Severe antenatally diagnosed renal disorders: background, prognosis and practical approach

Management of patients with posterior urethral valves "from the fetus to adolescence": French national diagnostic and care protocol (NDCP)

Posterior urethral valves (PUV) are congenital anomalies characterized by the persistence of mucosal folds in the urethra, leading to various degrees of obstruction. They are the most common cause of lower urinary tract obstruction in fetuses and children, with a severe prognosis, as one-third of affected children develop end-stage renal disease before adulthood. The French National Diagnostic and Care Protocol (NDCP) aim to provide healthcare professionals with guidelines for the optimal diagnostic and therapeutic management of PUV from the fetal stage to adolescence. The guidelines emphasize early diagnosis through prenatal ultrasound and the importance of a multidisciplinary approach involving pediatric urologists, nephrologists, and other specialists. It outlines prenatal interventions such as vesico-amniotic shunting and postnatal surgical options like endoscopic valve ablation to alleviate obstruction and preserve renal function. Long-term follow-up is crucial for monitoring renal function, managing bladder dysfunction, and preventing complications such as urinary tract infections and chronic kidney disease. The guidelines also identify off-label pharmaceuticals and necessary specialty products not typically covered by insurance. By standardizing care pathways and promoting consistent, high-quality care, the guidelines aim to improve the prognosis and quality of life for children with PUV, setting a benchmark for managing this rare condition in pediatric urology.

Improved prenatal assessment of kidney disease using multiple ultrasound features

BACKGROUND

Congenital anomalies of the kidney and urinary tract (CAKUT), often discovered in utero, cover a wide spectrum of outcomes ranging from normal postnatal kidney function to foetal death. The current ultrasound workup does not allow for an accurate assessment of the outcome. The present study aimed to significantly improve the ultrasound-based prediction of postnatal kidney survival in CAKUT.

METHODS

Histological analysis of kidneys of 15 CAKUT foetuses was performed to better standardize the ultrasound interpretation of dysplasia and cysts. Ultrasound images of 140 CAKUT foetuses with 2-year postnatal follow-up were annotated for amniotic fluid volume and kidney number, size, dysplasia and/or cysts using a standardized ultrasound readout. Association of ultrasound features and clinical data (sex and age at diagnosis) with postnatal kidney function was studied using logistic regression. Amniotic fluid proteome related to kidney dysplasia or cysts was characterized by mass spectrometry.

RESULTS

Histologically, poor ultrasound corticomedullary differentiation was associated with dysplastic lesions and ultrasound hyperechogenicity was associated with the presence of microcysts. Of all ultrasound and clinical parameters, reduced amniotic volume, dysplasia and cysts were the best predictors of poor outcome (odds ratio 57 [95% confidence interval (CI) 11-481], 20 [3-225] and 7 [1-100], respectively). Their combination into an algorithm improved prediction of postnatal kidney function compared with amniotic volume alone (area under the receiver operating characteristics curve 0.92 [95% CI 0.86-0.98] in a 10-fold cross-validation). Dysplasia and cysts were correlated (Cramer's V coefficient = 0.44, P < .0001), but amniotic fluid proteome analysis revealed that they had a distinct molecular origin (extracellular matrix and cell contacts versus cellular death, respectively), probably explaining the additivity of their predictive performances.

CONCLUSION

Antenatal clinical advice for CAKUT pregnancies can be improved by a more standardized and combined interpretation of ultrasound data.

Achievements, priorities and strategies in pediatric nephrology in Europe: need for unifying approaches or acceptance of differences?

Background

There is a lack of information on the current healthcare systems for children with kidney diseases across Europe. The aim of this study was to explore the different national approaches to the organization and delivery of pediatric nephrology services within Europe.

Methods

In 2020, the European society for Paediatric Nephrology (ESPN) conducted a cross-sectional survey to identify the existing pediatric nephrology healthcare systems in 48 European countries covering a population of more than 200 million children.

