Diagnosis and management of urinary tract infection and vesicoureteral reflux in the neonate

ACR Appropriateness Criteria® Urinary Tract Infection-Child: 2023 Update

Urinary tract infection (UTI) is a frequent infection in childhood. The diagnosis is usually made by history and physical examination and confirmed by urine analysis. Cystitis is infection or inflammation confined to the bladder, whereas pyelonephritis is infection or inflammation of kidneys. Pyelonephritis can cause renal scarring, which is the most severe long-term sequela of UTI and can lead to accelerated nephrosclerosis, leading to hypertension and chronic renal failure. The role of imaging is to guide treatment by identifying patients who are at high risk to develop recurrent UTIs or renal scarring. This document provides initial imaging guidelines for children presenting with first febrile UTI with appropriate response to medical management, atypical or recurrent febrile UTI, and follow-up imaging for children with established vesicoureteral reflux. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Causative organisms and antimicrobial susceptibility in jaundiced infants with significant bacteriuria

BACKGROUND

Jaundice may be one of the first signs of urinary tract infection (UTI) in infants. The most common pathogen is Escherichia coli. Currently recommended antibiotic treatment for neonatal UTI is ampicillin and an aminoglycoside. Recently, increasing ampicillin and gentamicin resistance in strains of E. coli has been isolated. The aim of this study was to determine causative organisms and antimicrobial susceptibility in jaundiced infants with significant bacteriuria (SB).

METHODS

We evaluated admitted afebrile, asymptomatic infants younger than 1-month old with hyperbilirubinemia (total bilirubin >15 mg/dl) requiring phototherapy between January 2011 and December 2015. A total of 615 asymptomatic jaundiced infants were enrolled. Urinalysis and urine cultures were performed on all jaundiced infants. A urine culture was defined as SB if a single pathogen with more than 105-colony forming units per milliliter (CFU/ml) by sterile urinary collection bag or 104 CFU/ml by catheterization was isolated.

RESULTS

A total of 88 (14.3%) of 615 asymptomatic jaundiced infants had positive urinary culture. E coli was the most common cultured bacteria (40 cases, [45.5%]). Enterococcus faecalis was the second most common bacteria (17 cases, [19.3%]). Seven cases (8.0%) of Streptococcus agalactiae and six cases (6.8%) of Klebsiella pneumoniae were also identified. Ampicillin sensitivity was found in 22.5% of E. coli infections, gentamicin sensitivity was found in 84.2%, and extended-spectrum β-lactamases were found in 7.5%.

CONCLUSION

E. coli was the most common causative organism for infants with SB. We suggest modifying current empiric antibiotics by changing gentamicin to amikacin for neonatal Gram-negative bacterial infections.

Practice Summary of Antimicrobial Therapy for Commonly Encountered Conditions in the Neonatal Intensive Care Unit: A Canadian Perspective

Neonates are highly susceptible to infections owing to their immature cellular and humoral immune functions, as well the need for invasive devices. There is a wide practice variation in the choice and duration of antimicrobial treatment, even for relatively common conditions in the NICU, attributed to the lack of evidence-based guidelines. Early decisive treatment with broad-spectrum antimicrobials is the preferred clinical choice for treating sick infants with possible bacterial infection. Prolonged antimicrobial exposure among infants without clear indications has been associated with adverse neonatal outcomes and increased drug resistance. Herein, we review and summarize the best practices from the existing literature regarding antimicrobial use in commonly encountered conditions in neonates.

Factors Affecting Prevalence of Urinary Tract Infection in Neonates with Unexplained Hyperbilirubinemia: A Systematic Review and Meta-Analysis Study in Iran

Background:

The prevalence and risk factors of urinary tract infection (UTI) in neonates with unexplained hyperbilirubinemia are not studied thoroughly. Since the prevalence of UTI is highly variable in different areas and countries, this study aimed to review the existing data of Iranian neonates with UTI presented with unexplained hyperbilirubinemia.

