Frequency of urinary tract infection in children with antenatal diagnosis of urinary tract dilatation

Isolated Hydronephrosis and Urinary Tract Infection by Two Years of Age: A Population-Based Study

OBJECTIVE

To evaluate the risk for urinary tract infection (UTI) in infants with isolated hydronephrosis (IH).

STUDY DESIGN

A retrospective, population-based study including all infants insured by Clalit Health Services and followed from birth to age 2 years in 3 regions of central Israel. Infants were divided into 3 groups based on electronic medical record diagnoses by age 6 months: (1) control: no urological diagnosis; (2) IH; and (3) complicated urological diagnosis (CUD): any additional nephrological/urological diagnosis with/without HN. The primary outcome was a diagnosis of UTI in the first 2 years of life.

RESULTS

The cohort included 340 619 infants (52% male): 333 920 controls, 4369 with IH, and 2331 with CUD. Infants with IH were associated with a greater risk for UTI than control patients (17% vs 4%, P < .001). UTI risk for a male infant with IH was greater than for a female infant in the control group (12.6% vs 6.5%, P < .001). In a multivariable logistic regression analysis, both IH (OR 7.04; 95% CI 6.46-7.66) and CUD (OR 14.9; 95% CI 13.6-16.4) were independently associated with UTI.

CONCLUSION

Infants with IH are at a greater risk for UTI in the first 2 years of life, supporting the recommendation for a high index of suspicion for UTI in this population.

Evidence-based clinical practice guideline for management of urinary tract infection and primary vesicoureteric reflux

We present updated, evidence-based clinical practice guidelines from the Indian Society of Pediatric Nephrology (ISPN) for the management of urinary tract infection (UTI) and primary vesicoureteric reflux (VUR) in children. These guidelines conform to international standards; Institute of Medicine and AGREE checklists were used to ensure transparency, rigor, and thoroughness in the guideline development. In view of the robust methodology, these guidelines are applicable globally for the management of UTI and VUR. Seventeen recommendations and 18 clinical practice points have been formulated. Some of the key recommendations and practice points are as follows. Urine culture with > 104 colony forming units/mL is considered significant for the diagnosis of UTI in an infant if the clinical suspicion is strong. Urine leukocyte esterase and nitrite can be used as an alternative screening test to urine microscopy in a child with suspected UTI. Acute pyelonephritis can be treated with oral antibiotics in a non-toxic infant for 7-10 days. An acute-phase DMSA scan is not recommended in the evaluation of UTI. Micturating cystourethrography (MCU) is indicated in children with recurrent UTI, abnormal kidney ultrasound, and in patients below 2 years of age with non-E. coli UTI. Dimercaptosuccinic acid scan (DMSA scan) is indicated only in children with recurrent UTI and high-grade (3-5) VUR. Antibiotic prophylaxis is not indicated in children with a normal urinary tract after UTI. Prophylaxis is recommended to prevent UTI in children with bladder bowel dysfunction (BBD) and those with high-grade VUR. In children with VUR, prophylaxis should be stopped if the child is toilet trained, free of BBD, and has not had a UTI in the last 1 year. Surgical intervention in high-grade VUR can be considered for parental preference over antibiotic prophylaxis or in children developing recurrent breakthrough febrile UTIs on antibiotic prophylaxis.

Revisiting the utility of prenatal ultrasound in the routine workup of first febrile UTI: A systematic review and meta-analysis of the negative predictive value of prenatal ultrasound for identification of urinary tract abnormalities after first febrile urinary tract infection in children

CONTEXT

The current EAU/ESPU and recently retired AAP pediatric UTI guidelines recommend renal bladder ultrasound after first febrile UTI in children to screen for structural abnormalities, regardless of findings on prenatal ultrasound.

OBJECTIVE

Test the hypothesis that a normal prenatal ultrasound could rule out urinary tract abnormality on post-UTI ultrasound.

DATA SOURCES

Medline, Embase, Cochrane Library.

STUDY SELECTION

Studies including pediatric patients with first febrile UTI who had both prenatal and post-UTI ultrasound.

