Congenital renal tract anomalies: outcome and follow-up of 402 cases detected antenatally between 1986 and 2001

Brain and spine malformations and neurodevelopmental disorders in a cohort of children with CAKUT

BACKGROUND

Congenital anomalies of the kidney and urinary tract (CAKUT) represent 20-30% of all birth defects and are often associated with extra-renal malformations. We investigated the frequency of brain/spine malformations and neurological features in children with CAKUT.

METHODS

We reviewed the clinico-radiological and genetic data of 199 out of 1,165 children with CAKUT evaluated from 2006 to 2023 (99 males, mean age at MRI 6.4 years) who underwent brain and/or spine MRI. Patients were grouped according to the type of CAKUT (CAKUT-K involving the kidney and CAKUT-H involving the inferior urinary tract). Group comparisons were performed using χ2 and Fisher exact tests.

RESULTS

Brain/spine malformations were observed in 101/199 subjects (50.7%), 8.6% (101/1165) of our CAKUT population, including midbrain-hindbrain anomalies (40/158, 25.3%), commissural malformations (36/158, 22.7%), malformation of cortical development (23/158, 14.5%), Chiari I anomaly (12/199, 6%), cranio-cervical junction malformations (12/199, 6%), vertebral defects (46/94, 48.9%), caudal regression syndrome (29/94, 30.8%), and other spinal dysraphisms (13/94, 13.8%). Brain/spine malformations were more frequent in the CAKUT-K group (62.4%, p < 0.001). Sixty-two subjects (62/199, 31.2%) had developmental delay/intellectual disability. Neurological examination was abnormal in 40/199 (20.1%). Seizures and/or electroencephalographic anomalies were reported in 28/199 (14%) and behavior problems in 19/199 subjects (9%). Developmental delay/intellectual disability was more frequent in kidney dysplasia (65.2%) and agenesis (40.7%) (p = 0.001).

CONCLUSIONS

We report a relative high frequency of brain/spine malformations and neurodevelopmental disorders in children with CAKUT who underwent MRI examinations in a tertiary referral center, widening the spectrum of anomalies associated with this condition.

Observed to expected lung area to head circumference ratio (O/E LHR) in fetuses with congenital anomalies of the kidney and urinary tract (CAKUT): assessment and evaluation as predictive factor for acute postnatal outcome-a single center study

Introduction

To assess the observed to expected lung area to head circumference ratio (O/E LHR) in fetuses with congenital anomalies of the kidney and urinary tract (CAKUT) and to explore its value as a potential predictive factor for postnatal outcome.

Methods

A retrospective single-center study was conducted on pregnancies complicated by CAKUT between 2007 and 2018. The lung-to-head ratio (LHR) was calculated for each fetus by two independent observers. Correlations between O/E LHR and various perinatal outcome factors were assessed with Spearman's rank correlation. Furthermore, nominal logistic regression was performed to assess O/E LHR as predictive factor for respiratory distress in newborn.

Results

Of 64 pregnancies complicated by CAKUT, 23 were terminated. In the 41 cases of continuation of pregnancy, newborn presenting respiratory distress with need for respiratory support in the delivery room showed earlier gestational age at onset of amniotic fluid abnormalities and at birth. Although median O/E LHR and median single deepest pocket (SDP) of amniotic fluid were significantly smaller in newborn that did develop respiratory distress with need of respiratory support in the delivery room, neither O/E LHR nor SDP were accurate predictors for the development of respiratory distress.

Conclusions

Our data show that O/E LHR alone cannot serve as a predictive marker for fetal outcome in pregnancies complicated by CAKUT, though it might still be a helpful parameter together with detailed renal ultrasound evaluation, onset of amniotic fluid abnormality and SDP, particularly in its extreme values.

A Spectrum of Congenital Anomalies of the Kidney and Urinary Tract (CAKUT)-Diagnostic Utility of Perinatal Autopsy

OBJECTIVE

To describe the spectrum of congenital renal anomalies and emphasize the critical role of comprehensive autopsy examination in identifying CAKUT, especially of lower urinary tract malformations correlating with prenatal imaging methods.

METHODS

Retrospective analyses of CAKUT diagnosed at fetal autopsy were analyzed over a 7-y period and correlated with prenatal imaging findings.

RESULT

Among the 255 fetal autopsies, 45 cases were detected with CAKUT. Isolated (27%), syndromic CAKUT (51%), and CAKUT associated with other system anomalies (22%) were found. Hydronephrosis, followed by cystic renal diseases and agenesis were the common renal malformations. The gastrointestinal tract (GIT) was the commonest system associated with CAKUT. Among the syndromic CAKUT, the urorectal septum malformation (URSM) was the most frequent one, followed by VACTER-L, acrorenal syndrome, and OEIS complex. When correlating prenatal USG and autopsy findings, a significant change in final diagnosis was observed in 60% of cases.

CONCLUSION

Extrarenal malformations and syndromic associations of CAKUT predominated over isolated ones. Detection of lower urinary tract anomalies in CAKUT is difficult through antenatal imaging methods if associated with oligohydramnios. In these circumstances, the perinatal autopsy has a significant role in arriving at the final diagnosis which guides the clinician in predicting the recurrence risk and the need for genetic workup.

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.

Long-term follow-up of congenital anomalies of the kidney and urinary tract diagnosed in utero: a longitudinal study

BACKGROUND

Congenital-anomalies of the kidney-and-urinary-tract (CAKUT) are diagnosed in 3-6 per 1000 live-births. The objective of the current study was to examine the short and long-term outcomes of children diagnosed prenatally with CAKUT.

METHODS

A retrospective study was performed in 2018 on all pregnancies diagnosed with CAKUT between 2004 and 2008 at our hospital. Pregnancy outcomes and long-term morbidity were evaluated. Comparison was made between mild and severe forms of CAKUT and between unilateral and bilateral anomalies.

