[Management of genetic renal disorders: local experience and importance of the network]

In nephrology, rare disorders are frequently encountered. In children, about 60% of the renal disorders are rare, with congenital abnormalities of the kidney and urinary tract disorders (CAKUT), being highly prevalent. In adults, about 22% of the disorders leading to renal replacement therapies are rare and include glomerulonephritis and genetic disorders. Rarity may preclude the rapid and extensive access to care for patients suffering of renal disorders, especially in Switzerland, which is small and fragmented. Only collaborative network and access to databases, shared resources and to specific competence may help patient management. Lausanne and Geneva University Hospitals have started specialized outpatient clinics for rare renal disorders several years ago and are part of national and international networks.

[Rare causes of Hypophosphatemia: diagnostic approach]

Hypophosphatemia is common and may be overlooked due to its asymptomatic nature or non-specific symptoms. Two main mechanisms are at its origin: a shift towards the intracellular sector and an increase in urinary phosphate excretion. A measurement of the urinary phosphate reabsorption threshold allows a diagnostic orientation. Alongside common forms of parathyroid hormone-dependent hypophosphatemia, one should not ignore rare FGF23-mediated forms, in particular X-linked hypophosphatemic rickets. The treatment, above all etiological, also includes the administration of phosphate and, in the event of an excess of FGF23, supplementation with calcitriol. In cases of oncogenic osteomalacia and X-linked hypophosphatemic rickets, the use of burosumab, an anti-FGF23 antibody, must be considered.

Diagnostic and therapeutic management of vesico-ureteral reflux in pediatric kidney transplantation-Results of an online survey on behalf of the European Society for Paediatric Nephrology

BACKGROUND

Vesico-ureteral reflux (VUR) is considered to be a risk factor for recurrent febrile urinary tract infections and impaired renal transplant survival.

METHODS

An online survey supported by the European Society for Paediatric Nephrology was designed to evaluate current management strategies of VUR in native and transplanted kidneys of recipients aged <18 years.

RESULTS

Seventy-three pediatric transplant centers from 32 countries contributed to the survey. All centers performed urological evaluation prior to pediatric kidney transplantation (KTx) with subsequent interdisciplinary discussion. Screening for VUR in native kidneys (30% in all, 70% in selected patients) led to surgical intervention in 78% (11% in all, 89% in selected patients) with a decided preference of endoscopic intervention over ureterocystoneostomy. Following KTx, continuous antibiotic prophylaxis was applied in 65% of the patients and screening for allograft VUR performed in 93% of selected patients. The main management strategies of symptomatic allograft VUR were continuous antibiotic prophylaxis (83%) and surgical treatment (74%) (endoscopic intervention 55%, redo ureterocystoneostomy 26%).

CONCLUSIONS

This survey demonstrates the high variability in the management of VUR in pediatric KTx recipients, points to knowledge gaps, and might serve as a starting point for improving the care for patients with VUR in native and transplanted kidneys.

Early urine output monitoring in very preterm infants to predict in-hospital neonatal outcomes: a bicentric retrospective cohort study

OBJECTIVE

To evaluate whether urine output (UO), rarely assessed in the literature, is associated with relevant neonatal outcomes in very preterm infants, and which UO threshold may be the most clinically relevant.

DESIGN

Retrospective cohort study.

SETTING

Two Level IV neonatal intensive care units.

PATIENTS

Very preterm infants born between 24^0/7 and 29^6/7 weeks of gestation documented with eight UO measurements per day between postnatal day 1 and day 7.

MAIN OUTCOME MEASURES

Composite outcome defined as death before discharge, or moderate to severe bronchopulmonary dysplasia, or severe brain lesions. The association between this outcome and UO was studied using several UO thresholds.

RESULTS

Among 532 infants studied, UO <1.0 mL/kg/hour for at least 24 consecutive hours was measured in 55/532 (10%) infants and the primary outcome was recorded in 25 patients. The association between a UO threshold <1.0 mL/kg/hour and the primary outcome was found marginally significant (crude OR 1.80, 95% CI 1.02 to 3.16, p=0.04). The primary outcome was recorded in 112/242 (46%) patients with a UO <2.0 mL/kg/hour and only 64/290 (22%) patients with a UO ≥2.0 mL/kg/hour (p<0.001). This UO threshold was found significantly associated with the primary outcome (crude OR 3.1, 95% CI 2.1 to 4.7, p<0.001), an association confirmed using a multivariate logistic regression model including baseline covariates (adjusted OR 3.7, 95% CI 2.2 to 6.4, p<0.001).

CONCLUSION

A UO <2 mL/kg/hour over 24 hours between postnatal day 1 and day 7 strongly predicts neonatal mortality or severe morbidities in very preterm infants.

Urine Output Monitoring for the Diagnosis of Early-Onset Acute Kidney Injury in Very Preterm Infants

BACKGROUND AND OBJECTIVES

The current threshold used for oliguria in the definition of neonatal AKI has been empirically defined as 1 ml/kg per hour. Urine output criteria are generally poorly documented, resulting in uncertainty in the most accurate threshold to identify AKI in very preterm infants with known tubular immaturity.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a bicentric study including 473 very preterm infants (24^0/7-29^6/7 weeks of gestation) born between January 2014 and December 2018 with urine output measurements every 3 hours during the first 7 days of life and two serum creatinine measurements during the first 10 days of life. AKI was defined using the neonatal Kidney Disease Improving Global Outcomes (KDIGO) definition. We tested whether higher urine output thresholds (1.5 or 2 ml/kg per hour) in modified AKI definitions may better discriminate neonatal mortality compared with the current definition.

RESULTS

Early-onset AKI was developed by 101 of 473 (21%) very preterm infants. AKI was diagnosed on the basis of urine output criteria alone (no rise in creatinine) for 27 of 101 (27%) participants. Early-onset AKI was associated with higher risk of death before discharge (adjusted odds ratio, 3.9; 95% confidence interval, 1.9 to 7.8), and the AKI neonatal KDIGO score showed good discriminative performance for neonatal mortality, with an area under the receiver operating characteristic (ROC) curve of 0.68 (95% confidence interval, 0.61 to 0.75). Modified AKI definitions that included higher urine output thresholds showed significantly improved discriminative performance, with areas under the ROC curve of 0.73 (95% confidence interval, 0.66 to 0.80) for the 1.5-ml/kg per hour threshold and 0.75 (95% confidence interval, 0.68 to 0.81) for the 2-ml/kg per hour threshold.

CONCLUSIONS

Early-onset AKI was diagnosed on the basis of urine output exclusively for a quarter of the cases. Furthermore, modified AKI definitions that included higher urine output improved the discriminative performance for predicting mortality.

Antibody-mediated rejection after kidney transplantation in children; therapy challenges and future potential treatments

Antibody‐mediated rejection (AMR) remains one of the most critical problems in renal transplantation, with a significant impact on patient and graft survival. In the United States, no treatment has received FDA approval jet. Studies about treatments of AMR remain controversial, limited by the absence of a gold standard and the difficulty in creating large, multi‐center studies. These limitations emerge even more in pediatric transplantation because of the limited number of pediatric studies and the occasional use of some therapies with unknown and poorly documented side effects. The lack of recommendations and the unsharp definition of different forms of AMR contribute to the challenging management of the therapy by pediatric nephrologists. In an attempt to help clinicians involved in the care of renal transplanted children affected by an AMR, we rely on the latest recommendations of the Transplantation Society (TTS) for the classification and treatment of AMR to describe treatments available today and potential new treatments with a particular focus on the pediatric population.

