Prenatal Hydronephrosis: Bridging Pre- and Postnatal Management

Evaluation of postoperative renal function in infants with congenital hydronephrosis using ROI from ultrasound technique in renography

The aim of this study was to assess the efficacy of GFR measured using ROI from ultrasound technique in diuretic renography for evaluating postoperative outcomes in infants under one year old with congenital hydronephrosis. A retrospective analysis was conducted on thirty infants who underwent abdominal ultrasound and diuretic renography before and after surgery, obtaining preoperative and postoperative gGFRs and uGFRs (measured using ROI from ultrasound technique) determined using the Gates method and ultrasonic-assisted drawing ROI technique, respectively. A comparative study was performed on total GFR as well as individual kidney GFR before and after intervention. The preoperative and postoperative total and single uGFRs were significantly lower than gGFRs, while the postoperative total and single renal function, along with relative renal function in the hydronephrotic kidneys, were also significantly higher than the preoperative results (p < 0.05). Among 30 infants, 23 cases exhibited substantial recovery of renal function in their hydronephrotic kidneys after surgery, 2 cases did not show significant improvement, while 5 cases continued to experience deterioration in renal function. The GFR measured using ROI from ultrasound technique provides a more accurate assessment of renal function changes before and after surgery in infants under one year old with congenital hydronephrosis, facilitating an effective evaluation of postoperative treatment efficacy.

The effect of urinary diversion on kidney function in posterior urethral valves and ureterovesical obstruction

INTRODUCTION

Posterior urethral valves (PUV) and ureterovesical junction obstruction (UVJO) are common etiologies of lower urinary tract obstruction. The primary objective of therapy is to alleviate the obstruction in the urinary system. Temporary urinary diversion may be necessary in certain situations, such as Urinary tract infection (UTI), sepsis, and unchanging hydronephrosis. This study, aims to assess kidney parameters after urinary diversion (either pyelostomy or ureterostomy) in patients with PUV and UVJO.

METHOD

We conducted a retrospective analysis of all patients diagnosed with PUV or UVJO and treated with urinary diversion following urinary undiversion at our facility between 2015 and 2020. The following variables were collected: demographic details, surgical interventions (type of diversion), serum creatinine throughout follow-up, anterior-posterior diameter of the pelvis (APP), anterior-posterior diameter of the ureter (APU), and sonographic findings of renal parenchymal thickness (PT) as documented by a pediatric radiologist. Additionally, before and after urinary diversion, a Dimercapto succinic acid (DMSA) nuclear renal scan was conducted to assess renal function.

RESULT

We analyzed 67 patients, with a mean follow-up of 38.3 months, undergoing either ureterostomy (42 patients) or pyelostomy (25 patients). This included 38 patients with PUV and 29 with UVJO. In PUV patients, significant improvements were observed in APP (MD = 5.56 ± 11.6, p = 0.0194), APU (MD = 5.57 ± 7.28, p < 0.001), and PT (MD = 3.66 ± 2.75, p < 0.001). Similarly, UVJO patients experienced significant improvements in APP (MD = 12.18 ± 18.63, p = 0.005), APU (MD = 7.82 ± 8.98, p = 0.001), and PT (MD = 2.79 ± 3.33, p = 0.001). DMSA scores did not significantly change in either group (p > 0.05). Notably, APP improved more in UVJO patients compared to PUV patients (p = 0.047).

CONCLUSION

Our study suggests that urinary diversion could improve APP, APU, and renal parenchymal thickness in PUV and UVJO patients. The improvement of APP in UVJO patients was greater than in the PUV group. We propose further multi-center studies with longer durations of follow-up and more detailed additional data to support and confirm our results.