RESULTS

Ninety-eight children were included in the study. Most of them were born with an adequate weight for gestational-age, and were born at term by vaginal-deliveries. Children with major renal anomalies suffered significantly more frequently from recurrent UTIs (33.3% vs. 8.4%), needed more preventive antibiotics (50% vs. 20.5%), and had more renal surgeries (75% vs. 28%) than those with milder forms of CAKUT. Significantly more children with polycystic/multicystic kidney disease had recurrent UTIs (50% compared to 25% of the children with renal agenesis, and 5.6% of the children with hydronephrosis/hydroureter). There were no significant differences in the need for neurodevelopmental follow-up between the different groups of severity. Unilateral CAKUT patients required longer periods of nephrologist follow-up and repeated sonographic exams compared to bilateral CAKUT patients. Children with bilateral CAKUT more often needed special educational support than peers with unilateral disease (29.4% vs. 11.1%, P = 0.03).

CONCLUSIONS

Pregnancies whose children are diagnosed with CAKUT in utero usually deliver at term, with adequate-weight for gestational-age. The most common long-term comorbidities in children were recurrent UTIs and the use of preventive antibiotics was often needed. Expecting couples can be reassured of a generally good outcome of their children, at least during the first decade of life.

Predictive accuracy of prenatal ultrasound findings for lower urinary tract obstruction: A systematic review and Bayesian meta-analysis

BACKGROUND

Lower urinary tract obstruction (LUTO) is a rare but critical fetal diagnosis. Different ultrasound markers have been reported with varying sensitivity and specificity.

AIMS

The objective of this systematic review and meta-analysis was to identify the diagnostic accuracy of ultrasound markers for LUTO.

MATERIALS AND METHODS

We performed a systematic literature review of studies reporting on fetuses with hydronephrosis or a prenatally suspected and/or postnatally confirmed diagnosis of LUTO. Bayesian bivariate random effects meta-analytic models were fitted, and we calculated posterior means and 95% credible intervals for the pooled diagnostic odds ratio (DOR).

RESULTS

A total of 36,189 studies were identified; 636 studies were available for full text review and a total of 42 studies were included in the Bayesian meta-analysis. Among the ultrasound signs assessed, megacystis (DOR 49.15, [15.28, 177.44]), bilateral hydroureteronephrosis (DOR 41.33, [13.36,164.83]), bladder thickening (DOR 13.73, [1.23, 115.20]), bilateral hydronephrosis (DOR 8.36 [3.17, 21.91]), male sex (DOR 8.08 [3.05, 22.82]), oligo- or anhydramnios (DOR 7.75 [4.23, 14.46]), and urinoma (DOR 7.47 [1.14, 33.18]) were found to be predictive of LUTO (Table 1). The predictive sensitivities and specificities however are low and wide study heterogeneity existed.

DISCUSSION

Classically, LUTO is suspected in the presence of prenatally detected megacystis with a dilated posterior urethra (i.e., the keyhole sign), and bilateral hydroureteronephrosis. However, keyhole sign has been found to have modest diagnostic performance in predicting the presence of LUTO in the literature which we confirmed in our analysis. The surprisingly low specificity may be influenced by several factors, including the degree of obstruction, and the diligence of the sonographer at searching for and documenting it during the scan. As a result, providers should consider this when establishing the differential for a fetus with hydronephrosis as the presence or absence of keyhole sign does not reliably rule in or rule out LUTO.

CONCLUSIONS

Megacystis, bilateral hydroureteronephrosis and bladder wall thickening are the most accurate predictors of LUTO. Given the significant consequences of a missed LUTO diagnosis, clinicians providing counselling for prenatal hydronephrosis should maintain a low threshold for considering LUTO as part of the differential diagnosis.

239-kb Microdeletion Spanning KMT2E in a Child with Developmental Delay: Further Delineation of the Phenotype

Pathogenic KMT2E variants underly O'Donnell-Luria-Rodan syndrome, a recently described neurodevelopmental disorder characterized by global developmental delay, variable degrees of intellectual disability, and subtle facial dysmorphism. Less common findings include autism, seizures, gastrointestinal (GI) problems, and abnormal head circumference. Occurrence of mostly truncating variants as well as the similar phenotype observed in individuals with deletions spanning KMT2E suggest haploinsufficiency of this gene as a common mechanism for the disorder, while a gain-of-function or dominant-negative effect cannot be ruled out for some missense variants. Deletions reported in the literature encompass several additional known or presumed haploinsufficient genes, thus leading to more complex phenotypes. Here, we describe a male with antenatal onset hydronephrosis, hypotonia, global developmental delay, prominent GI symptoms as well as facial dysmorphism. Chromosomal microarray revealed a 239-kb de novo microdeletion spanning KMT2E and LHFPL3. Clinical presentation of our proband, harboring one of the smallest deletions of the region confirms the core features of this disorder, suggests GI symptoms as a prominent finding in affected individuals while expanding the phenotypic spectrum to abnormalities of the urinary tract.

Diagnostic accuracy of an interdisciplinary tertiary center evaluation in children referred for suspected congenital anomalies of the kidney and urinary tract on fetal ultrasound - a retrospective outcome analysis

BACKGROUND

Fetal ultrasound organ screening has become a standard of care in most high-income countries. This has resulted in increased detection of congenital abnormalities, which may lead to major uncertainty and anxiety in expectant parents, even though many of them are of minor relevance. In order to optimize prenatal counselling, we introduced an interdisciplinary approach for all pregnant women referred to our center by private obstetricians for a co-assessment of suspected relevant fetal abnormalities of the kidney or urinary tract, involving both experienced prenatal ultrasound specialists and a pediatric nephrologist or urologist.

METHODS

In a retrospective analysis, we evaluated reports of intrauterine evaluation and postnatal follow-up in order to assess accuracy of explicit intrauterine diagnoses and outcome of hydronephroses according to their severity in this setting.

