Renal Scarring in the Randomized Intervention for Children with Vesicoureteral Reflux (RIVUR) Trial

Investigation of a targeted panel of gut microbiome-derived toxins in children with chronic kidney disease

BACKGROUND

The gut-kidney axis is implicated in chronic kidney disease (CKD) morbidity. We describe how a panel of gut microbiome-derived toxins relates to kidney function and neurocognitive outcomes in children with CKD, consisting of indoleacetate, 3-indoxylsulfate, p-cresol glucuronide, p-cresol sulfate, and phenylacetylglutamine.

METHODS

The Chronic Kidney Disease in Children (CKiD) cohort is a North American multicenter prospective cohort that enrolled children aged 6 months to 16 years with estimated glomerular filtration rate (eGFR) 30-89 ml/min/1.73 m2. Data from the 2-year study visit were used for this analysis. Toxin quantification (Metabolon Inc., Durham, NC) was performed with ultra-high performance liquid chromatography/tandem mass spectrometry. Executive function and echocardiograms were assessed. Regression analysis examined the association of toxin levels with eGFR, CKD etiology, and neurocognitive and cardiac assessments (adjusted for age, sex, and urine protein:creatinine [UPCR]).

RESULTS

There were 150 CKiD participants included in this study. All toxins levels were significantly inversely correlated with eGFR (Spearman's rho - 0.45 to - 0.69). Children with non-glomerular CKD had significantly higher levels of 3-indoxylsulfate, phenylacetylglutamine, and p-cresol glucuronide. The toxin levels did not associate with neurocognitive outcomes. P-cresol glucuronide and phenylacetylglutamine negatively associated with left ventricular mass index z score, but did not associate with left ventricular hypertrophy.

CONCLUSIONS

Children with CKD have high levels of circulating gut microbiome-derived toxins. The levels of these toxins are strongly correlated with eGFR. There appear to be differences in toxin level based on glomerular versus non-glomerular etiology, even when accounting for the differences in eGFR between these two subgroups. In this sample, we did not detect any associations between these toxin levels and neurocognitive or cardiac outcomes.

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.

Bilateral ureteral obstruction after open ureteral reimplantation in a 3-year-old patient with Williams Beuren syndrome

Vesicoureteral reflux (VUR) is a common urological problem in the pediatric population and can be corrected by ureteral reimplantation in severe or persistent cases. This procedure is generally well tolerated, although complications, including ureteral obstruction, may occur in the postoperative period. We present a rare case of a 3-year-old with Williams Beuren syndrome who underwent bilateral ureteral reimplantation for VUR and subsequently developed bilateral ureteral obstruction with acute renal failure requiring nephrostomy tube placement within 48 hours of surgery.

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.

Urinary Tract Infection in Children: An Up-To-Date Study

Urinary tract infections (UTIs) are common bacterial infections in children. UTIs may be limited to the bladder or involve the kidneys with possible irreversible damage. Congenital abnormalities of the kidney and urinary tract (CAKUT) are often associated with UTIs; kidney scars have been considered a consequence of untreated UTIs but may be congenital. The mechanism by which bacteria produce inflammation in the urinary system has been intensively investigated. Diagnostic tools, including invasive imaging procedures, have been advocated in infants and small children with UTIs but are not necessary in most cases. Effective antibiotic drugs are available, and prophylactic treatment has been questioned. Several guidelines on UTIs are available, but a simple one for general practitioners is needed.

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.

An evaluation of ureteral diameter ratio and vesicoureteral reflux index in the treatment of primary vesicoureteral reflux

Objective

Vesicoureteral reflux (VUR) index is a simple, validated tool that reliably predicts significant improvement and spontaneous resolution of primary reflux in children. The aim of this study was to evaluate and compare the ureter diameter ratio (UDR) and VUR index (VURx) of patients treated with endoscopic injection (EI) and ureteroneocystostomy (UNC) methods in the pediatric age group due to primary VUR.

Methods

Patients under the age of 18 years old who underwent EI and UNC with the diagnosis of primary VUR between January 2011 and September 2021 were determined as the participants. The UDR was assessed using voiding cystourethrography, and the VURx score was determined prior to treatment based on hospital records included in the study.

Results

A total of 255 patients, 60 (23.5%) boys and 195 (76.5%) girls, with a mean age of 76.5 (range 13.0-204.0) months, were included in the study. EI was applied to 130 (51.0%) patients and UNC was applied to 125 (49.0%) patients due to primary VUR. The optimum cut-off for the distal UDR was obtained as 0.17 with sensitivity and specificity of 73.0% and 63.0%, respectively. The positive and negative predictive values were 66.0% and 70.0%, respectively.

Conclusion

When the UDR and VURx score are evaluated together for the surgical treatment of primary VUR in the pediatric age group, it is thought that it may be useful in predicting the clinical course of the disease and evaluating surgical treatment options.

Review of Urinary Tract Infections and Pyelonephritis

Urinary tract infections (UTIs) are serious bacterial infections affecting children of all ages. An understanding of the methods of urine collection is important to prevent the contamination of urine specimens and to interpret results. The diagnosis of a UTI requires appropriate interpretation of both urinalysis and urine culture results because testing must indicate evidence of inflammation and the presence of bacteria. Rapid treatment of UTIs is imperative to prevent acute decompensation and systemic illness. Empiric antibiotics should be narrowed as soon as possible to tailor antibiotic treatment and limit antibiotic overuse. Imaging with a renal ultrasound scan is recommended for all infants with first febrile UTIs rather than a voiding cystourethrogram. An additional goal of UTI treatment is to prevent renal scarring, which can lead to lifelong health consequences. Children with anatomic abnormalities of the urinary tract and those who have recurrent UTIs are at increased risk of renal scarring. [Pediatr Ann. 2024;53(6):e217-e222.].

Role of dexamethasone in controlling the proinflammatory cytokine cascade in the first episode of paediatric acute pyelonephritis

AIM

Febrile urinary tract infection is a common bacterial infection in childhood. The kidney damage after acute pyelonephritis (APN) could be related to the stimulation of the proinflammatory response. We aimed to investigate the role of inflammatory cytokines and the effect of dexamethasone after a first episode of APN.

METHODS

Subanalysis of the DEXCAR RCT in which children with confirmed APN (1 month-14 years) were randomly assigned to receive a 3 days course of either intravenous dexamethasone or placebo. Urinary cytokine levels at diagnosis and after 72 h of treatment were measured.

RESULTS

Ninety-two patients were recruited. Younger patients, males and those with abnormalities in the ultrasound study or vesicoureteral reflux showed higher values of urinary cytokines. Patients with severe APN had higher Tumour Necrosis Factor (TNF)α levels (81.0 ± 75.8 vs. 33.6 ± 48.5 pg/mg creatinine, p = 0.015). Both intervention groups showed similar basal clinical characteristics, including urinary cytokine levels. Treatment reduced urinary cytokine levels irrespective of dexamethasone administration. Neither the intervention group nor the urinary cytokine levels modulated the development of kidney scars.

CONCLUSION

Basal urinary cytokines were associated with age, abnormal ultrasound and vesicoureteral reflux. Patients with severe APN had higher TNFa urinary levels. Administration of dexamethasone in children with APN does not improve the control of the proinflammatory cytokine cascade.

Risk factors for new renal scarring in children with vesicoureteral reflux receiving continuous antibiotic prophylaxis

To investigate the risk factors for new renal scarring (NRS) in children with vesicoureteral reflux (VUR) receiving continuous antibiotic prophylaxis (CAP). This was a single-center cohort study. The clinical data of 140 children with grade I-V VUR receiving CAP were analyzed. In this study, exposure variables were sex, younger age at the initial diagnosis of UTI ≤ 12 months, the occurrence of breakthrough urinary tract infection (BT-UTI), high-grade VUR, bilateral VUR, etiology, presence of renal scarring at the initial diagnosis and ultrasound abnormalities. The outcome was NRS. A total of 140 children were included in the risk factor analysis of NRS, 73 of whom experienced NRS, an incidence rate of 52.14%. Multivariate Cox regression suggested that the presence of renal function impairment after the initial diagnosis of UTI (OR 3.411, 95% CI 1.5751-6.646) and the occurrence of BT-UTI while receiving CAP (OR 1.995, 95% CI 1.089-2.958) were independent risk factors for NRS. Multivariate Cox regression showed that high-grade VUR had no significant effects on NRS (OR 0.940, 95% CI 0.462-1.912, P = 0.864). No significant difference was identified in multivariate Cox regression analysis in the IV-V group (vs I-III group) (OR 0.960, 95% CI 0.565-1.633, P = 0.960). Renal function impairment after the initial diagnosis of UTI and the occurrence of BT-UTI while receiving CAP were independent risk factors for NRS. Neither univariate analysis nor multivariate analysis found a correlation between VUR grade and NRS.

