Antenatal hydronephrosis as a predictor of postnatal outcome: a meta-analysis

Ureter development and associated congenital anomalies

Malformations of the ureter are among the most common birth defects in humans. Although some of these anomalies are asymptomatic, others are clinically relevant, causing perinatal lethality or progressing to kidney failure in childhood. The genetic causes and developmental aetiology of ureteral anomalies are difficult to study in humans; however, embryological and genetic analyses in the mouse have provided insights into the complex developmental programmes that govern ureter formation from simple tissue primordia, and the pathological consequences that result from disruption of these programmes. Abnormalities in the formation of the nephric duct and ureteric bud lead to changes in the number of ureters (and kidneys), whereas the formation of ectopic ureteric buds, failure of the nephric duct to target the cloaca or failure of the distal ureter to mature underlie vesicoureteral reflux, ureter ectopia, ureterocoele and subsequent hydroureter. Alterations in ureter specification, early growth or cyto-differentiation programmes have now also been associated with various forms of perinatal hydroureter and hydronephrosis as a consequence of functional obstruction. The characterization of cellular processes and molecular drivers of ureterogenesis in the mouse may not only aid understanding of the aetiology of human ureteral anomalies, improve prognostication and benefit the development of therapeutic strategies, but may also prove important for efforts to generate a bioartificial organ.

A retrospective analysis of prenatal genetic results in fetal hydronephrosis

OBJECTIVE

To discuss the application value of technologies such as chromosome microarray analysis (CMA) in fetuses with hydronephrosis and pyelectasis.

METHODS

Retrospectively collected the prenatal diagnostic data of 83 fetuses with hydronephrosis from January 2020 to July 2024. The positive rate of chromosomal abnormalities detected by different ultrasound abnormalities was statistically analyzed.

RESULTS

Among the 83 pregnant women, 10 cases of abnormal karyotypes were detected by invasive prenatal diagnosis, with an abnormality rate of 12.05%. Numerical chromosomal abnormalities accounted for 90%, mainly trisomy 21 and 13. In the fetuses with normal karyotype/no abnormality, CMA additionally detected 15 copy number variations (CNVs) in 12 cases. Divided into isolated hydronephrosis and non-isolated hydronephrosis groups, the detection rates of fetuses carrying pathogenic CNVs were 5.56% and 12.77% respectively, and the detection rates of fetuses carrying variants of uncertain significance (VUS) were 19.44% and 8.51% respectively. Still, the differences between the two groups were not statistically significant (P > 0.05). Divided into moderate to severe hydronephrosis group and mild hydronephrosis group, the detection rate of pathogenic abnormalities by CMA was 10% and 37.21% respectively, and the difference between the two groups was statistically significant (P < 0.05).

CONCLUSION

Hydronephrosis is associated with chromosomal abnormalities, and the rate of chromosomal abnormalities increases significantly as the degree of hydronephrosis increases. The combined use of CMA technology can detect abnormalities caused by chromosomal microdeletions and/or microduplications, which is of great value for clinical prenatal consultation.

Can ultrasound parameters predict the diagnostic yield of diuretic renal scintigraphy in pediatric hydronephrosis?

Diuretic renal scintigraphy (DRS) is a valuable imaging tool for distinguishing obstructive from non-obstructive hydronephrosis, especially in pediatric patients, but non-diagnostic results are not uncommon. In this retrospective analytical study, we examined if kidney ultrasound (US) parameters can predict non-diagnostic DRS, and DRS with an obstruction pattern, potentially guiding patient selection to reduce unnecessary radiation exposure. The study included 67 patients (134 kidneys), 1-month to 4-years of age who underwent both DRS and US. Receiver operating characteristic (ROC) curve analysis of US parameters including parenchymal thickness, cortical thickness, medullary pyramidal thickness, anterior-posterior renal pelvic diameter, was done to assess the predictiveness of these parameters for prediction of DRS results. None of the US parameters reliably predicted non-diagnostic DRS results (AUC range: 0.41-0.61). However, these parameters demonstrated good predictiveness for identifying DRS with an obstruction pattern (AUC range: 0.69-0.87), with anterior-posterior renal pelvic diameter showing the highest performance. These findings suggest that while US parameters cannot predict non-diagnostic DRS outcomes, they are effective in identifying obstruction patterns on DRS.

Second trimester soft markers: still worth to be mentioned?

Despite the widespread use of cell-free DNA in screening for trisomy 21, soft markers continue to be assessed in the second trimester, leading to confusion about how they affect the risk of trisomy 21, especially after an earlier screening test such as cell-free DNA screening. In this review, we provide an overview of commonly used second trimester soft markers, explain how they can be used to calculate the risk for trisomy 21, and discuss what other chromosomal or structural abnormalities might be associated with these markers. We especially focus on pathogenic copy number variants as these, in aggregate, are common and are very difficult to detect using cfDNA or even standard karyotyping.

Prenatal Urologic Consultation for Prenatal Hydronephrosis: True Equity or Hidden Disparity?

INTRODUCTION

Prenatal urologic consultation (PUC) is now offered to many prospective parents for fetal prenatal hydronephrosis (PH). This study aims to describe patient- and community-level differences in prenatal and postnatal urologic care patterns for patients with PH and to identify potentially modifiable factors that would improve timely access to care.

METHODS

We identified all patients with PH aged <6 mos seen at a single freestanding children's hospital from January 2021 to December 2022. Data were collected on patient gender, race/ethnicity, characteristics of upper tract dilatation, timing of delivery, and socioeconomic status. Patients with and without PUC were compared.

RESULTS

Two hundred and fifty patients met inclusion criteria. One hundred seventy-nine (71.6%) were male, 122 (48.8%) were White, and 56 (22.4%) had PUC. Patients with PUC had postnatal evaluation earlier than those without PUC (0.62 [0.2-5.0] versus 2.1 [0.1-12.8] months (P < 0.0001) but were equally likely to have bilateral PH (41.1% versus 41.2%, P = 0.73). Patients speaking English (54/229; 23.6%) and other languages (LOE; 2/21; 9.5%) were equally likely to have PUC. Children living in the least (Area Deprivation Index [ADI], 1-2) and moderately disadvantaged areas (ADI, 3-8) were equally (odds ratio [OR] = 1.52; 95% confidence interval [CI]: 0.55-4.23) and three times (OR = 2.99; 95% CI: 1.16-7.67) as likely to have PUC as those living in the most disadvantaged areas (ADI, 9-10), respectively. Of preterm infants, 25% of those living in ADI 1-2 had PUC, compared with 0% of those living in ADI 9-10 (OR = 3.32; 95% CI, 0.57-11.4), and 24% of those speaking English had PUC, compared with 0% of those with LOE (OR = 1.98; 95% CI, 0.09-45.6). The likelihood of PUC for patients with bilateral PH was similar for patients living in ADI 1-2 (6/33; 18.2%) and ADI 9-10 (2/19; 10.5%; OR = 1.89 [95% CI, 0.34-10.45]) and for those speaking English (23/96; 24%) and LOE (0/7; 0%; OR = 4.80 [95% CI, 0.26-87.2]).

CONCLUSIONS

PUC is associated with earlier postnatal urologic evaluation, but-in our series-not with PH laterality, language, race, or lowest levels of neighborhood disadvantage. However, the proportion with and without PUC in certain subgroups was notably low. Further research centering on patient groups with low PUC utilization may identify patient- and community-level factors associated with differential access to care.

