Antibiotic prophylaxis for prevention of urinary tract infections in prenatal hydronephrosis: An updated systematic review

Swiss Consensus on Prenatal and Early Postnatal Urinary Tract Dilation: Practical Approach and When to Refer

Urinary tract dilations (UTDs) are the most frequent prenatal renal anomaly. The spectrum of etiologies causing UTD ranges from mild spontaneously resolving obstruction to severe upper and lower urinary tract obstruction or reflux. The early recognition and management of these anomalies allows for improved renal endowment prenatally and ultimately better outcome for the child. The role of the general obstetrician and pediatrician is to recognize potential prenatal and postnatal cases addressed to their practice and to refer patients to specialized pediatric nephrology and urology centers with a sense of the urgency of such a referral. The aim of this paper is to offer clinical recommendations to clinicians regarding the management of neonates and children born with prenatally detected UTD, based on a consensus between Swiss pediatric nephrology centers. The aim is to give suggestions and recommendations based on the currently available literature regarding classifications and definitions of prenatal and postnatal UTD, etiologies, prenatal and postnatal renal function evaluation, investigations, antibiotic prophylaxis, and the need for referral to a pediatric nephrologist and/or urologist. The overarching goal of a systematic approach to UTD is to ultimately optimize kidney health during childhood and improve long-term renal function prognosis.

Impact of antibiotic prophylaxis on urinary tract infection recurrence in children Rapid review

INTRODUCTION

Given the potential consequences associated with urinary tract infections (UTIs), it has become standard practice to use continuous antibiotic prophylaxis (CAP) in children, even if controversial. We reviewed the effectiveness of CAP on recurrent UTI in a pediatric population to determine if equipoise remains and allows for a placebo control group to study the effectiveness of the vaccine MV140.

METHODS

We completed a rapid review. We searched Medline, Embase and the Cochrane Library and data extraction was completed by a single reviewer. Our search criteria were 2005-2022, English and French language, randomized controlled trials (RCTs) and systematic reviews only. The population was 19 years and younger, including: vesicoureteral reflux (VUR), congenital anomalies of the kidneys and urinary tracts (CAKUT), and bladder and bowel dysfunction (BBD).

RESULTS

Three RCTs and three systematic reviews found a benefit for CAP, mostly for a population with VUR, and those with severe VUR have more benefit. Most studies were not able to show a difference in the rate of UTIs or new renal scars (NRS). Three RCTs found a deleterious effect with CAP. Other studies were able to prove a benefit for patients with dilatation of the urinary tract without obstruction and high-grade VUR combined with BBD. The major adverse event found was antimicrobial resistance.

CONCLUSIONS

High-risk patients benefit from CAP. The potential consequences of UTIs makes it unethical to use a placebo-only control group for them; however, CAP use seems difficult to justify in a low-risk population.

Isolated Hydronephrosis and Urinary Tract Infection by Two Years of Age: A Population-Based Study

OBJECTIVE

To evaluate the risk for urinary tract infection (UTI) in infants with isolated hydronephrosis (IH).

STUDY DESIGN

A retrospective, population-based study including all infants insured by Clalit Health Services and followed from birth to age 2 years in 3 regions of central Israel. Infants were divided into 3 groups based on electronic medical record diagnoses by age 6 months: (1) control: no urological diagnosis; (2) IH; and (3) complicated urological diagnosis (CUD): any additional nephrological/urological diagnosis with/without HN. The primary outcome was a diagnosis of UTI in the first 2 years of life.

RESULTS

The cohort included 340 619 infants (52% male): 333 920 controls, 4369 with IH, and 2331 with CUD. Infants with IH were associated with a greater risk for UTI than control patients (17% vs 4%, P < .001). UTI risk for a male infant with IH was greater than for a female infant in the control group (12.6% vs 6.5%, P < .001). In a multivariable logistic regression analysis, both IH (OR 7.04; 95% CI 6.46-7.66) and CUD (OR 14.9; 95% CI 13.6-16.4) were independently associated with UTI.

CONCLUSION

Infants with IH are at a greater risk for UTI in the first 2 years of life, supporting the recommendation for a high index of suspicion for UTI in this population.