Methods:

This study is a meta-analysis of Iranian newborns with unexplained hyperbilirubinemia. We identified all studies indexed in international (Web of Science, PubMed, Scopus, Google Scholar) and national (Science Information Database, Magiran) databases from 2000–2018. Search terms included: Urinary Tract Infections OR UTI AND urine OR culture OR microbio, jaundice OR icter OR hyperbili, AND Iran.

Results:

Overall, 4210 neonates from 17 studies were included. The pooled prevalence of UTI in neonates with unexplained hyperbilirubinemia was 6.81% (95% CI: 4.86–8.77). Considering the subgroups analyses; the prevalence of UTI was higher in the prolonged vs. not-prolonged state (8.34% vs. 4.00%), low birth weight vs. normal birth weight (7.81% vs. 4.51%), and exclusive vs. non-exclusive breastfeeding (8.84% vs. 4.72%). Male gender and low birth weight increased the risk of UTI about two times compared to the female gender and normal birth weight, respectively. The results of the analyses in neonates with unconjugated hyperbilirubinemia also showed the above-mentioned subgroup differences.

Conclusion:

Due to considerable prevalence of UTI in neonates with unexplained hyperbilirubinemia and risk factors in this age group, investigation for UTI is essential for the workup in this situation.

Responsible genes in children with primary vesicoureteral reflux: findings from the Chinese Children Genetic Kidney Disease Database

BACKGROUND

Primary vesicoureteral reflux (VUR) is a common congenital anomaly of the kidney and urinary tract (CAKUT) in childhood. The present study identified the possible genetic contributions to primary VUR in children.

METHODS

Patients with primary VUR were enrolled and analysed based on a national multi-center registration network (Chinese Children Genetic Kidney Disease Database, CCGKDD) that covered 23 different provinces/regions in China from 2014 to 2019. Genetic causes were sought using whole-exome sequencing (WES) or targeted-exome sequencing.

RESULTS

A total of 379 unrelated patients (male: female 219:160) with primary VUR were recruited. Sixty-four (16.9%) children had extrarenal manifestations, and 165 (43.5%) patients showed the coexistence of other CAKUT phenotypes. Eighty-eight patient (23.2%) exhibited impaired renal function at their last visit, and 18 of them (20.5%) developed ESRD at the median age of 7.0 (IQR 0.9-11.4) years. A monogenic cause was identified in 28 patients (7.39%). These genes included PAX2 (n = 4), TNXB (n = 3), GATA3 (n = 3), SLIT2 (n = 3), ROBO2 (n = 2), TBX18 (n = 2), and the other 11 genes (one gene for each patient). There was a significant difference in the rate of gene mutations between patients with or without extrarenal complications (14.1% vs. 6%, P = 0.035). The frequency of genetic abnormality was not statistically significant based on the coexistence of another CAKUT (9.6% vs. 5.6%, P = 0.139, Chi-square test) and the grade of reflux (9.4% vs. 6.7%, P = 0.429). Kaplan-Meier survival curve showed that the presence of genetic mutations did affect renal survival (Log-rank test, P = 0.01). PAX2 mutation carriers (HR 5.1, 95% CI 1.3-20.0; P = 0.02) and TNXB mutation carriers (HR 20.3, 95% CI 2.4-168.7; P = 0.01) were associated with increased risk of progression to ESRD.

CONCLUSIONS

PAX2, TNXB, GATA3 and SLIT2 were the main underlying monogenic causes and accounted for up to 46.4% of monogenic VUR. Extrarenal complications and renal function were significantly related to the findings of genetic factors in children with primary VUR. Like other types of CAKUT, several genes may be responsible for isolated VUR.