RESULTS

A total of 175 fetuses were examined between 2012 and 2019 and followed postnatally at our Pediatric Nephrology or Urology Department. There was a high concordance (85.9%) between explicit intrauterine and final diagnoses. Resolution rate of hydronephrosis was higher in patients with intrauterine low-grade than high-grade hydronephrosis (61.8% versus 11.9%). An etiological diagnosis was found in 62.5%, 52.0%, and 11.1% of patients with intrauterine bilateral high-grade, unilateral high-grade, and unilateral high-grade with contralateral low-grade hydronephrosis, respectively, but in none of the patients with intrauterine low-grade hydronephrosis.

CONCLUSIONS

The results of our study demonstrate that, through interdisciplinary teamwork, intrauterine assessment of the fetal kidneys and urinary tract is highly accurate and allows a good discrimination between relevant and transient/physiological hydronephroses. A higher resolution version of the Graphical abstract is available as Supplementary information.

Postnatal management of bilateral Grade 3-4 ureteropelvic junction obstruction

Introduction:

Bilateral hydronephrosis on prenatal ultrasound can be managed expectantly or with surgical intervention. The treatment strategies and outcomes are not clearly defined.

Methods:

We conducted a retrospectively audit of outcomes of management of prenatally detected severe bilateral ureteropelvic junction obstruction (UPJO) in our institution.Patients with bilateral Grade 3–4 hydronephrosis were included. Those with complications like rupture, underwent bilateral intervention within 4 weeks; in the remaining, unilateral pyeloplasty was performed at 4–12 weeks. The contralateral renal unit was re-evaluated at a later date for further improvement or deterioration. All the patients were followed up with ultrasonography and renogram at 3 months, 6 months, and 1-year post operatively. The case records were analyzed for the resolution of antero-posterior diameter (APD) or the improvement in single-kidney glomerular filtration rate (s-GFR) in the operated units.

Results:

Over 15 years, 28 patients (56 renal units) had bilateral UPJO (male-to-female ratio = 13:1). Twelve units underwent neonatal intervention to tackle the complications (6 bilateral pyeloplasty), 17 units underwent early pyeloplasty, and 15 underwent late pyeloplasty. Twelve of the twenty-two (54%) contralateral units, which were stented/observed, resolved spontaneously. Receiver operating characteristics analysis revealed that those with initial APD <25 mm and initial s-GFR >35 ml/m were more likely to improve during the observation. Ten of the forty-four operated units (22%) failed to show an improvement. Units with initial s-GFR <10 ml/m had poor chance of postoperative functional recovery.

Conclusions:

In neonates with bilateral UPJO, the worse affected kidney is operated first, as it still has the potential to recover. The contralateral milder UPJO unit is known to recover spontaneously following unilateral pyeloplasty. In those with bilateral Grade 4 UPJO and mass, bilateral pyeloplasty is feasible. Alternatively, unilateral pyeloplasty + contralateral cystoscopic retrograde stenting may prevent rupture or functional deterioration in the opposite kidney.

Two infants with bilateral renal agenesis who were bridged by chronic peritoneal dialysis to kidney transplantation

Bilateral renal agenesis is associated with severe oligohydramnios and was considered incompatible with postnatal life due to severe pulmonary hypoplasia. The use of renal replacement therapy was limited by significant morbidity and mortality associated with dialysis in very young infants with major pulmonary pathology. In the United States, there is a tremendous controversy about whether or not the use of prenatal amniotic fluid infusions provides a benefit to fetuses with bilateral renal agenesis. One of the critical issues identified is that there are, as yet, no children reported who had achieved long-term survival. Previous reports all indicated these children died shortly after birth or after unsuccessful peritoneal dialysis. We present two infants with a prenatal diagnosis of bilateral renal agenesis whose mothers elected to undergo prenatal amnioinfusions. One was born at 28 weeks with a birthweight of 1230 g and the other born at 34 weeks with a birthweight of 1940 g. We present the details of both cases, with initial management on chronic peritoneal dialysis, which started shortly after birth, as a bridge to living related kidney transplants.

Value of urinary carbohydrate antigen 19-9 to predict failure of conservative management in children with ureteropelvic junction obstruction

OBJECTIVE

To assess the role of urinary carbohydrate antigen 19-9 (CA19-9) measurement in determining optimal management of ureteropelvic junction obstruction (UPJO) and predicting failure of conservative management.

PATIENTS AND METHODS

Children with UPJO diagnosed between December 2012 and April 2015 were included. Depending on clinical and para-clinical findings, patients were divided into three groups: Group 1 consisted of patients who were considered for non-operative management with improvement of the condition during the course of follow-up. Group 2 were suitable for observation; however due to deterioration of condition pyeloplasty was indicated after a period of observation. Group 3 patients required immediate pyeloplasty. Urinary CA19-9 was measured in all patients at baseline and compared between the study groups.

RESULTS

A total of 112 children (115 affected kidneys) with UPJO and mean age of 18.6 ± 3.3 months were assessed. Group 1, 2, and 3 consisted of 54(48.2%), 24(21.4%), and 34(30.4%) patients, respectively. Mean baseline urinary CA19-9 was 37.83 ± 5.20, 145.45 ± 18.38 and 244.62 ± 41.42 in groups 1, 2 and 3, respectively. Multivariate analysis showed that both CA19-9 and APD are independent predictors of need for surgery in patients on observation. ROC curve analysis revealed that urinary CA19-9 level at cut off value of 52.6 U/mL had sensitivity of 92.0% and specificity of 70.9% in predicting failure of non-operative management.

CONCLUSION

Higher urinary CA19-9 level is associated with failure of non-operative management in patients with UPJO. Such patients may require close follow-up and assessments to prevent irreversible damage to the kidney.

TYPE OF STUDY

Study of Diagnostic Test.

LEVEL OF EVIDENCE

Level II.

Outcomes of externalized pyeloureteral versus internal ureteral stent in pediatric robotic-assisted laparoscopic pyeloplasty

INTRODUCTION

After pyeloplasty, urinary drainage options include internal double-J (DJ) ureteral stents or externalized pyeloureteral (EPU) stents, which can avoid bladder symptoms and additional anesthetic exposure from stent removal. Comparative outcome studies, however, are lacking following primary pediatric robotic-assisted laparoscopic pyeloplasty (RALP).