Evidence-based clinical practice guideline for management of urinary tract infection and primary vesicoureteric reflux

We present updated, evidence-based clinical practice guidelines from the Indian Society of Pediatric Nephrology (ISPN) for the management of urinary tract infection (UTI) and primary vesicoureteric reflux (VUR) in children. These guidelines conform to international standards; Institute of Medicine and AGREE checklists were used to ensure transparency, rigor, and thoroughness in the guideline development. In view of the robust methodology, these guidelines are applicable globally for the management of UTI and VUR. Seventeen recommendations and 18 clinical practice points have been formulated. Some of the key recommendations and practice points are as follows. Urine culture with > 104 colony forming units/mL is considered significant for the diagnosis of UTI in an infant if the clinical suspicion is strong. Urine leukocyte esterase and nitrite can be used as an alternative screening test to urine microscopy in a child with suspected UTI. Acute pyelonephritis can be treated with oral antibiotics in a non-toxic infant for 7-10 days. An acute-phase DMSA scan is not recommended in the evaluation of UTI. Micturating cystourethrography (MCU) is indicated in children with recurrent UTI, abnormal kidney ultrasound, and in patients below 2 years of age with non-E. coli UTI. Dimercaptosuccinic acid scan (DMSA scan) is indicated only in children with recurrent UTI and high-grade (3-5) VUR. Antibiotic prophylaxis is not indicated in children with a normal urinary tract after UTI. Prophylaxis is recommended to prevent UTI in children with bladder bowel dysfunction (BBD) and those with high-grade VUR. In children with VUR, prophylaxis should be stopped if the child is toilet trained, free of BBD, and has not had a UTI in the last 1 year. Surgical intervention in high-grade VUR can be considered for parental preference over antibiotic prophylaxis or in children developing recurrent breakthrough febrile UTIs on antibiotic prophylaxis.

The role of circumcision in preventing urinary tract infections in children with antenatal hydronephrosis: Systematic review and meta-analysis

INTRODUCTION

Circumcision has been reported to reduce the risk of urinary tract infections (UTIs) in boys with antenatal hydronephrosis (HN). Our aim was to compare the incidence of UTIs in circumcised vs. uncircumcised boys with antenatal HN by conducting a systematic review and meta-analysis.

STUDY DESIGN

A comprehensive search was performed until December 2022. Comparative studies were evaluated according to Cochrane collaboration recommendations. Assessed measures included: UTIs, continuous antibiotic prophylaxis (CAP) use, renal outcomes, and circumcision complications. Odds ratios (OR) and mean difference with 95% confidence interval (CI) were extrapolated from available data. Random-effects meta-analysis were performed.

RESULTS

Twenty-three studies describing 9093 boys with antenatal HN were identified, including 4677 uncircumcised and 4416 circumcised boys. Overall effect estimates demonstrate that circumcised boys have significantly reduced odds of developing any UTI [OR 0.26, 95%CI 0.21, 0.32; p < 0.001]]. In addition, there a significantly reduced odds of developing UTI when circumcised and on CAP [OR 0.19, 95% CI 0.13, 0.30; p < 0.001]. When stratifying by etiology, circumcision reduced the odds of UTI in boys with isolated HN [OR 0.33, 95% CI 0.16, 0.68; p = 0.003], vesicoureteral reflux [OR 0.23, 95% CI 0.13, 0.42; P < 0.00001], or with posterior urethral valves [OR 0.29, 95% CI 0.13, 0.64; p = 0.002].

DISCUSSION

Circumcision reduces the incidence of UTIs in boys with antenatal HN. This review is limited by the varied definitions of UTIs and inconsistent reporting on HN etiology, renal outcomes, and circumcision complications.

CONCLUSIONS

Circumcision should be considered in boys with antenatal HN to prevent the risk of developing UTI. Further research is warranted to individualize the prophylactic role of circumcision for patients with HN.

