Vesicoureteral reflux is a phenotype, not a disease: A population-centered approach to pediatric urinary tract infection

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.

Spontaneous vesicoureteral reflux resolution curves based on ureteral diameter ratio

INTRODUCTION

Various factors influence the clinical course of vesicoureteral reflux (VUR) in the pediatric population. Distal ureteral diameter ratio (UDR) is an objective measure reflective of ureterovesical junction anatomy that has been shown to independently predict both spontaneous resolution and breakthrough febrile urinary tract infection (UTI) in children with primary reflux. UDR resolution curves were created, hypothesizing that a UDR value existed at which spontaneous resolution was unlikely to occur.

MATERIALS AND METHODS

UDR was computed by measuring largest ureteral diameter within the pelvis and dividing by the distance between L1-L3 vertebral bodies. Recursive partitioning with 10-fold cross validation methodology for time to event data, utilizing martingale residuals was used to create high and low risk groups based on UDR, and stratified by age at diagnosis and laterality.

RESULTS

Three hundred and four patients (226 female, 78 male) were analyzed with a mean age at diagnosis of 1.55 ± 1.98 years. Unilateral reflux (p = 0.02), VUR grades 1-3 (p < 0.001), and lower UDR (p < 0.001) were associated with spontaneous resolution on univariate analysis. UDR values were categorized into risk groups based on recursive partitioning. Low risk patients (those with UDR <0.30) achieved VUR resolution faster and with a continuing rate compared to the high-risk group (≥0.30), which had persistent reflux after 3 years [Summary Figure]. When the 0.30 cutoff was applied randomly to patients in test group, the cutoff significantly discriminated between low and high-risk patients (log rank test p = 0.02).

DISCUSSION

Primary VUR is often a self-limiting diagnosis, with conservative management favored in low-risk children, UDR may be used to help distinguish those children who may benefit from intervention. Unlike traditional VUR grading where children with any grade of reflux may spontaneously resolve, there appears to be a consistent UDR cutoff whereby patients are very unlikely to spontaneously resolve, regardless of length of follow-up. Therefore, parents of children with a UDR above the 0.3 cutoff, regardless of VUR grade, may be counselled that VUR is very unlikely to resolve over time - thereby reducing the number of VCUGs and length of time these patients are on prophylactic antibiotic prior to surgical intervention.

CONCLUSIONS

Children with primary VUR and a UDR of greater than 0.30 are significantly less likely to spontaneously resolve regardless of length of follow-up, and resolution after 3 years was rare. UDR provides objective prognostic information facilitating individualized patient management.

Renal scars in children with febrile urinary tract infection - Looking for associated factors

INTRODUCTION

Febrile urinary tract infection (UTI) is a common childhood infection related to renal scarring and potentially long-term complications like chronic kidney disease. It would be of great benefit to find a correlation between easy-accessible factors in the acute phase of a febrile UTI and the development of renal scar formation and/or decreased renal function in order to identify children at risk of future complications.

OBJECTIVE

The aim of this study was to identify factors associated with the development of decreased split renal function (DSRF) and/or permanent renal scar formation in children with febrile UTI.

STUDY DESIGN

The medical records of 212 Children aged 0 months to 15 years with febrile UTI admitted to The Pediatric Department of Lillebaelt Hospital, Kolding from January 2011 to September 2014 were systematically reviewed. We analyzed clinical, laboratory, and radiologic findings. Statistical analysis was performed to identify factors associated with renal scar formation and DSRF on nuclear imaging at 6 months follow-up.

RESULTS

A total of 113 medical records were eligible for further analysis, 99 girls and 14 boys, 34 patients younger than 12 months. In total 30 patients (26.5%) had an abnormal follow-up imaging (DSRF less than 45% and/or renal scarring). Nine patients (8%) had renal scarring. Four patients (3.5%) had renal scarring only, 21 patients (18.6%) had DSRF only, and five patients (4.4%) had both renal scarring and DSRF. Patients with renal scar formation on follow-up imaging had significantly higher C-reactive protein (CRP) than patients with no scarring (p < 0.01). CRP and absolute neutrophil count (ANC) was significantly higher in patients with abnormal follow-up imaging (p < 0.01 and p = 0.010), and these patients more often had positive nitrite in urine dipstick compared to patients with normal kidneys on follow-up (p = 0.048). Temperature above 38.5 °C and CRP >50 mg/L in combination were also associated with a higher risk of abnormal follow-up imaging (p = 0.016).

DISCUSSION

This study contributes with further knowledge to the ongoing debate regarding renal scarring but also reveals the possibility of associated factors for the development of DSRF following a febrile UTI in children. However, due to the retrospective design as well as the small number of events in our study definite conclusions on whether the above-mentioned factors are indeed prognostic for the development of renal scarring or DSRF following a febrile UTI can not be drawn.

