Predictors of grade 3-5 vesicoureteral reflux in infants ≤ 2 months of age with pyelonephritis

Do Systemic Inflammatory Indices, Urinalysis, and Radiological Findings Vary by Causative Pathogen in Neonatal Urinary Tract Infections?

OBJECTIVES

Urinary tract infections (UTI) are the most common occult infections in infants under three months of age with high fever, caused by various pathogens, and can progress with different symptoms from mild to severe. We planned to explore and compare pathogen-specific systemic inflammatory indices, urinalysis, and radiological findings in newborns.

METHODS

The retrospective study included preterm and term neonates with single pathogen growth of≥50.000 colony-forming units (CFU) /mL from urine cultures obtained by first-time catheterization between September 2019 and November 2021. Baseline hemogram parameters, acute phase reactants, systemic inflammatory indexes, urinalysis, and radiological findings were analyzed in pathogen-specific groups.

RESULTS

Of the 132 patients included in the study, gastrointestinal symptoms were the most common. C-reactive protein values were higher in the non- E. Coli group (p<0.05). Procalcitonin values were higher in patients with Klebsiella spp. isolates (p<0.05). Systemic inflammatory indexes were higher in patients with Coagulase-Negative Staphylococci isolates (p<0.05). Urinary acidity was higher in the non-E. Coli group (p<0.05). Escherichia Coli and Klebsiella Spp. were isolated in two-thirds of patients with leukocyte esterase positivity. The most common cause of UTI in patients with abnormal renal ultrasound findings was E. Coli (33.3%).

CONCLUSION

Our findings imply that unconventional tests could assist in pathogen differentiation, determining clinical presentation, and prognosis.

Vesico-ureteral reflux diagnosis after initial kidney abscess: Results from a Paediatric Tertiary Hospital

AIMS

Guidelines regarding voiding cystourethrogram (VCUG) indications following a paediatric kidney abscess are lacking. This study evaluates vesicoureteral reflux (VUR) prevalence and outcome after a first kidney abscess.

METHODS

This retrospective study included all children presenting to a tertiary paediatric reference centre with de-novo kidney abscesses from 2011 to 2022, diagnosed through imaging (ultrasonography or computed tomography). VCUG's clinical utility was assessed by exploring outcomes related to interventions.

RESULTS

Among the 17 patients (median age 9 months, IQR; 6 months-6 years), VCUG identified VUR in 7 (41%; 95% CI: 18-65%), including two with grade IV-V. Median abscess size was 19 mm (IQR; 14-27). 7/8 (88%) children with DMSA scan presented scars, including 4 with hypofunctioning (20%-44%), and one with a non-functioning kidney. Scarring on the DMSA scan was similar regardless of identified VUR. Six children had subsequent pyelonephritis. Three of the remaining 11 had grade I-III and two IV-V VUR. Surgery was required in four children overall: three for recurrent pyelonephritis and one for high-grade VUR and scars.

CONCLUSION

Among initial kidney abscess cases, 41% had VUR, similar to children experiencing their first uncomplicated pyelonephritis. VCUG results guided antibiotic prophylaxis but not surgical decisions. We suggest considering VCUG following recurrent pyelonephritis/kidney abscess and/or kidney scarring.

Increased prevalence of non-E. coli bacteria-caused urinary infection in neonates delivered by cesarian section

OBJECTIVES

to assess the association between delivery mode and causative pathogens of infants with urinary tract infections.

MATERIALS AND METHODS

We conducted a retrospective analysis of the medical records of neonates delivered in a tertiary academic pediatric hospital and diagnosed with urinary tract infections between January 1,2013 and December 31,2017. Excluded were newborns with urinary tract infections post-urological procedures or neurogenic bladders. The retrieved data included demographic characteristics, clinical presentations, laboratory findings, urine cultures, and renal imaging results. Multivariable logistic regressions were employed to identify associations.

RESULTS

95 of the 131 neonates' (72.5%) cultures were positive for Escherichia coli. Neonates born via cesarean section (C/S) had a significantly higher prevalence (12/25, 48%) of non-Escherichia coli infections (p = 0.01). The mode of delivery was the only variable associated with non-Escherichia coli infections (odds ratio = 3.1, p = 0.014). Two of the 12 neonates (17%) with non-Escherichia coli cultures in the C/S group were diagnosed as having dilating vesicoureteral reflux.

