The role of ultrasonography in predicting vesicoureteral reflux

Conflicting views of physicians and surgeons concerning pediatric urinary tract infection: a comparative review

BACKGROUND

A first febrile urinary tract infection (UTI) is a common condition in children, and pathways of management have evolved over time.

OBJECTIVE

To determine the extent to which pediatricians and surgeons differ in their investigation and management of a first febrile UTI, and to evaluate the justifications for any divergence of approach.

MATERIALS AND METHODS

A literature search was conducted for papers addressing investigation and/or management following a first febrile UTI in children published between 2011 and 2021. Searches were conducted on Medline, Embase, and the Cochrane Controlled Trials Register. To be eligible for inclusion, a paper was required to provide recommendations on one or more of the following: ultrasound (US) and voiding cystourethrogram (VCUG), the need for continuous antibiotic prophylaxis and surgery when vesicoureteral reflux (VUR) was detected. The authorship required at least one pediatrician or surgeon. Authorship was categorized as medical, surgical, or combined.

RESULTS

Pediatricians advocated less imaging and intervention and were more inclined to adopt a "watchful-waiting" approach, confident that any significant abnormality, grades IV-V VUR in particular, should be detected following a second febrile UTI. In contrast, surgeons were more likely to recommend imaging to detect VUR (p<0.00001), and antibiotic prophylaxis (p<0.001) and/or surgical correction (p=0.004) if it was detected, concerned that any delay in diagnosis and treatment could place the child at risk of kidney damage. Papers with combined authorship displayed intermediate results.

CONCLUSION

There are two distinct directions in the literature regarding the investigation of an uncomplicated first febrile UTI in a child. In general, when presented with a first febrile UTI in a child, physicians recommend fewer investigations and less treatment, in contrast to surgeons who advocate extensive investigation and aggressive intervention in the event that imaging detects an abnormality. This has the potential to confuse the carers of affected children.

A predictive score for detecting vesicoureteral reflux in children with their first Escherichia coli-induced urinary tract infection

OBJECTIVES

In children with a first Escherichia coli-induced febrile urinary tract infection (fUTI), routine voiding cytourethrography (VCUG) is not recommended for detecting vesicoureteral reflux (VUR). Meanwhile, the sensitivity of renal and bladder ultrasound (RBUS) for detecting VUR is insufficient. Aiming to implement VCUG properly for children with a first E. coli-induced fUTI, we attempted to construct a predictive scoring system for the early screening of VUR.

METHODS

This study enrolled patients aged <2 years of age hospitalized for their first E. coli-induced fUTI during the period when VCUG was implemented for all patients (2007-14, non-selective group [n = 111]) and only for those with VUR-suspected RBUS findings, bacteremia or acute focal bacterial nephritis (2016-19, selective group [n = 102]). We evaluated the accuracy of the current criteria and the VUR predictive score constructed using data from the non-selective group.

RESULTS

In the non-selective group, 32 patients had VUR (29%). In the selective group, 20 of 45 VCUG-tested patients had VUR (44%). Among 57 patients not undergoing VCUG in the selective group, 8 had a recurrence of fUTI, 3 of whom were diagnosed with VUR. In the non-selective group, 9 patients with VUR did not fulfill the current criteria and the VUR predictive score consisting of young age, female sex, prolonged fever, hypoproteinemia, hyponatremia and hyperglycemia, showed higher sensitivity, specificity than the current criteria.

CONCLUSIONS

The current imaging/bacteriological criteria were ineffective in screening for VUR in patients with their first E. coli-induced fUTI. The VUR predictive score can be an accurate indicator for implementing VCUG.

Evaluation of screening with urine dipsticks and renal ultrasonography for 3-year-olds in Chiba City over 30 years

BACKGROUND

Urinary screening for 3-year-olds cannot adequately detect congenital anomalies of the kidney and urinary tract (CAKUT).

METHODS

Urinary screening for 3-year-olds was investigated over 30 years. Dipsticks for proteinuria, hematuria, glycosuria, leukocyturia, and nitrite at first screening, and dipsticks, urinary sediments, and renal ultrasonography at second screening were performed. Screening results were evaluated.

