureteric reflux (VUR). (MCUG is only undertaken if the renal pelvic diameter (RPD) is >/= 10 mm or if there is calyceal or ureteric dilatation.)

MATERIAL AND METHODS

Data were collected prospectively over a 6-year period. Pre and postnatal imaging findings were collected for all infants in whom a RPD of >/= 5 mm was identified at any gestational age. The imaging records of all patients were reviewed in 2005 for evidence of pathology detected after re-presentation with symptoms. The age range at review varied from 2-8 years.

RESULTS

Complete data were available in 527 infants. The risk of significant pathology was related to the degree of antenatal renal pelvic dilatation varying from 6% for a RPD of 5 mm at 20 weeks gestation to 38% at 10 mm. At 28-33 weeks gestation the risk varied from 5% at 5mm to 15% at 10 mm. Subsequent imaging record review revealed only one patient with grade II VUR in the study population not picked up by our selective MCUG policy.

CONCLUSION

The present study provides prognostic information that can be given to parents both antenatally and postnatally, and reassurance that a selective MCUG policy is appropriate.

The magnitude of fetal renal pelvic dilatation can identify obstructive postnatal hydronephrosis, and direct postnatal evaluation and management

PURPOSE

Up to 1% of prenatal ultrasounds will detect fetal renal pelvic dilatation. We sought to evaluate and determine whether fetal renal pelvic measurements may appropriately direct prenatal counseling and postnatal evaluation and management.

MATERIALS AND METHODS

We performed a retrospective analysis of prospectively collected measurements of anteroposterior renal pelvic dilatation obtained at a single fetal maternal medicine center between 1990 and 2003. Fetuses with renal pelvic dilatation 4 mm or greater at less than 33 weeks of gestation, or 7 mm or greater at more than 33 weeks of gestation were evaluated postnatally at a single pediatric urology center. Infants with renal pelvic dilatation were evaluated with ultrasound, voiding cystourethrograms and renal scintigraphy. Renal obstruction was the main outcome measure assessed. Obstruction was defined as the need for surgery and was not based on the renal scan drainage time. Indications for surgery included declining function and increasing hydronephrosis.

RESULTS

There were 257 neonates with prenatally detected renal pelvic dilatation. A mean maximum prenatal renal pelvic dilatation of 11.8 mm was seen in 195 patients with nonobstructive dilatation. In the 62 patients with obstruction there was a nearly 2-fold increase in the mean renal pelvic dilatation (22.3 mm), which was statistically significant. Receiver operating characteristic analysis revealed that when 15 mm renal pelvic dilatation is used as a threshold it correctly discriminates obstruction in at least 80% of fetuses with a sensitivity of 73% and a specificity of 82%.

CONCLUSIONS

The magnitude of fetal renal pelvic dilatation is predictive of obstruction. Our results suggest that 15 mm renal pelvic dilatation represents a significant threshold. Receiver operating characteristic analysis provides a useful guide for prenatal counseling and may help to direct the postnatal evaluation.

Prenatal hydronephrosis

Hydronephrosis is the most common genitourinary tract anomaly identified on prenatal ultrasound studies. Ureteropelvic junction obstruction accounts for approximately 50% of the cases of prenatally detected hydronephrosis. Postnatal evaluation allows for the identification of the cause and further management. Rarely, in utero intervention may be performed for severe oligohydramnios associated with hydronephrosis. Prenatal consultation with a pediatric urologist is useful in decreasing parental anxiety and facilitating postnatal management.

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.

Primary vesicoureteral reflux detected in neonates with a history of fetal renal pelvis dilatation: a prospective clinical and imaging study

OBJECTIVE

To assess the clinical outcome and imaging features of neonatal primary vesicoureteral reflux (VUR).

STUDY DESIGN

We prospectively followed 43 infants with primary VUR identified from among a cohort of 497 infants with fetal renal pelvis dilatation. Postnatal renal ultrasound (US) examinations were performed at 5 days and 1, 3, 6, 12, and 24 months of life. Voiding cystourethrography was performed in the neonatal period and repeated at 12 and 24 months when VUR was persistent. Two radioisotopic examinations, including a 99mTc-MAG3 renogram and a plasma clearance of Cr-51 EDTA, were performed in all children with high-grade reflux.

RESULTS

The incidence of primary VUR in our study group was 9%. Among the 43 patients followed, 11 (26%) had high-grade (IV-V) VUR and 32 (74%) had low-grade VUR. Resolution of reflux occurred in 2 of 11 (18%) patients with high-grade VUR and in 29 of 32 (90.6%) patients with low-grade VUR at age 2 years (P < .001). At age 2 years, 91% of the low-grade refluxing kidneys were normal on US, compared with only 35% of the high-grade refluxing kidneys. Split renal function was within normal range and single-kidney GFR was significantly increased in 13 of the 17 high-grade refluxing kidneys during follow-up. Furthermore, a strong association between dysplasia on US and poor renal function outcome was found.

CONCLUSIONS

In most infants with VUR, the reflux is of low grade and resolves rapidly. In those children with high-grade VUR, spontaneous resolution is rare at age 2 years, but persistent reflux rarely impairs the maturation of renal function.