Results

The reported three most important priorities in the care of children with kidney diseases were better training of staff, more incentives for physicians to reduce staff shortages, and more hospital beds. Positive achievements in the field of pediatric nephrology included the establishment of new specialized pediatric nephrology centers, facilities for pediatric dialysis and transplant units in 18, 16, and 12 countries, respectively. The most common problems included no access to any type of dialysis (12), inadequate transplant programs for all ages of children (12), lack of well-trained physicians and dialysis nurses (12), inadequate reimbursement of hospitals for expensive therapies (10), and lack of multidisciplinary care by psychologists, dieticians, physiotherapists, social workers and vocational counsellors (6). Twenty-five of 48 countries (52%) expected to have a shortage of pediatric nephrologists in the year 2025, 63% of clinical nurses and 56% of dialysis nurses. All three groups of health care professionals were expected to be lacking in 38% of countries. Prenatal assessment and postnatal management of renal malformations by a multidisciplinary team including obstetricians, geneticists, pediatricians, and pediatric surgeons was available in one third of countries.

Conclusions

Our study shows that there are still very marked differences in pediatric health care systems across the European countries and highlights the need need for appropriate services for children with kidney disease in all European countries.

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.

Long-Term Outcomes, Including Fetal and Neonatal Prognosis, of Renal Oligohydramnios: A Retrospective Study over 22 Years

OBJECTIVE

To assess the long-term outcome of renal oligohydramnios and risk factors for fetal, neonatal, and postneonatal death.

STUDY DESIGN

This retrospective cohort study included fetuses with prenatally detected renal oligohydramnios between 2002 and 2023. Patients who were lost to follow-up were excluded. Fetal, neonatal, and long-term outcomes were evaluated, and their risk factors were analyzed.

RESULTS

Of 131 fetuses with renal oligohydramnios, 46 (35%) underwent a termination of pregnancy, 11 (8%) had an intrauterine fetal death, 26 (20%) had a neonatal death, nine (7%) had a postneonatal death, and 39 (30%) survived. Logistic regression analyses showed that an earlier gestational age at onset (OR 1.16, 95% CI 1.01-1.37) was significantly associated with intrauterine fetal death; anhydramnios (OR 12.7, 95% CI 1.52-106.7) was significantly associated with neonatal death as a prenatal factor. Although neonatal survival rates for bilateral renal agenesis, bilateral multicystic dysplastic kidney (MCDK), and unilateral MCDK with contralateral renal agenesis were lower than for other kidney diseases, 1 case of bilateral renal agenesis and two of bilateral MCDK survived with fetal intervention. Kaplan-Meier overall survival rates were 57%, 55%, and 51% for 1, 3, and 5 years, respectively. In the Cox proportional hazards model, birth weight <2000 g (hazard ratio 7.33, 95% CI 1.48-36.1) and gastrointestinal comorbidity (hazard ratio 4.37, 95% CI 1.03-18.5) were significant risk factors for postneonatal death.

CONCLUSION

Long-term survival following renal oligohydramnios is a feasible goal and its appropriate risk assessment is important.

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.

Exosomal miRNAs in prenatal diagnosis: Recent advances

Exosomes, small membranous microvesicles released by cells, contain a range of bioactive molecules, including proteins and miRNAs, which play critical roles in intercellular communication and physiological and pathological processes. Current research suggests that exosomal miRNAs could serve as valuable biomarkers for prenatal diseases, offering a noninvasive method for early detection and monitoring. Studies linking exosomal miRNAs to various birth defects, including fetal growth restriction, urinary tract malformations, cardiovascular system malformations, and hereditary diseases like Down syndrome, were discussed. However, there are some conflicting study findings due to different exosome separation methods. Here, we also discussed exosome separation methods, emphasizing the importance of method selection based on specific purposes and sample types. Further studies are needed to standardize isolation techniques, understand the specific mechanisms underlying exosomal miRNA function, and develop reliable noninvasive prenatal diagnostic indicators. Overall, exosomal miRNAs show promise as potential biomarkers for prenatal diagnosis, but further research is necessary to validate their clinical utility.