Practical Approach to Congenital Anomalies of the Kidneys: Focus on Anomalies With Insufficient or Abnormal Nephron Development: Renal Dysplasia, Renal Hypoplasia, and Renal Tubular Dysgenesis

Congenital anomalies of the kidney and urinary tract (CAKUT) accounts for up to 30% of antenatal congenital anomalies and is the main cause of kidney failure in children worldwide. This review focuses on practical approaches to CAKUT, particularly those with insufficient or abnormal nephron development, such as renal dysplasia, renal hypoplasia, and renal tubular dysgenesis. The review provides insights into the histological features, pathogenesis, mechanisms, etiologies, antenatal and postnatal presentation, management, and prognosis of these anomalies. Differential diagnoses are discussed as several syndromes may include CAKUT as a phenotypic component and renal dysplasia may occur in some ciliopathies, tumor predisposition syndromes, and inborn errors of metabolism. Diagnosis and genetic counseling for CAKUT are challenging, due to the extensive variability in presentation, genetic and phenotypic heterogeneity, and difficulties to assess postnatal lung and renal function on prenatal imaging. The review highlights the importance of perinatal autopsy and pathological findings in surgical specimens to establish the diagnosis and prognosis of CAKUT. The indications and the type of genetic testing are discussed. The aim is to provide essential insights into the practical approaches, diagnostic processes, and genetic considerations offering valuable guidance for pediatric and perinatal pathologists.

Trends in Management of Fetuses with Suspected Lower Urinary Tract Obstruction (LUTO): A High-Risk Fetal and Pediatric Center Experience in a Universal-Access-to-Care System

INTRODUCTION

 Neonates with lower urinary tract obstruction (LUTO) experience high morbidity and mortality associated with the development of chronic kidney disease. The prenatal detection rate for LUTO is less than 50%, with late or missed diagnosis leading to delayed management and long-term sequelae in the remainder. We aimed to explore the trends in prenatal detection and management at a high-risk fetal center and determine if similar trends of postnatal presentations were noted for the same period.

METHODS

 Prenatal and postnatal LUTO databases from a tertiary fetal center and its associated pediatric center between 2009 and 2021 were reviewed, capturing maternal age, gestational age (GA) at diagnosis, and rates of termination of pregnancy (TOP). Time series analysis using autocorrelation was performed to investigate time trend changes for prenatally suspected and postnatally confirmed LUTO cases.

RESULTS

 A total of 161 fetuses with prenatally suspected LUTO were identified, including 78 terminations. No significant time trend was found when evaluating the correlation between time periods, prenatal suspicion, and postnatal confirmation of LUTO cases (Durbin-Watson [DW] = 1.99, p = 0.3641 and DW = 2.86, p = 0.9113, respectively). GA at referral was 20.0 weeks (interquartile range [IQR] 12, 35) and 22.0 weeks (IQR 13, 37) for TOP and continued pregnancies (p < 0.0001). GA at initial ultrasound was earlier in terminated fetuses compared to continued (20.0 [IQR 12, 35] weeks vs. 22.5 [IQR 13, 39] weeks, p < 0.0001). While prenatal LUTO suspicion remained consistently higher than postnatal presentations, the rates of postnatal presentations and terminations remained stable during the study years (p = 0.7913 and 0.2338), as were GA at TOP and maternal age at diagnosis (p = 0.1710 and 0.1921).

CONCLUSION

 This study demonstrated that more severe cases of LUTO are referred earlier and are more likely to undergo TOP. No significant trend was detected between time and prenatally suspected or postnatally confirmed LUTO, highlighting the need for further studies to better delineate factors that can increase prenatal detection.

Fetal urinary tract dilation: What to tell the parents

Urinary tract dilation (UTD), which refers to the abnormal dilation of the urinary collection system, is the most common finding on prenatal ultrasound and presents with varying severity, presentation, etiology, and prognosis. Prenatal classification and risk stratification aim to prevent postnatal complications, such as urinary tract infections and further kidney dysfunction. Parents expecting a child with UTD should be counseled by a multidisciplinary team consisting of maternal-fetal medicine specialists, and pediatric urology and nephrology providers. This review summarizes the key points in the diagnostic evaluation and management during the prenatal and initial postnatal period, focusing on the information that should be provided to future parents. We address frequently asked parental questions and concerns that our multidisciplinary clinical practice faces.

The Toronto nomogram: A Bayesian meta-regression derived prenatal ultrasound index to predict lower urinary tract obstruction and prune belly syndrome

INTRODUCTION

A nomogram for predicting the diagnosis of lower urinary tract obstruction (LUTO) based on an antenatal ultrasound index generated from a Bayesian Meta-regression analysis has been in development and noted with superior diagnostic accuracy compared to the keyhole sign (KHS). We aim to assess the accuracy of the nomogram in expanded diagnostic utilization to predict LUTO.