DISCUSSION

While the impact of mode of delivery on microbiome composition and UTI risk in the pediatric population is well documented, to the best of our knowledge, our study is the first to evaluate and report on the clinical connection between mode of delivery and neonatal UTIs. Most noteworthy was our finding of an elevated prevalence of non-E. coli cultures in the C/S group (p = 0.014, OR 3.1). This bears important clinical implications, particularly in the setting of congenital anomaly of kidney and urinary tract (CAKUT) screening.

CONCLUSIONS

Our analyses in this study reveal a significant link between delivery by cesarean section and neonatal urinary tract infections with non- Escherichia coli urine cultures. These findings carry implications for vesicoureteral reflux screening in neonates by raising the level of awareness of the association between the 2 factors. Additional prospective studies on larger cohorts are warranted to further elucidate this relationship and refine clinical decision-making in neonatal care.

Imaging of Vesicoureteral Reflux: AJR Expert Panel Narrative Review

Vesicoureteral reflux (VUR) is a common congenital anomaly of the urinary tract that can present with collecting system dilation or as a febrile infection. VUR can lead to permanent renal sequelae requiring surgery but can also spontaneously resolve without complication. Therefore, recognizing patient populations who warrant imaging for screening, confirmation, or ongoing surveillance for VUR is important, as is avoiding overdiagnosis. In the appropriate patient populations, an accurate diagnosis of VUR allows early treatment and prevention of pyelonephritis and scarring. Various imaging modalities are available to diagnose and grade VUR, including voiding cystourethrography, radionucleotide cystography, and contrast-enhanced voiding urosonography (ceVUS). The objective of this article is to summarize the current understanding of VUR diagnosis and management and to discuss these imaging modalities' strengths and pitfalls. Considerations include indications for VUR imaging, patient preparation, conduct of the examination, issues related to radiologic reporting, and cost-effectiveness. An emphasis is placed on ceVUS, which is the most recently introduced of the three imaging modalities and is receiving growing support among pediatric radiologists.

Urinary Tract Infections in Children

Despite the American Academy of Pediatrics guidelines for the evaluation, treatment, and management of urinary tract infections (UTIs), UTI diagnosis and management remains challenging for clinicians. Challenges with acute UTI management stem from vague presenting signs and symptoms, diagnostic uncertainty, limitations in laboratory testing, and selecting appropriate antibiotic therapy in an era with increasing rates of antibiotic-resistant uropathogens. Recurrent UTI management remains difficult due to an incomplete understanding of the factors contributing to UTI, when to assess a child with repeated infections for kidney and urinary tract anomalies, and limited prevention strategies. To help reduce these uncertainties, this review provides a comprehensive overview of UTI epidemiology, risk factors, diagnosis, treatment, and prevention strategies that may help pediatricians overcome the challenges associated with acute and recurrent UTI management.

The relevance of practical laboratory markers in predicting high-grade vesicoureteral reflux and renal scarring

INTRODUCTION

A high vesicoureteral reflux (VUR) grade is among the specific risk factors for febrile urinary tract infection (febrile UTI) and renal scarring. The aim of this study was to examine the predictive value of some potential hematological parameters for high-grade VUR and renal scarring in children 2 to 24 months old with febrile UTI.

METHODS

We retrospectively examined the clinical features, laboratory tests, and imaging studies of 163 children 2 to 24 months old with a diagnosis of febrile UTI. The hematological parameters based on the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and white blood cell count (WBC) were calculated using a receiver operating characteristic (ROC) analysis to select which one is suitable.

RESULTS

Of the 163 children with febrile UTI, 57 patients (35%) exhibited high-grade VUR. Regarding the predictive power for high-grade VUR, the median area under the curve (AUC) was 0.692 for NLR (sensitivity 61.4%, specificity 69.8%, P < 0.001) and 0.681 for PLR (sensitivity 63.2%, specificity 62.3%, P < 0.001). White blood cell count demonstrated the highest area under the ROC curve for diagnosis of high-grade VUR (0.884, 95% confidence interval 0.834-0.934) and an optimal cutoff value of 13.5 (sensitivity 80.7%, specificity 80.2%, P < 0.001). White blood cell count, with the highest AUC of 0.892 while the sensitivity and specificity were 83.3% and 82.8, was the preferred diagnostic index for renal scarring screening.

CONCLUSIONS

White blood cell count, NLR, and PLR were useful biomarkers closely related to children with febrile UTI who are at risk for high-grade VUR can also act as a novel marker to accurate prediction of high-grade VUR and renal scarring. Also, NLR and PLR can serve as useful diagnostic biomarkers to distinguish high-grade VUR from low-grade VUR.