Imaging Diagnosis of Major Kidney and Urinary Tract Disorders in Children

Background and Objectives: Diagnostic imaging is essential for evaluating urinary tract disorders, offering critical insights into renal pathology. This review examines the strengths, limitations, and clinical applications of various imaging modalities, with a focus on pediatric populations. Materials and Methods: A narrative review was conducted, synthesizing current literature on ultrasound (US), computed tomography (CT), magnetic resonance imaging (MRI), nuclear medicine, and voiding cystourethrography (VCUG). Relevant studies were selected based on diagnostic accuracy, clinical utility, and safety considerations. Results: US is the preferred first-line imaging due to its safety, accessibility, and cost-effectiveness. CT excels in detecting renal calculi, trauma, and malignancies but is limited by radiation exposure. MRI offers superior soft tissue contrast without radiation but is costly and often requires sedation. Nuclear medicine evaluates renal function and scarring, while VCUG remains the gold standard for diagnosing vesicoureteral reflux and posterior urethral valves. Conclusions: Imaging modalities are vital for diagnosing and managing urinary tract disorders, with selection based on clinical needs, patient age, and safety. Ultrasound is the primary choice for its non-invasiveness and cost-effectiveness, while CT, MRI, nuclear medicine, and VCUG provide essential structural and functional insights. A balanced approach ensures accuracy while minimizing patient risk, especially in pediatrics.

Deep Learning Algorithms to Predict Differential Renal Function <40% in Unilateral Hydronephrosis Based on Key Parameters of Urinary Tract Ultrasound

OBJECTIVE

To identify the correlation between ultrasound findings and the incidence of differential renal function (DRF) <40%, we conducted an analysis of the key parameters of urinary tract ultrasound in children with unilateral hydronephrosis. For children with unilateral hydronephrosis, DRF <40% serves as a compelling indication for surgical intervention, and it can be assessed through diuretic renogram. However, a significant number of patients do not have convenient access to high-quality renograms. So we conducted this analysis aiming to identifying value of urinary tract ultrasound in surgical intervention decision.

METHODS

We retrospectively reviewed the dynamic renogram and urinary tract ultrasound data of 802 children with hydronephrosis presented to our department. Independent risk factors related to DRF <40% were screened out. Several machine learning models were employed. The area under receiving operating curves (AUROC) was calculated for each model to compare their efficiency.

RESULTS

The renal pelvis anterior-posterior diameter, upper calyx dilation, and renal length ratio were found to be independent risk factors for DRF <40%. Among these factors, the renal length ratio had the highest AUROC of 0.820. These 3 factors, alone with the patients' age, were then introduced into 3 machine learning models: random forest, logistic regression, and support vector machines (SVM), among which, the SVM exhibited the highest AUROC of 0.941, with a sensitivity of 90.32% and a specificity of 81.03%.

CONCLUSION

The length ratio exhibited the strongest correlation with DRF <40% among multiple ultrasound indices. Moreover, the SVM model exhibited significant improvement compared to individual factors. Therefore, it can be employed to identify high-risk children with impaired renal function in the assessment of congenital hydronephrosis.

Development of LncRNA Biomarkers in Extracellular Vesicle of Amniotic Fluid Associated with Antenatal Hydronephrosis

Background: Antenatal hydronephrosis (ANH) is the most common congenital renal and urinary tract anomaly, and parenchymal damage and renal fibrosis due to pathological hydronephrosis are the main causes of end-stage renal disease in children and chronic kidney disease in adults. At present, there is no validated biomarker for ANH, and diagnostic criteria other than prenatal ultrasonography (US) assessment are lacking. Therefore, we assessed to determine if biomarkers extracted from amniotic fluid small extracellular vesicles (sEVs) might be used as ANH diagnosis. Methods: With congenital ureteropelvic junction obstruction (UPJO) as the ultimate diagnosis, 10 pregnant women with Grade III-IV ANH and 10 normal pregnant women were recruited. The sEVs were extracted from amniotic fluid supernatant of all samples. Transcriptomic sequencing of sEVs in the discovery cohort identified the differential expression profiles for ANH. The known differentially expressed lncRNAs (DE-lncRNAs) were assessed by qRT-PCR in the validation cohort. Results: We explored the global RNA expression in sEVs from amniotic fluid. The differential expression profiles of both mRNAs and lncRNAs were related to fetal kidney development. Six known DE-lncRNAs were identified for ANH, and three of those with high expression were verified in more ANH samples. In particular, the upregulated LINC02863 and its target genes were associated with renal development and morphogenesis. The four predicted novel lncRNAs in high expression were also related to mesenchymal morphogenesis and the STAT3 signaling pathway and may play roles in ANH. Conclusions: We identified differentially expressed RNAs of all species in the sEVs from amniotic fluid, and the validated known DE-lncRNAs might serve as promising diagnostic biomarkers for ANH.

Trends and socioeconomic inequality of the burden of congenital abnormalities of the kidney and urinary tract among children and adolescents

BACKGROUND

Although congenital abnormalities of the kidney and urinary tract (CAKUT) is the leading cause of childhood-onset chronic kidney disease and kidney failure, comprehensive information on the disease burden among children and adolescents globally is lacking. We aim to report the trends and socioeconomic inequality of CAKUT burden for people aged 0-24 years from 1990 to 2019.

METHODS

We reported the prevalence, mortality and disability-adjusted life-years (DALYs) for CAKUT based on the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, quantified the association of disease burden and socio-demographic index (SDI), and calculated the slope index of inequality, the relative index of inequality and concentration index.

RESULTS

In 2019, the global prevalence, mortality and DALYs of CAKUT among individuals aged 0-24 years were 167.11 (95% confidence interval 166.97, 167.25), 0.30 (0.29, 0.30) and 32.22 (32.16, 32.29), respectively, per 100 000 population. The greatest prevalence, mortality and DALYs were recorded in the 0-4 years age group. The greatest mortality and DALYs were recorded in low SDI countries and territories. During 1990 to 2019, the prevalence, mortality and DALYs decreased globally, while in low and low-middle countries and territories the reduction was much less slower. India, Nigeria and Pakistan had the highest DALYs. Saudi Arabia and China exhibited a markedly decrease of CAKUT burden. Globally for every 0.1 increase in SDI, there was a 20.53% reduction in mortality and a 16.31% decrease in DALYs, but a 0.38% rise in prevalence.

CONCLUSIONS

Inequality for disease burden of varying SDI was increasing globally. Thus, specific preventive and health service measures are needed to reduce the global burden from CAKUT.

Congenital Abnormalities of Kidneys and Urinary Tract: A Top--Down Review of the Embryology and Imaging Appearance

Congenital abnormalities of the kidneys and urinary tract (CAKUT) encompass a spectrum of pathology ranging in severity from incidental findings to marked deviations of anatomic form and function. The imaging appearance of CAKUT generally reflects a deviation from normal embryologic development. Common and uncommon congenital abnormalities of the kidneys, ureters, bladder, and urethra are reviewed with an emphasis on the imaging appearance and embryologic origin so that they may be promptly identified and treated when encountered in clinical practice.

Upper tract dilation is an independent risk factor for febrile UTI in children with primary vesicoureteral reflux

BACKGROUND

Children with vesicoureteral reflux (VUR), particularly high-grade VUR, are known to be at increased risk for urinary tract infection (UTI). Current guidelines highlight certain clinical factors in the management of children with VUR; however, the clinical utility of upper tract dilation in the setting of VUR remains unclear.

OBJECTIVE

The purpose of this study is to evaluate risk factors for febrile UTI (fUTI) in children with primary VUR in a modern cohort with emphasis on upper tract dilation parameters, including hydronephrosis and hydroureter.

METHODS

A prospectively maintained database of children with VUR at a single academic institution from July 2013 to February 2023 was reviewed. Demographic and clinical data were included. Ultrasounds closest to initial VCUG were reviewed for upper tract dilation, including the presence of hydronephrosis, Society of Fetal Urology (SFU) hydronephrosis grade, presence of hydroureter, and anterior-posterior renal pelvic diameter (APRPD). The primary outcome of interest was the development of a fUTI after VUR diagnosis. Patients were censored after their first fUTI or after VUR surgery.