METHODOLOGY

The validation of the nomogram for expanded diagnostic utilization was based on data from a prospective institutional antenatal clinic database between January 2020 and June 2022. Diagnostic accuracy indices were determined for confirmed postnatal diagnosis of LUTO or prune belly syndrome (PBS). Receiver operating characteristics (ROC) curves were generated to compare the area under the curve (AUC) of the nomogram versus KHS.

RESULTS

Based on 84 male fetuses with antenatal ultrasound of moderate-severe hydronephrosis (PUV n = 15, PBS n = 4), the KHS had 26.3% (95%CI 9.1-51.2) sensitivity and 100% (95%CI 94.4%-100%) specificity, with 14 false-negatives. The nomogram showed a 84.2 (95%CI 60.4%-96.6%) sensitivity and 95.4 (95%CI 87.1%-99%) specificity with three false-positives. The nomogram also had a superior AUC compared to KHS (0.98 vs. 0.63).

CONCLUSION

The nomogram can be used as a valuable tool to trigger further postnatal screening and provide individualized risk assessments to families during prenatal counseling.

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.

The role of circumcision in preventing urinary tract infections in children with antenatal hydronephrosis: Systematic review and meta-analysis

INTRODUCTION

Circumcision has been reported to reduce the risk of urinary tract infections (UTIs) in boys with antenatal hydronephrosis (HN). Our aim was to compare the incidence of UTIs in circumcised vs. uncircumcised boys with antenatal HN by conducting a systematic review and meta-analysis.

STUDY DESIGN

A comprehensive search was performed until December 2022. Comparative studies were evaluated according to Cochrane collaboration recommendations. Assessed measures included: UTIs, continuous antibiotic prophylaxis (CAP) use, renal outcomes, and circumcision complications. Odds ratios (OR) and mean difference with 95% confidence interval (CI) were extrapolated from available data. Random-effects meta-analysis were performed.

RESULTS

Twenty-three studies describing 9093 boys with antenatal HN were identified, including 4677 uncircumcised and 4416 circumcised boys. Overall effect estimates demonstrate that circumcised boys have significantly reduced odds of developing any UTI [OR 0.26, 95%CI 0.21, 0.32; p < 0.001]]. In addition, there a significantly reduced odds of developing UTI when circumcised and on CAP [OR 0.19, 95% CI 0.13, 0.30; p < 0.001]. When stratifying by etiology, circumcision reduced the odds of UTI in boys with isolated HN [OR 0.33, 95% CI 0.16, 0.68; p = 0.003], vesicoureteral reflux [OR 0.23, 95% CI 0.13, 0.42; P < 0.00001], or with posterior urethral valves [OR 0.29, 95% CI 0.13, 0.64; p = 0.002].

DISCUSSION

Circumcision reduces the incidence of UTIs in boys with antenatal HN. This review is limited by the varied definitions of UTIs and inconsistent reporting on HN etiology, renal outcomes, and circumcision complications.

CONCLUSIONS

Circumcision should be considered in boys with antenatal HN to prevent the risk of developing UTI. Further research is warranted to individualize the prophylactic role of circumcision for patients with HN.

Implementation of a standardized clinical pathway in a dedicated posterior urethral valves clinic: short-term outcomes

BACKGROUND

To determine if the implementation of a posterior urethral valves (PUV) clinic and standardized management pathway improves the short-term kidney outcomes of infants with PUV.

METHODS

From 2016-2022, 50 consecutive patients were divided into groups after the implementation of the clinic (APUV, n = 29) and before (BPUV, n = 21) during a comparable timeframe. Assessed data included age at initial visit, timing and type of surgery, frequency of follow-up visits, medications, nadir creatinine, and development of CKD/kidney failure. Data are shown as median with interquartile range (IQR) and odds ratios (OR) with 95% confidence interval (CI).