RESULTS

The positive rates of proteinuria, hematuria, leukocyturia, and nitrite relative to 218,831 children at the first screening were 1.0%, 4.6%, 2.3%, and 0.88%, respectively. Thirty-seven glomerular disease, 122 CAKUT, and 5 urological disease cases were found. We detected 6 stage 3-4 chronic kidney disease (CKD) and 3 end-stage kidney disease cases, including 3 CAKUT, comprising 2 bilateral renal hypoplasia and 1 vesicoureteral reflux (VUR), and 6 glomerular diseases, comprising 4 focal segmental glomerulosclerosis and 2 Alport syndrome. The positive rates relative to 218,831 children and CKD detection rates for each tentative diagnosis of mild hematuria, severe hematuria, proteinuria and hematuria, proteinuria, and suspected urinary tract infection were 1.4% and 0.67%, 0.11% and 3.7%, 0.01% and 28.6%, 0.02% and 45.0%, and 0.08% and 9.7%, respectively. Among 14 VUR cases with significant bacteriuria, 13 were found by leukocyturia, 12 had grade ≥ IV VUR, and 10 had severe renal scars.

CONCLUSIONS

Nine stage 3-5 CKD cases comprising 3 CAKUT and 6 glomerular disease were found by urinary screening of 3-year-olds among 218,831 children. The combination of urine dipsticks including leukocyturia at the first screening and ultrasonography at the second screening appeared useful.

Model for predicting high-grade vesicoureteral reflux in young children presenting with febrile urinary tract infection

INTRODUCTION

High-grade vesicoureteral reflux (VUR) is associated with long-term renal outcome, and can be missed if voiding cystourethrogram (VCUG) is not performed. The current febrile urinary tract infection (UTI) guidelines have narrowed down the indications for VCUG. This study aimed to determine the predictors and develop a model to predict high-grade VUR (grade III-V) in young children presenting with febrile UTI.

METHODS

We retrospectively reviewed 324 children aged 2-60 months who presented with first or recurrent febrile UTI and underwent both renal and bladder ultrasonography (RBUS) and VCUG during 2004-2013. Multivariate logistic regression was used to identify independent predictors of high-grade VUR, and a predictive model and scoring system were developed. Sensitivity and specificity of the predictors were evaluated.

RESULTS

Sixty-two (67.4%) of 92 children with VUR were high-grade VUR. The independent risk factors for high-grade VUR were recurrent UTI (p < 0.001), non-Escherichia coli (non-E. coli) pathogen (p = 0.011), and abnormal RBUS (p < 0.001) including pelvicalyceal dilation only (p = 0.003), and with ureteric dilation (p < 0.001). Abnormal RBUS showed highest sensitivity (58.1%), while ureteric dilation had highest specificity (96.6%) to predict high-grade VUR. Combination of these predictors improved the specificity but decreased the sensitivity. The prediction score was calculated, as follows: recurrent UTI = 3 points + non-E. coli = 1 point + pelvicalyceal dilation only = 1 point + pelvicalyceal and ureteric dilation = 3 point. A cutoff score of 1 showed sensitivity of 82.3% and specificity of 63.7%. The specificity would increase (87.8, 92.7, 97.7, 100, 100, and 100%) for higher scores of 2, 3, 4, 5, 6 and 7, respectively.

DISCUSSION

High-grade VUR could be predicted by simple model using single or combined predictors. Sensitivity and specificity varied according to each predictor. The specificity of ureteral dilation was as high as recurrent UTI. The weighing score for each presenting predictor and the summation of the scores provided more detailed in sensitivity and specificity.

CONCLUSIONS

Children with febrile UTI who have the predictor(s) of high-grade VUR are recommended to undergo VCUG. The high-grade VUR prediction score may help for decision-making regarding whether to perform VCUG in a particular child.

Reliability of Sonography for the Prediction of Vesicoureteral Reflux in Children With Mild Hydronephrosis

Objectives:

Postnatal evaluation of vesicoureteral reflux (VUR) remains controversial in patients with antenatal hydronephrosis (HN). The objective of this study was to identify the significance of mild postnatal HN as a marker of VUR and its severity.

Materials and Methods:

Sonographic findings of 248 children (351 kidneys) with persistent postnatal HN were evaluated for the incidence and severity of primary VUR.

Results:

The majority of patients had mild (67.8%) HN, followed by moderate (27.6%) and severe (4.6%) HN. VUR was identified in 14.7% of patients with mild HN, 18.5% of patients with moderate HN, and 18.7% of patients with severe HN. About 11.44% of patients with mild HN had low-grade VUR, followed by moderate (45.71 %) and severe grades (42.85%).