Neutrophil gelatinase-associated lipocalin distribution in preterm newborns without acute kidney injury as defined by a reference method

INTRODUCTION

Neutrophil gelatinase-associated lipocalin (NGAL) has been proposed as an early acute kidney injury (AKI) biomarker in the neonatal population. Our goal is to describe this biomarker behavior in this high-risk population, in absence of AKI as confirmed by inulin clearance.

MATERIALS AND METHODS

Prospective study including 42 preterm newborns (mean gestational age: 30.7 ± 2.3 weeks) with a urinary NGAL collection between day 1 and 6 of life.

RESULTS

Median urinary neutrophil gelatinase-associated lipocalin (uNGAL) value is 122.8 ng/ml (7-1981.5 ng/ml). Statistically significant higher uNGAL values are found in female. uNGAL median values are decreasing when comparing extremely, very, and late preterm groups (812.2 ng/ml [75.8-1453.9] vs. 124.4 ng/ml [31.4-1981.5] vs. 65.3 ng/ml [7.1-1091]). There is a statistically significant inverse correlation between gestational age and uNGAL values (Pearson's coefficient r= -0.37). uNGAL median values are higher in groups exposed to gentamicin, neonatal asphyxia, early onset sepsis, or patent ductus arteriosus. Median inulin clearance is 18.8 ml/min/1.73 m² [14.8-25.5 ml/min/1.73 m²]. There is no correlation between uNGAL values and inulin clearance results (Pearson's coefficient r=-0. 29, p: .06).

CONCLUSIONS

In this preterm newborn's series without AKI, the median uNGAL and its high variability are in accordance with published reference ranges. Correlation between uNGAL and gestational age exists, as well as gender impact. Newborns exposed to different renal insults present higher uNGAL values, suggesting potential undetected tubular toxicity or reflecting NGAL production in case of inflammatory or ischemic processes.

Serum NGAL, BNP, PTH, and albumin do not improve glomerular filtration rate estimating formulas in children

Glomerular filtration rate (GFR) is difficult to measure, and estimating formulas are notorious for lacking precision. This study aims to assess if the inclusion of additional biomarkers improves the performance of eGFR formulas. A hundred and sixteen children with renal diseases were enrolled. Data for age, weight, height, inulin clearance (iGFR), serum creatinine, cystatin C, neutrophil gelatinase-associated lipocalin (NGAL), parathyroid hormone (PTH), albumin, and brain natriuretic peptide (BNP) were collected. These variables were added to the revised and combined (serum creatinine and cystatin C) Schwartz formulas, and the quadratic and combined quadratic formulas. We calculated the adjusted r-square (r²) in relation to iGFR and tested the improvement in variance explained by means of the likelihood ratio test. The combined Schwartz and the combined quadratic formulas yielded best results with an r² of 0.676 and 0.730, respectively. The addition of BNP and PTH to the combined Schwartz and quadratic formulas improved the variance slightly. NGAL and albumin failed to improve the prediction of GFR further. These study results also confirm that the addition of cystatin C improves the performance of estimating GFR formulas, in particular the Schwartz formula.Conclusion: The addition of serum NGAL, BNP, PTH, and albumin to the combined Schwartz and quadratic formulas for estimating GFR did not improve GFR prediction in our population. What is Known: • Estimating glomerular filtration rate (GFR) formulas include serum creatinine and/or cystatin C but lack precision when compared to measured GFR. • The serum concentrations of some biological parameters such as neutrophil gelatinase-associated lipocalin (NGAL), parathyroid hormone (PTH), albumin, and brain natriuretic peptide (BNP) vary with the level of renal function. What is New: • The addition of BNP and PTH to the combined quadratic formula improved its performance only slightly. NGAL and albumin failed to improve the prediction of GFR further.

SARS-CoV-2 / COVID-19 in patients on the Swiss national transplant waiting list

AIMS OF THE STUDY

The impact of coronavirus disease 2019 (COVID-19) on patients listed for solid organ transplantation has not been systematically investigated to date. Thus, we assessed occurrence and effects of infections with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on patients on the Swiss national waiting list for solid organ transplantation.

METHODS

Patient data were retrospectively extracted from the Swiss Organ Allocation System (SOAS). From 16 March to 31 May 2020, we included all patients listed for solid organ transplantation on the Swiss national waiting list who were tested positive for SARS-CoV-2. Severity of COVID-19 was categorised as follows: stage I, mild symptoms; stage II, moderate to severe symptoms; stage III, critical symptoms; stage IV, death. We compared the incidence rate (laboratory-confirmed cases of SARS-CoV-2), the hospital admission rate (number of admissions of SARS-CoV-2-positive individuals), and the case fatality rate (number of deaths of SARS-CoV-2-positive individuals) in our study population with the general Swiss population during the study period, calculating age-adjusted standardised incidence ratios and standardised mortality ratios, with 95% confidence intervals (CIs).

RESULTS

A total of 1439 patients were registered on the Swiss national solid organ transplantation waiting list on 31 May 31 2020. Twenty-four (1.7%) waiting list patients were reported to test positive for SARS-CoV-2 in the study period. The median age was 56 years (interquartile range 45.3&ndash;65.8), and 14 (58%) were male. Of all patients tested positive for SARS-CoV-2, two patients were asymptomatic, 14 (58%) presented in COVID-19 stage I, 3 (13%) in stage II, and 5 (21%) in stage III. Eight patients (33%) were admitted to hospital, four (17%) required intensive care, and three (13%) mechanical ventilation. Twenty-two patients (92%) of all those infected recovered, but two male patients aged &gt;65 years with multiple comorbidities died in hospital from respiratory failure. Comparing our study population with the general Swiss population, the age-adjusted standardised incidence ratio was 4.1 (95% CI 2.7&ndash;6.0).

CONCLUSION

The overall rate of SARS-CoV-2 infections in candidates awaiting solid organ transplantation was four times higher than in the Swiss general population; however, the frequency of testing likely played a role. Given the small sample size of affected patients, conclusions have to be drawn cautiously and results need verification in larger cohorts.

Spot urine samples to estimate 24-hour urinary calcium excretion in school-age children

Urinary calcium/creatinine ratio (UCa/Cr) on a single spot urine sample is frequently used in children to evaluate calciuria, but its accuracy to estimate 24-h urinary calcium excretion (24hUCa) has not been properly assessed. We analyzed the correlation between UCa/Cr in various spot samples and 24hUCa among healthy children. A 24-h urine specimen and three spot urine samples (evening, first, and second morning) were collected in a convenience sample of children aged 6 to 16 years (n = 101). Measured 24hUCa was compared with UCa/Cr in each of the three spot samples. The ability of UCa/Cr to discriminate between children with and without hypercalciuria (calciuria > 4 mg/kg/24 h, 1 mmol/kg/24 h) and optimal timing of the spot sample were determined. Eighty-five children completed an adequate 24-h urine collection. Pearson correlation coefficients between the UCa/Cr on the spot sample and 24hUCa were 0.64, 0.71, and 0.52 for the evening, first, and second morning spot samples, respectively. Areas under the ROC curve were 0.90, 0.82, and 0.75, respectively, for the corresponding spot samples.Conclusion: The relatively strong correlation between 24hUCa and UCa/Cr in evening and first morning spot urine samples suggests that these spots could be preferred in clinical practice.Trial registration: ClinicalTrials.gov , NCT02900261, date of trial registration 14 September 2016. What is Known: •Urinary calcium/creatinine ratio on a single spot urine sample is frequently used as a proxy for 24-h urinary calcium excretion. •Correlation of these indicators, including the best timing for spot urine sampling, has not been properly assessed. What is New: •Relatively strong correlations were found between the calcium/creatinine ratio on a single spot urine sample and 24-h urinary calcium excretion in healthy children. •Evening and first morning spot samples had the highest correlation.