RESULTS

A total of 235 children with primary VUR were evaluated, including 125 (53.2 %) females and 110 (46.8 %) males. The median age of VUR diagnosis was 10.8 months (IQR: 2.3-63.6 months). A total of 41 (17.4 %) children developed a fUTI after VUR diagnosis with a median follow up of 2.3 years (IQR: 0.9-4.6 years). On univariate analysis, variables found to be associated with fUTI included age <1 year at VUR diagnosis (p = 0.021), female sex (p = 0.013), high-grade VUR (p = 0.024), APRPD ≥7 mm (p = 0.007), high-grade hydronephrosis (p = 0.004), presence of hydronephrosis (p = 0.029), and hydroureter (p = 0.008). In children with VUR and high-grade hydronephrosis, a larger APRPD was associated with higher fUTI rates (p = 0.008). On multivariate analysis controlling for age, sex, and VUR grade, APRPD ≥7 mm (OR 2.8, p = 0.009), high-grade hydronephrosis (OR 2.5, p = 0.025), and presence of hydronephrosis (OR 2.3, p = 0.049) were independent risk factors for fUTI. On multivariate models controlling for other upper tract dilation parameters, APRPD ≥7 mm was the most significant parameter associated with increased fUTI risk in primary VUR.

CONCLUSION

Upper tract dilation is a novel, independent risk factor for fUTI in children with primary VUR, with APRPD being the strongest predictor. Clinicians may consider upper tract dilation parameters in addition to age, sex, and VUR grade when individualizing care in children with primary VUR.

Novel CO2 loaded nanoparticle ultrasound-activated contrast agent: A potential urinary catheter-free modality to detect vesicoureteral reflux

BACKGROUND

The current gold-standard for detecting vesicoureteral reflux (VUR) is the voiding cystourethrogram (VCUG). However, VCUGs require ionizing radiation and bladder catheterization that can be challenging to perform and traumatic for pediatric patients and their parents.

OBJECTIVE

To investigate the feasibility of a novel urinary catheter-free modality for diagnosing VUR using in vitro and ex vivo models.

DESIGN, SETTING, AND PARTICIPANTS

Polyethyleneimine (PEI) and pressurized CO2 gas were utilized to formulate our polymer in a standardized and reproducible method. The CO2-loaded PEI solution was stimulated using moderate intensity ultrasound in latex balloons and ev-vivo porcine bladders. Degassed, deionized water served as the control.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

A Butterfly iQ ultrasound imaging system connected to a 9th generation iPad was utilized to observe any effervescence (bubbles).

RESULTS

In both the balloon and ex vivo bladder models, CO2 effervescence is reproducible and visualizable from the CO2-loaded polymer solution under US imaging after stimulation.

CONCLUSIONS

We have demonstrated the ability to selectively release CO2 from CO2-loaded PEI nanoparticles to serve as an ultrasound contrast agent in both in vitro and ex vivo models. Future combined kidney-bladder porcine model experiments will be a critical step as we work towards validating and translating this agent as an effective modality for the diagnosis of VUR.

PATIENT SUMMARY

In this feasibility study, we evaluated early pre-clinical models of a urinary catheter-free modality for the diagnosis of vesicoureteral reflux. We utilized a novel CO2-loaded nanoparticle solution that creates bubbles when activated with moderate intensity ultrasound. These bubbles were clearly visualizable with regular diagnostic ultrasound imaging in both a latex balloon and porcine bladder model.

Outcome of Neonatal Hydronephrosis, a New Cut-Off to Identify Patients with Spontaneous Resolution

BACKGROUND/OBJECTIVES

The anteroposterior renal pelvis diameter (APRPD) is used to assess the grade of urinary tract dilatation (UTD). There is no univocal method stratifying the risk of complications related to postnatal UTD. This study aims to identify APRPD cut-offs at birth to determine outcome stratification and second-level exams.

METHODS

The records of a cohort of newborns with unilateral or bilateral UTD confirmed or detected by ultrasound after birth between 2010 and 2020 were analyzed. These children underwent further examinations at 3, 6, 12, and 24 months of age.

RESULTS

We managed 500 children with postnatal UTD, with a median APRPD at 0-2 months of age of 7.7 mm [IQR 6.0-10.0]. As for UTD resolution, 279 (55.8%) patients had a complete resolution at the age of 6 months; an additional 55, for a total of 344 (68.8%), at 9-12 months; and 19, for a total of 353 (70.6%), at 24 months. An APRPD value ≤ 8.5 mm showed a sensitivity of 80.4% (95% CI [76.0-84.4]) and a specificity of 100.0% (95% CI [76.8-100.0]) in identifying candidates for spontaneous resolution within 24 months of life. An APRPD value ≤ 8.5 mm was also an independent prognostic factor of resolution at the age of 24 months (p = 0.000).

CONCLUSIONS

Isolated hydronephrosis is the most frequent urinary tract abnormality detected in pregnancy. A well-structured prenatal and postnatal management plan is indeed necessary. According to our analyses, 8.5 mm can be used as a cut-off to reassure parents and clinicians of the benignity of the postnatal dilatation.

Maternal diseases and congenital anomalies of the kidney and urinary tract in offspring: a cohort study

BACKGROUND

Congenital anomalies of the kidneys and urinary tract (CAKUT) are the most common cause of prenatally diagnosed developmental malformation. This study aimed to assess the relationship between maternal diseases and CAKUT in offspring.

METHODS

This retrospective study enrolled all pregnant women registered from January 2020 to December 2022 at one medical center. Medical information on maternal noncommunicable diseases, including obesity, hypertension, diabetes mellitus, kidney disease, hyperthyroidism, hypothyroidism, psychiatric disease, epilepsy, cancer, and autoimmune disease was collected. Based on the records of ultrasound scanning during the third trimester, the diagnosis was classified as isolated urinary tract dilation (UTD) or kidney anomalies. Multivariate logistic regression was performed to establish models to predict antenatal CAKUT.

RESULTS

Among the 19,656 pregnant women, perinatal ultrasound detected suspicious CAKUT in 114 (5.8/1000) fetuses, comprising 89 cases with isolated UTD and 25 cases with kidney anomalies. The risk of antenatal CAKUT was increased in the fetuses of mothers who experienced gestational diabetes, thyroid dysfunction, neuropsychiatric disease, anemia, ovarian and uterine disorders. A prediction model for isolated UTD was developed utilizing four confounding factors, namely gestational diabetes, gestational hypertension, maternal thyroid dysfunction, and hepatic disease. Similarly, a separate prediction model for kidney anomalies was established based on four distinct confounding factors, namely maternal thyroid dysfunction, gestational diabetes, disorders of ovarian/uterine, and kidney disease.

CONCLUSIONS

Isolated UTD and kidney anomalies were associated with different maternal diseases. The results may inform the clinical management of pregnancy and highlight potential differences in the genesis of various subtypes of CAKUT.

Genetic and Clinical Factors Influencing Congenital Anomalies of the Kidney and Urinary Tract in Children: Insights from Prenatal and Postnatal Assessments

Congenital anomalies of the kidney and urinary tract (CAKUT) significantly contribute to pediatric morbidity, often necessitating ureterorenal surgery. This study explored the relationship between genetic mutations, renal surgery requirements, and prenatal, postnatal, and parental risk factors in children with CAKUT. A retrospective analysis of 651 children diagnosed with CAKUT included patient demographics, parental risk factors, ultrasound findings, genetic mutations, and surgical incidence. Antenatal ultrasounds showed normal findings in 32.1%, hydronephrosis in 46.9%, and other abnormalities in 21% of cases. Surgical intervention correlated with higher hydronephrosis reduction than non-intervention. Genetic mutations were identified in 5.4% of cases, with 24.6% requiring surgery. Low neonatal birth weight (odds ratio [OR] = 0.98, p < 0.001), advanced maternal age (OR = 1.06, p < 0.001), and postnatal abnormal ultrasound findings (OR = 2.62, p < 0.001) were associated with increased genetic mutation risks. Antenatal hydronephrosis (OR = 3.85, p < 0.001) and postnatal urinary tract infections (OR = 4.85, p < 0.001) increased the likelihood of surgical intervention. Neonatal birth weight, maternal age, and postnatal ultrasound findings were identified as independent risk factors for genetic mutations, while no significant link was found between these genetic factors and the need for surgery. Surgical needs were associated with urinary tract infections and antenatal hydronephrosis, indicating that timely surgical intervention may benefit these patients.