DATA EXTRACTION

Anatomical abnormalities detected by prenatal and post-UTI ultrasound as reported per individual study criteria were extracted. Meta-analyses of 9 studies (2981 patients) were performed using a random-effects model and composite estimates of the negative predictive value (NPV) of prenatal ultrasound were calculated.

RESULTS

Overall summary NPV of prenatal ultrasound for all pediatric patients was 77%, with heterogeneity score (I2) 97.9%. Summary NPV of prenatal ultrasound for all patients under two years of age was similar at 75%, with I2 98.2% For the 4 studies to which we could apply a more stringent definition of abnormality, summary NPV was 85% and I2 97.5% for prediction of moderate post-UTI ultrasound abnormalities and summary NPV was 93% and I2 90.4% for severe abnormalities.

DISCUSSION

While we calculated an 85% NPV for a normal prenatal ultrasound to rule out significant postnatal abnormality as defined within individual studies, substantial heterogeneity amongst publications limited the precision of our estimates. This highlights the need for more rigorous investigations with attention to timing of ultrasound and the application of clinically meaningful definitions for abnormal prenatal and post-UTI studies. This may allow judicious use of prenatal ultrasound to guide clinical management for children with first febrile UTI and minimize redundant imaging with potential for false positive results. Until then, the current guidelines are justified based on the limited and heterogenous data from the currently available published studies.

Fetal Renal Duplicated Collecting System at 14-16 Weeks of Gestation

(1) Background: To examine the incidence of the prenatal diagnosis of the renal double-collecting system (rDCS) and describe its clinical outcome and associated genetic abnormalities. (2) Methods: This retrospective study included women who attended the obstetric clinic for early fetal anatomic sonography with findings of a renal DCS. Diagnosis was conducted by an expert sonographer using defined criteria. (3) Results: In total, 29,268 women underwent early ultrasound anatomical screening at 14-16 weeks, and 383 cases of rDCS were diagnosed (prevalence: 1:76). Associated abnormalities were diagnosed in eleven pregnancies; four had chromosomal aberrations. No chromosomal abnormalities were reported in isolated cases. Ectopic uretrocele and dysplastic kidney were diagnosed in 6 (1.5%) and 5 (1.3%) fetuses, respectively. One girl was diagnosed with vesicoureteral reflux and recurrent UTIs, and two boys were diagnosed with undescended testis. The recurrence rate of rDCS was 8% in subsequent pregnancies. (4) Conclusions: In light of its benign nature, we speculate that isolated rDCS may be considered a benign anatomic variant, but a repeat examination in the third trimester is recommended to assess hydronephrosis.

Staphylococcus Epidermidis as a Uropathogen in Children

Historically, Staphylococcus epidermidis has been considered a contaminant when grown on urine cultures. However, a growing body of literature suggests that S. epidermidis can cause urinary tract infections (UTIs) in children with anatomic variants or a history of instrumentation. In this case report, we describe a previously healthy child who presented with symptoms of UTI and urine cultures grew this uropathogen. The patient was screened for anatomic abnormalities and none were found; nonetheless, appropriate treatment should be initiated even if no underlying pathology is found.

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.

The Evaluation of Genetic Diagnosis on High-Risk Fetal CAKUT

Background: It is challenging to make an accurate prenatal diagnosis for congenital anomalies of the kidney and urinary tract (CAKUT) because of its pathologic diversity. This study aims to evaluate the performance of whole-exome sequencing (WES) combined with karyotype analysis and copy number variations (CNVs) in diagnosing high-risk fetal CAKUT. Methods: We conducted a retrospective study on prenatal diagnoses of CAKUT in our hospital from January 2020 to April 2021. The research studied 24 high-risk fetuses with CAKUT who were scanned by ultrasonography at the prenatal diagnosis center of Tongji Hospital affiliated to Tongji Medical College of Huazhong University of Science and Technology. The likely pathogenic gene variants were screened for the patients and their parents by multiple approaches, including karyotype analysis, CNVs and WES, and further verified with Sanger sequencing. Results: ①We detected abnormal CNVs in 20.8% (5/24) of the fetuses but only 8.3% (2/24) fetuses had abnormal karyotypes. ②Of the 15 CAKUT fetuses, positive findings (40%) were detected by WES. Of the 9 high-risk fetuses with CAKUT (negative findings in ultrasound scan but with family history), we found abnormal variants (77.8%) through WES. Conclusion: The application of CNVs and WES showed advance in prenatal diagnosis of CAKUT and the pathogenic gene variants were detectable especially for high-risk fetuses with negative ultrasound findings on CAKUT in the preliminary study. The applied strategy could be used to improve the accuracy of prenatal diagnosis for CAKUT in the future.