Mild renal pyelectasis in the second trimester: determination of cut-off levels for postnatal referral

OBJECTIVE

To establish guidelines for postnatal referral of fetuses presenting with mild pyelectasis in the second trimester of pregnancy.

METHODS

In a retrospective study, 87 fetuses with a renal pelvis anteroposterior (RPAP) diameter of > or = 4 mm and < or = 10 mm before 28 weeks of gestation were included. All patients had a third-trimester scan and fetuses with an RPAP diameter of > or = 10 mm at that stage were referred for postnatal assessment. The family practitioner of all infants with an RPAP of < 10 mm in the third trimester was contacted for follow-up information. The RPAP diameter most predictive of renal pathology was determined with receiver-operating characteristics (ROC) curve analysis for both the first and second scans.

RESULTS

In 36 of 87 infants, 49 abnormal kidneys were diagnosed. Seven infants required surgery on eight renal tracts. The ROC curves of the first scan, second scan and differences between scans resulted in an area under the curve of 0.60, 0.87 and 0.85, respectively. The sensitivities and specificities for a cut-off level of 8, 9 and 10 mm at the second scan were 80%, 71% and 61% and 79%, 90% and 93%, respectively. At a cut-off level of 10 mm, only cases of insignificant minimal dilatation and a case of vesicoureteric reflux (VUR) requiring surgery were not detected.

CONCLUSION

After establishing a diagnosis of mild pyelectasis before 28 weeks, a second scan is mandatory to determine which infants need postnatal evaluation. A cut-off level of 8 mm has a low specificity but includes most cases of pathology. A cut-off level of 10 mm detects most significant pathology; however, VUR may not be detected.

[Neonatal pelvic ectasia: long-term outcome and association with ureterovesical anomalies]

OBJECTIVE

To analyze the outcome of neonatal pelvic ectasia (PE) and the association between this entity and vesicoureteral reflux and/or other urinary tract abnormalities.

PATIENTS AND METHODS

We performed a retrospective study of 255 children (205 boys, 50 girls) with an ultrasonographic diagnosis of PE in the first month of life. The initial ultrasonographic examination was indicated by urinary tract infection in 30 neonates, abnormalities in the prenatal ultrasonographic examination in 150 and by other reasons in 75. Pelvic ectasia was classified in four stages according to anteroposterior pelvic diameter: I < 1 cm, II 1-1.5 cm, III 1.6-2 cm, and IV > 2 cm.

RESULTS

Pelvic ectasia was bilateral in 153 children (60 %) and unilateral in 102 (left side in 81.4 % and right side in 18.6 %). Stage I was found in 75.49 %, stage II in 20.34 %, stage III in 3.9 % and stage IV in 0.24 %. The mean follow-up was 32.6 +/- 25.2 months. At the end of the first year, the results of renal ultrasound were normal in 70.2 % of left-sided PE and in 55.9 % of right-sided PE, but 46 patients (18 %) showed worsening of PE between the first and second ultrasound scans. Voiding cystourethrography was performed in 79.6 % of the children and some abnormalities were found in 50 (24.6 %): urethral dilatations in two patients and vesicoureteral reflux in 48. No correlation was found between vesicoureteral reflux and the degree of ectasia (74 % had an anteroposterior diameter of < or = 1 cm). Urinary tract infection was present in 24.3 % of the children and 13 required surgery (eight pyeloplasties, four urethral reimplantations and two resections of type III urethral valves).

CONCLUSIONS

Neonatal PE was more prevalent in boys (4:1) and was more frequently located on the left side in both sexes. Associated vesicourethral reflux was found in 23.64 % with no correlation between the degree of dilation and the presence or degree of reflux. Consequently, cystourethrography should be performed in any child with pelvic ectasia, regardless of stage, side or sex.

Diagnostic accuracy of fetal renal pelvis anteroposterior diameter as a predictor of uropathy: a prospective study

OBJECTIVE

The purpose of this study was to assess the accuracy of prenatal ultrasound measurement of anteroposterior renal pelvis diameter (APD) to discriminate between significant uropathy and idiopathic renal pelvis dilatation.

METHODS

One-hundred-and-three neonates who were found to have fetal renal pelvis dilatation, defined as presence of an APD > or = 5 mm, underwent systematic investigation for uropathies and were prospectively followed. An ultrasound scan was performed after the first week of postnatal life and all infants underwent a voiding cystourethrogram. Neonates with an APD larger than 10 mm underwent renal scintigraphy. Ultrasound scans, clinical examination and laboratory reviews were scheduled at 6-month intervals. Receiver-operating characteristics (ROC) curves were constructed to determine the best cut-offs for APD to identify renal units with significant uropathy as well as those requiring surgical intervention. Significant uropathy was defined as the presence of well-established urinary tract abnormalities or when there was abnormal renal scintigraphy.

RESULTS

The estimated area under the curve for APD was 0.900 (95% CI, 0.841-0.942) indicating excellent power to discriminate between idiopathic pelvis dilatation and significant uropathy. The sensitivity and specificity for the 7.5 mm cut-off point were 97.9% and 40.6%, respectively. To identify infants who required surgical intervention, the calculated area under the curve was 0.953 (95% CI, 0.908-0.980).