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.

Long Term Follow-Up Of Patients With Nonrefluxing Hydronephrosis

BACKGOUND

The aim of this study is to examine the long-term prognosis of children with ureteropelvic junction obstruction-like hydronephrosis (UPJO-like HN).

PATIENTS AND METHODS

The files of children with hydronephrosis (HN) were analyzed retrospectively. Patients with vesicoureteral reflux (VUR) and other genitourinary anomalies were excluded. The final status of the HN, the need for surgery, and urinary tract infection (UTI) frequency were evaluated.

RESULTS

The study included 219 patients with 302 renal units (RU) with HN. Surgery rate was higher in RUs with larger kidney size and parenchymal thinning (p:<0.001 for both). Hydronephrosis resolved in 113 (40.2%) RUs, improved in 66 (23.3%), unchanged in 100 (35.5%) and worsened in 4 (1.4%). The frequency of recovery and improvement was found to be less in RUs with severe HN, large kidney size, and thin parenchyma. The UTI frequency was higher in severe HN group (12.2% vs 30.6% p:<0.001).

CONCLUSIONS

Children with mild HN had an excellent prognosis. Although the majority of the patients with high-grade HN had also a good prognosis, it seems important to closely follow up patients with severe HN, increased kidney size, and accompanying parenchymal thinning. Clinicians should be aware of the increased frequency of UTIs in children with severe HN.

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.

Predicting clinically significant events in children with ureteropelvic junction obstruction

Introduction

Ureteropelvic junction obstruction (UPJO) syndrome is one of the most common causes of neonatal hydronephrosis. Management varies from simple monitoring to surgical intervention, with indications differing between institutions. A consensus of 8 societies recently described a new Urinary Tract Dilation (UTD) classification which aims to standardize ultrasound description of hydronephrosis, but which is also supposed to have predictive value in children with hydronephrosis. Our aim was to compare, in a monocentric prospective cohort of children with UPJO, the ability of UTD to predict the occurrence of a clinically significant event within the first year of life, as compared to anteroposterior diameter of the renal pelvis (APD).

Study design

We used a preexisting cohort of children followed in a prospective study on UPJO. A pediatric radiologist, blinded to the children's outcome, classified the last antenatal ultrasound and postnatal ultrasound according to the UTD-A and UTD-P classification. He also confirmed the APD-A and APD-P measures. We defined a clinically significant event as being: increased pelvic dilation (>5 mm) and/or the presence of a febrile urinary tract infection (fUTI) and/or impaired renal function on initial nuclear scan (<40%). We performed a ROC-AUC curve and Random Forest (RF) analysis to compare the ability of the APD-A, APD-P, UTD-A and UTD-P scores to predict a clinically significant event.

Results

The cohort included 28 children. Clinically significant events were noted in 20 out of 28 patients: 13 children presented an increase >5 mm in dilation, 6 presented an episode of fUTI and 9 had impaired function of the affected kidney. APD-A was the most effective individual criterion for predicting the occurrence of a significant clinical event (AUC = 0.867).

Conclusion

In our series, for children with UPJO, the most significant marker was prenatal APD >15 mm to predict an increase in dilation >5 mm.

A machine learning algorithm predicting risk of dilating VUR among infants with hydronephrosis using UTD classification

BACKGROUNDS

Urinary Tract Dilation (UTD) classification has been designed to be a more objective grading system to evaluate antenatal and post-natal UTD. Due to unclear association between UTD classifications to specific anomalies such as vesico-ureteral reflux (VUR), management recommendations tend to be subjective.

OBJECTIVE

We sought to develop a model to reliably predict VUR from early post-natal ultrasound.

STUDY DESIGN

Radiology records from single institution were reviewed to identify infants aged 0-90 days undergoing early ultrasound for antenatal UTD. Medical records were reviewed to confirm diagnosis of VUR. Primary outcome defined as dilating (≥Gr3) VUR. Exclusion criteria include major congenital urologic anomalies (bilateral renal agenesis, horseshoe kidney, cross fused ectopia, exstrophy) as well as patients without VCUG. Data were split into training/testing sets by 4:1 ratio. Machine learning (ML) algorithm hyperparameters were tuned by the validation set.

RESULTS

In total, 280 patients (540 renal units) were included in the study (73 % male). Median (IQR) age at ultrasound was 27 (18-38) days. 66 renal units were found to have ≥ grade 3 VUR. The final model included gender, ureteral dilation, parenchymal appearance, parenchymal thickness, central calyceal dilation. The model predicted VUR with AUC at 0.81(0.73-0.88) on out-of-sample testing data. Model is shown in the figure.

DISCUSSION

We developed a ML model that can predict dilating VUR among patients with hydronephrosis in early ultrasound. The study is limited by the retrospective and single institutional nature of data source. This is one of the first studies demonstrating high performance for future diagnosis prediction in early hydronephrosis cohort.

CONCLUSIONS

By predicting dilating VUR, our predictive model using machine learning algorithm provides promising performance to facilitate individualized management of children with prenatal hydronephrosis, and identify those most likely to benefit from VCUG. This would allow more selective use of this test, increasing the yield while also minimizing overutilization.

Stratifying Antenatal Hydronephrosis: Predicting High-Grade VUR Using Ultrasound and Scintigraphy

(1) Background: Antenatal hydronephrosis (AHN), detected in approximately one percent of prenatal ultrasounds, is caused by vesicoureteral reflux (VUR) in 15-21% of cases, a condition with significant risks such as urinary tract infections and renal scarring. Our study addresses the diagnostic challenges of VUR in AHN. Utilizing renal ultrasonography and scintigraphy, we developed a novel scoring system that accurately predicts high-grade VUR, optimizing diagnostic precision while minimizing the need for more invasive methods like voiding cystourethrogram (VCUG); (2) Methods: This retrospective study re-analyzed renal ultrasonography, scintigraphy, and VCUG images from infants admitted between 2003 and 2013, excluding cases with complex urinary anomalies; (3) Results: Our analysis included 124 patients (75% male), of whom 11% had high-grade VUR. The multivariate analysis identified visible ureter, reduced renal length, and decreased differential renal function (DRF) as primary predictors. Consequently, we established a three-tier risk score, classifying patients into low, intermediate, and high-risk groups for high-grade VUR, with corresponding prevalences of 2.3%, 22.2%, and 75.0%. The scoring system demonstrated 86% sensitivity and 79% specificity; (4) Conclusions: Our scoring system, focusing on objective parameters of the visible ureter, renal length, and DRF, effectively identifies high-grade VUR in AHN patients. This method enhances diagnostics in ANH by reducing reliance on VCUG and facilitating more tailored and less invasive patient care.

Voiding Cystourethrogram Before Pyeloplasty: To Do or Not To Do?

OBJECTIVE

To assess the incidence of concomitant vesicoureteral reflux (VUR) in unilateral cases of ureteropelvic junction obstruction (UPJO) and to identify factors that predict VUR.

METHODS

Files of 381 pediatric patients who underwent unilateral pyeloplasty between 2000 and 2017 were retrospectively reviewed. A total of 270 patients with available data and ≥5 years of follow-up were eligible for this study. Demographic parameters, preoperative hydronephrosis grade, renal pelvis anteroposterior diameter (APD), renal parenchymal thickness (PT), split renal functions on MAG-3 scan and VUR status were noted. The patients were divided into two groups: those with concomitant VUR (group I, n: 24, 8.9%) and those without VUR (group II, n: 246, 91.1%).