Child Health Needs and the Pediatric Nephrology Subspecialty Workforce: 2020-2040

Pediatric nephrology is dedicated to caring for children with kidney disease, a unique blend of acute care and chronic longitudinal patient relationships. Though historically a small field, trainee interest has declined over the past 2 decades. This has led to growing alarm about the health of the pediatric nephrology workforce, although concerns have been hampered by a lack of available data to enable feasible projections. This article is part of a supplement that anticipates the future pediatric subspecialty workforce supply. It draws on existing literature, data from the American Board of Pediatrics, and findings from a model that estimates the future supply of pediatric subspecialists developed by the Carolina Health Workforce Research Center at the University of North Carolina Chapel Hill's Cecil G. Sheps Center for Health Services Research and Strategic Modeling Analytics & Planning Ltd. The workforce projections from 2020 to 2040 incorporate population growth, clinical effort, and geographic trends and model alternate scenarios adjusting for changes in trainee interest, clinical efforts, and workforce attrition. The baseline model predicts growth of clinical work equivalents by 26% by 2040, but further widening geographic disparities worsen the existing mismatch between supply, clinical need, and market demand. The worst-case scenario projects 13% growth by 2040 which, at best, maintains the status quo of an already strained workforce. The models do not account for many factors expected to heighten demand over the coming decades. Urgent reforms are necessary now. Proposed solutions require multipronged changes in education and training pathways, remuneration, clinical practice models, and government policy.

Amniotic fluid content in children with kidney and urinary tract anomalies determines pre- and postnatal development

BACKGROUND

Renal oligohydramnios (ROH) describes an abnormally low volume of amniotic fluid (AF) during pregnancy. ROH is mostly caused by congenital fetal kidney anomalies. The ROH diagnosis frequently implies an increased risk of peri- and postnatal fetal mortality and morbidity. The present study aimed to evaluate the impact of ROH on pre-and postnatal development in children with congenital kidney anomalies.

METHODS

This retrospective study included 168 fetuses with anomalies in the kidney and urinary tract. Based on the amount of AF measured by ultrasound, patients were divided into three groups: normal amniotic fluid (NAF), amniotic fluid in the lower normal range (LAF), and ROH. These groups were compared with respect to prenatal sonographic parameters, perinatal outcomes, and postnatal outcomes.

RESULTS

Among the 168 patients with congenital kidney anomalies, 26 (15%) had ROH, 132 (79%) had NAF, and 10 (6%) had LAF. Of the 26 families affected by ROH, 14 (54%) decided to terminate pregnancy. Of 10 live-born children in the ROH group, 6 (60%) survived the observation time; of these, 5/6 presented with chronic kidney disease, stages I-III, at their last examination. The main differences in postnatal development between the ROH group and the NAF and LAF groups were: restricted height and weight gain, respiratory issues, complicated feeding, and the presence of extrarenal malformations.

CONCLUSIONS

ROH is not a mandatory indicator of severe postnatal kidney function impairment. However, children with ROH have complicated peri-and postnatal periods, due to the presence of concomitant malformations, which must be considered in prenatal care. A higher resolution version of the Graphical abstract is available as Supplementary information.

Fetal renal cystic disease and post-natal follow up-a single center experience

Introduction

Prenatal sonographic evidence of large, echogenic, or cystic kidneys may indicate any one of a diverse set of disorders including renal ciliopathies, congenital anomalies of the kidney and urinary tract (CAKUT), or multisystem syndromic disorders. Systematic transition planning for these infants from in utero detection to post-natal nephrology management remains to be established.

Aim of the work

We sought to evaluate the presentation and transition planning for infants identified in utero with bilateral renal cystic disease.

Methods

Our retrospective observational study identified 72 pregnancies with bilateral renal cystic disease in a single center from 2012 to 2022; 13 of which had a confirmed renal ciliopathy disorder. Clinical and imaging data, genetic test results, and documentation of postnatal follow-up were collected and compared.

Results

In our suspected renal ciliopathy cohort (n = 17), autosomal recessive polycystic disease (ARPKD) was the most common diagnosis (n = 4), followed by Bardet-Biedl syndrome (BBS, n = 3), autosomal dominant polycystic disease (ADPKD, n = 2), HNF1B-related disease (n = 2), and Meckel-Gruber syndrome (MKS, n = 2). Four cases were not genetically resolved. Anhydramnios was observed primarily in fetuses with ARPKD (n = 3). Polydactyly (n = 3) was detected only in patients with BBS and MKS, cardiac defects (n = 6) were identified in fetuses with ARPKD (n = 3), MKS (n = 2), and BBS (n = 1), and abnormalities of the CNS (n = 5) were observed in patients with ARPKD (n = 1), MKS (n = 2), and BBS (n = 3). In general, documentation of transition planning was incomplete, with post-natal nephrology management plans established primarily for infants with renal ciliopathies (n = 11/13; 85%).