Effectiveness of various treatment modalities in children with vesicoureteral reflux grades II-IV: a systematic review and network meta-analysis

BACKGROUND

Vesicoureteral reflux (VUR) is one of the most common risk factors of urinary tract infection (UTI) among children. Various treatment modalities including antibiotic prophylaxis, surgical or endoscopic corrections and conservative treatment were used depending on the severity of VUR. The aim of this study is to compare the effectiveness of these treatment modalities in children with VUR grades II-IV by conducting a systematic review and network meta-analysis.

METHODS

A systematic search from different databases was performed from their earliest records to December 2022 without any language restriction. Only randomised controlled trials were included in this study. Effectiveness of treatment modalities was mainly compared by UTI. Other outcomes for renal scarring and resolution by renal units were also measured between treatments.

RESULTS

A total of 11 studies with 1447 children were included in this study. While comparing with antibiotic prophylaxis in network meta-analysis for UTI recurrence, surgical treatment probably lowers the rate of UTI recurrence (Log OR -0.26, 95% CI -0.54 to 0.02, high quality). However, endoscopic treatment (Log OR 0.2, 95% CI -1.41 to 1.81, high quality) and conservative treatment (Log OR 0.15, 95% CI -0.45 to 0.75, high quality) revealed probably inferior to antibiotic treatment.

CONCLUSION

Both pairwise and network meta-analytic results probably showed no difference between the treatments in terms of their impact on UTI recurrence, progression of previous renal scars, or formation of new renal scars in children with VUR grades II-IV. These findings may offer a better understanding of each treatment and evidence-based suggestions for the choice of treatment, which should be individualised and based on the patient's risk factors.

The ureteral diameter ratio as a predictive factor in renal scarring associated with primary vesicoureteral reflux

INTRODUCTION

The ureteral diameter ratio (UDR) is reported to be effective in predicting the outcomes of vesicoureteral reflux (VUR) in several studies.

OBJECTIVE

The objective of the current study was to compare the risk of scarring in patients with VUR relative to UDR and the VUR grade. We also aimed to demonstrate other associated risk factors in scarring and investigate the long-term complications of VUR and their relationship with UDR.

STUDY DESIGN

Patients diagnosed with primary VUR were retrospectively enrolled in the study. UDR was calculated by dividing the largest ureteral diameter (UD) by the distance between L1-L3 vertebral bodies. Demographic and clinical data, laterality, VUR grade, UDR, delayed upper tract drainage on voiding cystourethrogram, recurrent urinary tract infections (UTI), and long-term complications of VUR were compared between the patients with and without renal scars.

RESULTS

A total of 127 patients and 177 renal units were included in the study. There was a significant difference between the patients with and without renal scars according to age at diagnosis, bilaterality, reflux grade, UDR, recurrent UTI, bladder bowel dysfunction, hypertension, decreased estimated glomerular filtration rate, and proteinuria. The logistic regression analysis revealed that UDR had the highest odds ratio among the factors affecting scarring in VUR.

DISCUSSION

VUR grading based on the evaluation of the upper urinary tract is one of the most important predictors for treatment options and prognosis. However, it is more likely to reflect ureterovesical junctional anatomy and function, which play a crucial role in the pathogenesis of VUR.

CONCLUSION

UDR measurement seems to be an objective method that can help clinicians predict renal scarring in patients with primary VUR.

Frequency of Urinary Tract Infection When Diagnosing Vesico Uretheral Reflux in Children in Tuzla Canton

Background

Vesicoureteral reflux (VUR) represents the return of urine from the bladder into the ureter and the renal canal system. Reflux can occur only on one or both kidneys. VUR most often occurs due to an incompetent ureterovesical junction, which consequently leads to hydronephrosis and dysfunction of the lower parts of the urinary system.

Objective

The aim of the study was to determine the frequency of urinary infection when diagnosing vesicouretheral reflux in children in the Tuzla Canton, in the five-year period from 01.01.2016 to 01.01.2021.

Methods

Through a retrospective study, we analyzed data from 256 children with vesiocouretheral reflux (VUR), examined in the Nephrology Outpatient Clinic, Clinic for Children's Diseases, University Clinical Center Tuzla, in the period from 01.01.2016 to 01.01.2021, from early neonatal to 15 years of age. The age and gender of children, the most common symptoms of urinary tract infections during the detection of VUR, and the degree of VUR were analyzed.

Results

From 256 children with VUR, 54% were male and 46% female. The highest prevalence of VUR was in the age group 0-2 years, and the lowest in the age of children > 15 years. There was no statistically significant difference between the groups of our respondents in relation to age groups, nor in relation to the gender of the children. Statistically significantly more children were without nonspecific symptoms and with asymptomatic bacteriuria in the group without UTI symptoms in children with VUR compared to the group with UTI symptoms in children with VUR. Pathological urine culture between the groups was without a statistically significant difference.

Conclusion

Although urinary tract infection in children is common, the possibility of permanent consequences should always be kept in mind if VUR is not diagnosed and treated in time.

How the 99mTc-DMSA scintigraphy findings are reflected in the adopted treatment of primary vesicoureteral reflux: One centre experience

BACKGROUND

Renal changes may have long-term sequalae and prevention is a main goal of management of primary vesicoureteral reflux (VUR).

AIM

This study aims to reveal how much ^99mTc-DMSA scintigraphy findings are reflected in the adopted surgical or non-surgical treatment in children with diagnosed primary VUR and to give the clinicians information regarding their final therapeutic decision.

PATIENTS AND METHODS

A total 207 children with primary VUR who underwent non-acute ^99mTc-DMSA scan were retrospectively evaluated. The presence of renal changes, their grading, differential function asymmetry (<45%) and grade of VUR were compared with subsequent choice of therapy.

RESULTS

Altogether 92 (44%) children had asymmetric differential function, 122 (59%) showed presence of renal changes, 79 (38%) had high-grade VUR (IV-V). Patients with renal changes had lower differential function (41%vs.48%) and higher grade of VUR. The incidence of high-grade changes (G3+G4B) afflicting more than one third of the kidney was significantly different between grade I-II, III and IV-V VUR (9%, 27%, 48%, respectively). Renal changes were detected in 76% of surgically and 48% of non-surgically treated patients, high-grade ^99mTc-DMSA changes in 69% and 31%, respectively. In children with no scars/dysplasia (G0+G4A), non-surgical treatment prevailed in 77%. The independent predictors for surgical intervention were presence of renal changes and higher grade of VUR, but not functional asymmetry.

DISCUSSION

Over the last 20 years, there has been a shift toward more non-surgical management of VUR. The long-term outcome of this approach should be thoroughly studied. This is the first study analysing renal status in VUR patients using ^99mTc-DMSA scan and its grading regarding the adopted treatment. Renal changes in almost half of non-surgically treated children with VUR should be an indicator for earlier diagnosis and effective treatment of acute pyelonephritis and VUR. We recommend distinguishing grade III VUR, as a moderate-grade VUR, because it is linked to higher incidence of high-grade ^99mTc-DMSA changes (G3+G4B); our findings of 65% of grade III VURs treated non-surgically should be cautionary. Grade III VUR does not mean a low-risk condition and should alert the clinician to evaluate the extent of renal changes and unmask high-risk cases.

CONCLUSIONS

Our data strengthens the need to investigate the extent of renal changes in VUR patients regarding treatment decision. Performing ^99mTc-DMSA scan individualizes the treatment of VUR patients; its grading can distinguish grade III-VUR as a separate risk entity because it differs significantly in terms of incidence of high-grade renal changes and chosen therapy.

