Familial Vesicoureteral Reflux—Is Screening Beneficial?

Primary vesicoureteral reflux

Primary vesicoureteral reflux (VUR) is one of the most common urological abnormalities in infants and children. The association of VUR, urinary tract infection (UTI) and renal parenchymal damage is well established. The most serious complications of VUR-associated reflux nephropathy are hypertension and proteinuria with chronic kidney disease. Over the past two decades, our understanding of the natural history of VUR has improved, which has helped to identify patients at increased risk of both VUR and VUR-associated renal injury. The main goals in the treatment of paediatric patients with VUR are the prevention of recurrent UTIs and minimizing the risk of renal scarring and long-term renal impairment. Currently, there are four options for managing primary VUR in infants and children: surveillance or intermittent treatment of UTIs with management of bladder and bowel dysfunction; continuous antibiotic prophylaxis; endoscopic subureteral injection of tissue-augmenting substances; and ureteral reimplantation via open, laparoscopic or robotic-assisted surgery. Current debates regarding key aspects of management include when to perform diagnostic imaging and how to best identify the paediatric patients that will benefit from continuous antibiotic prophylaxis or surgical intervention, including endoscopic injection therapy and minimally invasive ureteral reimplantation. Evolving technologies, such as artificial intelligence, have the potential to assist clinicians in the decision-making process and in the individualization of diagnostic imaging and treatment of infants and children with VUR in the future.

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.

A successful centre for translational paediatric surgical research

The National Children's Research Centre (NCRC), the single largest paediatric research centre in Ireland, has been in existence for over 50 years and is located on the grounds of the largest children's hospital in Ireland; Children's Health Ireland at Crumlin. Professor Puri was appointed as the Director of the Research in 1989 and became President of the NCRC in 2009, a position he held until 2016. Professor Puri is one of the most cited paediatric surgical researchers in the world. His research work has been cited over 23,500 times in peer-reviewed articles with an h-index of 76 and i10-index of 494. The aim of this review is to analyse the most relevant areas of academic research at the NCRC, Dublin, during the years when Prof. Puri was Director/President of the NCRC. In addition, the relevant factors essential to create a successful paediatric surgical research centre will be discussed. A literature search using PubMed/Medline was carried out using the search terms "Prem Puri" over a 40-year period (1980-2020). Articles were analysed to identify the most significant research areas in the field of paediatric surgical research and the relevant laboratory and clinical findings. In addition, a separate analysis of successful funding and human factors, such as research fellows working at the NCRC, was also carried out. During the period under review, Professor Puri's team published 750 articles in peer-reviewed journals. Three main areas of research were reviewed with a total number of 391 articles: congenital diaphragmatic hernia (CDH) was the topic with the largest number of publications (153), followed by Hirschsprung's disease (HSCR) (144) and Vesicoureteral reflux (VUR) (94). Eighty research fellows, all paediatric surgeons, from 18 different countries were trained in basic science under the supervision of Professor Puri at the NCRC. Over the last three decades, the NCRC has been one of the most successful centres for paediatric surgical research in the world. The three areas of research with the largest number of publications were identified as CDH, HSCR and VUR. Various factors can explain the success of the NCRC: (a) the constant presence, for over 30 years, of a very successful paediatric surgeon leading the centre, (b) a multicultural laboratory with research fellows from all over the world and (c) grants of more than 15 million raised over the years, which guaranteed a constant flow of resources for laboratory research.

Incidence of Urinary Tract Infection Among Siblings of Children With Vesicoureteral Reflux

BACKGROUND

Siblings of children with vesicoureteral reflux (VUR) are at elevated risk of VUR. Screening siblings may identify VUR before a clinical illness such as a urinary tract infection (UTI), but the benefit of screening has not been demonstrated. We sought to determine the incidence of UTI among siblings, and we hypothesized that the sibling UTI rate is similar between screened and unscreened siblings.

METHODS

We performed a retrospective cohort analysis using insurance claims data (January 1, 2000, to December 31, 2009). Within each family, we identified the index VUR patient and siblings; we included siblings who were enrolled in the insurance plan from birth for at least 1 year. We identified siblings who were screened for VUR and/or had UTI. We investigated the association of screening and UTI, controlling for patient characteristics and clustering within families.