Renal follow-up in pediatrician practice after discharge from neonatology units: about a survey

There is growing evidences of long-term renal and cardiovascular consequences of prematurity, intra-uterine growth restriction, and neonatal acute kidney injury (AKI). We performed an online survey to describe current pediatric management in this population, sent to 148 ambulatory pediatricians in Geneva. Among the 40% of pediatricians who completed the survey, 43% modify their blood pressure measurement practice in case of neonatal acute kidney injury, 24% and 19% in a context of prematurity or intra-uterine growth restriction, respectively. Twenty-five percent provide information about cardiovascular risk factors or catch up growth. In case of prematurity or intra-uterine growth restriction, renal tests (ultrasound, serum creatinine, micro albuminuria) or referral to nephrologist were realized by less than 5% of the pediatricians. For neonatal acute kidney injury, renal tests, and referral to specialists are performed by 30 and 60% of pediatricians, respectively. When prematurity or intra-uterine growth restriction was associated with abnormal blood pressure or abnormal renal tests, the referral to the specialist reached 80%.Conclusion: Ambulatory renal and cardio-vascular follow-up in case of neonatal medical history can be enhanced, with necessity to raise awareness and to edict guidelines available to pediatricians. What is Known: • There is a compelling evidence of long-term renal and cardiovascular consequences of prematurity and low birth weight. • Specific cardiovascular and renal follow-up guidelines, coming from professional organizations, are currently not available for these patients. What is New: • Pediatricians in ambulatory setting do not adapt their renal and cardiovascular follow-up in case of neonatal medical history. • There is a necessity to raise awareness about these long-term consequences among pediatricians and to edict guidelines available to them.

Results in the ESPN/ERA-EDTA Registry suggest disparities in access to kidney transplantation but little variation in graft survival of children across Europe

One of the main objectives of the European health policy framework is to ensure equitable access to high-quality health services across Europe. Here we examined country-specific kidney transplantation and graft failure rates in children and explore their country- and patient-level determinants. Patients under 20 years of age initiating kidney replacement therapy from January 2007 through December 2015 in 37 European countries participating in the ESPN/ERA-EDTA Registry were included in the analyses. Countries were categorized as low-, middle-, and high-income based on gross domestic product. At five years of follow-up, 4326 of 6909 children on kidney replacement therapy received their first kidney transplant. Overall median time from kidney replacement therapy start to first kidney transplantation was 1.4 (inter quartile range 0.3-4.3) years. The five-year kidney transplantation probability was 48.8% (95% confidence interval: 45.9-51.7%) in low-income, 76.3% (72.8-79.5%) in middle-income and 92.3% (91.0-93.4%) in high-income countries and was strongly associated with macro-economic factors. Gross domestic product alone explained 67% of the international variation in transplantation rates. Compared with high-income countries, kidney transplantation was 76% less likely to be performed in low-income and 58% less likely in middle-income countries. Overall five-year graft survival in Europe was 88% and showed little variation across countries. Thus, despite large disparities transplantation access across Europe, graft failure rates were relatively similar. Hence, graft survival in low-risk transplant recipients from lower-income countries seems as good as graft survival among all (low-, medium-, and high-risk) graft recipients from high-income countries.

Management of delivery of a fetus with autosomal recessive polycystic kidney disease: a case report of abdominal dystocia and review of the literature

Background

Autosomal recessive renal polycystic kidney disease occurs in 1 in 20,000 live births. It is caused by mutations in both alleles of the PKHD1 gene. Management of delivery in cases of suspected autosomal recessive renal polycystic kidney disease is rarely discussed, and literature concerning abdominal dystocia is extremely scarce. We present a case of a patient with autosomal recessive renal polycystic kidney disease whose delivery was complicated by abdominal dystocia, and we discuss the factors that determined the route and timing of delivery.

Case presentation

A 23-year-old Caucasian woman, G2 P0, with a prior unremarkable pregnancy was referred to our tertiary center at 31 weeks of gestation because of severe oligoamnios (amniotic fluid index = 2) and hyperechogenic, dedifferentiated, and enlarged fetal kidneys. She had no other genitourinary anomaly. Fetal magnetic resonance imaging showed enlarged, hypersignal kidneys and severe pulmonary hypoplasia. We had a high suspicion of autosomal recessive renal polycystic kidney disease, and after discussion with our multidisciplinary team, the parents opted for conservative care. Ultrasound performed at 35 weeks of gestation showed a fetal estimated weight of 3550 g and an abdominal circumference of 377 mm, both above the 90th percentile. Because of the very rapid kidney growth and suspected risk of abdominal dystocia, we proposed induction of labor at 36 weeks of gestation after corticosteroid administration for fetal lung maturation. Vaginal delivery was complicated by abdominal dystocia, which resolved by continuing expulsive efforts and gentle fetal traction. A 3300-g (P50–90) male infant was born with Apgar scores of 1-7-7 at 1, 5, and 10 minutes, respectively, and arterial and venous umbilical cord pH values of 7.23–7.33. Continuous peritoneal dialysis was started at day 2 of life because of anuria. Currently, the infant is 1 year old and is waiting for kidney transplant that should be performed once he reaches 10 kg. Molecular analysis of PKHD1 performed on deoxyribonucleic acid (DNA) from the umbilical cord confirmed autosomal recessive renal polycystic kidney disease.

Conclusions

Management of delivery in cases of suspected autosomal recessive renal polycystic kidney disease needs to be discussed because of the risk of abdominal dystocia. The route and timing of delivery depend on the size of the fetal abdominal circumference and the gestational age. The rate of kidney growth must also be taken into account.

Immunosuppressant therapeutic drug monitoring and trough level stabilisation after paediatric liver or kidney transplantation

BACKGROUND

Immunosuppressive therapy must be guided by therapeutic drug monitoring (TDM) in paediatric liver (LT) and kidney transplantation (KT) patients to prevent under- and overdosing, which have clinical consequences.

AIM

The purpose of our study was to analyse TDM results in our institutions and evaluate factors associated with blood level stabilisation after LT and KT.

METHODS

Blood levels of immunosuppressants were measured by immunoassay analysis. We compared blood level stabilisation between LT and KT, and evaluated associated factors in a retrospective study in two Swiss university hospitals.

RESULTS

Forty-six patients (27 LT [median age 1.0 y], 19 KT [15.1 y]) were included. During the first month after transplantation, 32.8% (LT) and 41.2% (KT) of tacrolimus, and 22.1% (KT) of ciclosporin trough levels (measured before the next dose) were within target. In KT, trough levels stabilised earlier for tacrolimus than for ciclosporin (p = 0.02). Intensive care and hospital discharge occurred earlier in KT patients (p &lt;0.001). Living-donor LT was associated with an earlier intensive care discharge compared with deceased donor (5.5 vs 11 days, p = 0.02). Primary metabolic disease and graft/recipient weight-ratio &ge;0.03 was associated with earlier tacrolimus level stabilisation (14 vs 18 days, p = 0.01 and 15 vs 22 days, p = 0.05, respectively). In KT, recipient age (&ge;15.1 years) and weight (&ge;39.4 kg) were associated with an earlier trough level stabilisation (both 13 days vs not reached, p &lt;0.001), and age with earlier hospital discharge (10 vs 14 days, p = 0.02).