Conclusion

Prenatal sonographic detection of echogenic kidneys should raise suspicion for a broad range of disorders, including renal ciliopathies and CAKUT. Multicenter collaboration will be required to standardize the implementation of transition guidelines for comprehensive nephrology management of infants identified in utero with enlarged, echogenic kidneys.

Congenital Anomalies of the Kidneys and Urinary Tract

Congenital anomalies of the kidneys and urinary tract (CAKUT) are some of the most common abnormalities detected on prenatal imaging assessment. It is estimated that CAKUT comprises 20% to 30% of all major birth defects. More than 200 clinical syndromes currently include CAKUT as a component of the phenotype. This chapter outlines the evaluation and management of the most common forms of CAKUT.

Definition, diagnosis and management of fetal lower urinary tract obstruction: consensus of the ERKNet CAKUT-Obstructive Uropathy Work Group

Fetal lower urinary tract obstruction (LUTO) is associated with high mortality and postnatal morbidity caused by lung hypoplasia and impaired kidney function. Specific diagnostic features that can guide clinical approach and decisions are lacking; thus, the European Reference Network for Rare Kidney Diseases established a work group to develop recommendations regarding the clinical definition, diagnosis and management of prenatally detected LUTO. The work group recommends the use of antero-posterior diameter of renal pelvis as the most reliable parameter for suspecting obstructive uropathies and for suspecting prenatal LUTO in the presence of fetal megacystis. Regarding prenatal and postnatal prognosis of fetuses with LUTO, the risk of fetal and neonatal death depends on the presence of oligohydramnios or anhydramnios before 20 weeks' gestation, whereas the risk of kidney replacement therapy cannot be reliably foreseen before birth. Parents of fetuses with LUTO must be referred to a tertiary obstetric centre with multidisciplinary expertise in prenatal and postnatal management of obstructive uropathies, and vesico-amniotic shunt placement should be offered in selected instances, as it increases perinatal survival of fetuses with LUTO.

Evaluation and fetal intervention in severe fetal hydronephrosis

PURPOSE OF REVIEW

Fetal hydronephrosis secondary to congenital anomalies of the kidney and urinary tract (CAKUT) can adversely affect neonates in the postnatal period with long-term consequences. A prenatal diagnosis of CAKUT can have an early fetal intervention to minimize these consequences. This review aims to provide an overview of the possible fetal intervention with severe hydronephrosis.

RECENT FINDINGS

Clinical course and outcomes of CAKUT are predicted based on biochemical markers and radiological findings. In spite of advancements and accurately diagnosing the severity of hydronephrosis, there are many controversies surround on selection of cases with antenatal hydronephrosis (ANH) that will benefit from fetal intervention. Despite better diagnosis and techniques fetal intervention is limited to mainly lower urinary tract obstruction patients to improve amniotic fluid volume and assist in lung development.

SUMMARY

ANH can potentially detect the severity of congenital renal anomalies but unable to recognize a specific disease. A multidisciplinary approach is required to diagnose and properly stage cases of severe CAKUT and potential surgical intervention can be considered.

Early clinical management of autosomal recessive polycystic kidney disease

Autosomal recessive polycystic kidney disease (ARPKD) is a rare but highly relevant disorder in pediatric nephrology. This genetic disease is mainly caused by variants in the PKHD1 gene and is characterized by fibrocystic hepatorenal phenotypes with major clinical variability. ARPKD frequently presents perinatally, and the management of perinatal and early disease symptoms may be challenging. This review discusses aspects of early manifestations in ARPKD and its clincial management with a special focus on kidney disease.

Amniotic fluid peptides predict postnatal kidney survival in developmental kidney disease