Localization of Pyelonephritis by 68Ga-FAPI PET CT

Fibroblast activation protein inhibitor (FAPI) is a quinoline-based membrane-bound glycoprotein enzyme that is not usually expressed in normal adult tissues, except for the myometrium and sometimes the pancreas. Its expression increases in inflammation and cancer-associated fibroblasts (CAF). As FAPI is a new molecule with a promising future, presented here is a case report of uncontrolled diabetes with abdominal pain that showed features of inflammation in the kidneys. The patient had been previously diagnosed with maxillary sinusitis with Aspergillus niger and was receiving antibiotic treatment. The urine culture performed later was negative, and the patient was referred for ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET Computed Tomography (CT) to look for the focus of infection. However, as blood sugar was 500 mg/dL, ¹⁸F-FDG PET CT could not be performed. Therefore, ⁶⁸Ga-FAPI PET CT was run instead after taking the patient's written informed consent. The ^99mTc-dimercaptosuccinic acid scan performed on another day confirmed the presence of pyelonephritis bilaterally. In situations where FDG cannot be used because of hyperglycemia, ⁶⁸Ga-FAPI PET CT scan may be considered an alternative in the detection of occult infection or inflammation, as demonstrated in this case report.

Febrile Urinary Tract Infections in Children: The Role of High Mobility Group Box-1

BACKGROUND

Differentiating between febrile lower urinary tract infection (LUTI) and acute pyelonephritis (APN) is crucial for prompt clinical management. We investigated whether the high mobility group box-1 (HMGB1) could be a useful biomarker in differentiating between LUTI or APN.

METHODS

We enrolled seventy-four pediatric patients with suspected LUTI/APN, according to the positive or negative renal scintigraphy (DMSA) scan. If the first DMSA findings were abnormal, a second DMSA was performed after six months. Voiding cystourethrography ruled out vesicoureteral reflux (VUR).

RESULTS

Higher serum (s) HMGB1 levels characterized the APN group when compared to LUTI patients (13.3 (11.8-14.3) versus 5.9 (5.2-6.8) ng/mL, p: 0.02), whereas there were no differences according to urine (u) HMGB1 values. sHMGB1 correlated with C-reactive protein (CRP) levels (β = 0.47; p: 0.02). Receiver operating characteristic curves identified the best diagnostic profile for detecting APN. sHMGB1 area under the curve was different from CRP (p: 0.01) and white blood cells (p: 0.003). After multivariate analyses, VUR (HR:4.81) and sHMGB1 (HR 1.16; p: 0.006) were independently associated with the risk of renal scarring development.

CONCLUSIONS

sHMGB1 could represent a marker to differentiate APN from LUTI. Measurement of sHMGB1 could select children for early intervention or long-term follow-up.

Primary Vesicoureteral Reflux and Renal Scarring

Vesicoureteral reflux (VUR) is the commonest congenital anomaly of urinary tract in children. It is mostly diagnosed after a urinary tract infection or during evaluation for congenital anomalies of the kidney and urinary tract. High-grade VUR, recurrent pyelonephritis, and delayed initiation of antibiotic treatment are important risk factors for renal scarring. The management of VUR depends on multiple factors and may include surveillance only or antimicrobial prophylaxis; very few patients with VUR need surgical correction. Patients with renal scarring should be monitored for hypertension and those with significant scarring should also be monitored for proteinuria and chronic kidney disease.

Dexamethasone to prevent kidney scarring in acute pyelonephritis: a randomized clinical trial

BACKGROUND

Urinary tract infection (UTI) is one of the most common bacterial infections in childhood and is associated with long-term complications. We aimed to assess the effect of adjuvant dexamethasone treatment on reducing kidney scarring after acute pyelonephritis (APN) in children.

METHODS

Multicenter, prospective, double-blind, placebo-controlled, randomized clinical trial (RCT) where children from 1 month to 14 years of age with proven APN were randomly assigned to receive a 3-day course of either an intravenous corticosteroid (dexamethasone 0.30 mg per kg/day) twice daily or placebo. The late technetium 99 m-dimercaptosuric acid scintigraphy (> 6 months after acute episode) was performed to assess kidney scar persistence. Kidney scarring risk factors (vesicoureteral reflux, kidney congenital anomalies, or urinary tract dilatation) were also assessed.

RESULTS

Ninety-one participants completed the follow-up and were finally included (dexamethasone n = 49 and placebo n = 42). Both groups had similar baseline characteristics. Twenty participants showed persistent kidney scarring after > 6 months of follow-up without differences in incidence between groups (22% and 21% in the dexamethasone and placebo groups, p = 0.907). Renal damage severity in the early DMSA (β = 0.648, p = 0.023) and procalcitonin values (β = 0.065 p = 0.027) significantly modulated scar development. Vesicoureteral reflux grade showed a trend towards significance (β = 0.545, p = 0.054), but dexamethasone treatment showed no effect.

CONCLUSION

Dexamethasone showed no effect on reducing the risk of scar formation in children with APN. Hence, there is no evidence for an adjuvant corticosteroid treatment recommendation in children with APN. However, the study was limited by not achieving the predicted sample size and the expected scar formation.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT02034851. Registered in January 14, 2014. "A higher resolution version of the Graphical abstract is available as Supplementary information."

Early endoscopic injection may prevent new scarring in idiopathic detrusor overactivity disorder with vesicoureteral reflux in children

OBJECTIVE

To present baseline characteristics and the long-term treatment results of three groups of patients with idiopathic detrusor overactivity (IDOD) and vesicoureteral reflux (VUR) according to different treatment regimens, which underwent endoscopic subureteric injection (STING) in the early phase of targeted treatment (TT) (ES group), underwent STING in the late phase of TT (LS group) and with TT only (TT group).

PATIENTS AND METHODS

A total of 49 IDOD cases with VUR which were divided into three groups according to treatment regimens were evaluated in terms of age, symptoms, bladder capacities, involuntary contraction pressures (ICP), presence and degree of renal scar, differential renal functions (DF), new scar formation and STING success.

RESULTS

There was no significant difference between the groups in terms of age, side, symptoms, presence of urinary tract infection (UTI), DF, ICP and bladder capacity at diagnosis. A high grade of reflux was found to be significantly lower in the TT group (p = 0.037). There was no significant difference in terms of ICP, DF, bladder capacity and reflux grade between ES and LS Group. But new scar formation was more in LS Group (p = 0.003).

CONCLUSION

The STING success is satisfactory in IDOD cases with VUR, waiting a long period of time for diminishing symptoms may cost new scar formation.

Reflux nephropathy and scarring nephropathy: So close and yet so different

OBJECTIVES

Reflux nephropathy is a radiologic condition commonly used to express the existence of renal morphological lesions in patients who have or had vesicoureteral reflux (VUR). This morphological concept is used based on the image data collected, without conducting basic complementary renal function studies. The present study was designed to demonstrate that patients with active VUR present different functional renal alterations from those shown by patients with disappeared VUR.

METHODS

Longitudinal descriptive retrospective analysis including 89 children (46M, 43F) with VUR diagnosis through a standard voiding cystourethrogram (VCUG). The basic renal function tests collected were the maximum urinary osmolality (UOsm) and the urinary albumin/creatinine and NAG/creatinine ratios. The data collected corresponded to two moments, when VUR was diagnosed and when it had already disappeared.

RESULTS

Quantitative differences were verified in the three functional parameters when comparing those corresponding to both moments of the study. In the qualitative analysis, in relation to the intensity of the VUR, differences were observed in UOsm at diagnosis and in the albumin/creatinine ratio once the VUR had cured. At this last moment, a significant increase in the albumin/creatinine ratio was observed in patients with loss of renal parenchyma in relation to those without residual morphological lesions.

CONCLUSIONS

Concentrating ability defect is the most frequent finding in children with active reflux (true reflux nephropathy), whereas the most frequent functional disturbance found, once VUR has cured, is an increase in urinary albumin excretion, related to parenchymal damage. The term dysplastic-scarring nephropathy, could be more appropriate for patients with residual morphological lesions and impaired renal function, once VUR is cured.

Evaluation of renal function and scars in children with primary vesicoureteral reflux

OBJECTIVE

To evaluate growth, glomerular and tubular function, renal damage, scars in children affected by primary VUR.