2021 Update on Pediatric Overuse

This update on pediatric medical overuse identifies and provides concise summaries of 10 impactful articles related to pediatric medical overuse from the years 2019 to 2020.

The microbiome in urinary tract infections in children - an update

PURPOSE OF REVIEW

Urinary tract infection (UTI) is one of the most common pediatric infections worldwide. Recently introduced 16S rRNA sequencing allows detailed identification of bacteria involved in UTI on a species-based level. The urogenital microbiome in children is scarcely investigated, with underlying conditions differing from adults. Improvement in diagnostic and therapeutic approaches can help to minimize unnecessary antibiotic treatments, thereby protecting the physiological microbiome.

RECENT FINDINGS

Healthy bladders of children display a distinct microbiome than those of adults. UTI is characterized by changes in bacterial composition, with a high prevalence of Enterobacterales. There is a correlation between bacterial species and the pH of the urine, so a characteristic age-related pathogen pattern can be found due to the acidic urine in infants and more alkaline urine in older children. Recently, new methods were proposed to overcome the suboptimal diagnostic performance of urine cultures and urine dipstick test. This allows precise treatment decisions and helps to prevent chronification of UTI, related voiding dysfunctions and renal scaring, systemic abiosis, and the development of antibiotic resistance.

SUMMARY

Uropathogens involved in UTIs in children should be identified with precision to allow targeted therapeutic decisions. This can also help preventing the destruction of the microbiome homeostasis, which could result in a life-long dysbiosis. New treatment approaches and recolonization with probiotics are necessary due to increasing intrinsic antibiotic resistance of bacteria.

Pathogen distribution and risk factors for urinary tract infection in infants and young children with retained double-J catheters

Objectives

To investigate the pathogens and potential risk factors for urinary tract infection (UTI) in patients with retained double-J catheters (DJCs).

Methods

In total, 107 infants and young children with DJCs were included in this retrospective analysis. Patients were included in the infection group (n = 30) or non-infection group (n = 77), according to UTI presence or absence. The species and characteristics of pathogens were investigated, and the clinical features of the patients were recorded for further analysis.

Results

Gram-negative bacilli were the most common causative pathogens (69.2%), among which Escherichia coli was most frequent (38.5%). The second most common causative pathogens were Gram-positive cocci (28.2%), among which Enterococcus faecalis was most frequent (10.3%). UTIs among patients in this study were associated with the following factors: catheter retention (long-term) (odds ratio [OR] = 2.514, 95% confidence interval [CI] = 1.176–5.373), sex (male) (OR = 2.966, 95% CI = 1.032–8.529), DJC retention (long-term) (OR = 1.869, 95% CI = 1.194–2.926), and DJC number (unilateral) (OR = 0.309, 95% CI = 0.103–0.922).

Conclusions

Infants and young children with DJCs were likely to experience UTIs, mainly caused by Gram-negative bacilli. Long-term catheter retention or DJC retention, male sex, and bilateral DJC retention were risk factors for UTI.

The different elements of the Urinary Tract Dilation (UTD) Classification System and their capacity to predict findings on mercaptoacetyltriglycine (MAG3) diuretic renography

INTRODUCTION

The UTD Classification System risk stratifies postnatal UTD into three groups: low risk (UTD P1), intermediate risk (UTD P2), and high risk (UTD P3). In the original consensus document, a functional scan is not recommended for UTD P1 and is left to the discretion of the clinician for UTD P2 and P3.