OBJECTIVE

To compare operative success, operative time, hospitalization, and postoperative complications of EPU versus DJ stents following RALP.

STUDY DESIGN

Consecutive children undergoing primary RALP from 10/2013 to 9/2015 were retrospectively identified. Data collected included patient demographics, stent type and duration, postoperative complications, and operative success. To control for confounding by indication for EPU stent, propensity score weighting was used to balance baseline covariates. Weighted regression analyses compared between-group differences in study outcomes.

RESULTS

At median follow-up of 12.3 months, 44 and 17 patients underwent DJ and EPU stenting, respectively. At baseline, DJ stent patients were older than EPU stent patients (median 7.7 vs 1.2 years, P = 0.01) and were less likely to be on postoperative antibiotic prophylaxis (25 vs 76%, P < 0.001). After weighting, these differences disappeared. All EPU stents were removed in the outpatient clinic; all DJ stents were removed under anesthesia. On weighted regression analyses (Summary Fig.), EPU stents had no different associations than DJ stents with operative success (95 vs 94%, between-group difference 1%, 95% CI -11, 13; P = 0.86), complications, or operative time, but did have 0.6 of a day more hospitalization (95% CI 0.04, 1.2; P = 0.04).

DISCUSSION

Patients receiving EPU stents were different at baseline from those receiving DJ stents. After propensity score weighting balanced these covariates, EPU stents were associated with similar operative success, complications, and operative time to DJ stents. Further study is warranted in larger prospective cohorts.

CONCLUSION

Use of EPU stents provided a viable alternative, particularly in younger patients, to DJ stenting with comparable success and complications, while avoiding the need for an additional anesthetic.

Infants with prenatally diagnosed kidney anomalies have an increased risk of urinary tract infections

AIM

This study estimated the urinary tract infection (UTI) risk in a nationwide cohort of infants prenatally diagnosed with parenchymal kidney anomalies compared with a comparison cohort.

METHODS

A Danish population-based nationwide cohort of foetuses diagnosed with parenchymal kidney anomalies between 2007 and 2012 had previously been identified. These were compared with foetuses without kidney anomalies who were prenatally scanned the same year. Live born infants were followed from birth until the diagnosis of UTI, emigration, death or two years of age. Cumulative incidences of UTIs were computed. Mortality was estimated using the Kaplan-Meier method.

RESULTS

We identified 412 foetuses with parenchymal kidney anomalies out of 362 069 who underwent ultrasound scans and 277 were born alive. The overall risk of a UTI before the age of two years was 19%, and it was 14% among infants without prenatally diagnosed co-occurring urinary tract malformations. The corresponding risk in the 4074 controls was 1%. After two years, mortality was 2.2% in infants with prenatally diagnosed parenchymal kidney anomalies and 0.2% in the controls.

CONCLUSION

Infants prenatally diagnosed with parenchymal kidney anomalies had a substantially increased risk of UTI. Awareness of this increased risk may facilitate earlier diagnosis of UTIs in this population.

Evidence-based, ethically justified counseling for fetal bilateral renal agenesis

BACKGROUND

Not much data are available on the natural history of bilateral renal agenesis, as the medical community does not typically offer aggressive obstetric or neonatal care asbilateral renal agenesis has been accepted as a lethal condition.

AIM

To provide an evidence-based, ethically justified approach to counseling pregnant women about the obstetric management of bilateral renal agenesis.

STUDY DESIGN

A systematic literature search was performed using multiple databases. We deploy an ethical analysis of the results of the literature search on the basis of the professional responsibility model of obstetric ethics.

RESULTS

Eighteen articles met the inclusion criteria for review. With the exception of a single case study using serial amnioinfusion, there has been no other case of survival following dialysis and transplantation documented. Liveborn babies die during the neonatal period. Counseling pregnant women about management of pregnancies complicated by bilateral renal agenesis should be guided by beneficence-based judgment informed by evidence about outcomes.

CONCLUSIONS

Based on the ethical analysis of the results from this review, without experimental obstetric intervention, neonatal mortality rates will continue to be 100%. Serial amnioinfusion therefore should not be offered as treatment, but only as approved innovation or research.

Severe congenital anomalies of the kidney and urinary tract: epidemiology can inform ethical decision-making

OBJECTIVE

Decision-making for pregnancies complicated by severe congenital anomalies of the kidneys and urinary tract (CAKUT) are ethically challenging, partly because the outcomes are not well studied.

STUDY DESIGN

Retrospective cohort study of severe cases of CAKUT over 14 years.

RESULTS

Seventy-one of the 108 cases could be completely analyzed. Forty-six percent (n=33) infants were live-born; one-third (n=11) survived to 12 months. Twice as many non-surviving infants received a trial of therapy vs comfort care only. Two-thirds of non-survivors who received a trial of therapy died within the first 9 h of life. Live-born infants faced morbidities such as pneumothorax and neonatal dialysis.

CONCLUSIONS

Over half of pregnancies complicated by severe CAKUT ended in termination or stillbirth, but one-third of live-born infants survived to 12 months and the majority of non-survivors died within hours. This may allay concerns about prolonged and futile intensive care for parents considering a trial of therapy.

The outcome of antenatal ultrasound diagnosed anomalies of the kidney and urinary tract in a large Danish birth cohort

OBJECTIVE

Antenatal ultrasound diagnosed anomalies of the kidney and urinary tract (AUDAKUT) are reported in 0.3%-5% on prenatal ultrasound (US) and 0.3%-4.5% on postnatal US. The anterior-posterior diameter of the renal pelvis (APD) is an essential measurement. Series with low threshold values of APD prenatally and postnatally will include healthy infants. It is important to avoid follow-up of such infants.

INTERVENTIONS

In 2006, new Danish guidelines for AUDAKUT were introduced.