Voiding cystourethrogram: Who gets a cyclic study and does it matter?

BACKGROUND

Voiding cystourethrogram (VCUG) images the urethra and bladder during both bladder filling and emptying, as well as the ureters and kidneys when vesicoureteral reflux (VUR) is present. Given the variation in VCUG technique and reporting, the American Academy of Pediatrics Sections on Urology and Radiology published a joint standardized VCUG protocol in 2016, which included the recommendation of at least 2 voiding cycles to identify intermittent VUR and/or ureteral ectopia.

STUDY DESIGN

VCUG were assessed for adherence to performance of cyclic study. Children who underwent cyclic evaluation were compared to those who underwent a single cycle VCUG. Radiation dosage was also analyzed. Studies performed on patients >18 years of age and those obtained as part of a trauma evaluation were excluded from study.

RESULTS

Two hundred and eighty-four VCUGs were analyzed, 97 (34.2%) were positive for VUR on the initial cycle. Of the remaining 187 studies, 116 (62%) had multiple filling-voiding cycles while in 71 (38%) only a single cycle was performed. One hundred and sixty-one (86.1%) were negative for vesicoureteral reflux. Twenty-six (13.9%) children were diagnosed with VUR after the initial filling-voiding cycle: 6 were diagnosed with grade I, 2 grade II, 11 grade III, 2 grade IV and 5 grade V. Of the 123 total children found to have VUR, 26 (21.2%) were diagnosed after an initial negative cycle. Younger children were significantly more likely to have a cyclic study performed; mean age of patients undergoing a cyclic study was 1.09 ± 2.16 years versus 3.86 ± 4.5 years (p ≤ 0.0001). Categorically, 74.1% of children less than 1 year of age underwent a cyclic study compared to 6.9% of children older than 5 years of age (p ≤ 0.0001). There was no difference based on sex with 49.1% of males and 50.9% of females (p = 0.667) undergoing cyclic evaluation. Children undergoing a cyclic study had lower median radiation dose 2.15 microGy m2 (range 0.09-111) compared to 4.41 (range 1.3-104) [p = 0.01].

DISCUSSION

Vesicoureteral reflux may occur intermittently and cyclic VCUG is thought to enhance the ability to detect reflux. In our cohort, 26 children (9.2%) were only diagnosed after an additional cycle - ie 21.1% of reflux would have been missed had a cyclic study not been performed. The majority of these patients (69.2%, 18 of 26) were found to have dilating, and thus perhaps more clinically significant, reflux. Our study highlights the importance of obtaining as much information as possible and adhering to the standardized VCUG protocol.

CONCLUSION

Younger children are more likely to undergo cyclic VCUG. While most reflux is detected with the initial filling-voiding cycle, 26 (21.2%) patients were diagnosed after an initial negative cycle with the majority being dilating VUR.

Armamentarium to treat primary vesicoureteral reflux in children

Primary vesicoureteral reflux often spontaneously resolves in children. However, in select patients, untreated reflux can contribute to recurrent pyelonephritis leading to irreversible renal damage. Management is therefore based on a given child's likelihood of recurrent urinary tract infections and risk of subsequent renal parenchymal injury. Therapeutic options for urinary reflux are diverse, ranging from observation with or without continuous low-dose antibiotic prophylaxis to a variety of operative interventions.

Evolving surgical management of pediatric vesicoureteral reflux: is open ureteral reimplantation still the 'Gold Standard'?

Vesicoureteral reflux, the retrograde flow of urine from the bladder into the upper urinary tract, is one of the most common urologic diagnoses in the pediatric population. Once detected, therapeutic options for urinary reflux are diverse, ranging from observation with or without continuous low-dose prophylactic antibiotics to a variety of operative interventions. While a standardized algorithm is lacking, it is generally accepted that management be tailored to individual patients based on various factors including age, likelihood of spontaneous resolution, risk of subsequent urinary tract infections with renal parenchymal injury, and parental preference. Anti-reflux surgery may be necessary in children with persistent reflux, renal scarring or recurrent pyelonephritis after optimization of bladder and bowel habits. Open, laparoscopic/robot-assisted and endoscopic approaches are all successful in correcting reflux and have been shown to reduce the incidence of febrile urinary tract infections.