Strengthening the success rate of suprapubic aspiration in infants by integrating point-of-care ultrasonography guidance: A parallel-randomized clinical trial

BACKGROUND

Urinary tract infection (UTI) is a common disease in childhood. A sterile collection of urine samples using suprapubic aspiration (SPA) and bladder catheterization (BC) is helpful for rapid and accurate diagnosis of UTI in infants. With the advent of point-of-care ultrasound (POCUS), the use of ultrasound by non-radiologists at the patient's bedside, great advancement has been noticed in various medical fields. Considering the importance and advantages of using POCUS in the physical examination and guiding procedures, the authors aimed to compare urine sampling's success rate by SPA, BC, and POCUS guided SPA (POCUS-SPA) in infants performed by three pediatricians.

MATERIALS AND METHODS

This study is a randomized clinical trial conducted on 114 neonates and infants with suspected UTI admitted to 17-Shahrivar children's hospital from April 2017 to September 2019. Neonates and infants were randomly assigned to three groups of BC, SPA, and POCUS-SPA. The primary outcome was the success of sampling defined by obtaining 1cc of urine in each method. The secondary outcome was assessing the pain level.

RESULTS

Results showed that the POCUS-SPA had the highest success rate in urine sampling, and a statistically significant relation was noted among the three groups (P = 0.0001). From 38 patients in each group, 37 patients of POCUS-SPA (97.4%), 34 patients of BC (89.5%), and 23 patients of SPA (60.5%) had a successful sampling. Most of the patients in all three groups experienced severe pain.

CONCLUSIONS

In the current study, results showed that the POCUS-SPA significantly increased the success rate of urine sampling and most of the patients in all three groups had severe pain. Based on the shortage of access to radiologists in emergency setups, it seems that the POCUS-SPA by the pediatricians can be one of the most appropriate and applicable diagnostic methods in infants with UTI.

Catheter-Obtained Urine Culture Contamination Among Young Infants: A Prospective Cohort Study

Objectives: A correct diagnosis of urinary tract infection in young infants requires an uncontaminated urine culture, commonly obtained by urethral catheterization. In the current study, we examined the rates and factors associated with contaminations of catheter-obtained urine cultures in very young infants. Methods: This prospective cohort study included 143 catheter-obtained urine cultures of infants ≤2 months of age admitted to the pediatric ward of a tertiary hospital in Israel from April 2019 to September 2020. Patient's and operator's study variables were documented at the time of catheter insertion. Positive urine cultures were reviewed by a pediatric nephrologist and a pediatric infectious disease specialist and designated as infection or contamination. The study variables were compared between those with or without contamination. Results: The contamination rate in our cohort was 29%. Females were more than twice as likely to have a contaminated urine culture (37 vs. 18%, respectively, P = 0.014). Circumcision status, official training about sterile catheterization, a sense of difficult catheterization, and the shift in which the culture was obtained did not influence the contamination rate. Conclusions: Catheter-obtained urine cultures have a high contamination rate among very young infants, especially among girls.

Which near-patient tests might improve the diagnosis of UTI in older people in urgent care settings? A mapping review and consensus process

PURPOSE

The aim of this study was to map out the existing knowledge on near-patient tests for urinary tract infections, and use a consensus building approach to identify those which might be worthy of further evaluation in the urgent care context, defined as clinically useful and feasible results available within 4-24 h.

METHODS

A systematic search for reviews describing diagnostic tests for UTI was undertaken in Medline, EMBASE, Cochrane database of systematic reviews and CINAHL selected reviews were retained according to a priori inclusion and exclusion criteria, and then graded for quality using the CASP tool for reviews. A consensus process involving microbiologists and chemical pathologists helped identify which test might conceivably be applied in the urgent care context (e.g. Emergency Department, giving results within 24 h).