CONCLUSION

Immunosuppressant trough levels were often outside the target range in the first month after LT and KT. Organ-specific factors were associated with trough stabilisation.

The ANTENATAL multicentre study to predict postnatal renal outcome in fetuses with posterior urethral valves: objectives and design

Background

Posterior urethral valves (PUV) account for 17% of paediatric end-stage renal disease. A major issue in the management of PUV is prenatal prediction of postnatal renal function. Fetal ultrasound and fetal urine biochemistry are currently employed for this prediction, but clearly lack precision. We previously developed a fetal urine peptide signature that predicted in utero with high precision postnatal renal function in fetuses with PUV. We describe here the objectives and design of the prospective international multicentre ANTENATAL (multicentre validation of a fetal urine peptidome-based classifier to predict postnatal renal function in posterior urethral valves) study, set up to validate this fetal urine peptide signature.

Methods

Participants will be PUV pregnancies enrolled from 2017 to 2021 and followed up until 2023 in >30 European centres endorsed and supported by European reference networks for rare urological disorders (ERN eUROGEN) and rare kidney diseases (ERN ERKNet). The endpoint will be renal/patient survival at 2 years postnatally. Assuming α = 0.05, 1–β = 0.8 and a mean prevalence of severe renal outcome in PUV individuals of 0.35, 400 patients need to be enrolled to validate the previously reported sensitivity and specificity of the peptide signature.

Results

In this largest multicentre study of antenatally detected PUV, we anticipate bringing a novel tool to the clinic. Based on urinary peptides and potentially amended in the future with additional omics traits, this tool will be able to precisely quantify postnatal renal survival in PUV pregnancies. The main limitation of the employed approach is the need for specialized equipment.

Conclusions

Accurate risk assessment in the prenatal period should strongly improve the management of fetuses with PUV.

[Vitamin D deficiency and rickets : screening and treatment, practical aspects for clinicians]

Vitamin D deficiency is increasing in Switzerland. If cases of rickets are scarce, pediatricians are often dealing with patients presenting vitamin D deficiency. The increase in vitamin D deficiency is certainly due to modification of life habits in recent decades. Clinical presentation varies according to age and severity of deficit. Treatments differ based on the level of vitamin D deficiency and symptoms. Vitamin D deficiency rickets is the most common cause of rickets and is predominantly seen in patients with risks factors They are other types of rickets like pseudo-vitamin D deficiency and hypophosphatemic rickets that the clinician needs to recognize. In which situation should the clinician suspect vitamin D deficiency or rickets ? Different types of rickets and practical aspects of treatment are reviewed in this article.

Early Urinary Biomarkers in Pediatric Autosomal Dominant Polycystic Kidney Disease (ADPKD): No Evidence in the Interest of Urinary Neutrophil Gelatinase-Associated Lipocalin (uNGAL)

Background: Autosomal Dominant Polycystic Kidney Disease (ADPKD) is increasingly diagnosed during childhood by the presence of renal cysts in patients with a positive familial history. No curative treatment is available and early detection and diagnosis confronts pediatricians with the lack of early markers to decide whether to introduce renal-protective agents and prevent the progression of renal failure. Neutrophil Gelatinase-Associated Lipocalin (NGAL) is a tubular protein that has been recently proposed as an early biomarker of renal impairment in the ADPKD adult population. Methods: Urinary NGAL (uNGAL) levels were measured in 15 ADPKD children and compared with 15 age and gender matched controls using parametric, non-parametric, and Bayesian statistics. We also tested the association of uNGAL levels with markers of disease progression, such as proteinuria, albuminuria, blood pressure, and Total Kidney Volume (TKV) using correlation analysis. TKV was calculated by ultrasound, using the ellipsoid method. Results: No difference in mean uNGAL levels was observed between groups (ADPKD: 26.36 ng/ml; Controls: 27.24 ng/ml; P = 0.96). Moreover, no correlation was found between uNGAL and proteinuria (P = 0.51), albuminuria (P = 0.69), TKV (P = 0.68), or mean arterial pressure (P = 0.90). By contrast, TKV was positively correlated with proteinuria (P = 0.04), albuminuria (P = 0.001), and mean arterial pressure (P = 0.03). Conclusion: uNGAL did not confirm its superiority as a marker of disease progression in a pediatric ADPKD population. In the contrary, TKV appears to be an easy measurable variable and may be promising as a surrogate marker to follow ADPKD progression in children.

Clinical and genetic heterogeneity in familial steroid-sensitive nephrotic syndrome

BACKGROUND

Familial steroid-sensitive nephrotic syndrome (SSNS) is a rare condition. The disease pathophysiology remains elusive. However, bi-allelic mutations in the EMP2 gene were identified, and specific variations in HLA-DQA1 were linked to a high risk of developing the disease.

METHODS

Clinical data were analyzed in 59 SSNS families. EMP2 gene was sequenced in families with a potential autosomal recessive (AR) inheritance. Exome sequencing was performed in a subset of 13 families with potential AR inheritance. Two variations in HLA-DQA1 were genotyped in the whole cohort.

RESULTS

Transmission was compatible with an AR (n = 33) or autosomal dominant (AD, n = 26) inheritance, assuming that familial SSNS is a monogenic trait. Clinical features did not differ between AR and AD groups. All patients, including primary (n = 7) and secondary steroid resistant nephrotic syndrone (SRNS), (n = 13) were sensitive to additional immunosuppressive therapy. Both HLA-DQA1 variations were found to be highly linked to the disease (OR = 4.34 and OR = 4.89; p < 0.001). Exome sequencing did not reveal any pathogenic mutation, neither did EMP2 sequencing.

CONCLUSIONS

Taken together, these results highlight the clinical and genetic heterogeneity in familial SSNS. Clinical findings sustain an immune origin in all patients, whatever the initial steroid-sensitivity. The absence of a variant shared by two families and the HLA-DQA1 variation enrichments suggest a complex mode of inheritance.

Balancing competing needs in kidney transplantation: does an allocation system prioritizing children affect the renal transplant function?

Children often merit priority in access to deceased donor kidneys by organ-sharing organizations. We report the impact of the new Swiss Organ Allocation System (SOAS) introduced in 2007, offering all kidney allografts from deceased donors <60 years preferentially to children. The retrospective cohort study included all paediatric transplant patients (<20 years of age) before (n = 19) and after (n = 32) the new SOAS (from 2001 to 2014). Estimated glomerular filtration rate (eGFR), urine protein-to-creatinine ratio (UPC), need for antihypertensive medication, waiting times to kidney transplantation (KTX), number of pre-emptive transplantations and rejections, and the proportion of living donor transplants were considered as outcome parameters. Patients after the new SOAS had significantly better eGFRs 2 years after KTX (Mean Difference, MD = 25.7 ml/min/1.73 m² , P = 0.025), lower UPC ratios (Median Difference, MeD = -14.5 g/mol, P = 0.004), decreased waiting times to KTX (MeD = -97 days, P = 0.021) and a higher proportion of pre-emptive transplantations (Odds Ratio = 9.4, 95% CI = 1.1-80.3, P = 0.018), while the need for antihypertensive medication, number of rejections and living donor transplantations remained stable. The new SOAS is associated with improved short-term clinical outcomes and more rapid access to KTX. Despite lacking long-term research, the study results should encourage other policy makers to adopt the SOAS approach.