AIM OF STUDY

Investigations of incidences and type of AUDAKUT based on Danish guidelines, including long-term follow-up.

DESIGN

Cohort study.

SETTING

Copenhagen University Hospital Hvidovre and Copenhagen University Hospital Rigshospitalet, Denmark.

PATIENTS

Consecutive cases with AUDAKUT in the second and third trimesters, which were either terminated before 22 completed weeks of gestation or born in the 8-year period January 2006-December 2013. Patients were followed until June 2014.

RESULTS

50 193 live born children and 24 terminated fetuses (0.05%) were included. The prevalence of AUDAKUT was only 0.39% prenatally, 0.29% at first postnatal US and 0.22% at the end of follow-up, including terminated cases. The greater the prenatal and postnatal APD, the higher risk of febrile urinary tract infection (fUTI) and surgical intervention, and lower probability of resolution. 25% of the identified patients had fUTI and/or surgery.

CONCLUSIONS

We recommend threshold values of APD at least 10 mm in the third trimester and in general at least 12 mm at first postnatal US for intensive follow-up. In this largest to date unselected birth cohort of AUDAKUT, the incidences of clinically significant AUDAKUT were in the lowest range of those previously published.

Disparities in treatment rates of paediatric end-stage renal disease across Europe: insights from the ESPN/ERA-EDTA registry

BACKGROUND

Considerable disparities exist in the provision of paediatric renal replacement therapy (RRT) across Europe. This study aims to determine whether these disparities arise from geographical differences in the occurrence of renal disease, or whether country-level access-to-care factors may be responsible.

METHODS

Incidence was defined as the number of new patients aged 0-14 years starting RRT per year, between 2007 and 2011, per million children (pmc), and was extracted from the ESPN/ERA-EDTA registry database for 35 European countries. Country-level indicators on macroeconomics, perinatal care and physical access to treatment were collected through an online survey and from the World Bank database. The estimated effect is presented per 1SD increase for each indicator.

RESULTS

The incidence of paediatric RRT in Europe was 5.4 cases pmc. Incidence decreased from Western to Eastern Europe (-1.91 pmc/1321 km, P < 0.0001), and increased from Southern to Northern Europe (0.93 pmc/838 km, P = 0.002). Regional differences in the occurrence of specific renal diseases were marginal. Higher RRT treatment rates were found in wealthier countries (2.47 pmc/€10 378 GDP per capita, P < 0.0001), among those that tend to spend more on healthcare (1.45 pmc/1.7% public health expenditure, P < 0.0001), and among countries where patients pay less out-of-pocket for healthcare (-1.29 pmc/11.7% out-of-pocket health expenditure, P < 0.0001). Country neonatal mortality was inversely related with incidence in the youngest patients (ages 0-4, -1.1 pmc/2.1 deaths per 1000 births, P = 0.10). Countries with a higher incidence had a lower average age at RRT start, which was fully explained by country GDP per capita.

CONCLUSIONS

Inequalities exist in the provision of paediatric RRT throughout Europe, most of which are explained by differences in country macroeconomics, which limit the provision of treatment particularly in the youngest patients. This poses a challenge for healthcare policy makers in their aim to ensure universal and equal access to high-quality healthcare services across Europe.

Fetal renal anomaly: factors that predict survival

OBJECTIVE

To find out the relative prevalence of renal anomalies detected in the antenatal period, and to look at factors that predict the postnatal outcome.

METHODS

In this prospective study, all antenatal-detected renal anomalies booked at the tertiary health centre were evaluated and counselled. Aspects such as type of renal anomaly, oligohydramnios and presence of additional anomalies were noted. Stillborn babies underwent autopsy; all live born babies were followed for one year. Appropriate statistical analyses were performed to compare the antenatal factors with outcomes.

RESULTS

Renal anomalies were detected in 136 out of 587 cases with major fetal anomalies. Most of the women were primiparous (65.4%). The mean gestation at presentation was 30 weeks; in 12 cases, diagnosis was possible before 20 weeks (8.8%). Antenatal hydronephrosis was the most commonly seen anomaly, with 61 cases; this was followed by bilateral cystic kidney in 50 cases. Out of the 136 cases, 12 (8.8%) underwent termination of pregnancy and 60 (44.1%) babies were stillborn. Autopsy was performed in 58 out of 72 (80.6%) cases after consent. Karyotyping was performed in 49 cases and abnormalities were detected in two (4.1%) of them. A total of 64 (47.1%) babies were live born; after one year, 49 (36.0%) of them were alive. Postnatal survival was highest in unilateral disease (85.7%). In cases with oligohydramnios, there was only 3.4% survival after one year; none of the cases with cystic kidney and oligohydramnios survived. The period of gestation at presentation of non-survivors was 25.9 weeks compared to 32.5 weeks with survivors. Among the cases with extra renal anomaly, 7.0% survived; none of the cases with associated cranio-vertebral defect or polydactyly survived after a year.

CONCLUSION

Out of the different renal pathologies that were diagnosed, survival was highest in the unilateral group. The factors associated with poor prognosis included bilateral disease, absence of amniotic fluid and presence of associated malformation.

Antenatal diagnosis, prevalence and outcome of congenital anomalies of the kidney and urinary tract in Saudi Arabia

Objective:

To study the prevalence, pattern of distribution, and the outcome of different types of kidney and urinary tract anomalies (CAKUT) diagnosed during the antenatal period. The second objective is to test the accuracy of antenatal diagnosis of CAKUT.

Materials and Methods:

In a cross-sectional hospital-based study, all cases diagnosed antenatally with urinary tract anomalies at King Abdulaziz University Hospital (KAUH), Jeddah, Kingdom of Saudi Arabia, were studied. The prevalence, pattern of distribution, and immediate postnatal outcomes, in addition to the accuracy of antenatal diagnosis, of those cases are reported.