OBJECTIVE

This study aims to understand which patients with postnatal urinary tract dilation would benefit from a functional study. We investigated how different elements of the UTD classification system predict differential renal function (DRF) and diuretic half-life (T½) on MAG3 scan in infants undergoing evaluation for prenatally detected UTD.

STUDY DESIGN

This is a multicenter retrospective chart review of infants 6 months of age or younger evaluated for prenatal UTD, correlating their first MAG3 scan and first postnatal renal ultrasound (RUS). Multivariable logistic regression was used to find UTD elements predictive of DRF < 40% and/or T½ > 20 min.

RESULTS

A total of 517 patients met study criteria. Median age at time of RUS and MAG3 renal scan was 48 days (IGR 31-81) and 63 days (IQR 45-98), respectively. DRF < 40% was found in 6% of kidneys with UTD P2 and 35% of kidneys with UTD P3. T½ > 20 min was found in 31% of kidneys with UTD P2 and 79% of kidneys with UTD P3. An abnormal ureter (OR 2.7, 95% CI 1.2-6.0) and parenchymal thinning (OR 16, 95% CI 5.8-41.4) were significant at predicting DRF < 40%. Parenchymal thinning (OR 3.0, 95% CI 1.5-6.1) also predicted T½ > 20 min, as did each cm increase in the anterior-posterior renal pelvic diameter (APRPD) (OR 4.8, 95% CI 3.0-7.7).

DISCUSSION

The UTD system discriminates well and correlates with the likelihood of finding adverse features on diuretic renography. Patients in the UTD P3 high-risk category had a significantly higher incidence of decreased differential renal function and delayed drainage than those in UTD P1 and P2. Of the individual components of the UTD Classification system, the presence of parenchymal thinning was the most important factor in predicting both decreased differential renal function and delayed drainage.

CONCLUSION

Given the high incidence of poor function and delayed drainage seen in the UTD P3 group, we believe a functional study should be recommended in the evaluation of these patients. Our findings support leaving the performance of a functional study at the discretion of the physician for UTD P2.

Novel loss of function variants in FRAS1 AND FREM2 underlie renal agenesis in consanguineous families

INTRODUCTION

Congenital anomalies of the kidney and urinary tract (CAKUT) are a group of abnormalities that affect structure of the kidneys or other structures of the urinary tract. The majority of CAKUT are asymptomatic and are diagnosed prenatally by ultrasound scanning or found incidentally in postnatal life. CAKUT varies in severity and may lead to life-threatening kidney failure and end-stage kidney disease. Renal agenesis, a severe form of CAKUT, is a congenital absence of one or both kidneys. Bilateral renal agenesis belongs to a group of prenatally lethal renal diseases and is often detected on fetal ultrasound scanning during the investigation of oligohydramnios. Approximately 40% of fetuses with bilateral renal agenesis are stillborn or die a few hours postnatally. Mutations in many renal development genes have been shown to be associated with renal agenesis.

METHODS

Six consanguineous Saudi Arabian families were recruited to study the molecular genetic causes of recurrent miscarriages and lost fetuses due to oligohydramnios, renal agenesis and other congenital anomalies. Whole exome sequencing was employed to underlying detect genetic defects.

RESULTS

Novel loss of function variants were detected in FRAS1 and FREM2. In FRAS1, a homozygous splice site variant c.9780+2T>C was found in an affected fetus, segregating form each parent. In addition, in three other families both parents were heterozygous for a frameshift variant (c.8981dupT; p.His2995Profs*3) and splice site variants (c.5217+1G>C and c.8098+2T>A), respectively. In FREM2, a homozygous nonsense variant (c.2303C>G; p.Ser768*) was found in an affected fetus, segregating from both parents. In another family, both parents carried a FREM2 heterozygous frameshift variant (c.3969delC; p.Asn1323Lysfs*5).

CONCLUSION

We describe consanguineous families with clinical features of antenatal oligohydramnios and bilateral renal agenesis, in whom we have identified novel pathogenic variants in FRAS1 and FREM2. These finding highlights the association between mutations in FRAS1 and FREM2 and antenatal/perinatal death.