RESULTS

Among 270 patients (205 boys, 75.9%) with a median age of 4 months (2-98), 197 (72.9%) had antenatal hydronephrosis. Median follow-up was 11 years (5-22). Among 24 patients with concurrent VUR, 6 (25%) had grade II VUR, whereas grade III-V VUR was detected in 18 (75%). Of these, 12 (50%) had ipsilateral VUR, 3 (12.5%) had contralateral, and 9 (37.5%) had bilateral VUR. In a median 137-month follow-up, spontaneous VUR resolution was observed in 6 (25%) patients, whereas 15 (62.5%) patients underwent endoscopic subureteral injection and 3 (12.5%) patients ureteroneocystostomy, respectively. Preoperative APD [35.5, (Inter Quantile Range) IQR (27.6-36.0) vs 26.5 IQR (25.0-35.0), P = .004] were significantly higher in group I, whereas group I had significantly lower PT [3.7, IQR (3.4-6.4) vs 5.8 IQR (4.4-6.1), P = .026]. Predictive factors for concomitant VUR were presentation with febrile UTI (odds ratio (OR): 2.769, P = .048), PT <3.95 mm (OR: 1.367, P = .043), and APD >28.8 mm (OR: 1.035, P = .001).

CONCLUSION

Our results indicated that concomitant VUR and UPJO might be detected in 1 out of every 11 patients undergoing pyeloplasty, while some type of surgical intervention for VUR was required in 75% of these patients. Thus, voiding cystourethrogram prior to pyeloplasty may be limited in those presenting with febrile urinary tract infection, having higher APD and lower PT on preoperative urinary ultrasonography.

Epidemiology of Infantile Ureteropelvic Junction Obstruction in the US

OBJECTIVE

To describe sex- and diagnosis-specific comorbidities, outcomes, and secular trends associated with ureteropelvic junction obstruction (UPJO) in a large, real-world population diagnosed with hydronephrosis in infancy.

MATERIALS AND METHODS

We identified all infants ≤1 year old with ≥1 claim in the Optum Clinformatics 2007-2020 nationwide population database and used univariable and multivariable Cox regression analyses to estimate associations of demographic and clinical characteristics of infants with a UPJO diagnosis with surgical status.

RESULTS

Of 22,349 infants with hydronephrosis (1.1% of infants; males-1.4%, females-0.7%), 1722 (7.7%; 7.9%-males, 7.2%-females) had UPJO. Follow-up was ≥1 year in 1198 (70%) and ≥3 years in 555 (32%) cases, and UPJO repair was performed in 542 children (31.5%; 32.3%-males, 29.5%-females); 77.7% within 1 year and 97.3% within 3 years. UPJO repair was associated with prior urinary tract infection (UTI) (hazard ratio (HR) 1.41, 95% confidence interval (CI) 1.12-1.76) and South (HR 1.42, 95% CI 1.14-1.78) or Midwest (HR 1.60, 95% CI 1.26-2.04) geographic region but did not change over time.

CONCLUSION

This population-based study provides a real-world view of postnatally diagnosed hydronephrosis, focusing on UPJO, for which 522 cases (∼1/3) had ≥3 years continuous coverage. UPJO-associated comorbidities were more common in females, and the frequencies of UPJO-associated surgery and comorbidities were higher than in other studies. Other than UTI, no other associated kidney or urinary tract diagnoses were associated with UPJO repair. We identified unique sex- and diagnosis-specific differences in associated comorbidities and interventions in children diagnosed with UPJO in the first year of life.

Outcomes of children with isolated antenatal hydronephrosis

BACKGROUND

Antenatal hydronephrosis (ANH) is one of the most common abnormalities detected during prenatal ultrasound. There is significant variability in the postnatal management of ANH. Our objective was to report the outcomes of patients with ANH, spontaneous resolution rates, surgical intervention rates, and factors contributing to these parameters.

METHODS

A total of 227 patients and 264 renal units with ANH were included in this study. We used the renal pelvis anteroposterior diameter and the Society for Fetal Urology grading system to classify and compare ANH as mild, moderate, and severe.

RESULTS

The patients' median follow-up period was 48 months (with a minimum of 6 months and a maximum of 136 months). Of the 264 renal units, 123 (46.6%) had mild, 101 (38.26%) had moderate, and 40 (15.15%) had severe antenatal hydronephrosis. The spontaneous resolution rate was 91.9% in the mild hydronephrosis group (n = 113), 81.2% (n = 82) in the moderate hydronephrosis group, and 37.5% (n = 15) in the severe hydronephrosis group. The patients with higher hydronephrosis grades required a longer time to resolve. Only one patient with a posterior urethral valve had reduced estimated glomerular filtration. None of the patients had proteinuria or hypertension.

CONCLUSION

Although the outcome of the patients with mild hydronephrosis was excellent, there was a progression of the disease, especially within the first 6 months, and 6% of our cases required surgical intervention. Additional prospective studies are needed to define the risk of urinary tract abnormalities with any degree of ANH.

Just Get in Line: Rural-Urban Differences in Access to Pediatric Renal-Bladder Ultrasounds

INTRODUCTION

Health-care disparities in rural and underserved areas may be exacerbated by the pandemic, personnel challenges, and supply chain limitations. This study aimed to quantify current variation in rural and urban pediatric renal ultrasound availability.

METHODS

We identified all hospitals statewide and contacted radiology departments posing as a parent trying to schedule an appointment for a routine pediatric renal-bladder ultrasound. Intervals between day of contact and first available appointment were compared between rural and urban institutions.

RESULTS

We were able to contact 42/48 (87.5%) rural hospitals, and 20/39 (51.3%) urban hospitals. Scheduling could not be completed in 5 rural and 7 urban hospitals. The median wait time for the 37 remaining rural and 13 remaining urban hospitals was similar: 7 (range: 0-21) days in rural hospitals and 6 (range: 0-17) days in urban hospitals (P = 0.81). If contact was made, the likelihood of scheduling within 7 d was similar in rural and urban areas (odds ratio [OR] = 0.23; 95% confidence interval [CI] 0.03-1.97; P = 0.18). However, patients were much more likely to have a completed call at a rural hospital (OR = 6.65; 95% CI: 2.3-19.2; P = 0.0005), and so in reality, patients were 2.89 times as likely to be able to schedule an renal-bladder ultrasound within 7 d at a rural compared with an urban institution (95% CI: 1.19-7.03; P = 0.019).

CONCLUSIONS

While access to pediatric renal sonograms was similar within a week at rural and urban institutions once telephone contact was made, it was significantly more difficult to schedule appointments at urban institutions.

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.

Congenital anomalies of the kidney and urinary tract: defining risk factors of disease progression and determinants of outcomes

Congenital anomalies of the kidney and urinary tract (CAKUT) result from disruptions in normal kidney and urinary tract development during fetal life and collectively represent the most common cause of kidney failure in children worldwide. The antenatal determinants of CAKUT are diverse and include mutations in genes responsible for normal nephrogenesis, alterations in maternal and fetal environments, and obstruction within the normal developing urinary tract. The resultant clinical phenotypes are complex and depend on the timing of the insult, the penetrance of underlying gene mutations, and the severity and timing of obstruction related to the sequence of normal kidney development. Consequently, there is a broad spectrum of outcomes for children born with CAKUT. In this review, we explore the most common forms of CAKUT and those most likely to develop long-term complications of their associated kidney malformations. We discuss the relevant outcomes for the different forms of CAKUT and what is known about clinical characteristics across the CAKUT spectrum that are risk factors of long-term kidney injury and disease progression.

Influence of foetal position on the degree of isolated antenatal hydronephrosis

BACKGROUNDS

The effect of foetal position on the degree of antenatal hydronephrosis (ANH) is unknown. We hypothesized that foetal position is an important contextual factor in ANH, with consequences on prenatal counselling and postnatal management. The current study aimed to investigate the effect of foetal position on the degree of ANH.

METHODS

A retrospective study was carried out on consecutive pregnancies with isolated ANH over a 10-year period. Gestational age, foetal presentation (cephalic vs. breech), and degree of ANH (as measured by the AP diameter) were retrieved. Foetuses with other ultrasound findings of the renal tract (renal parenchymal abnormality, ureteric dilatation, or bladder abnormalities) were excluded. Logistic regression analysis was conducted to examine the relationship between the anterior-posterior diameter (APD) and the mode of presentation (cephalic or breech). A P-value of <0.05 was considered significant.