METHOD

We retrospectively evaluated the clinical records of our Unit from January 2006 to September 2020. For each patient we evaluated growth, laboratoristic and scintigraphic glomerular and tubular function, renal damage and collective system urodynamics at baseline and at the last visit.

RESULT

We enrolled 41 patients affected by primary VUR and treated with continuous antibiotic prophylaxis. Glomerular function and urodynamics did not change over time. EFNa directly correlated with weight (r 0.44 p 0.004) and TRP inversely correlated with severity of reflux (r -0.32, p 0.04). Female sex was associated to nephrolithiasis (OR 17.0, p 0.02) and proteinuria (at T0 OR 5.8 p 0.03 at T1 OR 5.8, p 0.03). Daily proteinuria increased with age (r 0.66, p <0.0001 at T0 and r 0.44 p 0.004 at T1) while protein-to-creatinine ratio decreased. Renal scars at T0 inversely correlated with glomerular and tubular function at T1 but they did not correlate with severity or laterality of reflux.

CONCLUSION

Even if renal function remains stable through years, it is critical to identify the subjects with significant congenital renal damage.

Urologic Considerations in Pediatric Chronic Kidney Disease

Common causes of pediatric ESRD are distinct from those seen in the adult population. In the pediatric population, the most common are congenital anomalies of the kidney and urinary tract (CAKUT), affecting approximately 30% of children with CKD. These structural anomalies often require coordinated care with the pediatric urology team to address voiding issues, bladder involvement, and the potential need for surgical intervention. For pediatric nephrologists and urologists, common CAKUT that are encountered include antenatal hydronephrosis, obstructive uropathies (eg, posterior urethral valves), and vesicoureteral reflux. As more pediatric patients with CAKUT, CKD, and ESRD transition to adult care, it is important for receiving adult nephrologists to understand the clinical presentation, natural history, and prognosis for these diagnoses. This review outlines the diagnosis and potential interventions for these conditions, including strategies to address bladder dysfunction that is often seen in children with CAKUT. A discussion of these management decisions (including surgical intervention) for CAKUT, which are quite common to pediatric nephrology and urology practices, may provide unique learning opportunities for adult nephrologists who lack familiarity with these pediatric conditions.

Risk factors for renal scarring and clinical morbidity in children with high-grade and low-grade primary vesicoureteral reflux

INTRODUCTION

Primary vesicoureteral reflux (VUR) is associated with urinary tract infections (UTIs) and renal damage. However, the importance of early diagnosis of VUR has been questioned. Moreover, most studies have few patients with high-grade VUR. Hence, we retrospectively analyzed a large cohort of patients with primary high-grade and low-grade VUR and assessed risk factors for renal damage and clinical morbidity.

MATERIAL AND METHODS

We included patients (<18 years) at diagnosis with low-grade (1-3) or high-grade (4-5) primary VUR and noted their clinical history and presence of hypertension, low eGFR (<60ml/in/1.73 m²), renal scarring (focal or generalised) and reduced differential renal function (DRF; <45%). Risk factors were assessed (in patients and renal units) by logistic regression and generalised estimating equation.

RESULTS

Of 399 primary VUR patients, 255 (64%) had high-grade VUR. Indications for voiding cystourethrogram were recurrent UTI (38%), first UTI (28%) and antenatal hydronephrosis (17%). At diagnosis, 252 (65%) had renal scars (focal in 170 [44%], generalised in 82 [21%]), and 188 (47%) had reduced DRF. High-grade VUR patients were more likely than low-grade VUR patients to have renal scarring (75% vs. 49%, p < 0.01), low eGFR (23% vs. 13%, p = 0.04) and significant hypertension (26% vs. 13%, p = 0.02). High-grade VUR was associated with generalised scars (odds ratio [OR] 11, p < 0.001), focal scars (OR 3.1, p < 0.001) and reduced DRF (OR 2.3, p < 0.001) shown in the table. Male sex was a risk factor for generalised scars (OR 2.3, p = 0.005). Focal scars were associated with recurrent UTIs (OR = 1.8, p = 0.004) and reduced DRF (OR 1.4, p = 0.027). Patients with multiple focal scars were diagnosed at an older age (2 years [1,4] than those with single scars (1.5 years [1,4] or no scars (1 year [0, 3]), p = 0.04).

DISCUSSION

The prevalence of renal damage and clinical morbidity at VUR diagnosis was higher than other studies. High-grade VUR patients had a greater prevalence of renal damage, low eGFR and hypertension than low-grade VUR patients and was a risk factor for focal scars, generalised scars and reduced DRF. Focal scars were independently associated with recurrent UTI. Those with multiple scars were diagnosed later than those with single scars or no scars.

CONCLUSIONS

High-grade VUR was associated with renal damage and clinical morbidity. Our study highlights the importance of diagnosing VUR early to identify patients who may warrant long-term follow-up and intervention to minimize morbidity.

Kidney Echogenicity and Vesicoureteral Reflux in Children with Febrile Urinary Tract Infection

OBJECTIVE

To evaluate increased kidney echogenicity as a predictor of vesicoureteral reflux (VUR) in young children with first febrile urinary tract infection (UTI).

STUDY DESIGN

We performed a single center retrospective study of hospitalized children with first febrile UTI diagnosed in accordance with the American Academy of Pediatrics guidelines. All patients had kidney bladder ultrasound (KBUS) and voiding cystourethrography. Variables analyzed using χ² test or Mann-Whitney U test as appropriate. Multivariable logistic regression analysis was performed for the abnormal KBUS findings and OR and 95% CI were calculated.

RESULTS

Our cohort included 415 children (830 kidney units) with median age of 5 months (1 month to 5 years) and 80% were female. One hundred thirty-two (31.8%) patients had abnormal KBUS, including increased echogenicity in 45 patients. Overall, 42.2% of patients with increased echogenicity had VUR vs 23.3% with normal ultrasound (P = .013) and 31.1% of patients with increased echogenicity had high-grade III-V VUR vs 8.1% with normal ultrasound (P = .001). In total, 24.3% of kidneys with increased echogenicity had VUR vs 20% with normal ultrasound (P = .246) and 20% of kidneys with increased echogenicity had high-grade III-V VUR vs 9.9%with normal ultrasound (P = .005).

CONCLUSIONS

These data support adding increased kidney echogenicity to the list of other KBUS findings that are helpful in decision making about a need for voiding cystourethrography in young children with first febrile UTI.

Prevalence of reflux nephropathy in Iranian children with solitary kidney: results of a multi-center study

Background

Given the importance of the function of the remnant kidney in children with unilateral renal agenesis and the significance of timely diagnosis and treatment of reflux nephropathy to prevent further damage to the remaining kidney, we aimed to determine the prevalence of reflux nephropathy in this subgroup of pediatric patients.

Methods

In general, 274 children referred to pediatric nephrologists in different parts of Iran were evaluated, of whom 199 had solitary kidney and were included in this cross-sectional study. The reasons for referral included urinary tract infection (UTI), abnormal renal ultrasonography, being symptomatic, and incidental screening. Demographic characteristics, including age and gender were recorded. History of UTI and presence of vesicoureteral reflux (VUR) were evaluated.

Results

Of the 274 children evaluated in this study with the mean age (SD) of 4.71 (4.24) years, 199 (72.6%) had solitary kidney. Among these, 118 (59.3%) were male and 81 (60.7%) were female, 21.1% had a history of UTI, and VUR was present in 23.1%. The most common cause of referral was abnormal renal ultrasonography (40.2%), followed by incidental screening (21.1%), being symptomatic (14.1%), and UTI (5.5%). In 116 children (58.3%), the right kidneys and in 83 (41.7%) the left kidneys were absent. Besides, 14.6% of the participants had consanguineous parents and 3% had a family history of solitary kidney. Upon DMSA scan, the single kidney was scarred in 13.1%, of which only 7.5% were associated with VUR. In addition, proteinuria and hematuria were observed in 6.5% and 1.5% of children, respectively.

Conclusions

The prevalence of reflux nephropathy was 7.5% in children with solitary kidney with a male predominance. Given the relatively high prevalence of reflux nephropathy in these children, screening for VUR in the remnant kidney appears to be essential in this population.