Current Management of Urinary Tract Infection and Vesicoureteral Reflux

Urinary tract infection (UTI) is defined as the growth of a significant number of microorganisms of a single species in the urine, in the presence of symptoms. Symptoms in young children are non-specific such as fever without focus; young infants may manifest with irritability, failure to thrive, jaundice, vomiting and diarrhea. Older children usually have symptoms of cystitis or pyelonephritis. Symptoms of cystitis are dysuria, frequency, new onset incontinence and malodorous urine while symptoms of pyelonephritis are high grade fever, flank pain and vomiting. Rapid urine testing by microscopy for pus cells, dipstick testing for leukocyte esterase and nitrite, and enhanced urinalysis are supportive tests. Urine culture samples should be collected with proper technique and results interpreted for significant growth accordingly. Antibiotic therapy for 7-14 d for complicated UTI and 3-4 d for uncomplicated UTI is adequate. Further evaluation is recommended clinically for bladder-bowel dysfunction and obvious anatomical defects and by imaging for vesicoureteral reflux (VUR), usually by micturating cystourethrography (MCU). Since MCU involves exposure to radiation and urethral catheterization, it is now reserved for children with parenchymal involvement or recurrent UTI. VUR is the backward flow of urine into one or both ureters. Clinical manifestations other than UTI include incidental diagnosis on antenatal ultrasonography. Reflux nephropathy, the renal scarring associated with VUR may manifest clinically as hypertension, proteinuria and renal failure. The management of VUR is primarily with antibiotic prophylaxis. Anatomical correction is indicated in case of breakthrough febrile UTI. No intervention has been shown to reduce renal scarring.

Cost-Utility of Antimicrobial Prophylaxis for Treatment of Children With Vesicoureteral Reflux

Objective: Antimicrobial prophylaxis for children with vesicoureteral reflux (VUR) reduces recurrences of urinary tract infection (UTI) but requires daily antimicrobials for extended periods. We used a cost-utility model to evaluate whether the benefits of antimicrobial prophylaxis outweigh its risks and, if so, to investigate whether the benefits and risks vary according to grade of VUR. Methods: We compared the cost per quality-adjusted life-year (QALY) gained in four treatment strategies in children aged <6 years diagnosed with VUR after a first UTI, considering these treatment strategies: (1) prophylaxis for all children with VUR, (2) prophylaxis for children with Grade III or Grade IV VUR, (3) prophylaxis for children with Grade IV VUR, and (4) no prophylaxis. Costs and effectiveness were estimated over the patient's lifetime. We used $100,000/QALY gained as the threshold for considering a treatment strategy cost effective. Results: Based on current data and plausible ranges to account for data uncertainty, prophylaxis of children with Grades IV VUR costs $37,903 per QALY gained. Treating children with Grade III and IV VUR costs an additional $302,024 per QALY gained. Treating children with all grades of VUR costs an additional $339,740 per QALY gained. Conclusions: Treating children with Grades I, II, and III VUR with long-term antimicrobial prophylaxis costs substantially more than interventions typically considered economically reasonable. Prophylaxis in children with Grade IV VUR is cost effective.

Holding Water: Congenital Anomalies of the Kidney and Urinary Tract, CKD, and the Ongoing Role of Excellence in Plumbing

Congenital anomalies of the kidneys and urinary tracts can result in diminished natal kidney function, possibly through common embryologic pathway disruption or as a result of development taking place in the face of disordered 'post-renal' drainage. Impaired conduit and reservoir function present potential for an ongoing assault leading to further deterioration and progression of chronic kidney disease, a risk that extends to adults with these conditions, even after "correction". The drainage and storage aspects of the urinary system that can impact kidney function are reviewed with attention to correctable or manageable problems including: Bladder dysfunction wherein the low pressure storage of urine is compromised requiring the kidney to work against a pressure gradient, the classic post renal failure problem. The kidney in the aftermath of obstruction which may have lost concentrating capacity leading to a tendency to dehydration ('pre-renal' failure) and through polyuria which exacerbates bladder pressure problems. Further there is an added challenge in evaluation for ongoing or reemergent obstruction in a significantly dilated system where the capacious system leads to slow turnover of urine often requiring a ureteral stent or nephrostomy to clearly establish clinical significance of delayed drainage. Stasis where slow urine flow leads to buildup of debris (stone) or potentiates infection. Vessicoureteral reflux which allows for introduction of lower urinary tract bacteria to the kidney and can lead to pyelonephritis. Conditions which combine problems such as posterior urethral valves where the bladder outlet obstruction compromises kidney function potentially impairing concentrating ability, creates bladder compromise often reducing emptying efficiency or elevating bladder storage pressures, as well as dilating the system potentially promoting stasis. Cognizance of the potential for plumbing problems to further kidney deterioration as patients with congenital urinary tract anomalies, even after they have been repaired is incumbent on those caring for these patients as they age. Thoughtful evaluation of those patients in whom kidney compromise maybe aggravated by drainage and storage disorder will optimize native renal function.