RESULTS

Initially 745 scans were identified, with 436 included in the final analysis. Overall, there was an association between foetal presentation and APD regardless of trimester, with cephalic presentations having a greater APD (OR 1.07, 95% CI 1.02-1.11, P = 0.04).

CONCLUSION

Cephalic presentations are associated with a significantly greater APD indicating that foetal position should be considered when stratifying ANH. Furthermore, foetal position may be a contributing factor in the mechanism of 'physiological' hydronephrosis.

Congenital Anomalies of the Kidney and Urinary Tract: A Continuum of Care

Congenital anomalies of the kidney and urinary tract (CAKUT) are the leading cause of kidney failure in children and adolescents. CAKUT describes a wide spectrum of structural disorders with a prenatal origin. The etiology of CAKUT is multifactorial, including environmental, nongenetic, and genetic causes that impact kidney development as well as upper and lower urinary tract development. Adult nephrologists who treat patients with CAKUT may be challenged by the underlying diseases they are not familiar with and the accumulation of chronic kidney disease complications in childhood. This article discusses CAKUT etiology and presentation, the course during childhood and adolescence, as well as adult issues in CAKUT patients including CKD complications, urologic interventions, and genetic counseling. A smooth transition of CAKUT patients from pediatric to adult care can be challenging. Semin Nephrol 43:x-xx © 2023 Elsevier Inc. All rights reserved.

Antenatally detected urinary tract dilatation: long-term outcome

This review provides updated knowledge on the long-term outcomes among children with antenatally diagnosed urinary tract dilatation (UTD), previously often referred to as antenatal hydronephrosis. Different definitions of UTD exist, which makes comparison between studies and generalized conclusions difficult. Roughly, one-third of antenatally diagnosed UTD, defined as a renal pelvis anterior posterior diameter (APD) of ≥ 4 mm in the second trimester and/or ≥ 7 mm in the third trimester, will resolve before birth, another third will resolve within the first years of life, and in the remaining cases, UTD will persist or a congenital abnormality (CAKUT) will be diagnosed postnatally. The risk of a postnatal CAKUT diagnosis increases with the degree of prenatal and postnatal dilatation, except for vesicoureteral reflux (VUR), which cannot be predicted from the degree of UTD. Urinary tract infections (UTIs) occur in 7-14% of children with UTD during the first years of life. The risk of UTI is higher in children with traditional risk factors for UTI, such as dilated VUR, hydroureteronephrosis, female gender, and intact foreskin. Continuous antibiotic prophylaxis may be considered in selected patients during the first years of life. In long-term follow-ups, permanent kidney damage is diagnosed in approximately 40% of children with moderate or severe UTD, but hypertension, proteinuria, and/or reduced eGFR are uncommon (0-5%). In children with mild UTD, the long-term outcome is excellent, and these children should not be subjected to unnecessary examinations and/or follow-up.

Assessment of lower urinary tract function in pediatrics using ultrasonography

Ultrasound imaging is a less invasive imaging modality without radiation exposure and is available for repeated tests. It is the gold standard examination for diagnosing and managing disorders of the urinary tract, including lower urinary tract dysfunction (LUTD) in pediatric urology. Ultrasound imaging is effective for screening underlying diseases and determining treatment strategies. Ultrasound examination at the bedside should focus on post-voided residual urine (PVR), bladder wall thickening, renal morphology, and rectal diameter. Since PVR must be tested immediately after voiding, examining infants who cannot complain of the urge to void is difficult. PVR measurement combined with a 4-h voiding observation or alarm system activated by urine is recommended for these infants. Early diagnosis is important because LUTD is associated with the risk of morbid residual urine and high voiding pressure, which can result in renal deterioration, urinary leakage, and febrile urinary tract infection.

Vesicoureteral Reflux: Current Care Trends and Future Possibilities

Although investigations over the past 2 decades have improved our understanding of the natural history of vesicoureteral reflux (VUR) and helped identify those at higher risk of both VUR itself as well as its potential severe sequelae, debate exists regarding key aspects of care, including when to perform diagnostic imaging and which patients benefit from continuous antibiotic prophylaxis. Artificial intelligence and machine learning have the potential to distill large volumes of granular data into practical tools that clinicians can use to guide diagnosis and management decisions. Surgical treatment, when indicated, remains highly effective and is associated with low morbidity.

Ureteropelvic Junction Obstruction/Hydronephrosis

Congenital hydronephrosis can be classified and managed based on the Urinary Tract Dilation consensus scoring system. Ureteropelvic junction obstruction is one of the most common causes of hydronephrosis in the pediatric population. Although most cases can be managed conservatively with follow-up and serial imaging, some patients need surgical repair because of renal function deterioration, infections, or symptoms. Additional research to create predictive algorithms or develop noninvasive biomarkers for renal deterioration is necessary to better identify surgical candidates. The robotic-assisted approach for pyeloplasty is becoming increasingly widespread and associated with shorter hospital stay, high success rates, and low complication rates.

Postnatal Outcomes of Fetuses with Prenatal Diagnosis of 6-9.9 mm Pyelectasis

Pyelectasis, also known as renal pelvic dilatation or hydronephrosis, is frequently found on fetal ultrasound. This study correlated prenatally-detected, moderate pyelectasis with postnatal outcomes. This retrospective, observational study was conducted at a tertiary medical center in Israel. The study group consisted of 54 fetuses with prenatal diagnosis of pyelectasis on ultrasound scan during the second trimester, defined as anteroposterior renal pelvic diameter (APRPD) 6-9.9 mm. Long-term postnatal outcomes and renal-related sequelae were obtained using medical records and telephone-based questionnaires. The control group included 98 cases with APRPD < 6 mm. Results indicate that fetal pyelectasis 6-9.9 mm was more frequent among males (68.5%) than females (51%, p = 0.034). We did not find significant correlations between 6-9.9 mm pyelectasis and other anomalies or chromosomal/genetic disorders. Pyelectasis resolved during the pregnancy in 15/54 (27.8%) cases. There was no change in 17/54 (31.5%) and 22/54 (40.7%) progressed to hydronephrosis Among the study group, 25/54 (46.3%) were diagnosed with neonatal hydronephrosis. There were more cases of renal reflux or renal obstruction in the study group compared to the control group 8/54 (14.8%) vs. 1/98 (1.0%), respectively; p = 0.002. In conclusion, most cases of 6-9.9 mm pyelectasis remained stable or resolved spontaneously during pregnancy. There was a higher rate of postnatal renal reflux and renal obstruction in this group; however, most did not require surgical intervention.

Congenital anomalies of the kidney and urinary tract (CAKUT) in critically ill infants: a multicenter cohort study

BACKGROUND

The aim of the study was to determine the prevalence of congenital anomalies of the kidney and urinary tract (CAKUT) in the neonatal intensive care unit (NICU) and to evaluate risk factors associated with worse outcomes. We hypothesized that infants with CAKUT with extra-renal manifestations have higher mortality.

METHODS

This is a cohort study of all inborn infants who were diagnosed with any form of CAKUT discharged from NICUs managed by the Pediatrix Medical Group from 1997 to 2018. Logistic and linear regression models were used to analyze risk factors associated with in-hospital mortality.

RESULTS

The prevalence of CAKUT was 1.5% among infants hospitalized in 419 NICUs. Among the 13,383 infants with CAKUT analyzed, median gestational age was 35 (interquartile range [IQR] 31-38) weeks and median birth weight was 2.34 (IQR 1.54-3.08) kg. Overall in-hospital mortality for infants with CAKUT was 6.8%. Oligohydramnios (adjusted odds ratio [aOR] 4.5, 95% confidence interval [CI] 2.2-9.1, p < 0.001), extra-renal anomalies (aOR 2.5, 95% CI 2.0-3.1, p < 0.001), peak SCr (aOR 1.02, 95% CI 1.01-1.03, p < 0.001) and exposure to nephrotoxic medications (aOR 1.4, 95% CI 1.1-1.7, p = 0.01) were associated with increased mortality, while a history of urological surgery or intervention was associated with lower mortality (aOR 0.6, 95% CI 0.4-0.7, p < 0.001).