RESULTS

The initial search identified 1079 papers, from which 26 papers describing 35 diagnostic tests were retained for review. The overall quality was limited, with only 7/26 retained papers scoring more than 50% on the CASP criteria. Reviews on urine dipstick testing reported wide confidence intervals for sensitivity and specificity; several raised concerns about urine dip testing in older people. A number of novel biomarkers were reported upon but appeared not to be helpful in differentiating infection from asymptomatic bacteriuria. Blood markers such as CRP and procalcitonin were reported to be helpful in monitoring rather than diagnosing UTI. The consensus process helped to refine the 35 test down to 17 that might be useful in the urgent care context: urinalysis (nitrites and leucocytes), uriscreen catalase test, lactoferrin, secretory immunoglobulin A, xanthine oxidase, soluble triggering receptor expressed on myeloid cells, A-1 microglobulin (a1 Mg) and a1 Mg/creatinine ratio, cytokine IL-6, RapidBac, MALDI-TOF, electronic noses, colorimetric sensor arrays, electro chemical biosensor, WBC count (blood), C-reactive peptide, erythrocyte sedimentation rate.

CONCLUSIONS

A wide range of diagnostic tests have been explored to diagnose UTI, but, in general, have been poorly evaluated or have wide variation in predictive properties. This study identified 17 tests for UTI that seemed to offer some primes and merit further evaluation for diagnosing UTI in older people in urgent care settings.

Acquired Infection and Antimicrobial Utilization During Initial NICU Hospitalization in Infants With Congenital Diaphragmatic Hernia

BACKGROUND

In addition to substantial medical and surgical intervention, neonates with congenital diaphragmatic hernia often have concurrent concerns for acquired infection. However, few studies focus on infection and corresponding antimicrobial utilization in this population.

METHODS

The Children's Hospital Neonatal Database was queried for congenital diaphragmatic hernia infants hospitalized from January 2010 to February 2016. Patient charts were linked to the Pediatric Health Information Systems database. Descriptive clinical data including delivery history, cultures sent, diagnosed infection, antimicrobial use and outcomes were reported.

RESULTS

A total of 1085 unique patients were identified after data linkages; 275 (25.3%) were born at <37 weeks' gestation. Bacteremia at delivery (2/1085) and in the first 7 days of life (8/1085) was less common than later infection, but 976 patients (89.9%) were treated with antibiotics. Median number of days on antibiotics was 6 [3,11] for those without a documented infection and 21 [13,36] for those with positive cultures. Incidence of urinary tract infection, bacteremia and pneumonia increased significantly over time and was most common after 28 days. Antibiotic use, conversely, decreased over time (92% of infants in week 1 to 44% in week 4 and beyond).

CONCLUSIONS

Although culture positivity increased with age, risk of these selected infections was relatively low for a population in neonatal intensive care unit. An important mismatch is observed between culture negativity and high rates of antibiotic utilization. These data identify opportunities for antibiotic stewardship quality improvement programs.

ACR Appropriateness Criteria® Urinary Tract Infection-Child

Urinary tract infection (UTI) is common in young children and may cause pyelonephritis and renal scarring. Long-term complications from renal scarring are low. The role of imaging is to evaluate for underlying urologic abnormalities and guide treatment. In neonates there is increased risk for underlying urologic abnormalities. Evaluation for vesicoureteral reflux (VUR) may be appropriate especially in boys because of higher prevalence of VUR and to exclude posterior urethral valve. In children older than 2 months with first episode of uncomplicated UTI, there is no clear benefit of prophylactic antibiotic. Ultrasound is the only study that is usually appropriate. After the age of 6 years, UTIs are infrequent. There is no need for routine imaging as VUR is less common. In children with recurrent or complicated UTI, in addition to ultrasound, imaging of VUR is usually appropriate. Renal cortical scintigraphy may be appropriate in children with VUR, as renal scarring may support surgical intervention. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Proteinuria and hematuria in the neonate

PURPOSE OF REVIEW

Neonatal proteinuria and hematuria while not common can have potentially devastating consequences if left undiagnosed and untreated. It is important to distinguish between inherited and acquired causes of proteinuria to initiate appropriate and timely treatment. With regards to hematuria, it is critical to identify true hematuria from pseudo-hematuria to balance between thorough investigation and unnecessary laboratory work up. This review provides an overview of the common causes of hematuria and proteinuria in a neonate.