Risk factors for imaging abnormalities after the first febrile urinary tract infection in infants ≤3 months old: a retrospective cohort study

OBJECTIVES

To assess the association of clinical factors and investigation results (blood and urine) with imaging abnormalities (ultrasound of the kidneys, ureters and bladder; dimercaptosuccinic acid scan; and/or micturating cystourethrogram) and recurrent urinary tract infections (UTIs) in infants ≤3 months old presenting with their first febrile UTI.

METHODS

We conducted a retrospective cohort study of infants ≤3 months old with first febrile UTI admitted from 2010 to 2016. Multivariable logistic regression model was used to analyse the association of imaging abnormalities and recurrent UTI with covariates selected a priori: age at presentation, maximum temperature, duration of illness at presentation, interval between start of antibiotics and fever resolution, C-reactive protein, total white cell count on the full blood count, bacteraemia, white cell count on the urinalysis and non-Escherichia coli growth in the urine culture (non-E. coli UTI).

RESULTS

There were 190 infants but 12 did not undergo any imaging. Median age at presentation was 63 days (IQR 41-78). Twenty-four patients had imaging abnormalities. Non-E. coli UTI (adjusted OR (aOR) 5.01, 95% CI 1.65 to 15.24, p=0.004) was independently associated with imaging abnormalities, while bacteraemia (aOR 4.93, 95% CI 1.25 to 19.43, p=0.022) and non-E. coli UTI (aOR 5.06, 95% CI 1.90 to 13.48, p=0.001) were independently associated with recurrent UTI.

CONCLUSION

Non-E. coli UTI at the first febrile UTI in infants ≤3 months old may be useful in predicting imaging abnormalities while bacteraemia and non-E. coli UTI may be useful to predict recurrent UTI.

Can diagnostic and imaging recommendations from the 2011 AAP UTI guidelines be applied to infants <2 months of age?

INTRODUCTION

In 2011, the American Academy of Pediatrics (AAP) published guidelines regarding diagnosis and management of children 2-to-24-months-old with initial febrile urinary tract infection (fUTI). Available data were insufficient to determine whether evidence from studies of 2-to-24-month-olds applies to those <2-months-old, so they were excluded.

OBJECTIVE

This study aimed to 1) compare demographic, clinical, imaging and outcomes between patients <2-months-old and those 2-to-24-months-old hospitalized with fUTI, and 2) assess whether diagnostic and imaging recommendations of the AAP 2011 guidelines apply to those <2-months-old.

STUDY DESIGN

A cohort study of patients ≤24-months-old hospitalized at a children's hospital with fUTI from 2016 to 2018 was conducted. Data were collected via a prospectively generated electronic medical record note template, supplemented with retrospective chart review. Primary outcomes included differences in demographics, clinical presentation, urine culture results, and imaging utilization/results by age group. Secondary outcomes included surgical procedures, UTI recurrence, and 90-day all-cause readmissions and emergency department (ED) revisits. Univariate and bivariate statistics were utilized to compare age groups.

RESULTS

Overall, 137 patients were included (median age 70 days, 55.5% male [92.1% uncircumcised], 53.3% Hispanic/Latino, 89.8% 1st fUTI). There were no demographic differences between groups, except children <2-months-old were more frequently male (71.2 vs 43.6%, p = 0.002). The Summary Table compares clinical factors and imaging utilization by age. There were no differences in urinalysis or urine culture results between groups. Patients <2-months-old had shorter fever duration, lower maximum temperature, and lower white blood cell counts. Voiding cystourethrograms (VCUGs) were recommended and obtained more frequently in patients <2-months-old, but there were no differences in renal and bladder ultrasound (RBUS) or VCUG results between age groups. There were no differences in UTI recurrence (13.6% of <2-months-old vs 14.1% of 2-to-24-months-old, p = 1.00) or fUTI recurrence (13.6 vs 7.7%, p = 0.40) within 1 year, 90-day readmission (6.8 vs 6.4%, p = 1.00), or 90-day ED revisit (22.0 vs 20.5%, p = 1.00).

DISCUSSION

There were minimal differences between the <2-months-old and 2-to-24-months-old age groups in demographics, laboratory (including microbial) or imaging results, or clinical outcomes. Patients <2-months-old were more frequently male and less ill. These data support applying urinalysis and urine culture diagnostic criteria, and universal RBUS, from the AAP guidelines to patients <2-months-old. Given utilization differences, applicability of VCUG guideline recommendations requires further clarification for patients <2-months-old.

CONCLUSION

Laboratory testing and RBUS recommendations from the AAP guidelines may be safely applied to infants <2-months-old. Further studies are needed to clarify optimal VCUG recommendations.