Allograft Vesicoureteral Reflux after Kidney Transplantation

Allograft vesicoureteral reflux (VUR) is a leading urological complication of kidney transplantation. Despite the relatively high incidence, there is a lack of consensus regarding VUR risk factors, impact on renal function, and management. Dialysis vintage and atrophic bladder have been recognized as the most relevant recipient-related determinants of post-transplant VUR, whilst possible relationships with sex, age, and ureteral implantation technique remain debated. Clinical manifestations vary from an asymptomatic condition to persistent or recurrent urinary tract infections (UTIs). Voiding cystourethrography is widely accepted as the gold standard diagnostic modality, and the reflux is generally graded following the International Reflux Study Committee Scale. Long-term transplant outcomes of recipients with asymptomatic grade I-III VUR are yet to be clarified. On the contrary, available data suggest that symptomatic grade IV-V VUR may lead to progressive allograft dysfunction and premature transplant loss. Therapeutic options include watchful waiting, prolonged antibiotic suppression, sub-mucosal endoscopic injection of dextranomer/hyaluronic acid copolymer at the site of the ureteral anastomosis, and surgery. Indication for specific treatments depends on recipient's characteristics (age, frailty, compliance with antibiotics), renal function (serum creatinine concentration < 2.5 vs. ≥ 2.5 mg/dL), severity of UTIs, and VUR grading (grade I-III vs. IV-V). Current evidence supporting surgical referral over more conservative strategies is weak. Therefore, a tailored approach should be preferred. Properly designed studies, with adequate sample size and follow-up, are warranted to clarify those unresolved issues.

The Spectrum of Parenchymal Changes in Kidneys Affected by Intrarenal Reflux, Diagnosed by Contrast-Enhanced Voiding Urosonography and DMSA Scan

PURPOSE

To describe the parenchymal defects in kidneys with intrarenal reflux (IRR) diagnosed using contrast-enhanced voiding urosonography (ceVUS) and ^99mTc-DMSA scintigraphy (DMSA scan).

MATERIALS AND METHODS

A group of 186 uretero-renal units (URUs) was analyzed using ceVUS and DMSA scans: 47 without vesicoureteral reflux (VUR) (group A) and 139 with VURs, comprising 73 VURs without (group B), and 66 with IRR (group C). VURs included non-dilating (grades I-II), mildly non-dilating (grade III), and non-dilating (grades IV-V) grades. The parenchymal changes were analyzed using a DMSA scan.

RESULTS

The median age for VUR diagnosis was 16.5 months in girls, and 8.5 months in boys (Z = 3.9; p = 0.001). IRR occurred in 51.4% of boys and in 25.9% of girls (χ² = 12.4; p < 0.001). The non-dilating VUR occurred in 44% of boys and 24.1% of girls (χ² = 7.7; p = 0.005). IRRs characterized upper and lower renal segments (81.8 and 63.6%) and middle segments (33.3%). Both incidence and increase in IRR correlated with the grade of VUR (p < 0.001). The incidence of reduced DMSA signal was statistically different among groups A + B and C, but not between groups A and B (χ² = 32.2; p < 0.001). No statistically significant relationship existed between the reduced DMSA signal and the grade of VUR in group C. The reduced DMSA signal appeared in 9.9% positions in kidneys from group A, 14% from group B, and 32% from group C. Out of all 118 IRRs, 38.1% had reduced and 61.9% had normal DMSA signal. Among 11 parenchymal scars found in all three groups, 2 belonged to group B, 9 to group C, while group A had no scars.

CONCLUSION

The parenchymal changes are the most prominent in the group with IRR, but they do not significantly differ among kidneys with different grades of VUR. VURs of higher grades are associated with a higher incidence of IRR and early clinical presentation. Scars can also appear in lower-grade VURs accompanied by IRR. Boys with VUR have earlier clinical presentation than girls, as they have significantly higher grades of VUR with a higher proportion of IRRs. Therefore, we suggest a subdivision of VURs into those with IRR and abundant parenchymal damage, and those without IRR and less parenchymal damage.

The impact of constant antibiotic prophylaxis in children affected by spinal dysraphism performing clean intermittent catheterization: a 2-year monocentric retrospective analysis

INTRODUCTION

Spinal dysraphism (SD) is a general term used to refer to developmental abnormalities of the spine that involves many clinical conditions including myelomeningocele (MMC). In these patients, neurogenic bladder (NB) is a common and predisposing factor for renal damage; the most frequently used approach to manage this situation is based on clean intermittent catheterization (CIC) and anticholinergic drugs. Urinary tract infections (UTIs) are a significant concern for these patients, and antibiotic prophylaxis is frequently used even if it is still a debated topic of literature. The purpose of this paper is to investigate the role and the real effectiveness of antibiotic prophylaxis in the reduction of incidence of UTIs in patients with spina bifida performing CIC.

METHODS

We collected data of all patients performing CIC, who did their last follow-up visit in the period between January 2019 and January 2021, followed at the children multidisciplinary Spina Bifida Center of A. Gemelli Hospital in Rome. Data collected included age at referral, gender, type of SD lesion, serum creatinine and cystatin C levels, the use of anticholinergic medications, antibiotic prophylaxis and type of prophylaxis (oral/endovesical), age of starting prophylaxis with its duration/adherence, number of CIC/day and its duration, episodes of UTIs in the 2 years prior to the last follow-up, and presence and grade of vesical-ureteric reflux (VUR) on cystourethrogram.

RESULTS

A total of 121 patients with SD performing CIC was included in the study; 66 (54%) presented ≥ 1 episode of UTIs in the last two years and 55 (46%) none. During the study period, 85 (70%) patients received antibiotic prophylaxis (ABP group) and 36 (30%) did not (NABP group): no statistically significative difference in terms of UTI development was observed between the two groups (p = 0.17). We also evaluated compliance to the therapy; 71 patients (59%) took antibiotic prophylaxis constantly (CABP group) and 50 (41%) did not do antibiotic prophylaxis constantly or did not do antibiotic prophylaxis at all (NCABP group): we observed a statistically significative difference in terms of UTIs with a 2.2 times higher risk of development at least one episode of UTIs in NCABP group.

CONCLUSION

In conclusion, antibiotic prophylaxis performed constantly, without interruption, is associated with a lower risk of developing urinary tract infections and consequently to develop renal failure in adulthood.

The RiVUR Study Outcomes and Implications on the Management of Vesicoureteral Reflux

The Randomized intervention for Vesicoureteral Reflux (RiVUR) study was an effort by the National Institute of Health to identify the most significant question on the management of vesicoureteral reflux (VUR), i.e. Did antibiotic prophylaxis reduce the incidence of recurrent urinary tract infections (UTI) in children with VUR? During the initial phases of the RiVUR study, several similar studies were performed that seemed to indicate a lack of benefit of antibiotic prophylaxis in VUR. However, few of these studies had the rigorous methodology and true randomization of the pediatric cohort that was studied in RiVUR. Additionally, many of these studies included children of wide age ranges and inconsistent assessments were used for identification of UTI and VUR. In 2011, the American Academy of Pediatrics (AAP) published a guideline statement for the evaluation of initial UTI in febrile children aged 2 to 24 months, which recommended against performing a Voiding Cystourethrogram (VCUG) in all children with a confirmed UTI. The goal of the AAP guidelines was to reduce the number of VCUGs being performed and potentially to reduce the number of children diagnosed with low grade VUR that seems to have low potential to cause renal injury. The RiVUR study included over 600 children identified with VUR after a 1^st or 2^nd febrile UTI randomized to prophylaxis with trimethoprim/sulfamethoxazole (TMP/SMZ), or placebo and followed over a study timeline for 2 years. Overall, a 50% reduction was noted in the incidence of recurrent febrile UTI with the utilization of prophylaxis as compared to placebo. Additional sub-group analyses have been performed on the cohorts of the study; these are also evaluated in this review to determine the overall impact of the RiVUR study on the current management of VUR.

Risk factors for breakthrough urinary tract infection in children with vesicoureteral reflux receiving continuous antibiotic prophylaxis

BACKGROUND

To investigate the risk factors for breakthrough urinary tract infection (BT-UTI) in children with vesicoureteral reflux (VUR) receiving continuous antibiotic prophylaxis (CAP).