[Genetic kidney diseases: new perspectives on diagnosis]

Suspected renal inherited disorders are regularly evaluated in nephrology consultations both in adults and children. A positive family history and/or a typical phenotype should lead to genetic investigations. A confirmatory diagnosis integrated in a multidisciplinary genetic counseling approach gives patient guidance for further pregnancy. It also allows physician to better stratify disease risk and indicates treatment in some cases. The time to diagnosis and costs have been dramatically reduced thanks to next generation sequencing in several cases of complex inherited nephrologic syndromes.

Successful treatment of neonatal atypical hemolytic uremic syndrome with C5 monoclonal antibody

Hemolytic uremic syndrome (HUS) is rare in neonates. We report the case of atypical HUS (aHUS) revealed by neonatal seizures. This 18-day-old baby presented with repeated clonus of the left arm and eye deviation. Four days earlier, she had suffered from gastroenteritis (non-bloody diarrhea and vomiting without fever). Her work-up revealed hemolytic anemia (120 g/L), thrombocytopenia (78 g/L), and impaired renal function (serum creatinine=102 μmol/L) compatible with the diagnosis of HUS. Levels of C3 and C4 in the serum were normal. Shiga-toxin in the stools as well as the IgM and IgG against Escherichia coli O157 were negative. ADAMTS 13 deficiency, inborn error of the cobalamin pathway, deficiency in the H and I protein, and factor H antibodies were excluded and we concluded in aHUS. Genetic screening of the alternative complement pathway was normal. Cerebral magnetic resonance imaging performed after 24 h and 1 week showed restricted diffusion areas with periventricular white matter ischemic-hemorrhagic lesions. Extensive infectious work-up was negative. Upon admission the baby received antiepileptic drugs and 2 days later C5 monoclonal antibody (eculizumab) and two transfusions of packed erythrocytes because the hemoglobin value had dropped to 55 g/L. The platelet value was minimal at 30 g/L. Renal function normalized in 48 h without dialysis and neurological examination was normal in 1 week. She was discharged from the hospital at day 10 with eculizumab perfusions (300 mg) planned every 3 weeks. After 24 months, she was relapse-free and seizure-free, with a normal neurological examination.

Widespread intracranial calcifications in the follow-up of a patient with cartilage-hair hypoplasia--anauxetic dysplasia spectrum disorder: a coincidental finding?

BACKGROUND/PURPOSE

Intracranial calcifications have been identified in many neurological disorders. To our knowledge, however, such findings have not been described in cartilage-hair hypoplasia - anauxetic dysplasia spectrum disorders (CHH-AD), a group of conditions characterized by a wide spectrum of clinical manifestations.

METHODS/RESULTS

We report a 22-year old female patient, diagnosed with this disorder during her first year of life, and in whom bilateral intracranial calcifications (frontal lobes, basal ganglia, cerebellar dentate nuclei) were discovered by brain MRI at the age of 17 years.

CONCLUSION

The etiology of this finding remains unclear. Some causes of such deposits can be of a reversible nature, thus prompting early recognition although their consequences on clinical outcome remain mostly unknown.

Mineral metabolism in European children living with a renal transplant: a European society for paediatric nephrology/european renal association-European dialysis and transplant association registry study

BACKGROUND AND OBJECTIVES

Data on mineral metabolism in pediatric renal transplant recipients largely arise from small single-center studies. In adult patients, abnormal mineral levels are related to a higher risk of graft failure. This study used data from the European Society for Paediatric Nephrology/European Renal Association-European Dialysis and Transplant Association Registry to study the prevalence and potential determinants of mineral abnormalities, as well as the predictive value of a disturbed mineral level on graft survival in a large cohort of European pediatric renal transplant recipients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This study included 1237 children (0-17 years) from 10 European countries, who had serum calcium, phosphorus, and parathyroid hormone measurements from 2000 onward. Abnormalities of mineral metabolism were defined according to European guidelines on prevention and treatment of renal osteodystrophy in children on chronic renal failure.

RESULTS

Abnormal serum phosphorus levels were observed in 25% (14% hypophosphatemia and 11% hyperphosphatemia), altered serum calcium in 30% (19% hypocalcemia, 11% hypercalcemia), and hyperparathyroidism in 41% of the patients. A longer time since transplantation was associated with a lower risk of having mineral levels above target range. Serum phosphorus levels were inversely associated with eGFR, and levels above the recommended targets were associated with a higher risk of graft failure independently of eGFR.

CONCLUSIONS

Abnormalities in mineral metabolism are common after pediatric renal transplantation in Europe and are associated with graft dysfunction.

[Transition in kidney transplantation]

Transition from pediatric to adult care in renal transplantation has emerged as a critical step in the life of a young kidney recipient. During this phase, young patients are faced with the physiological and psychological changes associated with adolescence that can lead to non-compliance and potentially graft loss. To date, there is not a unique accepted model of transition, however it has been proved that the presence of a multidisciplinary team including specialists in adolescent management and in the transition from pediatric to adult transplant care is beneficial during this at-risk phase. The goal of this team is to ensure a progressive transition of the patients according to a precise plan and time line.

[Premature kidneys and oligonephronia: long term repercussion]

The premature has a reduced number of nephrons. This condition, added to an immature renal function at birth, increases the vulnerability to hemodynamic changes, drug toxicity, and nephrocalcinosis. The oligonephronia worsens the risk to present in adulthood, hypertension and renal insufficiency. Nephrocalcinosis appears in the postnatal period, secondary to renal calcifications. This condition increases the risk of further renal endowment. The nephrocalcinosis is closely related to rickets in the premature. Indeed, an excess of vitamin D and calcium, increases the risk of nephrocalcinosis. The early recognition of markers, such as microalbuminuria, hypertension and hypercalciuria, allow targeting prevention measures.

[Quadratic formula: a new pediatric advance for glomerular filtration rate estimation]

A new formula for glomerular filtration rate estimation in pediatric population from 2 to 18 years has been developed by the University Unit of Pediatric Nephrology. This Quadratic formula, accessible online, allows pediatricians to adjust drug dosage and/or follow-up renal function more precisely and in an easy manner.

Urinary low-molecular-weight protein excretion in pediatric idiopathic nephrotic syndrome

BACKGROUND

Minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) are the most common causes of idiopathic nephrotic syndrome (INS). We have evaluated the reliability of urinary neutrophil-gelatinase-associated lipocalin (uNGAL), urinary alpha1-microglobulin (uα1M) and urinary N-acetyl-beta-D-glucosaminidase (uβNAG) as markers for differentiating MCD from FSGS. We have also evaluated whether these proteins are associated to INS relapses or to glomerular filtration rate (GFR).

METHODS

The patient cohort comprised 35 children with MCD and nine with FSGS; 19 healthy age-matched children were included in the study as controls. Of the 35 patients, 28 were in remission (21 MCD, 7 FSGS) and 16 were in relapse (14 MCD, 2 FSGS). The prognostic accuracies of these proteins were assessed by receiver operating characteristic (ROC) curve analyses.

RESULTS

The level of uNGAL, indexed or not to urinary creatinine (uCreat), was significantly different between children with INS and healthy children (p = 0.02), between healthy children and those with FSGS (p = 0.007) and between children with MCD and those with FSGS (p = 0.01). It was not significantly correlated to proteinuria or GFR levels. The ROC curve analysis showed that a cut-off value of 17 ng/mg for the uNGAL/uCreat ratio could be used to distinguish MCD from FSGS with a sensitivity of 0.77 and specificity of 0.78. uβNAG was not significantly different in patients with MCD and those with FSGS (p = 0.86). Only uα1M, indexed or not to uCreat, was significantly (p < 0.001) higher for patients in relapse compared to those in remission.

CONCLUSIONS

Our results indicate that in our patient cohort uNGAL was a reliable biomarker for differentiating MCD from FSGS independently of proteinuria or GFR levels.