RESULTS

Among 617 siblings (associated with 497 index patients), 317 (51%) were girls. Median insurance enrollment time was 53.0 months, with 424 enrolled ≥3 years. Among those with 1 or 3 years of enrollment, the proportions of siblings who experienced UTI was 8.4% (52 of 617) and 10.4% (44 of 424), respectively. Median age at initial UTI was 32.7 months. A total of 223 siblings (36.0%) underwent sibling screening. There was no significant difference in UTI between screened and unscreened siblings (odds ratio 1.57, 95% confidence interval 0.87-2.85; P = .14). In multivariate analysis, screening was not associated with sibling UTI incidence (odds ratio 1.33, 95% confidence interval 0.68-2.60; P = .40).

CONCLUSIONS

Although UTI is relatively common among siblings of VUR patients, there was no statistically significant difference in UTI incidence between screened and unscreened siblings.

Developmental Genetics and Congenital Anomalies of the Kidney and Urinary Tract

Congenital anomalies of the kidney and urinary tract (CAKUT) are common birth defects and the leading cause of end-stage renal disease in children. There is a wide spectrum of renal abnormalities, from mild hydronephrosis to more severe cases, such as bilateral renal dysplasia. The etiology of the majority of cases of CAKUT remains unknown, but there is increasing evidence that genomic imbalance contributes to the pathogenesis of CAKUT. Advances in human and mouse genetics have contributed to increased understanding of the pathophysiology of CAKUT. Mutations in genes involved in both transcription factors and signal transduction pathways involved in renal development are associated with CAKUT. Large cohort studies suggest that copy number variants, genomic, or de novo mutations may explain up to one-third of all cases of CAKUT. One of the major challenges to the use of genetic information in the clinical setting remains the lack of strict genotype-phenotype correlation. However, identifying genetic causes of CAKUT may lead to improved diagnosis of extrarenal complications. With the advent of decreasing costs for whole genome and exome sequencing, future studies focused on genotype-phenotype correlations, gene modifiers, and animal models of gene mutations will be needed to translate genetic advances into improved clinical care.

A new genome scan for primary nonsyndromic vesicoureteric reflux emphasizes high genetic heterogeneity and shows linkage and association with various genes already implicated in urinary tract development

Primary vesicoureteric reflux (VUR), the retrograde flow of urine from the bladder toward the kidneys, results from a developmental anomaly of the vesicoureteric valve mechanism, and is often associated with other urinary tract anomalies. It is the most common urological problem in children, with an estimated prevalence of 1–2%, and is a major cause of hypertension in childhood and of renal failure in childhood or adult life. We present the results of a genetic linkage and association scan using 900,000 markers. Our linkage results show a large number of suggestive linkage peaks, with different results in two groups of families, suggesting that VUR is even more genetically heterogeneous than previously imagined. The only marker achieving P < 0.02 for linkage in both groups of families is 270 kb from EMX2. In three sibships, we found recessive linkage to KHDRBS3, previously reported in a Somali family. In another family we discovered sex-reversal associated with VUR, implicating PRKX, for which there was weak support for dominant linkage in the overall data set. Several other candidate genes are suggested by our linkage or association results, and four of our linkage peaks are within copy-number variants recently found to be associated with renal hypodysplasia. Undoubtedly there are many genes related to VUR. Our study gives support to some loci suggested by earlier studies as well as suggesting new ones, and provides numerous indications for further investigations.

[Primary vesicoureteral reflux]

The never ending discussion about the diagnostics and treatment of vesicoureteral reflux (VUR) now includes arguments for diagnostic nihilism as well as invasive diagnostics and therapy, which is reminiscent of the debate on prostate cancer in adulthood. The common goal of all currently competing diagnostic strategies and approaches is the prevention of renal scars by the most effective and least burdensome approach. There is a difference between acquired pyelonephritic scars with VUR (acquired reflux nephropathy) and congenital reflux nephropathy (primary dysplasia) which cannot be influenced by any therapy.The VUR can be verified by conventional radiological voiding cystourethrography (VCUG), by urosonography, radionuclide cystography or even by magnetic resonance imaging (MRI). The guidelines of the European Association of Urology/European Society for Paediatric Urology (EAU/ESPU) recommend radiological screening for VUR after the first febrile urinary tract infection. Significant risk factors in patients with VUR are recurrent urinary tract infections (UTI) and parenchymal scarring and the patients should undergo patient and risk-adapted therapy. Infants with dilating reflux have a higher risk of renal scarring than those without dilatation of the renal pelvis. Bladder dysfunction or dysfunctional elimination syndrome represents a well-known but previously neglected risk factor in combination with VUR and should be treated prior to any surgical intervention as far as is possible.Certainly not every patient with VUR needs therapy. The current treatment strategies take into account age and gender, the presence of dysplastic or pyelonephritic renal scars, the clinical symptoms, bladder dysfunction and frequency and severity of recurrent UTI as criteria for the therapy decision. The use of an antibacterial prophylaxis as well as the duration is controversially discussed. Endoscopic therapy can be a good alternative to antibacterial prophylaxis or a surveillance strategy in patients with low grade VUR. In patients with dilating VUR and given indications for surgery, endoscopic treatment can be offered. However, parents should be completely informed about the significantly lower success rate of endoscopic therapy compared to open surgical procedures. The open surgical techniques guarantee the highest success rates and should be used in patients with a dilating VUR and high risk of renal damage.