Conclusion:

A large number (89%) of patients with mild HN had moderate to severe VUR. In this cohort, renal sonography was not a reliable method for the prediction of VUR and its severity in patients with mild postnatal HN. However, it was reliable for high grades of VUR. These results are limited due to the study design and the inability to generalize these findings. These results should be replicated across other multiple clinics, thereby recruiting more variety of patients, to validate these study recommendations.

[Clinical features of neurogenic bladder with vesicoureteral reflux in children]

OBJECTIVE

To study the clinical features of vesicoureteral reflux (VUR) in children with neurogenic bladder (NB), and to provide a reference for its early diagnosis and treatment.

METHODS

Clinical data were collected from 26 children with NB and urinary tract infection who were admitted to the Department of Pediatric Nephrology from January 2014 to December 2019. According to the presence or absence of VUR, the children were divided into a VUR group with 11 children and a non-VUR group with 15 children. Clinical features were compared between the two groups.

RESULTS

Compared with the non-VUR group, the VUR group had a significantly higher proportion of children with non-Escherichia coli urinary tract infection, hydronephrosis (the severity of hydronephrosis increased with the grade of VUR), abnormal ^99mTc-DMSA renal scanning findings, elevated ratios of urinary albumin, urinary IgG and urinary transferrin to creatinine, increased residual urine volume, and increased detrusor leak point pressure (P < 0.05).

CONCLUSIONS

When NB children have the clinical manifestations of non-Escherichia coli urinary tract infection, hydronephrosis, abnormal ^99mTc-DMSA renal scanning findings, glomerular proteinuria, increased bladder residual urine volume, and high detrusor leak point pressure, such children may already have VUR, and so diagnosis and intervention should be performed as early as possible.

Guidelines for the medical management of pediatric vesicoureteral reflux

Urinary tract infection is a bacterial infection that commonly occurs in children. Vesicoureteral reflux is a major underlying precursor condition of urinary tract infection, and an important disorder in the field of pediatric urology. Vesicoureteral reflux is sometimes diagnosed postnatally in infants with fetal hydronephrosis diagnosed antenatally. Opinions vary regarding the diagnosis and treatment of vesicoureteral reflux, and diagnostic procedures remain debatable. In terms of medical interventions, options include either follow‐up observation in the hope of possible spontaneous resolution of vesicoureteral reflux with growth/development or provision of continuous antibiotic prophylaxis based on patient characteristics (age, presence/absence of febrile urinary tract infection, lower urinary tract dysfunction and constipation). Furthermore, there are various surgical procedures with different indications and rationales. These guidelines, formulated and issued by the Japanese Society of Pediatric Urology to assist medical management of pediatric vesicoureteral reflux, cover the following: epidemiology, clinical practice algorithm for vesicoureteral reflux, syndromes (dysuria with vesicoureteral reflux, and bladder and rectal dysfunction with vesicoureteral reflux), diagnosis, treatment (medical and surgical), secondary vesicoureteral reflux, long‐term prognosis and reflux nephropathy. They also provide the definition of bladder and bowel dysfunction, previously unavailable despite their close association with vesicoureteral reflux, and show the usefulness of diagnostic tests, continuous antibiotic prophylaxis and surgical intervention using site markings.

First urinary tract infections in children: the role of the risk factors proposed by the Italian recommendations

AIM

In 2009, the Italian society for paediatric nephrology suggested the need for cystography, following a first febrile urinary tract infection (UTI), only in children at high risk for dilating vesicoureteral reflux or in the event of a second infection. The aim of this study was to evaluate the adequacy of the risk factors proposed by the Italian guidelines.

METHODS

Children aged 2-36 months, managed by 10 Italian hospitals between 2009 and 2013, with a first febrile UTI were retrospectively evaluated.

RESULTS

Four hundred and fourteen children were included: 51% female, mean age eight months. Escherichia coli was responsible of 84% UTIs. 269 children (65%) presented at least one risk factor, thus were further investigated: 44% had a reflux. The presence of a pathogen other than E. coli significantly predicted high-grade reflux, both in the univariate (Odd Ratio 2.52, 95% Confidence Interval 1.32-4.81, p < 0.005) and multivariate analysis (OR 2.74, 95% CI: 1.39-5.41, p: 0.003). 26/145 children (18%) with no risk factors experienced a second UTI, which prompted the execution of cystography, showing a dilating reflux in 11.