CONCLUSIONS

Infants hospitalized in the NICU who have CAKUT and the independent risk factors for mortality (e.g., oligohydramnios and presence of extra-renal anomalies) require close monitoring, minimizing of exposure to nephrotoxic drugs, and timely urological surgery or intervention. A higher resolution version of the Graphical abstract is available as Supplementary information.

Antenatally Diagnosed Kidney Anomalies

Congenital anomalies of the kidney and urinary tract encompass a broad spectrum of developmental conditions that together account for the majority of childhood chronic kidney diseases. Kidney abnormalities are the most commonly diagnosed congenital anomaly in children, and detection of this anomaly is increasing as a result of improved antenatal care and widespread access to more sensitive screening ultrasonography. Most paediatricians will encounter children with congenital kidney anomalies across a wide spectrum of disorders, and a broad understanding of the classification, investigation, and basis of management is important to appropriately direct their care.

Idiopathic bilateral ureteral stenosis presenting as bilateral hydronephrosis

Ureteral stenosis is typically seen in the setting of genitourinary tract manipulation or nephrolithiasis. Bilateral idiopathic ureteral stenosis is an exceedingly rare clinical entity that has been described in only a small number of cases. More specifically, we describe a case of idiopathic bilateral, distal ureteral stenosis resulting in hydronephrosis and deterioration of renal function in an adolescent patient. The patient was successfully treated with robotic bilateral ureteral implants. This case brings to light a rare, but clinically relevant, cause of hydronephrosis, highlights the importance of early intervention in minimizing renal dysfunction, and describes a novel treatment option.

Tubular and glomerular biomarkers of renal tissue function in the urine of fetuses with posterior urethral valves

INTRODUCTION

Posterior urethral valve (PUV) is a congenital malformation characterized by a membranous structure located in the prostatic portion of the male posterior urethra that obstructs the urinary flow. Efforts have been made to determine the degree of impairment of fetal kidney function in this condition.

OBJECTIVE

This study aimed to measure the levels of urinary biomarkers of glomerular and tubular functions in fetuses with PUV and to compare with the levels of the same molecules in healthy male premature newborns.

STUDY DESIGN

Urine samples from 43 fetuses with PUVs were collected and compared with urine samples from 40 healthy male newborns of the same gestational age (controls). Tubular and glomerular biomarkers levels were measured in urine samples by MILLIPLEX® assay kits. Levels of the molecules were related to creatinine (Cr) measurements at same urine samples and expressed as pg/mg Cr. Results were analysed with Graphpad Prism version 7.0 and SPSS version 20.0.

RESULTS

Fetuses with PUV showed a significant reduction in urine levels of Epidermal Growth Factor (EGF), Calbindin, Osteoactivin, Molecule Renal Injury 1 (KIM-1 and Factor of trefoil 3 (TFF-3) when compared to controls. On the other hand, urine levels of cystatin C and renin were higher in PUV fetuses. The levels of molecules also differed according to urine osmolality and grade of hydronephrosis.

DISCUSSION

Some urinary excreted molecules may indicate kidney damage in several segments along the nephron, while others may exert important functions. Mechanical and immunological mechanisms related to PUV might significantly modulate the synthesis of cytokines related to glomerular and tubular physiology, leading to alterations in urinary concentrations of those molecules. These biomarkers can be used as future diagnostic and prognostic markers in clinical practice.

CONCLUSION

Early kidney structural and functional impairment influenced the synthesis of glomerular and tubular molecules related to kidney physiological processes in fetuses with PUV.

Urologic Considerations in Pediatric Chronic Kidney Disease

Common causes of pediatric ESRD are distinct from those seen in the adult population. In the pediatric population, the most common are congenital anomalies of the kidney and urinary tract (CAKUT), affecting approximately 30% of children with CKD. These structural anomalies often require coordinated care with the pediatric urology team to address voiding issues, bladder involvement, and the potential need for surgical intervention. For pediatric nephrologists and urologists, common CAKUT that are encountered include antenatal hydronephrosis, obstructive uropathies (eg, posterior urethral valves), and vesicoureteral reflux. As more pediatric patients with CAKUT, CKD, and ESRD transition to adult care, it is important for receiving adult nephrologists to understand the clinical presentation, natural history, and prognosis for these diagnoses. This review outlines the diagnosis and potential interventions for these conditions, including strategies to address bladder dysfunction that is often seen in children with CAKUT. A discussion of these management decisions (including surgical intervention) for CAKUT, which are quite common to pediatric nephrology and urology practices, may provide unique learning opportunities for adult nephrologists who lack familiarity with these pediatric conditions.

2021 update on the urinary tract dilation (UTD) classification system: clarifications, review of the literature, and practical suggestions

In 2014, a multidisciplinary consensus on the classification of pre- and postnatal urinary tract dilation (UTD classification) was developed. Its goal was to provide a standardized system for evaluating and reporting urinary tract dilation both in the prenatal and postnatal periods. In this review, we summarize insights learned from the implementation of the UTD classification system since its inception, providing clarifications on common points of confusion. In addition, we review current literature in the clinical validation of the UTD classification system to provide credence for its use in managing fetuses and children with urinary tract dilation.

Postnatal urinary tract dilatation classification: improvement of the accuracy in predicting kidney injury

BACKGROUND

The grading of urinary tract dilatation (UTD) on postnatal sonography is a fundamental step to establish rational management for infants with antenatal hydronephrosis (ANH). The aim of this study was to compare the prediction accuracy of UTD grading systems for relevant clinical outcomes. In addition, we propose a refinement of the UTD classification by adding quantitative measurements and evaluate its impact on accuracy.

METHODS

Between 1989 and 2019, 447 infants diagnosed with isolated AHN were prospectively followed. The events of interest were surgical interventions and kidney injury. Comparison of performance of the grading systems and the impact on the accuracy of a modified UTD classification (including the size of the kidney parenchyma) was assessed by the area under the receiver-operating characteristic curve (AUC).

RESULTS

Of 447 infants, 131 (29%) underwent surgical intervention and 26 (5.8%) had developed kidney injury. The median follow-up time was 9 years (IQ range, 7-12 years). The performance for detecting the need for surgical intervention was excellent for all grading systems (AUC > 0.90). However, for predicting kidney injury, the modified UTD classification exhibited significant improvement in accuracy (AUC = 0.913, 95%CI, 0.883-0.937) as compared with UTD classification (AUC = 0.887, 95%CI, 0.854-0.915) (P = 0.027).

CONCLUSIONS

Our study confirms that the hydronephrosis grading systems provide excellent accuracy in discriminating patients who need surgical intervention among infants with AHN. Our findings suggest that the inclusion of kidney parenchymal thickness to UTD classification might increase the accuracy for predicting infants who may develop kidney injury. A higher resolution version of the Graphical abstract is available as Supplementary information.

Urinary HSP70 can predict the indication of surgery in unilateral ureteropelvic junction obstruction

BACKGROUND

Distinguishing hydronephrosis that requires surgical intervention is a clinical challenge. The aim of this study is to determine the level of urinary heat shock protein 70 (HSP70) in children who required surgery for ureteropelvic junction obstruction and its potential use as a biomarker for prediction of surgery in children with isolated unilateral hydronephrosis.

METHODS

The data of 43 children with ureteropelvic junction obstruction who underwent pyeloplasty, 25 patients with non-obstructive dilation (NOD) and 30 healthy children (control group) were collected prospectively for this study. Preoperative and postoperative urinary HSP70/Cr levels were also analyzed in 30 children in the pyeloplasty group who had available follow-up information. HSP70 levels were assessed using ELISA.