METHODS

This was a single-centre cohort study (January 2016 to December 2019). The clinical data of 256 children with grade I-V VUR receiving CAP were analysed. In this study, exposure variables were sex, younger age at the initial diagnosis of UTI ≤12 months, high-grade VUR, bilateral VUR, aetiology, presence of renal scarring at the initial diagnosis, presence of renal function impairment at the initial diagnosis, ultrasound abnormalities, antibiotic used and bladder and bowel dysfunction (BBD). Outcome was BT-UTI.

RESULTS

BT-UTI occurred in 81 out of 256 children with grade I-V VUR who received CAP, an incidence of 31.64%. Univariate analysis showed that younger age at the initial diagnosis of UTI (≤12 months), bilateral VUR, renal scarring on the dimercaptosuccinic acid (DMSA) scan at the initial diagnosis of UTI and BBD were correlated with the occurrence of BT-UTI. Multivariate analysis showed that younger age at the initial diagnosis of UTI (≤12 months) [hazard ratio (HR): 4.629; 95% confidence interval (CI): 1.302-16.462], bilateral VUR (HR: 2.078; 95% CI: 1.084-4.022) and BBD (HR: 3.194; 95% CI: 1.243-8.206) were independent risk factors for the occurrence of BT-UTI.

CONCLUSIONS

For VUR children receiving CAP, younger age at the initial diagnosis of UTI (≤12 months), bilateral VUR, and BBD were independent risk factors for the occurrence of BT-UTI.

[Reflux nephropathy and scarring nephropathy: So close and yet so different]

OBJECTIVES

Reflux nephropathy is a radiologic condition commonly used to express the existence of renal morphological lesions in patients who have or had vesicoureteral reflux (VUR). This morphological concept is used based on the image data collected, without conducting basic complementary renal function studies. The present study was designed to demonstrate that patients with active VUR present different functional renal alterations from those shown by patients with disappeared VUR.

PATIENTS AND METHODS

Longitudinal descriptive retrospective analysis including 89 children (46M, 43F) with VUR diagnosis through a standard voiding cystourethrogram (VCUG). The basic renal function tests collected were the maximum urinary osmolality (UOsm) and the urinary albumin/creatinine and NAG/creatinine ratios. The data collected corresponded to two moments, when VUR was diagnosed and when it had already disappeared.

RESULTS

Quantitative differences were verified in the three functional parameters when comparing those corresponding to both moments of the study. In the qualitative analysis, in relation to the intensity of the VUR, differences were observed in UOsm at diagnosis and in the albumin/creatinine ratio once the VUR had cured. At this last moment, a significant increase in the albumin/creatinine ratio was observed in patients with loss of renal parenchyma in relation to those without residual morphological lesions.

CONCLUSIONS

Concentrating ability defect is the most frequent finding in children with active reflux (true reflux nephropathy), whereas the most frequent functional disturbance found, once VUR has cured, is an increase in urinary albumin excretion, related to parenchymal damage. The term dysplastic-scarring nephropathy, could be more appropriate for patients with residual morphological lesions and impaired renal function, once VUR is cured.

Abnormal DMSA renal scan findings and associated factors in older children with vesicoureteral reflux

AIM

There are scanty data on the rate of abnormal Tc-99 m dimercaptosuccinic acid (DMSA) renal scintigraphy and associated factors in children older than 5 years with diagnosis of VUR. We do not have knowledge about which older children should undergo DMSA after VUR diagnosis. This study aims to assess the rate of abnormal DMSA findings and associated factors in children older than 5 years of age diagnosed with VUR.

MATERIALS AND METHODS

We retrospectively reviewed the medical records of 258 children with VUR diagnosed at or older than 5 year age. 179 children [42 (23.5%) males and 137 (76.5%) females] with complete data were included. 268 reflux units were compared according to gender, bilaterality, grade, reflux phase at voiding cystourethrography, febrile urinary tract infection (fUTI), lower urinary tract dysfunction (LUTD), and DMSA findings with uni- and multivariate analysis.

RESULTS

The median age was 110 (60-216) months. VUR grades were I, II, and III in 197 (73.6%) units and IV-V in 71 (26.4%). 138 (51.5%) renal units had abnormal DMSA. VUR grade (p < 0.01), unilaterality (p = 0.048), and fUTI (p = 0.031) in univariate but only grade and unilaterality in multivariate analysis are significantly associated with abnormal DMSA. Although reflux at filling phase was predominant in high-grade VUR group, reflux at voiding phase (p = 0.006) in low-medium-grade (1-3) VUR was associated with abnormal DMSA.

CONCLUSION

Children older than 5 years of age diagnosed with VUR should be regarded as a high-risk group for abnormal DMSA regardless of gender, unilaterality, grade, reflux phase, fUTI, and LUTD.

Surgical indications for operative management of vesicoureteral reflux in children

PURPOSE OF REVIEW

Vesicoureteral reflux (VUR) management has been steadily evolving over the last several years. There is not a definitive algorithm for operative intervention, but there are some recognized patterns to follow when caring for this patient base. It is extremely relevant to review the rationale behind practice patterns as both literature and clinical practice are dynamic.

RECENT FINDINGS

VUR is a common malady that is emotionally, physically, and financially draining for families. As new treatment options emerge with minimally invasive techniques and older methods are re-explored, it is imperative to re-evaluate care strategies. This article reviews the mainstays of treatment in addition to newer therapeutic modalities.

SUMMARY

The decision to operate on any patient, particularly pediatric patients, must be preceded by sound clinical judgment. Thoughtful planning must be utilized to ensure every patient receives individualized and up-to-date VUR management. This article reviews indications for surgical intervention to consider when managing these patients.

Types of Parenchymal Changes Diagnosed on DMSA Scans of Kidneys Affected by Different Grades of Vesicoureteral Reflux

Background

Renal parenchymal damage and scarring usually is associated with urinary tract infection (UTI), whereas the impact of vesicoureteral reflux (VUR) on the kidneys is unclear. We aimed to compare kidneys with all grades of VUR (grades Io-V) and those without VUR by using direct radionuclide cystography, voiding cystourethrography, and findings from ^99mTc-DMSA scintigraphy (DMSA scan).

Material/Methods

The present analysis included 253 renal ureteral units (RUU) from 129 children with VUR and recurrent UTI and children with a single febrile UTI associated with abnormal ultrasonographic findings. The 6 grades of VUR (Io, I, II, III, IV, and V) and 35 RUUs without VUR were divided into 4 groups: 1. Non-dilated VUR (grades Io-II); 2. Mildly dilated VUR (grade III); 3. Dilated VUR (grades IV–V); and 4. The control group.

Results

DMSA scanning showed significant differences between the groups with non-dilated VUR, grade III VUR, grades IV–V VUR, and the control group in kidney width (χ²=30.5; P<0.001); position and shape (χ²=30.6; P<0.001); intensity of activity (χ²=38.1; P<0.001); distribution of activity (χ²=34.5; P<0.001); and existence of scars (χ²=16; P<0.001). The probability of abnormalities on DMSA scans increased with the VUR grade. However, inside the groups of dilated and non-dilated VUR we found no significant statistical differences between those characteristics.

Conclusions

Our results indicate that kidneys without VUR or with non-dilated lateral VUR and dilated VUR on the contralateral side represent 2 different categories of parenchymal changes.

Contemporary Management of Urinary Tract Infection in Children

Urinary tract infection (UTI) is common in children, and girls are at a significantly higher risk, as compared to boys, except in early infancy. Most cases are caused by Escherichia coli Collection of an uncontaminated urine specimen is essential for accurate diagnosis. Oral antibiotic therapy for 7 to 10 days is adequate for uncomplicated cases that respond well to the treatment. A renal ultrasound examination is advised in all young children with first febrile UTI and in older children with recurrent UTI. Most children with first febrile UTI do not need a voiding cystourethrogram; it may be considered after the first UTI in children with abnormal renal and bladder ultrasound examination or a UTI caused by atypical pathogen, complex clinical course, or known renal scarring. Long-term antibiotic prophylaxis is used selectively in high-risk patients. Few patients diagnosed with vesicoureteral reflux after a UTI need surgical correction. The most consequential long-term complication of acute pyelonephritis is renal scarring, which may increase the risk of hypertension or chronic kidney disease later in life. Treatment of acute pyelonephritis with an appropriate antibiotic within 48 hours of fever onset and prevention of recurrent UTI lowers the risk of renal scarring. Pathogens causing UTI are increasingly becoming resistant to commonly used antibiotics, and their indiscriminate use in doubtful cases of UTI must be discouraged.