Fetal Renal Duplicated Collecting System at 14-16 Weeks of Gestation

(1) Background: To examine the incidence of the prenatal diagnosis of the renal double-collecting system (rDCS) and describe its clinical outcome and associated genetic abnormalities. (2) Methods: This retrospective study included women who attended the obstetric clinic for early fetal anatomic sonography with findings of a renal DCS. Diagnosis was conducted by an expert sonographer using defined criteria. (3) Results: In total, 29,268 women underwent early ultrasound anatomical screening at 14-16 weeks, and 383 cases of rDCS were diagnosed (prevalence: 1:76). Associated abnormalities were diagnosed in eleven pregnancies; four had chromosomal aberrations. No chromosomal abnormalities were reported in isolated cases. Ectopic uretrocele and dysplastic kidney were diagnosed in 6 (1.5%) and 5 (1.3%) fetuses, respectively. One girl was diagnosed with vesicoureteral reflux and recurrent UTIs, and two boys were diagnosed with undescended testis. The recurrence rate of rDCS was 8% in subsequent pregnancies. (4) Conclusions: In light of its benign nature, we speculate that isolated rDCS may be considered a benign anatomic variant, but a repeat examination in the third trimester is recommended to assess hydronephrosis.

Antenatally Diagnosed Kidney Anomalies

Congenital anomalies of the kidney and urinary tract encompass a broad spectrum of developmental conditions that together account for the majority of childhood chronic kidney diseases. Kidney abnormalities are the most commonly diagnosed congenital anomaly in children, and detection of this anomaly is increasing as a result of improved antenatal care and widespread access to more sensitive screening ultrasonography. Most paediatricians will encounter children with congenital kidney anomalies across a wide spectrum of disorders, and a broad understanding of the classification, investigation, and basis of management is important to appropriately direct their care.

Continuous antibiotic prophylaxis in isolated prenatal hydronephrosis

BACKGROUND

Prenatal hydronephrosis (PNH) is one of the most common congenital anomalies and can increase the risk of developing a urinary tract infection (UTI) in the first two years of life. Continuous antibiotic prophylaxis (CAP) has been recommended empirically to prevent UTI in children with PNH, but its use has been controversial.

OBJECTIVE

We describe the incidence of UTI in children with isolated PNH of the renal pelvis without ureteral dilation. Our objective was to compare patients receiving and not receiving CAP and determine whether CAP is beneficial at preventing UTI in children with isolated PNH.

STUDY DESIGN

Children with confirmed PNH were enrolled between 2008 and 2020 into the Society for Fetal Urology Hydronephrosis Registry. Children with isolated dilation of the renal pelvis without ureteral or bladder abnormality were included. The primary outcome was development of a UTI, comparing patients who were prescribed and not prescribed CAP.

RESULTS

In this cohort of 801 children, 76% were male, and 35% had high grade hydronephrosis (SFU grades 3-4). CAP was prescribed in 34% of children. The UTI rate among all children with isolated PNH was 4.2%. Independent predictors of UTI were female sex (HR = 13, 95% CI: 3.8-40, p = 0.0001), intact prepuce (HR = 5.1, 95% CI: 1.4-18, p = 0.01) and high grade hydronephrosis (HR = 2.0, 95% CI: 0.99-4.0, p = 0.05; Table) on multivariable analysis. For patients on CAP, the UTI rate was 4.0% compared to 4.3% without CAP (p = 0.76). The risk of UTI during follow-up was not significantly different between patients who received CAP and patients who were not exposed to CAP; adjusting for sex, circumcision status and hydronephrosis grade (HR = 0.72, 95% CI: 0.34-1.5, p = 0.38). In sub-group analysis of patients at higher risk of UTI (uncircumcised males, females and high grade hydronephrosis), CAP use was not associated with a statistically significant reduction in UTI.

CONCLUSIONS

The overall UTI rate in children with isolated PNH is very low at 4.2%. In the overall population of patients with isolated PNH, CAP was not associated with reduction in UTI risk, although the limitations in our study make characterizing CAP effectiveness difficult. Clinicians should consider risk factors prior to placing all patients with isolated PNH on CAP.

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.