RESULTS

The median age of the pyeloplasty group was 13 months (IQR 7-36 months), NOD group was 42.5 months (IQR 16-73) and it was 36 months (IQR 24-47.5) in the control group. The mean preoperative urinary HSP70/Cr was significantly higher in the pyeloplasty group when compared to controls as well as the NOD group (150.6 pg/mgCr vs. 65.0 pg/mgCr and vs. 64.7 pg/mgCr, p < 0.001 and p < 0.001, respectively). The urinary HSP70 levels significantly decreased in the postoperative period (151.5 vs 79.5, p < 0.001). Using the cutoff value of 94.7 pg/mgCr, the sensitivity and specificity of urinary HSP70 for predicting the risk of surgical intervention were 69.7% and 68%, respectively (AUC = 0.689).

CONCLUSION

Urinary HSP70 may be used as an adjunct tool to clinical parameters to identify patients that would require surgery due to ureteropelvic junction obstruction.

Urinary Tract Dilation in the Fetus and Neonate

Urinary tract dilation (UTD), previously known as hydronephrosis, is the most common congenital condition identified on prenatal ultrasonography. UTD can be physiologic and resolve spontaneously or can be caused by various congenital anomalies of the urinary tract, which can lead to renal failure if not treated properly. In 2014, a multidisciplinary consensus group established UTD definitions, a classification system, and a standardized scheme for perinatal evaluation. Various imaging modalities are available to help diagnose the cause of UTD in fetuses and neonates and to help identify those patients who may benefit from fetal or early postnatal intervention. In this article, we will review the diagnosis and quantification of antenatal and postnatal UTD based on the UTD classification system, outline the imaging studies available to both evaluateUTD and determine its cause, briefly review the most common causes of UTD in the fetus and neonate, outline management strategies for UTD including the role for fetal intervention and prophylactic antibiotics, and report on the outcome and prognosis in patients with UTD.

Pyeloplasty effectiveness in cases of ureteropelvic junction obstruction in children: methodology and assessment parameters

The article presents the analysis of published data (Scopus, Web of Science, PubMed/MedLine, The Cochrane Library, and eLIBRARY databases) devoted to the study of existing criteria for assessment of pyeloplasty effectiveness. Published sources most often refer to the dynamics of reduction of the renal collecting system (RCS) and postoperative renal functional status as the assessment criteria. However, there are no consistent values, which could be employed as assessment criteria indicating success as soon as they are registered. The tools used to estimate RCS reduction are not standardized in terms of research techniques, projection of RCS dilatation measurement, and the locations between which renal and pelvic anatomic structures are measured. A variety of approaches to measuring the anteroposterior renal pelvis dimension in children with hydronephrosis tends to blur the analysis of actual pyeloplasty results. This review of published sources demonstrates the lack of agreement as regards the criteria for assessment of pyeloplasty effectiveness. There is a pressing need for appropriate steps to harmonize ultrasonography methods, to standardize the anatomic landmarks for measurement, and to define the criteria to be used to assess the effectiveness of pyeloplasty.

Prenatal Diagnosis of Severe Fetal Hydronephrosis Due to Pyeloureteral Junction Syndrome with False Neonatal Resolution

A case of severe fetal hydronephrosis due to isolated bilateral stenosis of the pyelo-ureteral junction was diagnosed at our centre. Surprisingly, a negative renal ultrasound scan was performed on the 3rd postnatal day. An ultrasound follow-up showed severe bilateral pyelectasis a few weeks later. The infant underwent bilateral pyeloplasty at six months of age with an excellent outcome. Such a neonatal picture may be due to the reduction of urinary output secondary to excessive postnatal weight loss and dehydration. In this case, prenatal ultrasound result was more reliable than postnatal ultrasound, emphasizing the importance of postnatal urologic follow-up after prenatal indication.

Mothers' perception of prenatal counseling following diagnosis of congenital anomalies of the urinary tract

Congenital abnormalities of the genitourinary tract are the most common sonographically identified malformations. Although prenatal diagnosis seldom modifies perinatal management, it can cause significant anxiety in parents. We aimed to assess how parents perceived the prenatal counseling they had received in our institution. Using a questionnaire, we evaluated by phone the mothers of 78 children diagnosed prenatally with urological tract anomalies between January 2018 and May 2019. Overall, mothers were satisfied and reassured by the prenatal counseling they received, although 19% of the mothers found the time from diagnosis to specialist consultation to be too long. Forty percent of the responders stated that the most important information they needed to hear during the specialist consultation was management and not diagnosis. Specialist counseling should focus on explaining postnatal management, should be offered as soon as possible, and should include practical aspects, especially concerning outpatient care.

Association between severity of prenatally diagnosed hydronephrosis and receipt of surgical intervention postnatally among patients seen at a fetal-maternal center

Background

Hydronephrosis (HN) is the most common abnormality detected on prenatal ultrasound. This study sought to stratify outcomes of patients by severity of prenatal HN with postnatal outcomes.

Methods

This was a retrospective review of patients referred to a tertiary care fetal-maternal clinic with diagnosis of prenatal HN from 2004 to 2019. HN severity was categorized as mild, moderate, or severe. Data were analyzed to determine the association between HN severity and surgical intervention. Decision for surgery was based on factors including history of multiple urinary tract infections, evidence of renal scarring, and/or reduced renal function. Surgery-free survival time was represented by the Kaplan–Meier method, and hazard ratios were calculated using the log-rank test.

Results

131 kidneys among 101 infants were prenatally diagnosed with hydronephrosis; 35.9% had mild HN, 29.0% had moderate HN, and 35.1% had severe HN. 8.5% of patients with mild HN, 26.3% of patients with moderate HN, and 65.2% of patients with severe HN required surgery. Patients with severe HN were 12.2 (95% CI 6.1–24.4; p < 0.001) times more likely to undergo surgery for HN than patients with mild HN and 2.9 (95% CI 1.5–5.3; p = 0.003) times more likely to undergo surgery than patients with moderate HN. Patients with moderate HN were 4.3 times more likely to require surgery than patients with mild HN (95% CI 1.5–12.9; p = 0.01). Median age at surgery was 11.8 months among patients with mild HN (IQR 11.7–14.1 months), 6.6 months among patients with moderate HN (IQR 4.2–16.4 months), and 5.4 months among patients with severe HN (3.7–12.4 months).

Conclusion

Among this cohort of referrals from a fetal-maternal clinic, severity of HN correlated with increased likelihood of surgical intervention. Continued assessment of patients with prenatal HN should be evaluated to best determine the role of the pediatric urologist in cases of prenatal HN.

Postnatal ultrasound follow-up in neonates with prenatal hydronephrosis

OBJECTIVES

Renal anomalies are the most common fetal abnormalities that occur during prenatal development, and are typically detected by observing hydronephrosis on fetal ultrasound imaging. Follow-up with post-natal ultrasound is important to detect clinically-important obstruction, because many of the pre-natal abnormalities resolve spontaneously. This study aimed to evaluate the postnatal hydronephrosis follow-up rate, and reasons for non follow-up in affected neonates.

METHODS

In this cross-sectional study all neonates born during a period of one year at Ayatollah Mousavi Hospital with hydronephrosis on fetal ultrasound imaging were recruited. All mothers were also given face-to-face information about fetal hydronephrosis and its postnatal outcomes, and follow-up with at least a postnatal ultrasound was recommended from the fourth day of their neonates' birth until the end of the fourth week. The neonates were subsequently observed for one month to determine the postnatal ultrasound follow-up rate and to reflect on diagnostic test results, reasons for failure to follow-up, as well as causes of hydronephrosis.

RESULTS

In this study, 71 cases (1.2%) out of 5,952 neonates had fetal hydronephrosis on prenatal ultrasound images. The postnatal ultrasound imaging showed kidney involvement in 18 neonates (25%), particularly in the left kidney (61.1%). Seven neonates had no follow-up at one month (10%). No significant relationship was found between lack of follow-up and the neonates' place of residence (p=0.42), maternal education (p=0.90), number of siblings (p=0.33), or gender (p=0.64).

CONCLUSIONS

Postnatal ultrasound follow-up rate in these neonates with a history of fetal hydronephrosis was incomplete even though parents had been provided with education and advice at their birth time. Accordingly, it is recommended to perform postnatal ultrasound once neonates are discharged from hospitals.