Although a rare disease, bilateral congenital anomalies of the kidney and urinary tract (CAKUT) are the leading cause of end stage kidney disease in children. Ultrasound-based prenatal prediction of postnatal kidney survival in CAKUT pregnancies is far from accurate. To improve prediction, we conducted a prospective multicenter peptidome analysis of amniotic fluid spanning 140 evaluable fetuses with CAKUT. We identified a signature of 98 endogenous amniotic fluid peptides, mainly composed of fragments from extracellular matrix proteins and from the actin binding protein thymosin-β4. The peptide signature predicted postnatal kidney outcome with an area under the curve of 0.96 in the holdout validation set of patients with CAKUT with definite endpoint data. Additionally, this peptide signature was validated in a geographically independent sub-cohort of 12 patients (area under the curve 1.00) and displayed high specificity in non-CAKUT pregnancies (82 and 94% in 22 healthy fetuses and in 47 fetuses with congenital cytomegalovirus infection respectively). Change in amniotic fluid thymosin-β4 abundance was confirmed with ELISA. Knockout of thymosin-β4 in zebrafish altered proximal and distal tubule pronephros growth suggesting a possible role of thymosin β4 in fetal kidney development. Thus, recognition of the 98-peptide signature in amniotic fluid during diagnostic workup of prenatally detected fetuses with CAKUT can provide a long-sought evidence base for accurate management of the CAKUT disorder that is currently unavailable.

Antenatal hydronephrosis and fetal urine sampling

The aim of this study is to evaluate the significance of renal pelvis aspiration (RPA) in the management of antenatal hydronephrosis (AHN). This study enrolled 15 AHN cases (one twin pregnancy) that necessitated RPA for AHN. Chromosomal abnormalities, gene disorders, and additional life-threatening congenital abnormalities were eliminated prior to intrauterine interventions. Urine analysis were performed for the evaluation of renal function. Normal renal function was observed in six neonates/infants (40%) (group 1), whereas impaired renal function and various type of urinary system anomalies were observed in 9 neonates/infants (60%) (group 2) during the short-term and longitudinal follow-up periods. There were statistically significant differences in the oligohydroamniosis rate, mean fetal urine sodium value, mean fetal urine β2-microglobulin, mean gestational week at birth, and mean birthweight values between the groups (P = 0.007, P < 0.001, P = 0.035, P < 0.001, and P = 0.001, respectively). Renal pelvis aspiration and urine analysis were substantial for the management of AHN in necessary cases. β2-microglobulin and sodium are clinically useful markers to detect the presence of severe renal damage due to obstructive uropathy and thus, important adjuvants in the proper selection of fetuses for further antenatal interventions.

Prenatal diagnosis of congenital megalourethra with imperforate anus

Background

Congenital megalourethra is a rare prenatal finding while prenatal diagnosis of imperforate anus poses high challenge. This is the first prenatally ultrasound diagnosed case which had congenital megalourethra and imperforate anus. This case demonstrated the possibility of using the prenatal imaging findings to evaluate the postnatal prognostic outcomes in multi-organ anomalies.

Case

We present a case of congenital megalourethra, diagnosed prenatally at 22 weeks’ gestation, in which the penis appeared severe dilated with complete absence of the corpora spongiosa and cavernosa. This case also revealed absence of perianal muscle which was in associated with imperforate anus. Detailed prenatal ultrasonographic findings predicted the high possibility of poor outcome of the fetus in the pulmonary, renal, and sexual functions.

Conclusion

This case serves to identify not only the marked bilateral hydronephrosis features but also the striking lower urethral malformation with obstruction flow effect of the penis. Indeed we believe this is the first case report of a rare case of fetal megalourethra associated with imperforate anus at early second trimester on ultrasonography imaging.

Posterior urethral valves: comparison of clinical outcomes between postnatal and antenatal cohorts

BACKGROUND

Posterior urethral valves (PUVs) constitute the most common infravesical urinary obstruction in boys and are often accompanied by severe consequences to the lower and upper urinary tract. Currently, about two-thirds of diagnosis of PUVs has been suspected by prenatal ultrasonography findings. The aim of this study was to compare long-term clinical outcomes in two groups of patients with PUVs, with antenatal vs. postnatal diagnosis.

STUDY DESIGN

This was a retrospective cohort study of 173 patients with PUVs systematically followed up in a tertiary center. Median follow-up time was 66.5 months (interquartile range [IQ], 11.4-147.9 months) for those patients who survived neonatal period. Seventy-nine (45.6%) patients were followed up for more than 5 years and 55 (32%) for more than 10 years. For analysis, the cohort was stratified into two groups according to the clinical presentation (prenatal vs. postnatal). The events of interest were urinary tract infection (UTI), surgical interventions, proteinuria, hypertension, chronic kidney disease (CKD), and death. Survival analyses were performed to evaluate time until occurrence of the events.