Update of the EAU/ESPU guidelines on urinary tract infections in children

INTRODUCTION/BACKGROUND

Urinary tract infections (UTIs) are common in children and require appropriate diagnostic evaluation, management and follow-up.

OBJECTIVE

To provide a summary of the updated European Association of Urology (EAU) guidelines on Pediatric Urology, which were first published in 2015 in European Urology.

STUDY DESIGN

A structured literature review was performed of new publications between 2015 and 2020 for UTIs in children. The guideline was updated accordingly with relevant new literature.

RESULTS

The occurrence of a UTI can be the first indication of anatomical abnormalities in the urinary tract, especially in patients with a febrile UTI. The basic diagnostic evaluation should include sufficient investigations to exclude urinary tract abnormalities, but should also be as minimally invasive as possible. In recent years, more risk factors have been identified to predict the presence of these anatomical anomalies, such as a non-E. Coli infection, high grade fever and ultrasound abnormalities. When these risk factors are factored into the diagnostic work-up, some invasive investigations can be omitted in a larger group of children. In addition to the treatment of active UTIs, it is also essential to prevent recurrent UTIs and consequent renal scarring. With the increase of antimicrobial resistance good antibiotic stewardship is needed. In addition, alternative preventative measures such as dietary supplements, bladder and bowel management and antibiotic prophylaxis could decrease the incidence of recurrent UTI.

CONCLUSION

This paper is a summary of the updated 2021 EAU guidelines on Pediatric Urology. It provides practical considerations and flowcharts for the management and diagnostic evaluation of UTIs in children.

[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.

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.

A clinical predictive model of renal injury in children with isolated antenatal hydronephrosis

Background

Antenatal hydronephrosis (ANH) affects ∼1-5% of pregnancies. The aim of this study was to develop a clinical prediction model of renal injury in a large cohort of infants with isolated ANH.

Methods

This is a longitudinal cohort study of 447 infants with ANH admitted since birth between 1989 and 2015 at a tertiary care center. The primary endpoint was time until the occurrence of a composite event of renal injury, which includes proteinuria, hypertension and chronic kidney disease (CKD). A predictive model was developed using a Cox proportional hazards model and evaluated by C-statistics.

Results

Renal pelvic dilatation (RPD) was classified into two groups [Grades 1-2 (n = 255) versus Grades 3-4 (n = 192)]. The median follow-up time was 6.4 years (interquartile range 2.8-12.5). Thirteen patients (2.9%) developed proteinuria, 6 (1.3%) hypertension and 14 (3.1%) CKD Stage 2. All events occurred in patients with RPD Grades 3-4. After adjustment, three covariables remained as predictors of the composite event: creatinine {hazard ratio [HR] 1.27, [95% confidence interval (CI) 1.05-1.56]}, renal parenchyma thickness at birth [HR 0.78(95% CI 0.625-0.991)] and recurrent urinary tract infections [HR 4.52 (95% CI 1.49-13.6)]. The probability of renal injury at 15 years of age was estimated as 0, 15 and 24% for patients assigned to the low-risk, medium-risk and high-risk groups, respectively (P < 0.001).

Conclusion

Our findings indicate an uneventful clinical course for patients with Society for Fetal Urology (SFU) Grades 1-2 ANH. Conversely, for infants with SFU Grades 3-4 ANH, our prediction model enabled the identification of a subgroup of patients with increased risk of renal injury over time.

Congenital Anomalies of the Kidney and Urinary Tract: A Clinical Review

Purpose of review

This review highlights the most common congenital anomalies of the kidney and urinary tract (CAKUT) that are encountered in pediatric practices. CAKUT are the most common cause of prenatally diagnosed developmental malformations and encompass a spectrum of disorders impacting lower urinary tract development as well as kidney development and function. In pediatric and adolescent populations, developmental abnormalities are the leading cause of end-stage kidney disease. The goal of this review is to provide pediatric providers a framework for appropriate clinical management as well as highlight when referral to subspecialty care is needed.

Recent findings

While the exact etiologies of CAKUT are not completely defined, new evidence demonstrates that genetic and molecular changes impact embryonic kidney and urinary tract development. As a result, phenotypes and clinical outcomes may be affected.

Summary

Because pediatric providers provide front-line care to children and adolescents with developmental kidney and urinary tract anomalies, updated knowledge of CAKUT pathogenesis, embryology, clinical management, and patient outcomes is needed. This manuscript reviews CAKUT etiologies and essential diagnostic, prognostic, and management strategies.