Results:

One hundred and forty-one cases of urinary tract anomalies were antenatally diagnosed; postnatal diagnosis was confirmed in 128 cases (90.1%). The prevalence of CAKUT in our population is 3.26 per 1000 births. The most common abnormalities detected were hydronephrosis, polycystic kidney disease, multicystic dysplastic kidney, and renal agenesis, in descending order of frequency. The perinatal mortality rate among fetuses with CAKUT is 310 per 1000, the majority of these cases (90%) occurred in cases with renal parenchyma involvement.

Conclusions:

The prevalence of different types of CAKUT is higher than that reported in developed countries. Urinary tract anomalies can be accurately diagnosed and classified in the antenatal period using ultrasonography imaging. Antenatal diagnosis is a helpful tool in planning immediate postnatal care and deciding the place for delivery. This might prevent or slow renal function deterioration and help in early identification of patients who need early surgical intervention.

Prediction of the outcome of antenatal hydronephrosis: significance of urinary EGF

BACKGROUND

Down-regulation of epidermal growth factor (EGF) in the renal parenchyma has been demonstrated in children who underwent pyeloplasty due to ureteropelvic junction obstruction (UPJO). Urine levels of EGF were confirmed to parallel this finding before and after surgery. The aim of our study was to evaluate the relationship between urinary EGF (uEGF) concentrations and Society of Fetal Urology (SFU) high-grade hydronephrosis in infants presenting unilateral antenatal hydronephrosis (ANH).

METHODS

This was a prospective study involving 45 infants (33 in the observational group, 12 in the surgical group) who presented with unilateral ANH. Postnatal evaluation included a clinical examination, renal ultrasonography, and voiding cystourethrography. Diuretic renal scans were performed in infants with an initial SFU grade 3 or 4 hydronephrosis or increasing hydronephrosis during follow-up. Pyeloplasty was performed when a well-tempered renogram showed an obstructive drainage curve with a half-life of >20 min and/or an obstructive washout curve pattern during the diuretic phase. We studied the longitudinal changes in SFU hydronephrosis grade and uEGF in each group and compared concentration levels at three time points in both groups. The enzyme-linked immunosorbent assay (ELISA) method was used to measure EGF concentrations in the urine. The results were normalized with urinary creatinine (Cr).

RESULTS

During the first 6 months, from 6 to 12 months, and in the second year of life, median SFU hydronephrosis grade and uEGF levels were 2, 2 (p = 0.015), and 1 (p < 0.01), and 50, 59 (p = 0.015), and 69.5 ng/mg Cr (p < 0.01), respectively, in the observational group. In the first 6 months, preoperatively and at 3-12 months postoperatively, the median SFU hydronephrosis grade and uEGF levels were 4, 4, and 3 (p > 0.05), and 38, 46, (p > 0.05), and 55 ng/mg Cr (p < 0.01), respectively, in the surgical group. uEGF levels in the first 6 months of life were significantly lower in the surgical group than in the observational group (p < 0.01). Patients in the observational group with SFU grade 3-4 hydronephrosis showed higher uEGF levels than those in the surgical group with SFU grade 3-4 in (p = 0.048).

CONCLUSIONS

Urinary EGF changes over time are associated with inverse changes in SFU hydronephrosis grade, which suggests a role for uEGF as a predictive marker of worsening hydronephrosis grades in infants with ANH. uEGF in the first 6 months of life may predict the need for surgery in infants with ANH.

Congenital urinary tract obstruction: defining markers of developmental kidney injury

Congenital urinary tract obstruction (diagnosed antenatally by ultrasound screening) is one of the main causes of end-stage kidney disease in children. The extent of kidney injury in early gestation and the resultant abnormality in kidney development determine fetal outcome and postnatal renal function. Unfortunately, the current approach to diagnostic evaluation of the severity of injury has inherently poor diagnostic and prognostic value because it is based on the assessment of fetal tubular function from fetal urine samples rather than on estimates of the dysplastic changes in the injured developing kidney. To improve the outcome in children with congenital urinary tract obstruction, new biomarkers reflecting these structural changes are needed. Genomic and proteomic techniques that have emerged in the past decade can help identify the key genes and proteins from biological fluids, including amniotic fluid, that might reflect the extent of injury to the developing kidney.

Early risk factors for neonatal mortality in CAKUT: analysis of 524 affected newborns

BACKGROUND

Congenital abnormalities of the kidney and urinary tract (CAKUT) are significant causes of morbidity. The aim of the study was to determine predictive factors of mortality in newborns with CAKUT.

METHODS

All 29,653 consecutive newborns hospitalized in a tertiary neonatal unit between 1996 and 2006 were evaluated. The main outcome was neonatal mortality. The variables analyzed as risk factors were maternal age, first pregnancy, low birth weight (LBW), prematurity, oligohydramnios, and CAKUT associated with other malformations (Associated CAKUT).

RESULTS

CAKUT was detected in 524 newborns, with an overall prevalence of 17.7 per 1,000 live births. A total of 325 (62%) cases were classified as urinary tract dilatation, 79 (15.1%) as renal cystic disease, and 120 (22.9%) as other subgroups. In the urinary tract dilatation subgroup, independent risk factors for early mortality were Associated CAKUT [odds ratio (OR) 20.7], prematurity (OR 4.5) LBW (OR 3.8), oligohydramnios (OR 3.0), and renal involvement (OR 3.0). In the renal cystic disease subgroup, two variables remained associated with neonatal mortality: LBW (OR 12.3) and Associated CAKUT (OR 21.4).

CONCLUSION

The presence of extrarenal anomalies was a strong predictor of poor outcome in a larger series of infants with CAKUT.

Outcome of prenatally detected bilateral higher urinary tract obstruction or megacystis: sex-related study on a series of 709 cases

OBJECTIVE

To compare the sex specific outcome of fetuses with prenatally detected urinary tract dilatation, with the exclusion of pyelectasia.

METHOD

Included in the study were 709 cases of major dilatation of the fetal urinary tract, diagnosed at routine ultrasound scan. For each sex group, cases were divided into two subgroups depending on the level of dilatation. Final diagnosis was based on postnatal evaluation or on fetal autopsy. Postnatal renal function was evaluated using serum creatinine at two years of age.