RESULTS

Sixty-two patients (35.8%) were diagnosed by fetal sonography. Patients of postnatal group presented a higher incidence rate of UTI episodes (6.5, 95% confidence interval [CI], 4.9-8.3) than antenatal group (1.2, 95% CI, 0.4-2.7) (P < 0.001). Thirty-six patients (21%) presented hypertension, and 77 (44.5%) had persistent mild proteinuria. There was no significant difference in the estimated incidence of hypertension (P = 0.28) and proteinuria (P = 0.78) between antenatal and postnatal groups. The cumulative incidence of CKD stage ≥3 was estimated to be about 37% at 10 years of age, and 56% at 18 years of age. By survival analysis, there was no significant difference in the estimated incidence of CKD stage ≥3 (log-rank = 0.32, P = 0.57) and CKD stage 5 (log-rank = 1.08, P = 0.28, Figure) between antenatal and postnatal groups. Of 173 patients included in the analysis, 13 (7.5%) died during follow-up with a median age of 2.6 months (IQ, 15 days-62 months). Survival analyses have not shown any significant difference in the estimated incidence of death between antenatal and postnatal groups (log-rank = 1.38, P = 0.24).

CONCLUSION

The study findings did not corroborate the initial hypothesis that the rates of renal function declining in patients with PUVs would be attenuated by an early diagnosis and intervention after antenatal diagnosis.

A clinical predictive model of chronic kidney disease in children with posterior urethral valves

BACKGROUND

Posterior urethral valves (PUVs) are associated with severe consequences to the urinary tract and are a common cause of chronic kidney disease (CKD). The aim of this study was to develop clinical predictive model of CKD in a cohort of patients with PUVs.

METHODS

In this retrospective cohort study, 173 patients with PUVs were systematically followed up at a single tertiary unit. The primary endpoint was CKD ≥ stage 3. Survival analyses were performed by Cox regression proportional hazard models with time-fixed and time-dependent covariables.

RESULTS

Mean follow-up time was 83 months (SD, 70 months). Sixty-five children (37.6%) developed CKD stage ≥ 3. After adjustment by the time-dependent Cox model, baseline creatinine, nadir creatinine, hypertension, and proteinuria remained as predictors of the endpoint. After adjustment by time-fixed model, three variables were predictors of CKD ≥ stage 3: baseline creatinine, nadir creatinine, and proteinuria. The prognostic risk score was divided into three categories: low-risk (69 children, 39.9%), medium-risk (45, 26%), and high-risk (59, 34.1%). The probability of CKD ≥ stage 3 at 10 years age was estimated as 6%, 40%, and 70% for patients assigned to the low-risk, medium-risk, and high-risk groups, respectively (P < 0.001). The main limitation was the preclusion of some relevant variables, especially bladder dysfunction, that might contribute to a more accurate prediction of renal outcome.

CONCLUSION

The model accurately predicts the risk of CKD in PUVs patients. This model could be clinically useful in applying timely intervention and in preventing the impairment of renal function.

Reference ranges for ultrasound measurements of fetal kidneys in a cohort of low-risk pregnant women

PURPOSE

Alterations in renal dimensions may be an early manifestation of deviation from normality, with possible repercussions beyond intrauterine life. The objective of this study was to establish reference curves for fetal kidney dimensions and volume from 14 to 40 weeks of gestation.

METHODS

This is a prospective longitudinal study of 115 Brazilian participants in the "WHO multicentre study for the development of growth standards from fetal life to childhood: the fetal component". Pregnant women with clinical and sociodemographic characteristics allowing the full potential fetal growth were followed up from the first trimester until delivery. These women underwent serial sonographic evaluation of fetal kidneys. The longitudinal, anteroposterior and transverse diameters of both fetal kidneys were measured, in addition to calculation of kidney volume. By quantile regression analysis, reference curves of renal measurements related to gestational age were built.

RESULTS

Standard normal sonographic values of renal biometry were defined during pregnancy. Reference values for the 10th, 50th and 90th centiles of different fetal kidney measurements (longitudinal, anteroposterior, transverse and volume) from the 14th to the 40th week of gestation were fitted.

CONCLUSION

The reference curves presented should be of the utmost importance for screening and diagnosis of alterations in renal development during the intrauterine period.