Swiss consensus recommendations on urinary tract infections in children

The kidneys and the urinary tract are a common source of infection in children of all ages, especially infants and young children. The main risk factors for sequelae after urinary tract infections (UTI) are congenital anomalies of the kidney and urinary tract (CAKUT) and bladder-bowel dysfunction. UTI should be considered in every child with fever without a source. The differentiation between upper and lower UTI is crucial for appropriate management. Method of urine collection should be based on age and risk factors. The diagnosis of UTI requires urine analysis and significant growth of a pathogen in culture. Treatment of UTI should be based on practical considerations regarding age and presentation with adjustment of the initial antimicrobial treatment according to antimicrobial sensitivity testing. All children, regardless of age, should have an ultrasound of the urinary tract performed after pyelonephritis. In general, antibiotic prophylaxis is not recommended.Conclusion: Based on recent data and in line with international guidelines, multidisciplinary Swiss consensus recommendations were developed by members of Swiss pediatric infectious diseases, nephrology, and urology societies giving the clinician clear recommendations in regard to diagnosis, type and duration of therapy, antimicrobial treatment options, indication for imaging, and antibiotic prophylaxis. What is Known: • Urinary tract infections (UTI) are a common and important clinical problem in childhood. Although children with pyelonephritis tend to present with fever, it can be difficult on clinical grounds to distinguish cystitis from pyelonephritis, particularly in young children less than 2 years of age. • Method of urine collection is based on age and risk factors. The diagnosis of UTI requires urine analysis and significant growth of a pathogen in culture. What is New: • Vesicoureteric reflux (VUR) remains a risk factor for UTI but per se is neither necessary nor sufficient for the development of renal scars. Congenital anomalies of the kidney and urinary tract (CAKUT) and bladder-bowel dysfunction play a more important role as causes of long-term sequelae. In general, antibiotic prophylaxis is not recommended. • A switch to oral antibiotics should be considered already in young infants. Indications for invasive imaging are more restrictive and reserved for patients with abnormal renal ultrasound, complicated UTI, and infections with pathogens other than E. coli.

New-onset ESRD secondary to reflux nephropathy has decreased in incidence in the United States

INTRODUCTION AND OBJECTIVE

Vesicoureteral reflux (VUR) has been associated with the development and progression of reflux nephropathy (RN). Management of VUR has become more conservative over time as therapies have not been reliably proven to prevent renal scarring. We sought to examine the incidence of end stage renal disease (ESRD) due to RN over recent decades in the United States.

STUDY DESIGN

The United States Renal Data System (USRDS) is a national data system that collects information about chronic kidney disease and ESRD. Since 1995, the USRDS has mandated that all dialysis centers enroll and submit data on new-onset ESRD patients. Of the over 2.5 million patients enrolled since 1996, 7314 were enrolled with a diagnosis code for RN as the primary cause of ESRD. We examined the trends seen in this patient population from 1996 to 2014 and used US census data to calculate incidence.

RESULTS

The incidence of patients with new-onset ESRD attributed primarily to RN saw a steady decrease over time: from 1.9 per million in 1996 to 0.6 per million in the US population in 2014 (exp(B) = 0.941, p < 0.001). 58.8% of the patients were female, 87.4% white. The mean age at the time of ESRD onset was 47 years (IQR 30-65) and this did not significantly vary over the period (P > 0.05). When comparing pediatric new-onset ESRD to adult-onset, a non-significant trend (p = 0.093) was seen with a decrease in incidence of adult ESRD, but a relatively stable incidence of pediatric ESRD (mean age 12, incidence 0.2-0.6 cases per million US children/year). 44.5% of patients received renal transplantation at a mean age of 36 years, 18.9 months (IQR 5-40) after ESRD diagnosis. The mean age of mortality was 62 years old (IQR 50-76), and 5-year survival after RN ESRD diagnosis was 65.8%.

DISCUSSION

As with any public database study, our findings may be limited by disease coding or reporting practices. Medical and surgical management trends practiced since the 1960s may have contributed to a decrease in the incidence of ESRD primarily attributed to RN in the United States between 1996 and 2014. Our findings may also reflect changes in diagnostic practices.

CONCLUSIONS

ESRD attributed primarily to RN has gradually decreased in incidence in the United States between 1996 and 2014, but the age of ESRD onset has been unchanged.

Acute pyelonephritis in children and the risk of end-stage kidney disease

BACKGROUND

Pyelonephritis is the most common serious bacterial infection during childhood. The long-term importance of kidney scarring is unclear.

OBJECTIVE

To assess the risk of end-stage kidney disease (ESKD) in adolescents and young adults with history of pyelonephritis.

STUDY DESIGN

A nationwide, population-based, historical cohort study, including 1,509,902 persons (62% male) examined for military service between 1967 and 1997. Participants with a history of pyelonephritis were sub-grouped according to presence of kidney scarring and baseline kidney function. Data were linked to the Israeli ESKD registry to identify incident ESKD cases. Cox proportional hazards models were used to estimate the hazard ratio (HR) of treated ESKD (dialysis or kidney transplant).

RESULTS

Pyelonephritis was diagnosed in 6979 participants (0.46%). 6479 had normal kidney function and no evidence of kidney scarring, 400 had normal kidney function with evidence of scarring, and 100 demonstrated reduced baseline kidney function. Treated ESKD developed in 2352 individuals (0.2%) without history of pyelonephritis, 58 individuals (0.9%) with normal kidney function, history of pyelonephritis and no kidney scarring, 14 individuals (3.5%) with normal kidney function, history of pyelonephritis and kidney scarring, and 23 individuals (23.0%) with history of pyelonephritis and reduced baseline kidney function, yielding HR of 3.3, 34.8 and 43.2, respectively, controlling for age, gender, paternal origin, enrollment year, body mass index, and blood pressure, and accounting for death as a competing risk.

CONCLUSION

History of pyelonephritis was associated with significantly increased risk of treated ESKD, particularly when associated with kidney scarring or reduced baseline kidney function.

Vesicoureteral Reflux in Adults with Urinary Tract Infections: Is There a Role for Treatment?

PURPOSE OF REVIEW

Urinary tract infections (UTI) place a significant burden on individual patients and the healthcare system as a whole. Vesicoureteral reflux (VUR) is a risk factor for UTIs and is the focus of much research in the pediatric field due to the opportunity for early intervention and prevention of long-term sequelae. However, VUR in the adult population is not well studied and can present different treatment challenges. The goal of this review article is to discuss the role VUR plays in UTIs in the adult population with a specific focus on complications and treatment.

RECENT FINDINGS

The true prevalence of VUR in the adult population remains unknown, and urologists need to maintain an index of suspicion for VUR when evaluating adult patients with recurrent pyelonephritis or complicated UTIs. A number of case series and smaller retrospective studies have documented successful endoscopic treatment of adult VUR patients with recurrent pyelonephritis. Ureteral reimplantation remains an option for adult patients who are refractory to endoscopic treatment of VUR. The current treatments and recommendations for VUR in adults have been extrapolated from the pediatric population due to the scarcity of research. VUR is uncommon in the adult population and requires a high index of suspicion by the clinician. Accurate diagnosis and treatment of VUR can relieve patients from recurrent infections, repetitive antibiotic use, and the risk of hospitalization.