RESULTS

Bilateral higher urinary tract dilatation was prenatally observed in 148 (20.8%) and lower urinary tract obstruction or bladder dilatation in 561 (79.1%) of the 709 cases (121 female and 588 male fetuses) (P <0.001). Bladder dilatation was less frequent in female fetuses (62%) than in males (82.6%) (P <0.001). At final diagnosis, associated malformations were observed in 53.7% of female fetuses versus 11% in males (P <0.001). The survival rate was 42.7%. Postnatal renal function, evaluated in 289/303 live infants, was impaired in 29.7% of cases and depended on the level of obstruction, but not on the sex.

CONCLUSION

Prenatally detected urinary tract dilatation has a poor prognosis both in male and female fetuses. Associated malformations are observed more frequently in female than in male fetuses.

Clinical course of 822 children with prenatally detected nephrouropathies

BACKGROUND AND OBJECTIVES

With the advent of fetal screening ultrasonography, the detection of congenital anomalies of the kidney and urinary tract (CAKUT) in utero has permitted early management of these conditions. This study aims to describe the clinical course of a large cohort of patients with prenatally detected nephrouropathies.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In this retrospective cohort study, 822 patients were prenatally diagnosed with CAKUT and systematically followed up at a tertiary Renal Unit for a median time of 43 months. Variables included in the analysis were sex, laterality, fetal ultrasonography (isolated versus associated hydronephrosis), and presence/absence of nephrouropathies. The events of interest were urinary tract infection, surgical interventions, hypertension, CKD, and death. Survival analyses were performed to evaluate time until occurrence of the events of interest.

RESULTS

Urinary tract infection occurred in 245 (29.8%) children, with higher risk in females (hazard ratio=1.30, 95% confidence interval=1.02-1.70, P=0.05); 22 patients (2.7%) had hypertension, and 49 (6%) patients developed CKD. The risk of CKD was greater in patients with associated hydronephrosis (hazard ratio=5.20, 95% confidence interval=2.90-9.30, P<0.001). Twelve patients (1.5%) died during follow-up. Death was significantly associated with being born during the first period of the study (hazard ratio=6.00, 95% confidence interval=1.60-22.50, P<0.001), associated hydronephrosis (hazard ratio=9.30, 95% confidence interval=2.90-29.30, P<0.001), and CKD (hazard ratio=170.00, 95% confidence interval=41.00-228.00, P<0.001).

CONCLUSIONS

In our series, the clinical course of prenatally detected CAKUT was heterogeneous, and those infants with associated hydronephrosis at baseline were identified as a high-risk subgroup.

Prenatal sonographic evaluation and postnatal outcome of renal anomalies

OBJECTIVE

To determine the prognosis of antenatally detected renal anomalies by sonographic evaluation.

MATERIALS AND METHODS

This was a follow-up study of all antenatally detected renal anomalies from January 2008 to Dec 2009 referred to fetal medicine clinic. Prenatal evaluation was done and cases were divided into four groups depending upon their prenatal sonographic findings. Post natal follow-up was done up to one year in cases of live babies. Autopsy was carried out in still born fetus after consent.

RESULTS

The renal anomaly was detected in 55 cases, which were fully followed. The prognosis was said to be poor for group I cases with gross extra renal anomaly along with the renal anomaly, and for group II in which there was organic renal pathology with loss of renal function suggested by non-visualization of bladder and almost absent liquor. Prognosis was guarded and depended upon the gestational age of presentation in group III, which had obstructive uropathy; prognosis was good in group IV cases, which were mild, unilateral or which presented late.

CONCLUSION

Prenatal sonographic evaluation gives reasonably accurate picture of the prognosis and can be very helpful in counseling the parents regarding prognosis and help in deciding the timing and route of delivery.

Fetal surgery for severe lower urinary tract obstruction

Fetal interventions have been proposed for treatment of severe lower urinary tract obstruction (LUTO), as this condition is associated with high rates of perinatal mortality and postnatal renal impairment. The rationale for in utero treatment for those cases is based on the possibility of relieving the obstruction, improving the amniotic fluid volume, and preventing renal and bladder damage. Candidates for fetal intervention should be rigorously selected based on the confirmation of severe LUTO (dilated bladder and bilateral hydronephrosis), oligohydramnios or anyhydramnios and 'favorable' fetal urinalysis (dependent on gestational age). Nowadays there are two different therapeutic options with specific technical approaches. Vesico-amniotic shunting is an easier procedure, but with a higher frequency of related complications. Fetal cystoscopy can be used for diagnostic purpose and for treatment of posterior urethral valves, with suggestive advantage of allowing a more physiological release of the obstruction. According to the literature, estimated survival rates and postnatal normal renal function frequencies are approximately 40 and 50% after vesico-amniotic shunting and 75 and 65% after fetal cystoscopy, respectively.

Management of severe bilateral ureteropelvic junction obstruction in neonates with prenatally diagnosed bilateral hydronephrosis

PURPOSE

The management of prenatally detected bilateral ureteropelvic junction obstruction (UPJO) remains controversial. We attempted to develop a treatment plan for patients with severe bilateral UPJO.

MATERIALS AND METHODS

We evaluated the records of 13 patients with prenatally diagnosed grade 3 or more bilateral hydronephrosis that led to the postnatal diagnosis of severe bilateral UPJO. Ultrasonography and (99m)technetium mercaptoacetyltriglycine ((99m)Tc-MAG3) renal scans were performed within 1 month. Four renal units had grade 3 and 22 had grade 4 hydronephrosis. All 13 patients were managed by unilateral pyeloplasty, and the patients' mean age was 3 months. At 1 month postoperatively, we decided whether delayed surgery in the opposite renal unit was necessary according to the findings of ultrasonography and (99m)Tc-MAG3 scans.