CONCLUSION

Among the risk factors proposed by the Italian guidelines, only the presence of a pathogen other than E. coli significantly predicted reflux. Cystography can be postponed in children with no risk factors.

Pediatric voiding cystourethrography: An essential examination for urologists but a terrible experience for children

Voiding cystourethrography is the most important fluoroscopic examination in pediatric urology for the investigation of lower urogenital tract diseases, such as vesicoureteral reflux or urethral stricture. However, this invasive procedure imposes a significant burden on children and their parents, and recently there has been a paradigm shift in the diagnosis and treatment of vesicoureteral reflux. In the 2011 revision, the American Academy of Pediatrics guidelines on urinary tract infection recommended abandoning routine voiding cystourethrography after the first febrile urinary tract infection. In 2014, the randomized intervention for children with vesicoureteral reflux study recommended discontinuation of routine continuous antibiotic prophylaxis for vesicoureteral reflux. The time is now ripe to radically reconsider indications for voiding cystourethrography and the procedure itself.

Antimicrobial Resistance and Diagnostic Imaging in Infants Younger Than 2 Months Old Hospitalized With a First Febrile Urinary Tract Infection: A Population-based Comparative Study

BACKGROUND

Data on urinary tract infection (UTI) in infants ≤2 months of age are limited. We examined clinical characteristics, antimicrobial resistance, imaging findings and clinical outcomes in infants ≤2 months of age and children 2-24 months of age hospitalized with the first febrile UTI.

METHODS

Children ≤24 months of age hospitalized with their first-diagnosed febrile UTI were prospectively studied. Renal ultrasonography, Tc-dimercaptosuccinic acid scanning and voiding cystourethrography were performed in all children.

RESULTS

Of the 388 children analyzed (255 boys and 133 girls), 61 patients were ≤2 months of age, representing 15.7% of the whole population, whereas 327 patients were 2-24 months of age. Escherichia coli was the predominant bacterium, with similar antimicrobial resistance in the 2 groups, and associated E. coli bacteremia occurred in 9 patients (2.3%). Renal ultrasonography showed abnormal findings in 130 patients (33.5%), but there was no difference in the rate of abnormal findings between the groups. Vesicoureteral reflux (VUR) was present in 130 children (33.5%), including 93 (24%) with grades III-V VUR. VUR was more prevalent in the infants ≤2 months of age (P = 0.007), but there was no difference in the prevalence of grades III-V VUR between the groups. The incidence of renal scarring was 28.6% (111/388), and it did not differ between the groups.

CONCLUSIONS

There are similarities in clinical characteristics, antimicrobial resistance, imaging findings and clinical outcomes after a first UTI between the young infants ≤2 months and children 2-24 months of age. The same guidelines for the diagnosis and management after the first febrile UTI can be applied to children who are ≤24 months of age.

Increasing the Reliability of the Grading System for Voiding Cystourethrograms Using Ultrasonography: An Inter-Rater Comparison

BACKGROUND

To assess the effectiveness of the current vesicoureteral reflux (VUR) grading system according to the international classification of VUR (ICVUR) and to evaluate whether VUR grading accuracy could be improved by renal ultrasonography (RU) according to the Society for Fetal Urology (SFU) grading system.

OBJECTIVES

Therefore, this study assessed the accuracy of the current VCUG staging system by assessing inter-rater reliability among pediatric radiologists and urologists; it also evaluated whether accuracy is increased by RU without consensus (with respect to VCUG grading).

METHODS

Four pediatric urologists and four pediatric radiologists independently graded 120 voiding cystourethrograms (VCUGs). Middle VUR grades were divided into the following three groups: VUR consensus grade III (group 1), VUR consensus grade IV (group 3), and VUR non-consensus grades III and IV (group 2). All groups were compared with respect to hydronephrosis grade using RU.

RESULTS

The intraclass correlation coefficient (ICC) values ranging from 0.86 to 0.89 reflected good reliability. The lowest agreement was associated with middle grades (III and IV). A marked difference in sensitivity was observed between groups 1 and 3 (35% and 95%, respectively, P < 0.05), indexed by SFU hydronephrosis grade, suggesting that VCUG cases in group 2 (n = 16 at SFU 0 or 1) could be accepted as grade III, and SFU scores of 2, 3, or 4 could be considered grade IV.

CONCLUSIONS

Inter-rater accuracy could be improved at middle grades using renal ultrasonography (USG), which could promote communication between different specialists.