Management of antenatal hydronephrosis

Antenatal hydronephrosis (AHN) is the most frequently detected abnormality by prenatal ultrasonography. Differential diagnosis of AHN includes a wide variety of congenital abnormalities of the kidney and urinary tract ranging from mild abnormalities such as transient or isolated AHN to more important ones as high-grade congenital vesicoureteral reflux or ureteropelvic junction obstruction. It is well known that the outcome depends on the underlying etiology. Various grading systems have been proposed for the classification of AHN on prenatal and postnatal ultrasonography. Mild isolated AHN represents up to 80% of cases, is considered to be benign, and majority of them resolve, stabilize, or improve during follow-up. Controversies exist regarding the diagnosis and management of some important and severe causes of AHN such as high-grade vesicoureteral reflux and ureteropelvic junction obstruction. Current approach is becoming increasingly conservative during diagnosis and follow-up of these patients with less imaging and close follow-up. However, there is still no consensus regarding the clinical significance, postnatal evaluation, and management of infants with AHN. The aim of this review is to discuss the controversies and provide an overview on the management of AHN.

Antenatally detected urinary tract dilatation: a 12-15-year follow-up

BACKGROUND

Antenatally diagnosed urinary tract dilatation (UTD) still burdens healthcare providers and parents. This study was conducted to establish long-term outcome in an unselected group of children with antenatally detected UTD.

METHODS

Seventy-one out of 103 children born in 2003-2005 and diagnosed with antenatal UTD agreed to participate in a 12-15-year follow-up including blood and urine samples, a kidney ultrasound exam, and kidney scintigraphy. The records were searched for previous urinary tract infections.

RESULTS

Among children with an anteroposterior diameter (APD) ≤ 7 mm and no calyceal, kidney, ureteral, or bladder pathology in the early postnatal period, no one tested had reduced estimated glomerular filtration rate (eGFR), albuminuria, or UTD at the follow-up at a mean age of 13.6 years. One child had kidney damage not affecting kidney function. Among children with postnatal APD > 7 mm and/or kidney, calyceal, ureteral, or bladder pathology, 15% had persistent UTD and 32-39% (depending on the method used) had kidney damage. Major postnatal urinary tract ultrasound abnormalities and a congenital anomalies of the kidney and urinary tract (CAKUT) diagnosis were factors associated with an increased risk for permanent kidney damage (odds ratios 8.9, p = 0.016; and 14.0, p = 0.002, respectively). No one had reduced eGFR. One child (1/71, 1%) had a febrile urinary tract infection after the age of 2.

CONCLUSIONS

We conclude that in children with postnatal APD ≤ 7 mm, no calyceal dilatation, normal bladder, ureters, and kidney parenchyma, the outcome is excellent. There is no need for long-term follow-up in these patients.

Role of Antibiotic Prophylaxis in the Management of Antenatal Hydronephrosis, Vesicoureteral Reflux, and Ureterocele in Infants

Widespread prenatal screening has resulted in increased detection of anomalies of the kidneys and urinary tract. Antenatal hydronephrosis (AHN) and vesicoureteral reflux (VUR) are among the most common congenital anomalies diagnosed in utero or after birth. Pediatric urologists frequently rely on continuous antibiotic prophylaxis (CAP) for managing AHN, VUR, and ureterocele, unless definitive treatment is performed. The main aim of antibiotic prophylaxis (ABP) is to prevent urinary tract infection and long-term complications. Nevertheless, the efficacy of ABP has been a source of considerable debate, and pediatricians have varied opinions on who would benefit from ABP. In this review article, we searched the currently available literature, for evidence of the role of ABP in the setting of AHN, VUR, and ureterocele. Most of our studies showed a limited benefit of ABP for HN and VUR. The data on the use of CAP in the management of ureterocele is scarce. However, due to the involvement of independent risk factors and other variables, a conclusion cannot be drawn from these studies alone. Pediatric urologists are urged to conduct randomized controlled trials to compare patients followed up with and without ABP. Given the lack of guidelines, an individualized approach should be used for the use of ABP, until precise guidelines and recommendations are developed.