RESULTS

Of 13 patients, 11 underwent initial pyeloplasty on renal units with more severe hydronephrosis or lower relative renal function (RRF) on (99m)Tc-MAG3 scans. The remaining 2 patients simultaneously underwent percutaneous nephrostomy on renal units with a lower RRF and initial pyeloplasty on renal units with a higher RRF. In 5 patients, contralateral hydronephrosis had spontaneously improved at 1 month postoperatively, and 8 patients underwent delayed contralateral pyeloplasty at 2 months postoperatively.

CONCLUSIONS

In children with severe bilateral UPJO, the non-operated renal units with grade 3 and some with grade 4 hydronephrosis improved spontaneously after unilateral pyeloplasty. Therefore, delayed pyeloplasty of the opposite side should be considered at 1 month following initial pyeloplasty.

Unilateral multicystic dysplastic kidney: a meta-analysis of observational studies on the incidence, associated urinary tract malformations and the contralateral kidney

BACKGROUND

Many papers are published on cohorts with unilateral multicystic dysplastic kidney (MCDK) patients, but show variable results as to the incidence of associated urinary tract abnormalities. The objective of this study was to describe the status of the urinary tract, including contralateral hypertrophy and malformations, in patients with unilateral MCDK based on a meta-analysis of the literature, taking into account the timing of diagnosis (pre- versus postnatal) as a possible source of bias.

METHODS

A systematic review of the scientific literature in English was conducted using PubMed and Embase. A meta-analysis was performed with the studies that were identified using our reproducible search.

RESULTS

Based on analysis of the data in 19 populations, the overall incidence of unilateral MCDK is 1 in 4300 with an increasing trend over the years. A total of 67 cohorts with over 3500 patients with unilateral MCDK were included in the meta-analysis. Fifty-nine percent of patients were male and the MCDKs were significantly more often found on the left side (53.1%). Associated anomalies in the solitary functioning kidney were found in 1 in 3 patients, mainly vesicoureteric reflux (VUR, in 19.7%). In patients with VUR, 40% have severe contralateral VUR, defined as grade III-V. Contralateral hypertrophy, present in 77% of patients after a follow-up of at least 10 years, showed a trend to be less pronounced in patients with VUR. Timing of the diagnosis of MCDK did not essentially influence the results.

CONCLUSIONS

These aggregate results provide insight into the incidence, demographic data and associated anomalies in patients with unilateral MCDK. One in three patients with unilateral MCDK show anomalies in the contralateral, solitary functioning kidney. However, studies into the long-term consequences of these anomalies are scarce.

Vesico-ureteral reflux in children with prenatally detected hydronephrosis: a systematic review

OBJECTIVE

To investigate the value of prenatally detected hydronephrosis (PNH) as a prognostic factor for vesico-ureteral reflux (VUR).

METHODS

The MEDLINE database was searched for articles on PNH and VUR published between 1980 and 2004. A total of 18 studies were identified and reviewed for various aspects. Results were separated for primary and/or secondary VUR whenever possible, because of the different underlying pathogenic mechanisms.

RESULTS

There was considerable variation between the different studies with respect to methodology and study design. One of the main discrepancies was the way in which postnatal abnormalities were ascertained: by postnatal ultrasound, voiding cystourethrogram (VCUG) alone, or combined or sequential ultrasound and VCUG. Taking these limitations into account, the published data showed there to be a mean prevalence of 15% for postnatal primary VUR after PNH. Of all patients with PNH, 53% had no postnatal anomalies, whereas 29% had other anomalies, such as duplex collecting systems.

CONCLUSIONS

Of all infants with PNH, 15% had primary VUR proven postnatally and 53% had no other anomalies detected. We suggest a standardized protocol for future studies, to enable better comparison of follow-up protocols. Published by John Wiley & Sons, Ltd.

Conservative Treatment of Ureteropelvic Junction Obstruction in Children with Antenatal Diagnosis of Hydronephrosis: Lessons Learned after 16 Years of Follow-Up

OBJECTIVES

We attempted to define predictive factors for surgery in children with antenatal diagnosis of hydronephrosis that led to postnatal diagnosis of ureteropelvic junction (UPJ) obstruction.

METHODS

We retrospectively evaluated our 16-yr experience (1988-2003) with 343 children (260 male and 83 female) with antenatal diagnosis of hydronephrosis that led to postnatal diagnosis of UPJ obstruction and who were followed conservatively. Right-sided hydronephrosis was present in 110 and left-sided in 233 children. According to the Society for Fetal Urology (SFU) classification none had grade 0 of postnatal hydronephrosis, 20 had grade 1, 118 grade 2, 147 grade 3, and the remaining 58 children grade 4 postnatal hydronephrosis. Relative renal function (RRF) on radionuclide scans revealed 235 children with RRF>40%, 68 with RRF between 30% and 40%, and 40 patients with RRF<30%. Renal function deterioration >5% was the main indication for surgery. Commercially available software GraphPad Prism 4.0 (GraphPad prism, Prism 4 for Windows, version 4) using the Fisher exact test was used for statistical evaluation.

RESULTS

Surgical correction was needed in 179 children (52.2%) during the course of conservative management. The average age at surgery was 10.6 mo (range, 1 mo to 7 yr). Of those, 50% underwent surgery during the first 2 yr of life and the majority of the remaining patients underwent surgery between the 2 and 4 yr of age; only two patients required surgery later on. Univariate analysis revealed that child sex, side of hydronephrosis, and SFU grade of prenatal hydronephrosis were not significant predictive factors for surgery. However, SFU grade 3-4 of postnatal hydronephrosis (p<0.0001; odds ratio, 0.06281) and RRF<40% (p<0.0001; odds ratio, 0.1022) were significant independent risk factors for surgery.

CONCLUSION

In contrast with previous publications by others and by us these data show that >50% of children with antenatal diagnosis of UPJ obstruction in this series required surgical correction while on conservative protocol. SFU grade 3-4 of postnatal hydronephrosis and RRF<40% are significant independent predictive factors for surgery.