Prenatal parental decision-making and postnatal outcome in renal oligohydramnios

BACKGROUND

Previous studies on renal oligohydramnios (ROH) report highly variable outcome and identify early onset of ROH and presence of extrarenal manifestations as predictors of adverse outcome in most cases. Data on termination of pregnancy (TOP) and associated parental decision-making processes are mostly missing, but context-sensitive for the interpretation of these findings. We provide here a comprehensive analysis on the diagnosis, prenatal decision-making and postnatal clinical course in all pregnancies with ROH at our medical centre over an 8-year period.

METHODS

We report retrospective chart review data on 103 consecutive pregnancies from 2008 to 2015 with a median follow-up of 554 days.

RESULTS

After ROH diagnosis, 38 families opted for TOP. This decision was associated with onset of ROH (p < 0.001), underlying renal disease (p = 0.001) and presence of extrarenal manifestations (p = 0.02). Eight infants died in utero and 8 cases were lost to follow-up. Of the 49 liveborn children, 11 received palliative and 38 underwent active care. Overall survival of the latter group was 84.2% (n = 32) corresponding to 31% of all pregnancies (32 out of 103) analysed. One third of the surviving infants needed renal replacement therapy during the first 6 weeks of life.

CONCLUSIONS

Over one third of pregnancies with ROH were terminated and the parental decision was based on risk factors associated with adverse outcome. Neonatal death was rare in the actively treated infants and the overall outcome promising. Our study illustrates that only careful analysis of the whole process, from prenatal diagnosis via parental decision-making to postnatal outcome, allows sensible interpretation of outcome data.

Causes of renal oligohydramnios: impact on prenatal counseling and postnatal outcome

The presence of renal oligohydramnios (ROH) in a fetus has been associated in the past with a poor prognosis for survival, although recent studies have shown that survival has improved considerably due to the advances in neonatology and pediatric nephrology. In an article recently published in Pediatric Nephrology, evaluation of a large series by Mehler and colleagues confirms the improved prognosis, showing a survival rate of 32 of 38 (84%). In addition, only 12 of 35 (34%) neonates required renal replacement therapy. In five of these 12 children the dialysis could be terminated after the neonatal period. This study has important implications on the decision-making process and counseling of families. While 37% of families of the study opted for termination of pregnancies, palliative care was chosen by 8% of the families, representing an important option when a decision cannot be made rapidly by affected families. A multidisciplinary approach is not only necessary in the active treatment of neonates with a history of ROH but also in antenatal counseling. In this regard future efforts should establish consensus on an ethical framework for the decision-making process in ROH.

Association between cord blood cystatin C levels and early mortality of neonates with congenital abnormalities of the kidney and urinary tract: a single-center, retrospective cohort study

BACKGROUND

Some fetuses with congenital abnormalities of the kidney and urinary tract (CAKUT) have severe renal dysfunction during the prenatal period that can result in oligohydramnios, pulmonary hypoplasia, and death following birth. We hypothesized that cord blood cystatin C (CysC) levels are elevated in neonates who have life-threatening pulmonary hypoplasia and oligohydramnios due to severe renal dysfunction. In this study we compared cord blood CysC levels between a non-survivor group with CAKUT and a survivor group.

METHODS

This was a single-center, retrospective cohort study conducted between January 2007 and December 2015. Eighty-seven neonates who were prenatally diagnosed with CAKUT were included in the study. Cord blood CysC and creatinine levels were compared between the survivor and non-survivor groups at discharge from hospital.

RESULTS

Of the 87 neonates enrolled in the study, 67 survived and 21 died before discharge. Median cord blood CysC levels were higher in the non-survivor group than in the survivor group (4.28 vs. 1.96 mg/L, respectively; p < 0.001). Cord blood creatinine levels were not significantly different between the two groups. In patients with oligohydramnios (n = 28), cord blood CysC levels were significantly higher in the non-survivor group than in the survivor group (4.28 vs. 2.23 mg/L, respectively; p = 0.002).

CONCLUSIONS

In this study population, cord blood CysC levels were significantly higher in the non-survivor group with CAKUT than in the survivor group. These results suggest that cord blood CysC levels may be a good marker of the severity of renal dysfunction at birth.