Familial vesicoureteral reflux and reflux related morbidity in relatives of index patients with high grade vesicoureteral reflux

PURPOSE

The familial nature of vesicoureteral reflux is well recognized. However, there is little information about the prevalence of vesicoureteral reflux and reflux related morbidity in the relatives of index patients with vesicoureteral reflux. Therefore, we determined the prevalence of vesicoureteral reflux and reflux related morbidity in first, second and third-degree relatives of index patients with high grade vesicoureteral reflux.

MATERIALS AND METHODS

Between 1998 and 2010 the parents of 259 index patients with grade III-V vesicoureteral reflux were asked permission to screen siblings younger than age 6 years for vesicoureteral reflux. Parents of index patients with affected siblings were contacted to obtain detailed information regarding vesicoureteral reflux, recurrent urinary tract infections, end stage renal disease, hypertension and nephrectomy among first, second and third-degree relatives.

RESULTS

A total of 300 siblings of the 259 index patients were found to have vesicoureteral reflux on voiding cystourethrography. In terms of the other relatives of the 259 index patients 127 also had radiologically proven vesicoureteral reflux. Reflux related morbidity among the first, second and third-degree relatives included end stage renal disease in 21, nephrectomy in 12 and hypertension in 4. Of the 212 siblings who had dimercapto-succinic acid scans 49 (23.1%) showed evidence of renal scarring. In 73% of the relatives vesicoureteral reflux was seen on the mother's side.

CONCLUSIONS

This study, the first to our knowledge, provides important information regarding reflux related morbidity in a large cohort of familial vesicoureteral reflux in first, second and third-degree relatives of index patients. Our data clearly show that there is an increased risk of reflux related morbidity among the relatives of index patients with vesicoureteral reflux and this finding has implications for counseling.

Genetics of vesicoureteral reflux

Primary vesicoureteral reflux (VUR) is the most common urological anomaly in children, affecting 1-2% of the pediatric population and 30-40% of children presenting with urinary tract infections (UTIs). Reflux-associated nephropathy is a major cause of childhood hypertension and chronic renal failure. The hereditary and familial nature of VUR is well recognized and several studies have reported that siblings of children with VUR have a higher incidence of reflux than the general pediatric population. Familial clustering of VUR implies that genetic factors have an important role in its pathogenesis, but no single major locus or gene for VUR has yet been identified and most researchers now acknowledge that VUR is genetically heterogeneous. Improvements in genome-scan techniques and continuously increasing knowledge of the genetic basis of VUR should help us to further understand its pathogenesis.

Sibling vesicoureteral reflux in twins

AIM OF STUDY

Few studies have evaluated the incidence of familial vesicoureteral reflux (VUR) among multiple gestation births. The purpose of this study was to determine the incidence and characteristics of VUR in twins in a large cohort of families with VUR.

METHODS

Between 1998 and 2010, data were collected on 251 families (538 children) with at least 2 siblings who had VUR. The incidence of affected twins among the families was analysed. Data were assessed for age at presentation, gender, grading of VUR, laterality of affectation and renal scarring. VUR was diagnosed by voiding cystourethrography (VCUG) and dimercaptosuccinic acid (DMSA) scans were used to assess renal scarring.

RESULTS

There were 12 families (4.8%) in which twins were affected with VUR. There were 12 index cases (7 males/5 females), and 12 siblings (1 male/11 females). All index cases presented with urinary tract infection (UTIs), whereas 2 siblings had UTIs and 10 were screened. All cases presented between 3 months and 2 years. Among the index cases, three had unilateral and nine had bilateral VUR. Among the siblings, four had unilateral and eight had bilateral VUR. Thirty-seven (90%) of the 41 affected renal refluxing units had high-grade VUR. Three index cases had renal scarring. No scarring was seen in the siblings.

CONCLUSIONS

The vast majority of twins with VUR are females who have high grade VUR and a low incidence of renal scarring. Twins with VUR may represent a genetically different subgroup with female preponderance and severe reflux.