RECENT FINDINGS

The identification of genetic mutations in nephrotic syndrome has improved our understanding of the role of various proteins that play an important role in maintaining the glomerular filtration barrier. With the advancement in our ability to provide care for extreme premature neonates, the incidence of acute kidney injury has increased in these neonates along with proteinuria and hematuria.

SUMMARY

Persistent proteinuria after neonatal acute kidney injury would be of interest in regards to the risk of developing future chronic kidney disease and hypertension.

Development and validation of a CE-MS method for the targeted assessment of amino acids in urine

A CE-ESI-MS method was developed and validated for the separation and quantitative analysis of amino acids (AA) in urine. Experimental parameters related to the CE-MS interface, BGE, and mass spectrometer (MS) settings were optimized providing a good separation of 27 AA, including the isomers L-leucine, L-isoleucine, and L-alloisoleucine, in less than 30 min. The sheath liquid was composed by 0.50% formic acid in 60% (v,v) methanol-water delivered at a flow rate of 5 μL/min. The BGE consisted of 0.80 mol/L formic acid at pH 1.96 and 15% methanol. A pH stacking procedure was implemented to enhance sensitivity (a 12.5% NH4 OH solution was injected at 0.5 psi/9 s prior to samples injected at 0.6 psi/20 s). The proposed method was validated according to FDA and ICH protocols exhibiting acceptable parameters. Analytical curves presented coefficients of determination from 0.996 to 0.9997 (with large F statistics and low p-values). LODs and quantification ranged from 0.63 to 29 μmol/L and from 1.9 to 86 μmol/L, respectively. Practical repeatability was obtained for all AA with coefficients of variation better than 0.55% CV (migration time) and 1.7% CV (peak area ratios; methionine sulfone as internal standard). Recoveries of AA in spiked urine ranged from 92.0 to 123% with few exceptions. Moreover, a successful quantification of AA in pooled control and test urine samples, which compose a vesicoureteral reflux cohort, was achieved showing the potential applicability of the proposed method for targeted metabolomics studies using CE-ESI-MS with an Ion Trap as mass analyzer.

Urinary microprotein concentrations in the long-term follow-up of dilating vesicoureteral reflux patients who underwent medical or surgical treatment

PURPOSE

This study examined the relationship between urinary microprotein concentrations and renal functional parameters in children with dilating (grade III-V) vesicoureteral reflux (VUR) who underwent either medical or surgical treatment.

METHODS

All 44 dilating VUR patients who were followed for 4 years were screened for inclusion in this study. The patients' clinical features and clinical outcomes, as well as the urinary activities of albumin (ALB), transferrin (TRF), immunoglobulin G (IgG), alpha-1-microglobulin (α1-MG), and N-acetyl-β-glucosaminidase (NAG), were retrospectively analyzed.

RESULTS

High values of NAG, α1-MG, IgG, TRF, and ALB were noted in 73.33, 58.33, 43.33, 24.14, and 53.33 % of patients, respectively, at the first examination. Cystatin C, eGFR, and urinary microprotein levels were associated with a good prognosis after 4 years of follow-up. No differences in recurrent UTI, cystatin C concentration, most microprotein/creatinine (Cr) ratios, eGFR, or ΔGFR4 % were found between the groups. High levels of urinary proteins were found in 2.38-9.52 % of cases after 4 years of follow-up. ALB/Cr, IgG/Cr, and α1-MG/Cr levels were positively correlated with 99mTc-dimercaptosuccinic acid (DMSA) grade, and α1-MG excretion was inversely correlated with eGFR.

CONCLUSIONS

The levels of microprotein were elevated at diagnosis in a higher proportion of patients than for the other markers examined. At long-term follow-up, the reflux level had decreased or completely resolved in all patients, and the proportions of microproteins that were elevated were significantly reduced. Renal impairment measured by eGFR and DMSA grade was related to increased urinary α1-MG levels.