Frequency of urinary tract infection in children with antenatal diagnosis of urinary tract dilatation

BACKGROUND

Neonates with congenital urinary tract dilatation (UTD) may have an increased risk of urinary tract infections (UTI). At present, the management of these patients is controversial and the utility of continuous antibiotic prophylaxis (CAP) remains uncertain as the literature presents contradicting evidence. The aim of this observational study was to assess UTI occurrence in children with prenatal diagnosis of urinary collecting system dilatation without antibiotic prophylaxis.

METHODS

Between June 2012 and August 2016, we evaluated the incidence of UTI and the clinical and ultrasonography evolution in 407 children with a prenatally diagnosed UTD. All subjects underwent two prenatal ultrasounds scans (USs) at 20 weeks and 30 weeks of gestation and within 1 month of birth. Patients with a confirmed diagnosis of UTD underwent US follow-up at 6, 12 and 24 months of life. According to the UTD classification system stratify risk, after birth UTD were classified into three groups: UTD-P1 (low risk group), UTD-P2 (intermediate risk group), and UTD-P3 (high risk group). Voiding cystourethrogram was performed in all patients who presented a UTI and in those with UTD-P3. No patient underwent CAP.

RESULTS

Postnatal US confirmed UTD in 278 out of 428 patients with the following rates: UTD-P1 (126), UTD-P2 (95) and UTD-P3 (57). During postnatal follow-up, 6.83% patients presented a UTI (19 out of 278). Eleven out of 19 had vesicoureteral reflux (VUR), and other four were diagnosed with obstructive uropathy and underwent surgical correction. Five patients presented a UTI reinfection.

CONCLUSION

The occurrence of UTI in patients with urinary collecting system dilatation was low. The recent literature reports an increased selection of multirestistant germs in patients with VUR exposed to CAP. This study constitutes a strong hint that routine continuous antibiotic prophylaxis could be avoided in patients with UTD.

The role of antibiotic prophylaxis in mild to moderate isolated hydronephrosis detected in antenatal screening

Purpose

To determine whether continuous antibiotic prophylaxis (CAP) could prevent urinary tract infection (UTI) in mild to moderate antenatal isolated hydronephrosis (IH), characterized by hydronephrosis without ureter and bladder abnormalities, and anteroposterior renal pelvis diameter <16 mm and the Society for Fetal Urology grade <4, in neonatal renal ultrasound.

Materials and Methods

Eighty neonates aged 7 to 30 days, with antenatal hydronephrosis and mild to moderate IH on neonatal renal ultrasound, were recruited from August 2015 to December 2016. Neonates were randomly assigned to CAP until hydronephrosis resolution or aged 12 months (CAP group, n=40) or to watchful observation (control group, n=40). The primary outcome was UTI. The probability of UTI was compared between the randomized groups using the Kaplan-Meier method and the log-rank test.

Results

Nonadherence occurred in 6/40 parents in the CAP arm (15.0%). Thus, only 34 patients received CAP. UTI occurred in 5/34 patients in the CAP group (14.7%) and in 4/40 controls (10.0%). The probability of UTI was increased in the CAP group (hazard ratio, 1.38; 95% confidence interval, 0.37-5.16; p=0.63). UTI caused by cotrimoxazole resistant bacteria was four times higher in the CAP group than in controls (relative risk, 4.0; 95% confidence interval, 1.2-13.5; p=0.02). The trial was prematurely terminated due to the negative impact of CAP on bacterial sensitivity.

Conclusions

The benefits of CAP in infants with mild to moderate IH were inconclusive. CAP conferred a high risk of resistant bacterial organisms when UTI occurs.

Continuous Antibiotic Prophylaxis in Pediatric Urology

Continuous antibiotic prophylaxis (CAP) for urinary tract infection prevention in children with vesicoureteral reflux, hydronephrosis, and hydroureteronephrosis is reviewed. A more selective use of CAP is advocated based on a review of known individual risk factors in each of these conditions that subsequently helps identify the children most likely to benefit from CAP. Both short-term and potential long-term side effects of CAP are reviewed, including the impact of prophylactic antibiotics on bacterial resistance and the microbiome. Alternatives to continuous antibiotic prophylaxis including Vaccinium macrocarpon (Cranberry), probiotics, and vaccines are reviewed.