RESULTS

APUV had higher rates of prenatal diagnoses (12/29 vs. 1/21; p = 0.0037), earlier initial surgical intervention (8 days; IQR 0, 105 vs. 33 days; IQR 4, 603; p < 0.0001), and higher rates of primary diversions (10/29 vs. 0/21; p = 0.0028). Standardized management led to earlier initiation of alpha blockers (326 days; IQR 6, 860 vs. 991; IQR 149, 1634; p = 0.0019) and anticholinergics (57 days; IQR 3, 860 vs. 1283 days; IQR 477, 1718; p < 0.0001). Nadir creatinine was reached at earlier ages in APUV (105 days; IQR 2, 303 vs. 164 days; IQR 21, 447; p = 0.0192 BPUV). One patient progressed to CKD5 in APUV compared to CKD3, CKD5 and one transplant in BPUV.

CONCLUSION

Implementing the PUV clinic with standardized treatment expedited postnatal management and resulted in a higher number of cases detected prenatally, a shift in primary treatment, younger ages at initial treatment, reduced time to nadir creatinine, and timely initiation of supportive medications. A higher resolution version of the Graphical abstract is available as Supplementary information.

Sex differences in children operated with pyeloplasty for pelvoureteric junction obstruction

PURPOSE

Pelvoureteric junction obstruction (UPJO) is a common cause of hydronephrosis in children but no previous studies have evaluated differences between boys and girls operated with pyeloplasty. This study aimed to evaluate potential differences between sexes in children operated with pyeloplasty for PUJO in terms of presentation, surgery, and long-term results.

METHODS

Data was retrospectively collected from all children operated on with pyeloplasty between January 2002 and December 2020. Data contained several variables covering presentation, surgery, and long-term results.

RESULTS

In total, 194 patients were included of which 126 (64.9%) were boys. There were no significant differences in prenatal findings, pelvic dilation on ultrasound, function of the affected kidney, surgical method, obstruction type, resolution of hydronephrosis, or improvement of function. Boys presented with pain more often than girls (47.4 vs 25.0%, p < 0.01) while girls were more prone to infections preoperatively (17.2 vs 7.0%, p = 0.04). All nine patients requiring reoperation were boys (p = 0.03).

CONCLUSION

Girls with UPJO seem to experience infections as presenting symptoms more often than boys, while boys significantly more often present with pain. There is also a higher percentage of boys needing reoperation.

Primary ablation versus urinary diversion in posterior urethral valve: Systematic review and meta-analysis

PURPOSE

To determine differences in long-term kidney and bladder outcomes in boys with posterior urethral valves (PUV) managed by a primary valve ablation or primary urinary diversion.

MATERIALS AND METHODS

A systematic search was performed in March 2021. Comparative studies were evaluated according to Cochrane collaboration recommendations. Assessed measures included kidney outcomes (chronic kidney disease, end-stage renal disease, kidney function) and bladder outcomes. Odds ratios (OR) and mean difference (MD) with 95% confidence interval (CI) were extrapolated from available data for quantitative synthesis. Random-effects meta-analysis and meta-regression were performed according to study design, and potential covariates were assessed with subgroup analysis. The systematic review was prospectively registered on PROSPERO (CRD42021243967).

RESULTS

Thirty unique studies describing 1547 boys with PUV were included in this synthesis. Overall effect estimates demonstrate that patients undergoing primary diversion have significantly increased odds of developing renal insufficiency [OR 0.60, 95% CI 0.44, 0.80; p < 0.001]. However, when adjusting for baseline kidney function between intervention groups, there was no significant difference in long term kidney outcomes [p = 0.09, 0.35], or the development of bladder dysfunction or requiring clean-intermittent catheterization with primary ablation rather than diversion [OR 0.89, 95% CI 0.49, 1.59; p = 0.68].

CONCLUSIONS

Current low-quality evidence suggests that medium-term kidney outcomes in children are similar between primary ablation and primary diversion after adjusting for baseline kidney function, while bladder outcomes are highly heterogenous. Further research with covariate control is warranted to investigate sources of heterogeneity.

LEVEL OF EVIDENCE

Level III.