New combined serum creatinine and cystatin C quadratic formula for GFR assessment in children

BACKGROUND AND OBJECTIVES

The estimated GFR (eGFR) is important in clinical practice. To find the best formula for eGFR, this study assessed the best model of correlation between sinistrin clearance (iGFR) and the solely or combined cystatin C (CysC)- and serum creatinine (SCreat)-derived models. It also evaluated the accuracy of the combined Schwartz formula across all GFR levels.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Two hundred thirty-eight iGFRs performed between January 2012 and April 2013 for 238 children were analyzed. Regression techniques were used to fit the different equations used for eGFR (i.e., logarithmic, inverse, linear, and quadratic). The performance of each model was evaluated using the Cohen κ correlation coefficient and the percentage reaching 30% accuracy was calculated.

RESULTS

The best model of correlation between iGFRs and CysC is linear; however, it presents a low κ coefficient (0.24) and is far below the Kidney Disease Outcomes Quality Initiative targets to be validated, with only 84% of eGFRs reaching accuracy of 30%. SCreat and iGFRs showed the best correlation in a fitted quadratic model with a κ coefficient of 0.53 and 93% accuracy. Adding CysC significantly (P<0.001) increased the κ coefficient to 0.56 and the quadratic model accuracy to 97%. Therefore, a combined SCreat and CysC quadratic formula was derived and internally validated using the cross-validation technique. This quadratic formula significantly outperformed the combined Schwartz formula, which was biased for an iGFR≥91 ml/min per 1.73 m(2).

CONCLUSIONS

This study allowed deriving a new combined SCreat and CysC quadratic formula that could replace the combined Schwartz formula, which is accurate only for children with moderate chronic kidney disease.

Combined serum creatinine and cystatin C Schwartz formula predicts kidney function better than the combined CKD-EPI formula in children

BACKGROUND

The combined serum creatinine (SCreat) and cystatin C (CysC) CKD-EPI formula constitutes a new advance for glomerular filtration rate (GFR) estimation in adults. Using inulin clearances (iGFRs), the revised SCreat and the combined Schwartz formulas, this study aims to evaluate the applicability of the combined CKD-EPI formula in children.

METHOD

201 iGFRs for 201 children were analyzed and divided by chronic kidney disease (CKD) stages (iGFRs ≥90 ml/min/1.73 m(2), 90 > iGFRs > 60, and iGFRs ≤59), and by age groups (<10, 10-15, and >15 years). Medians with 95% confidence intervals of bias, precision, and accuracies within 30% of the iGFRs, for all three formulas, were compared using the Wilcoxon signed-rank test.

RESULTS

For the entire cohort and for all CKD and age groups, medians of bias for the CKD-EPI formula were significantly higher (p < 0.001) and precision was significantly lower than the solely SCreat and the combined SCreat and CysC Schwartz formulas. We also found that using the CKD-EPI formula, bias decreased and accuracy increased while the child age group increased, with a better formula performance above 15 years of age. However, the CKD-EPI formula accuracy is 58% compared to 93 and 92% for the SCreat and combined Schwartz formulas in this adolescent group.

CONCLUSIONS

The performance of the combined CKD-EPI formula improves in adolescence compared with younger ages. Nevertheless, the CKD-EPI formula performs more poorly than the SCreat and the combined Schwartz formula in pediatric population.

Glomerular and tubular function following orthotopic liver transplantation in children treated with tacrolimus

The aim of this study was to analyze the impact of TAC on medium term (three-yr follow-up) renal function in pediatric liver transplant (OLT) recipients. Glomerular and tubular indices were retrospectively analyzed in 24 consecutive OLT pediatric recipients on TAC. CrCl increased significantly each month post-OLT (p = 0.003), with a trend toward significance between pre-OLT and 36 months (p = 0.17). There was no correlation between CrCl and TAC troughs (p = 0.783). Sixteen percent of patients had CrCl <60 mL/min/1.73 m(2) pre-OLT vs. none at 36 months post-OLT. TRP values were normal throughout the study. UPr/Cr decreased insignificantly over time and correlated significantly with TAC trough levels (p = 0.031). UCa/Cr values normalized by the third-month post-OLT, decreasing significantly over the time (p = 0.000) but did not correlate with TAC troughs. At three months post-OLT, 65.2% of patients needed antihypertensive therapy, and no patients needed more than one antihypertensive treatment after one yr. Despite nephrotoxic side effects in the early postoperative phase, this study shows that 65.5% patients had a normal renal function by three yr post-OLT. Tubular indices correlated with TAC trough levels.

Third-party mesenchymal stromal cell infusion is associated with a decrease in thrombotic microangiopathy symptoms observed post-hematopoietic stem cell transplantation

TA-TMA is a pathology that occurs after allogenic HSC transplantation with an incidence of 4-13%, and represents one of the most severe vascular damage related with this therapy. We report here the case of a nine-yr-old girl suffering from a severe refractory aplastic anemia who received an unrelated, 9/10 HLA-matched HSC. Soon after transplantation, the patient developed a graft-versus-host disease (GvHD), a TA-TMA, and renal insufficiency. These pathologies remained refractory to the various treatments undertaken and required several hospitalizations in the intensive care unit. On day 106 post-HSC transfusion, after several episodes of intensive care, the patient was infused with mismatched, third-party MSCs. Schizocyte levels rapidly decreased after MSC infusion, and two wk later, most biological parameters returned to normal. Erythrocyte and thrombocyte transfusions were discontinued, and the patient remained stable for 10 wk. Thereafter, TA-TMA symptoms, viral reactivation, pleural and cardiac effusions reappeared and lead to the death of the patient. Our observations suggest that allogenic MSC infusion may decrease the symptoms of TA-TMA, but further investigation is required to determine how and when MSC should be infused to develop a long-lasting protective effect.

Successful use of bisphosphonate and calcimimetic in neonatal severe primary hyperparathyroidism

Neonatal primary hyperparathyroidism (NPHT) is associated with an inactivating homozygous mutation of the calcium sensing receptor (CaSR). The CaSR is expressed most abundantly in the parathyroid glands and the kidney and regulates calcium homeostasis through its ability to modulate parathormone secretion and renal calcium reabsorption. NPHT leads to life threatening hypercalcemia, nephrocalcinosis, bone demineralization, and neurologic disabilities. Surgery is the treatment of choice. While waiting for surgery, bisphosphonates offer a good alternative to deal with hypercalcemia. Cinacalcet is a class II calcimimetic that increases CaSR affinity for calcium, leading to parathormone suppression and increased calcium renal excretion. At present, there is little evidence as to whether cinacalcet could improve the function of mutant CaSR in NPHT. We report a case of NPHT, treated successfully with bisphosphonates and cinacalcet after surgery failure. To our knowledge, it is the first time cinacalcet has been used for NPHT.

Encephalitis associated with glutamic acid decarboxylase autoantibodies in a child: a treatable condition?

OBJECTIVE

To increase the recognition of glutamic acid decarboxylase autoantibodies-related encephalitis in childhood.

DESIGN

Case report and review of the literature.

PATIENT

A 6-year-old girl who had developed refractory seizures, developmental regression, and type 1 diabetes mellitus at age 25 months.

INTERVENTIONS

Blood analysis, electroencephalogram, cerebral magnetic resonance imaging, positron emission tomography scan, lumbar puncture, and measurement of glutamic acid decarboxylase activity were performed. Treatment with repeated plasmapheresis and rituximab, with concomitant antiepileptic drugs, was administered.