Disorders of fatty acid oxidation and autosomal recessive polycystic kidney disease-different clinical entities and comparable perinatal renal abnormalities

BACKGROUND

Differential diagnosis of prenatally detected hyperechogenic and enlarged kidneys can be challenging as there is a broad phenotypic overlap between several rare genetic and non-genetic disorders. Metabolic diseases are among the rarest underlying disorders, but they demand particular attention as their prognosis and postnatal management differ from those of other diseases.

METHODS

We report two cases of cystic, hyperechogenic and enlarged kidneys detected on prenatal ultrasound images, resulting in the suspected diagnosis of autosomal recessive polycystic kidney disease (ARPKD). Postnatal clinical course and work-up, however, revealed early, neonatal forms of disorders of fatty acid oxidation (DFAO) in both cases, namely, glutaric acidemia type II, based on identification of the novel, homozygous splice-site mutation c.1117-2A > G in the ETFDH gene, in one case and carnitine palmitoyltransferase II deficiency in the other case.

RESULTS

Review of pre- and postnatal sonographic findings resulted in the identification of some important differences that might help to differentiate DFAO from ARPKD. In DFAO, kidneys are enlarged to a milder degree than in ARPKD, and the cysts are located ubiquitously, including also in the cortex and the subcapsular area. Interestingly, recent studies have pointed to a switch in metabolic homeostasis, referred to as the Warburg effect (aerobic glycolysis), as one of the underlying mechanisms of cell proliferation and cyst formation in cystic kidney disease. DFAO are characterized by the inhibition of oxidative phosphorylation, resulting in aerobic glycolysis, and thus they do resemble the Warburg effect. We therefore speculate that this inhibition might be one of the pathomechanisms of renal hyperproliferation and cyst formation in DFAO analogous to the reported findings in ARPKD.

CONCLUSIONS

Neonatal forms of DFAO can be differentially diagnosed in neonates with cystic or hyperechogenic kidneys and necessitate immediate biochemical work-up to provide early metabolic management.

[Congenital anomalies of poor prognosis. Genetics Consensus Committee]

INTRODUCTION

The Genetic Branch of the Chilean Society of Paediatrics, given the draft Law governing the decriminalisation of abortion on three grounds, focusing on the second ground, which considers the "embryo or foetus suffering from a congenital structural anomaly or a genetic disorder incompatible with life outside the womb", met to discuss the scientific evidence according to which congenital anomalies (CA) may be included in this draft law.

METHODOLOGY

Experts in clinical genetics focused on 10 CA, reviewed the literature evidence, and met to discuss it.

RESULTS

It was agreed not to use the term "incompatible with life outside the womb", as there are exceptions and longer survivals, and change to "congenital anomaly of poor prognosis (CAPP)". Ten CA were evaluated: serious defects of neural tube closure: anencephaly, iniencephaly and craniorachischisis, pulmonary hypoplasia, acardiac foetus, ectopia cordis, non-mosaic triploidy, "limb body wall" complex, "body stalk" anomaly, trisomy 13, trisomy 18, and bilateral renal agenesis. Findings on the prevalence, natural history, prenatal diagnostic methods, survival, and reported cases of prolonged survival were analysed. Post-natal survival, existence of treatments, and outcomes, as well as natural history without intervention, were taken into account in classifying a CA as a CAPP.

CONCLUSION

A CAPP would be: anencephaly, severe pulmonary hypoplasia, acardiac foetus, cervical ectopia cordis, non-mosaic triploidy, limb body wall complex, body stalk anomaly, non-mosaic trisomy 13, non-mosaic trisomy 18, and bilateral renal agenesis. For their diagnosis, it is required that all pregnant women have access to assessments by foetal anatomy ultrasound and occasionally MRI, and cytogenetic and molecular testing.

Why do we need more data on MR volumetric measurements of the fetal lung?

Fetal lung hypoplasia is associated with a series of congenital anomalies, particularly the congenital diaphragmatic hernia. Evaluation of the severity of the lung hypoplasia is important for parental counseling, assessment of prognosis and planning of postnatal management. Although a large number of studies have been performed to measure fetal lung volumes in order to predict outcome, there are little data on fetuses younger than 24 weeks of gestation, the age when parental counseling is crucial if termination is considered. Few studies have evaluated prognosis of lung hypoplasia in fetuses with congenital chest anomalies other than congenital diaphragmatic hernia. We review the studies on measurements of the fetal lung volumes by MRI.