Prenatal Detection of a FOXF1 Deletion in a Fetus with ACDMPV and Hydronephrosis

Alveolar capillary dysplasia with misalignment of pulmonary veins (ACDMPV) is a lethal lung developmental disorder caused by the arrest of fetal lung formation, resulting in neonatal death due to acute respiratory failure and pulmonary arterial hypertension. Heterozygous single-nucleotide variants or copy-number variant (CNV) deletions involving the FOXF1 gene and/or its lung-specific enhancer are found in the vast majority of ACDMPV patients. ACDMPV is often accompanied by extrapulmonary malformations, including the gastrointestinal, cardiac, or genitourinary systems. Thus far, most of the described ACDMPV patients have been diagnosed post mortem, based on histologic evaluation of the lung tissue and/or genetic testing. Here, we report a case of a prenatally detected de novo CNV deletion (~0.74 Mb) involving the FOXF1 gene in a fetus with ACDMPV and hydronephrosis. Since ACDMPV is challenging to detect by ultrasound examination, the more widespread implementation of prenatal genetic testing can facilitate early diagnosis, improve appropriate genetic counselling, and further management.

The effect of primary urinary diversion on kidney function in posterior urethral valve: A matched comparison

OBJECTIVE

To determine long-term kidney outcomes in boys with posterior urethral valve (PUV) undergoing either primary valve ablation or urinary diversion with matched baseline kidney function.

METHODS

After retrospective review of patients managed for PUV at our institution, propensity score matched analysis was conducted using nadir serum creatinine with logistic regression analysis. Nearest neighbor matching was used to allocate boys to primary urinary diversion and primary ablation groups. Primary outcomes included kidney function by creatinine or estimated glomerular filtration rate, chronic kidney disease, and end-stage renal disease. Comparative statistics by odds ratio (OR) and hazard ratios on survival analysis were calculated.

RESULTS

A total of 21 boys undergoing primary diversion were matched with 42 boys undergoing ablation using nadir serum creatinine and follow-up time with a median follow-up of 4.8 years. After matching, there was no significant difference in last follow-up kidney function by creatinine (P = .99) or estimated glomerular filtration rate (P = .98). Primary diversion was not associated with increased likelihood of developing chronic kidney disease stage 3 (OR 1.33; P = .31) or end-stage renal disease (OR 1.88; P = .35 and hazard ratios 1.85; P = .30) compared to primary ablation.

CONCLUSIONS

Our propensity matched study suggests that long-term kidney function and kidney outcomes are similar between primary ablation and primary diversion after adjusting for baseline kidney function in boys with PUV.

Risk Factors of Urinary Tract Infection in Pediatric Patients with Ureteropelvic Junction Obstruction after Primary Unilateral Pyeloplasty

Objective

Ureteropelvic junction obstruction (UPJO) represents to a leading cause of fetal hydronephrosis, which is associated with urinary tract infection (UTI) and urinary stone disease. This study is aimed at investigating risk factors of UTI in pediatric patients with UPJO after primary unilateral pyeloplasty.

Methods

The records of a consecutive series of patients undergoing primary pyeloplasty at a single institution between June 2015 and November 2021 were retrospectively reviewed. Demographic and clinical characteristics, including age, gender, weight, height, body mass index (BMI), creatinine (Cr), blood urea nitrogen (BUN), estimated glomerular filtration rate (eGFR), neutrophil ratio, lymphocyte ratio, neutrophil/lymphocyte ratio, renal pelvis anteroposterior diameter (APD), renal cortex thickness, caliectasis, open or laparoscopic pyeloplasty, and internal drainage or external drainage, were collected and analyzed. The incidence of postoperative UTI and its risk factors was analyzed.

Results

A total of 504 patients were enrolled in the study, and they were classified into the UTI group (n = 188) and non-UTI group (n = 361). Univariate analysis of the incidence of UTI revealed that age, gender, weight, height, BMI, surgical modality, Cr level, BUN level, neutrophil ratio, lymphocyte ratio and neutrophil/lymphocyte ratio, renal cortex thickness, and postoperative drainage modality were associated with UTI incidence after pyeloplasty in pediatric patients with UPJO. Multivariate analysis revealed that male gender, <19 months, weight < 11.5 (kg), height < 83 (cm), BMI < 17.09, BUN > 4.08 (mmol/L), and internal drainage were risk factors of postoperative UTI in pediatric patients with UPJO.

Conclusion

Our study demonstrated that male gender, <19 months, weight < 11.5 (kg), height < 83 (cm), BMI < 17.09, BUN > 4.08 (mmol/L), and internal drainage were risk factors of UTI in pediatric patients with UPJO after primary unilateral pyeloplasty, which may provide reference for prophylactic antibiotics for those patients with risk factors.