RESULTS

Highly elevated titers of glutamic acid decarboxylase autoantibodies were found in the serum, as well as in the cerebrospinal fluid. Major clinical improvement in parallel with a decrease in the levels of serum and cerebrospinal fluid antibodies was observed with treatment.

CONCLUSIONS

Encephalitis associated with glutamic acid decarboxylase autoantibodies is a severe epileptic disorder that occurs in young children as well as adults. It may be partially reversible with aggressive immunomodulatory treatment, including plasmapheresis and rituximab. Studies are warranted to determine whether early treatment leads to complete remission.

Do NK cells contribute to the pathophysiology of transplant-associated thrombotic microangiopathy?

Transplant-associated thrombotic microangiopathy (TA-TMA) is a life-threatening complication caused by the aggregation of platelets exposed to the thrombogenic subendothelial matrix of injured endothelial cells. Here, we present a case of a patient transplanted for idiopathic aplastic anemia with a T-cell depleted hematopoietic stem cell graft from an HLA-C mismatched unrelated donor. At day 7 posttransplant, she suffered from acute renal failure with hematuria. The presence of numerous schistocytes, an increased level of lactate dehydrogenase and a renal biopsy with multiple vascular injuries confirmed the diagnosis of severe TA-TMA. At day 14, she developed graft versus host disease and died 7 months posttransplantation of multiorgan failure. At day 15, we observed a sizable population of natural killer (NK) cells in the peripheral blood, the number of which reached 0.8 G/L at 4 months posttransplant. Most NK cells lacked inhibitory killer immunoglobulin-like receptors (KIR) specific for the KIR-ligands expressed in the patient. NK cells were also abundantly present in pericardial and pleural fluids and had invaded the kidney, where they colocalized with the renal vasculopathy. Because there are several mechanisms through which NK cells and platelets can activate each other reciprocally, it is conceivable that NK cells contribute to TA-TMA and its progression.

Antenatal and postnatal ultrasound in the evaluation of the risk of vesicoureteral reflux

Antenatal hydronephrosis (ANH) is a frequent anomaly detected on fetal ultrasound scans. There is no consensus recommendation for the postnatal follow-up and/or the necessity to perform a voiding cystourethrography (VCUG) to diagnose vesicoureteral reflux (VUR). We conducted a cohort/non-randomized trial of 121 patients with ANH, defined as an anterior posterior diameter (APD) >or=5 mm after the 20th week of gestation, to evaluate the ability of the antenatal and postnatal ultrasonography results to predict VUR. All infants had two successive ultrasounds at 5 days and 1 month, respectively, after birth. A VCUG was performed at 6 weeks in children with a persistent APD >or=5 mm and/or an ureteral dilatation observed on at least one of two postnatal ultrasounds. In total, 88 patients had VCUG and nine had VUR, with five having high-grade reflux (>grade II). The risk of VUR increased significantly with the degree of APD detected on the postnatal ultrasound scan (p = 0.03). The odds ratios were 5.0 [95% confidence interval (CI) 0.5-51.2] for APD = 7-9 mm and 9.1 (95% CI 1.0-80.9) for APD >or=10 mm. The results of this study show that among our patient cohort antenatal ultrasound was not predictive of reflux. There was, however, a relation between the importance of the postnatal renal pelvis diameter and the risk of VUR. A cut-off of 7 mm showed a fair ability of ultrasonography to predict VUR and a cut-off of 10 mm enabled all severe refluxes in the 88 patients who had a VCUG to be diagnosed.

[Perinatal asphyxia and neonatal hydronephrosis]

Perinatal asphyxia. Perinatal asphyxia remains one of the most important causes for high mortality and morbidity in the neonatal population. Despite intensive animal and clinical research in this field, no pharmocological strategy has been shown neuroprotective in humans. Moderate hypothermia for severely and moderately asphyctic babies has been aknowledged since a few years as therapeutical approach to improve the outcome of these infants, specifically the long-term follow up (18 months). Neonatal hydronephrosis. Neonatal hydronephrosis is a pathology that requires regular and efficient follow up by a multidisciplinary team. One of the causes of neonatal hydronephrosis is obstructive pathologies which may endanger the kidney. We have developed a strategy that allows a rapid diagnosis of obstructive pathologies with minimal radiological exams. Moreover, this strategy assures the coordination between obstetricians, neonatologists, pediatric urologists, and pediatric nephrologists.

Randomised trial of oral versus sequential intravenous/oral cephalosporins in children with pyelonephritis

The hypothesis was tested that oral antibiotic treatment in children with acute pyelonephritis and scintigraphy-documented lesions is equally as efficacious as sequential intravenous/oral therapy with respect to the incidence of renal scarring. A randomised multi-centre trial was conducted in 365 children aged 6 months to 16 years with bacterial growth in cultures from urine collected by catheter. The children were assigned to receive either oral ceftibuten (9 mg/kg once daily) for 14 days or intravenous ceftriaxone (50 mg/kg once daily) for 3 days followed by oral ceftibuten for 11 days. Only patients with lesions detected on acute-phase dimercaptosuccinic acid (DMSA) scintigraphy underwent follow-up scintigraphy. Efficacy was evaluated by the rate of renal scarring after 6 months on follow-up scintigraphy. Of 219 children with lesions on acute-phase scintigraphy, 152 completed the study; 80 (72 females, median age 2.2 years) were given ceftibuten and 72 (62 females, median age 1.6 years) were given ceftriaxone/ceftibuten. Patients in the intravenous/oral group had significantly higher C-reactive protein (CRP) concentrations at baseline and larger lesion(s) on acute-phase scintigraphy. Follow-up scintigraphy showed renal scarring in 21/80 children treated with ceftibuten and 33/72 with ceftriaxone/ceftibuten (p = 0.01). However, after adjustment for the confounding variables (CRP and size of acute-phase lesion), no significant difference was observed for renal scarring between the two groups (p = 0.2). Renal scarring correlated with the extent of the acute-phase lesion (r = 0.60, p < 0.0001) and the grade of vesico-ureteric reflux (r = 0.31, p = 0.03), and was more frequent in refluxing renal units (p = 0.04). The majority of patients, i.e. 44 in the oral group and 47 in the intravenous/oral group, were managed as out-patients. Side effects were not observed. From this study, we can conclude that once-daily oral ceftibuten for 14 days yielded comparable results to sequential ceftriaxone/ceftibuten treatment in children aged 6 months to 16 years with DMSA-documented acute pyelonephritis and it allowed out-patient management in the majority of these children.

Postnatal management of isolated mild pelvic dilatation detected in antenatal period

AIM

Mild antenatal renal pelvic dilatation (ARPD) revealed by prenatal ultrasound (US) raises the question whether or not screening for vesicoureteral reflux (VUR) is mandatory. The aim of our study was to suggest guidelines for postnatal management of infants with mild ARPD defined as an antero-posterior (AP) dilatation >5 and <10 mm.

METHOD

Therefore we assessed the value of postnatal US at day 30 to predict VUR, the incidence of VUR at day 30 and the rate of spontaneous resolution at 1 year. Two hundred (200) infants with ARPD were included and had renal US and voiding cystourethrography (VCUG) at day 30. If VUR was present, VCUG was repeated 1 year later.

RESULTS

Incidence of VUR was 10% (20/200) at day 30 after birth and only 3% (6/200) 1 year later. VUR at day 30 was twice as frequent in children with postnatal dilatation (11%) than in nondilated kidneys (6%).