Predictive factors for bacteremia in febrile infants with urinary tract infection

This study aimed to investigate the predictive factors of concomitant bacteremia occurring in febrile infants who initially presented with pyuria and fever, and were subsequently diagnosed with culture-proven urinary tract infection (UTI). We conducted a retrospective cohort study for January 2010–October 2018 that included infants younger than six months with febrile UTI at a tertiary hospital. The study included 463 patients, of whom 34 had a concomitant bacteremic UTI. Compared to those in the non-bacteremic urinary tract infection (UTI) group, the bacteremic UTI group had a lower mean age; higher levels of C-reactive protein (CRP), delta neutrophil index (DNI, reflects the fraction of immature granulocytes) and blood urea nitrogen (BUN); lower levels of hemoglobin (Hb) and albumin; and a lower platelet count. Vesicoureteral reflux (VUR) was detected nearly twice as often in patients with bacteremic UTI compared to those with non-bacteremic UTI (59.3% vs. 30.6%; P = 0.003). Univariate logistic analyses showed that age ≤90 days; higher DNI, CRP, and creatinine levels; lower Hb and albumin levels; and the presence of VUR were predictors for bacteremic UTI. On multivariate logistic regression analysis, age ≤90 days, higher DNI and CRP levels, and the presence of VUR were independent predictors of bacteremic UTI. The area under the receiver operating characteristic curve of the multivariate model was 0.859 (95% CI, 0.779–0.939; P < 0.001). Age ≤90 days, higher DNI and CRP values may help predict bacteremia of febrile infants younger than 6 months with UTI. Vesicoureteral reflux imaging is also recommended in infants with bacteremic UTI to evaluate VUR.

The pathogenesis and management of renal scarring in children with vesicoureteric reflux and pyelonephritis

Bacterial urinary tract infections (UTIs) are one of the most common reasons for children to be admitted to hospital. Bacteria infect and invade the bladder (the lower urinary tract) and if the infection disseminates to the upper urinary tract, significant inflammation in the kidneys may arise. Inflammation is a double-edged sword: it is needed to clear bacteria, but if excessive, kidney tissue is injured. During injury, nephrons are destroyed and replaced with deposition of extracellular matrix and a renal scar. In this review, we explore the pathogenesis of UTIs and discuss the risk factors that result in dissemination of bladder infection to the kidneys. Three major risk factors predispose to kidney infections: the presence of vesicoureteric reflux, the presence of bladder and bowel dysfunction, and defects in the ability of the host immune response to clear bacteria. In this review, we will discuss these factors, their relationship to renal scarring, and potential treatments that might be beneficial to prevent renal scar formation in children.

Laboratory Findings After Urinary Tract Infection and Antimicrobial Prophylaxis in Children With Vesicoureteral Reflux

It is a common practice to monitor blood tests in patients receiving long-term trimethoprim-sulfamethoxazole (TMP-SMZ) prophylaxis for recurrent urinary tract infections. This multicenter, randomized, placebo-controlled trial enrolled 607 children aged 2 to 71 months with vesicoureteral reflux diagnosed after symptomatic urinary tract infection. Study participants received TMP-SMZ (n = 302) or placebo (n = 305) and were followed for 2 years. Serum electrolytes (n ≥ 370), creatinine (n = 310), and complete blood counts (n ≥ 206) were measured at study entry and at the 24-month study conclusion. We found no significant electrolyte, renal, or hematologic abnormalities when comparing the treatment and placebo groups. We observed changes in several laboratory parameters in both treatment and placebo groups as would normally be expected with physiologic maturation. Changes were within the normal range for age. Long-term use of TMP-SMX had no treatment effect on complete blood count, serum electrolytes, or creatinine. Our findings do not support routine monitoring of these laboratory tests in children receiving long-term TMP-SMZ prophylaxis.

Current status of long-term antibiotic prophylaxis for urinary tract infections in children: An antibiotic stewardship challenge

Recurrent urinary tract infections (UTIs) in children are associated with development of pyelonephritis and renal scarring. Traditionally, continuous antibiotic prophylaxis (CAP) has been used to prevent recurrent UTI. Recent studies have challenged the efficacy of CAP for preventing renal scarring and have raised concerns about inducing bacterial resistance. This review focuses on studies published between January 2000 and April 2019 and evaluates the use of CAP in children for avoiding recurrent UTIs and renal scarring. A systematic literature search was carried out using the following search terms and related medical subject headings in the MEDLINE electronic database: ‘urinary tract infection’, ‘antimicrobial/antibiotic prophylaxis’, and ‘children/pediatrics’. Randomized clinical trials (RCTs), original research articles, guidelines, systematic reviews, and meta-analyses describing antibiotic prophylaxis for UTIs were included. A total of 34 RCTs, 9 systematic reviews, and 3 guidelines describing antibiotic prophylaxis were included in this review. The efficacy of CAP for preventing recurrent UTI remains unclear due to non-generalizability of results obtained from suboptimally designed clinical trials. CAP has not been proven as beneficial for preventing new renal scarring in children. Additionally, CAP is associated with increased risk of multidrug resistant infections in children. No conclusive evidence can be drawn from the available clinical data to support routine use of CAP for prevention of renal scarring. Accumulation of evidence from additional well designed studies may result in different conclusions in the future. It is important to identify specific risks for recurrent UTI and ensuing renal injury to ensure more judicious use of CAP.

The long-term prognosis of nephropathy in operated reflux

OBJECTIVE

To investigate the postoperative long-term prognosis and the factors predicting the renal function of patients with reflux nephropathy. As the serum creatinine (s-Cr) level tends to increase during infancy, the degree of reflux and renal parenchymal damage are thought to be more important factors in pediatric patients than in older patients.

MATERIALS AND METHODS

This study examined s-Cr, urinary protein, and blood pressure of patients who underwent anti-reflux surgery 10 years before. It also calculated the postoperative estimated glomerular filtration rate (eGFR) and examined the correlation between the eGFR and preoperative factors (age, gender, number of urinary tract infections [UTIs], primary diagnosis, reflux grade, percentage of dimercaptosuccinic acid uptake, degree of renal parenchymal damage, s-Cr abnormality, proteinuria, and hypertension), and analyzed the factors associated with the long-term prognosis.

RESULTS

The study population was 51 infants (37 boys and 14 girls). The mean age of the patients before surgery and at the follow-up examination was 3.41 ± 3.61 and 14.63 ± 3.74 years, respectively. After surgery, the s-Cr, urinary protein, and blood pressure values showed (44.7%, 26.7%, and 18.2%, respectively) were abnormal. The postoperative eGFR was a mean 90.27 ± 20.42 ml/min/1.73 m² and primary correlated with an older age (P = 0.0361), no UTI at the primary diagnosis (P = 0.0044), reflux grade ≥8 (P = 0.0180), degree of renal parenchymal damage (group ≥2b, P < 0.0001), s-Cr abnormality (P < 0.0001), and proteinuria (P = 0.0001) at baseline. A total of 20 patients had chronic kidney disease (CKD; Fig. 1). The multiple regression analysis of these factors revealed that an older age (P = 0.0021), reflux grade ≥8 (P = 0.0134), and degree of renal parenchymal damage (group ≥2b, P < 0.0001) were significantly associated with the long-term postoperative prognosis of reflux nephropathy. Using these three factors, this study derived a multiple regression equation estimating eGFR in the 10th year after surgery (Fig. 1).

DISCUSSION

In this study, severe vesico-ureteral reflux (reflux grade ≥8) and severe renal parenchymal damage (group ≥2b) were associated with a long-term decrease in the eGFR. In particular, renal parenchymal damage was closely correlated with the postoperative eGFR; thus, this was clearly a critical factor. The age at surgery showed a better correlation with the postoperative eGFR in the multiple regression analysis; thus, age was regarded as an independent prognostic factor.

CONCLUSIONS

The age, reflux grade, and degree of renal parenchymal damage at baseline were factors that affected the long-term postoperative prognosis of reflux nephropathy. Patients with high-grade reflux and severe renal parenchymal damage were more likely to show a reduced CKD level at 10 years after anti-reflux surgery.

An update on renal scarring after urinary tract infection in children: what are the risk factors?

AIM

The aim of this study was to present updated information on clinical, laboratory, and imaging risk factors and predictors of renal scarring after first or recurrent febrile UTIs, which may be associated with renal scarring.

METHODS

PubMed was searched for current data on possible risk factors and predictors of renal scarring after febrile urinary tract infections in children.

RESULTS

Recurrence of acute pyelonephritis is an independent risk factor for renal scarring, while the duration of fever before treatment initiation is mainly associated with acute pyelonephritis and its severity. Severe vesicoureteral reflux is an important independent risk factor for the development of renal scarring after a febrile urinary tract infection.

CONCLUSIONS

Certain clinical parameters could be used to identify children at high risk for renal scarring after febrile urinary tract infection, helping clinicians to reserve dimercaptosuccinic acid scan for selected cases.