CONCLUSION

Our results suggest that measurement of APD is an excellent test to identify fetuses with significant uropathy, as well as those requiring postnatal intervention.

A 5-year audit of 778 neonatal renal scans (Part 1): Perplexing pyelectasis and suggested protocol for investigation

In this 5-year review of 778 neonatal renal scans seen in an Obstetric Hospital, most infants were referred because of antenatal ultrasound findings, 92% with fetal pyelectasis. The results were classified according to the ultrasound findings. The majority of neonates (76%) had a normal postnatal scan. A number had vesicoureteric reflux (VUR) found on a micturating cystourethrogram. Persistant mild to moderate pyelectasis or hydronephrosis (15%) proved to be a normal variant in many infants, but had a similar appearance to those with an early obstructive cause (1%). Pyelectasis has proved to be a poor predictor of VUR. A protocol outlining paediatric management for neonates with persisting pyelectasis is included. There were 59 infants (8%) with a miscellaneous group of renal anomalies, many with a characteristic antenatal ultrasound appearance suggesting the diagnosis. These infants have been separately reported and illustrated (Part 2). Overall, 13% of infants were found to have significant findings of obstruction, VUR or miscellaneous anomalies affecting management.

Isolated minimal renal pelvic dilatation detected antenatally in a non-tertiary setting is an uncommon predictor of significant vesicoureteric reflux

OBJECTIVES

To study in a non-tertiary centre the prevalence and grade of vesicoureteric reflux detected postnatally in infants already identified antenatally with isolated minimal renal pelvic dilatation.

METHODS

Retrospective review over the years 1998-2000 inclusive of a central computerized database in the single paediatric practice within Albury Wodonga.

RESULTS

Ninety-three (65 male) infants detected antenatally with isolated renal pelvic dilatation (>or=3 mm at 18 weeks gestation, >or=5 mm at 32 weeks gestation,<10 mm dilatation at any gestation) had a Micturating Cystourethrogram result. Thirteen infants (seven male) had vesicoureteric reflux detected, with a total of 18 refluxing renal units. Of these 13 infants five had bilateral vesicoureteric reflux (two male), and eight had unilateral vesicoureteric reflux. The median reflux grade was 2.0, with significant vesicoureteric reflux (greater than grade II) occurring in 5.4% (5/93).

CONCLUSIONS

Significant vesicoureteric reflux (greater than grade II) occurred in only 5.4% (5/93) of infants. It is concluded that isolated minimal renal pelvic dilatation detected antenatally is a poor screening test for clinically significant vesicoureteric reflux.

Antenatal Hydronephrosis: Negative Predictive Value of Normal Postnatal Ultrasound—a 5-year Study

AIM

To determine whether normal postnatal ultrasound, as part of a strict screening protocol for the detection and follow-up of antenatal hydronephrosis, effectively excludes the majority of babies with congenital urinary tract abnormalities that would otherwise present with a urinary tract infection.

MATERIALS AND METHODS

We retrospectively reviewed all babies who had postnatal follow-up of antenatally detected hydronephrosis over a 5-year period at our institution, a district general Trust with a specialist paediatric unit. We then studied all babies presenting with urinary tract infection before their first birthday to our institution over the same period. By cross-referencing these two study groups we were able to determine which babies developed a urinary tract infection having been previously discharged after normal postnatal ultrasound.

RESULTS

Four hundred and twenty-five babies had postnatal follow-up of antenatal hydronephrosis. Of these, 284 were investigated with ultrasound alone. In the same 5-year period, 230 babies presented with urinary tract infection before their first birthday. Only three of these babies had been previously discharged after normal postnatal ultrasound. The negative predictive value of a normal postnatal ultrasound was therefore 98.9% (281/284) for babies who subsequently presented with a urinary tract infection before their first birthday.

CONCLUSION

Careful antenatal and postnatal ultrasound with strict protocols is effective in detecting congenital renal tract abnormalities. Infants discharged after normal postnatal ultrasound are highly unlikely to still have an undetected urinary tract abnormality. We suggest that all babies with antenatal hydronephrosis are started on prophylactic antibiotics at birth, pending further investigation. All babies without features of severe obstruction antenatally should have their postnatal ultrasound delayed for a month. We recommend selective use of micturating cystourethrogram (MCUG), and delaying this investigation until the baby is 3 to 4 months old to allow for spontaneous resolution of vesicoureteric reflux. We do not believe that all babies with antenatal hydronephrosis require MCUG, providing a clear protocol is followed.

Antenatal hydronephrosis: evaluation and outcome

We present a comprehensive and current review of the etiology, evaluation, treatment, and outcome of antenatal hydronephrosis. When a diagnosis of antenatal hydronephrosis is made, many questions regarding pregnancy, prenatal care, intervention, and what may be expected after birth are raised. Debate and controversy exist on the diagnosis and subsequent evaluation and management of the child with antenatal hydronephrosis. A review of the literature and our own experience with antenatal hydronephrosis are presented in order to guide the physician who is caring for mother and child.