CONCLUSIONS

Considering the low incidence of VUR at 1 year, screening for VUR in mild ARDP seems not to be justified. However follow-up by US to detect increase in dilatation and clinical monitoring for signs of urinary infection is required.

NFIA haploinsufficiency is associated with a CNS malformation syndrome and urinary tract defects

Complex central nervous system (CNS) malformations frequently coexist with other developmental abnormalities, but whether the associated defects share a common genetic basis is often unclear. We describe five individuals who share phenotypically related CNS malformations and in some cases urinary tract defects, and also haploinsufficiency for the NFIA transcription factor gene due to chromosomal translocation or deletion. Two individuals have balanced translocations that disrupt NFIA. A third individual and two half-siblings in an unrelated family have interstitial microdeletions that include NFIA. All five individuals exhibit similar CNS malformations consisting of a thin, hypoplastic, or absent corpus callosum, and hydrocephalus or ventriculomegaly. The majority of these individuals also exhibit Chiari type I malformation, tethered spinal cord, and urinary tract defects that include vesicoureteral reflux. Other genes are also broken or deleted in all five individuals, and may contribute to the phenotype. However, the only common genetic defect is NFIA haploinsufficiency. In addition, previous analyses of Nfia^−/− knockout mice indicate that Nfia deficiency also results in hydrocephalus and agenesis of the corpus callosum. Further investigation of the mouse Nfia^+/− and Nfia^−/− phenotypes now reveals that, at reduced penetrance, Nfia is also required in a dosage-sensitive manner for ureteral and renal development. Nfia is expressed in the developing ureter and metanephric mesenchyme, and Nfia^+/− and Nfia^−/− mice exhibit abnormalities of the ureteropelvic and ureterovesical junctions, as well as bifid and megaureter. Collectively, the mouse Nfia mutant phenotype and the common features among these five human cases indicate that NFIA haploinsufficiency contributes to a novel human CNS malformation syndrome that can also include ureteral and renal defects.

Central nervous system (CNS) and urinary tract abnormalities are common human malformations, but their variability and genetic complexity make it difficult to identify the responsible genes. Analysis of human chromosomal abnormalities associated with such disorders offers one approach to this problem. In five individuals described herein, a novel human syndrome that involves both CNS and urinary tract defects is associated with chromosomal disruption or deletion of NFIA, encoding a member of the Nuclear Factor I (NFI) family of transcription factors. This syndrome includes brain abnormalities (abnormal corpus callosum, hydrocephalus, ventriculomegaly, and Chiari type I malformation), spinal abnormalities (tethered spinal cord), and urinary tract abnormalities (vesicoureteral reflux). Nfia disruption in mice was already known to cause hydrocephalus and abnormal corpus callosum, and is now shown to exhibit renal defects and disturbed ureteral development. Other genes besides NFIA are also disrupted or deleted and may contribute to the observed phenotype. However, loss of one copy of NFIA is the only genetic defect common to all five patients. The authors thus provide evidence that genetic loss of NFIA contributes to a distinct CNS malformation syndrome with urinary tract defects of variable penetrance.

[Pyelonephritis treatment in children in 2007: current literature review]

Four studies, including two being published as an abstract, have recently demonstrated the feasibility of oral treatment of pyelonephritis in children, with no increased risk of treatment failure, early urinary tract re-infection, or renal scars. To do so, the pediatrician must ensure that: (1) the patient does not appear toxic, has no vomiting; (2) there is no known severe obstructive or refluxing uropathy and (3) parents are deemed to be adherent to the treatment. If these criteria are fulfilled, the pediatrician can start an oral treatment with a 3rd generation cephalosporine for 10 to 14 days. Ambulatory follow-up is crucial, and persistance of fever after 3 days is a reason for a new outpatient visit, additional or supplementary imaging studies (renal ultrasonography) and eventually a switch to intravenous treatment.

Derivation and Validation of Cystatin C–Based Prediction Equations for GFR in Children

BACKGROUND

Cystatin C (CysC) may be a better marker of glomerular filtration rate (GFR) than serum creatinine (SCr) level. Few studies derived CysC-based GFR prediction equations for children. Objectives of this study are to: (1) derive CysC-based GFR prediction equations for children, and (2) compare these equations with published formulae.

METHODS

Patients younger than 18 years undergoing iothalamate GFR (IoGFR) testing were studied prospectively. Data collected were age, sex, CysC level, SCr level, IoGFR, height, weight, and diagnosis. By using linear regression, 2 equations were derived and compared with 3 previously published formulae by using Bland-Altman analysis and diagnostic characteristics. Local coefficients were derived for comparison formulae.

RESULTS

There were 111 GFR tests from 103 patients (age, 12.7 +/- 4.7 years; IoGFR, 73.6 +/- 35.7 mL/min/1.73 m(2) [1.23 +/- 0.60 mL/s/1.73 m(2)]; 60% male; and 25% post-renal transplantation). The 2 equations derived were the CysEq (including CysC level) and the CysCrEq (including CysC and SCr levels). Overall, the 2 new equations had bias and precision similar to previously published formulae when local coefficients were used. However, in patients with a renal transplant or spina bifida, the 2 new equations were less biased and more precise. All CysC-based equations performed better than the Schwartz formula.

CONCLUSION

This study provides 2 CysC-based GFR prediction equations that are accurate, precise, and sensitive for detecting abnormal GFRs. Three previously published CysC GFR prediction equations have been validated for the first time. Prediction equations based on CysC level are likely to provide more accurate estimates of GFR than SCr-based equations.

[Enuresis and voiding disorders in childhood]

Nocturnal enuresis is a common problem seen by the primary care physician. It is mandatory to distinguish between children having monosymptomatic nocturnal enuresis with normal daytime voiding habits and patients having polysymptomatic bed wetting (associated with urgency, frequency, or other signs of unstable bladder). Investigations and treatment of polysymptomatic enuresis are different than treatment of monosymptomatic nocturnal enuresis. A thorough and thoughtful history of voiding pattern is important to separate urge syndrome from organic causes of enuresis. Management of patients who have urge syndrome include general advices like regular voiding routine, physiotherapy, anticholinergic medication and prevention or treatment of urinary tract infections. If the nocturnal enuresis persists after the control of the voiding dysfunctions, treatment of nocturnal enuresis must be undertaken.

[Antenatally detected hydronephrosis: practical approach for the pediatrician]

Approximately 1% of the fetuses present some dilatation of their urinary tract in utero. More than 50% of these antenatally detected hydronephrosis will disappear spontaneously after birth. The other 50% comprises ureteropelvic junction obstruction, vesico-ureteral reflux and primary megaureters. Postnatal radiological evaluation (renal ultrasonography and VCUG) is performed in every infant with a significantly dilated renal pelvis (> 8 mm between 20 and 30 weeks or > 10 mm after 30 weeks in utero). Renal nuclear scan should be done in every child with significant/worsening post-natal hydronephrosis. Antibioprophylaxis will be started from birth to prevent urinary tract infection. Medical or surgical approach will be chosen in the light of the uroradiological exam results and the clinical progress.

[Hematuria and proteinuria in childhood]

Hematuria and proteinuria are often the first signs of potentially severe kidney diseases. Investigations of a child with proteinuria +/- hematuria should start at the primary care physician office, and will permit to rapidly identify the most serious kidney diseases, such as the glomerulonephritis, but also to avoid excessive and costly investigations in patients with a benign condition such as orthostatic proteinuria. Isolated microscopic hematuria is also relatively frequently found during routine pediatric office visit. Secondary to a glomerulonephritis, it is often associated with proteinuria. Urologic causes should be excluded in case of isolated microscopic or macroscopic hematuria.