Associations Between Prematurity, Birthweight, and Adolescence Blood Pressure in a Nationwide Cohort.

Introduction: Prematurity is associated with incomplete nephrogenesis and an increased incidence of acute kidney injury, that may increase the risk of future kidney disease, including hypertension, proteinuria and reduced glomerular filtration rate. The aim of this study was to evaluate the risk of hypertension or proteinuria in adolescents born prematurely or small for gestational age, in a nationwide cohort. Methods: The study cohort included potential recruits examined in the Israel Defense Forces (IDF) medical facilities, between November 2005 and October 2018. Clinical and anthropometric data, including blood pressure (BP) measurement, were retrieved from the IDF medical files. Adolescents born between January 1993 and December 2000 had additional data on gestational age at birth, retrieved from the Israeli Ministry of Health database. Results: The study cohort included 513,802 participants, aged 17.3 ± 0.9 years, of whom 48,994 had gestational age data. Adolescents born as very preterm, as extremely preterm infants, those born with very low birthweight (VLBW), or with extremely low birthweight (ELBW) had higher incidence of hypertensive-range BP (55%, 47%, 19% and 12%, respectively). No significant association between birthweight (BW) adjusted to gestational age and hypertension was observed. Within the overweight and obese adolescents, those born with VLBW and ELBW, had further increased hypertensive-range BP rate. Proteinuria was diagnosed in 0.33% of the study cohort, with no significant difference between BW or gestational age categories. Conclusion: Adolescents born with VLBW or as significant preterm were associated with high BP and should be monitored for hypertension development and its potential complications.

Apparent mineralocorticoid excess in Israel: a case series and literature review.

BACKGROUND AND OBJECTIVE: Apparent mineralocorticoid excess (AME) syndrome is an ultra-rare autosomal-recessive tubulopathy, caused by mutations in HSD11B2, leading to excessive activation of the kidney mineralocorticoid receptor, and characterized by early-onset low-renin hypertension, hypokalemia, and risk of chronic kidney disease (CKD). To date, most reports included few patients, and none described patients from Israel. We aimed to describe AME patients from Israel and to review the relevant literature. DESIGN: Retrospective cohort study. METHODS: Clinical, laboratory, and molecular data from patients' records were collected. RESULTS: Five patients presented at early childhood with normal estimated glomerular filtration rate (eGFR), while 2 patients presented during late childhood with CKD. Molecular analysis revealed 2 novel homozygous mutations in HSD11B2. All patients presented with severe hypertension and hypokalemia. While all patients developed nephrocalcinosis, only 1 showed hypercalciuria. All individuals were managed with potassium supplements, mineralocorticoid receptor antagonists, and various antihypertensive medications. One patient survived cardiac arrest secondary to severe hyperkalemia. At last follow-up, those 5 patients who presented early exhibited normal eGFR and near-normal blood pressure, but 2 have hypertension complications. The 2 patients who presented with CKD progressed to end-stage kidney disease (ESKD) necessitating dialysis and kidney transplantation. CONCLUSIONS: In this 11-year follow-up report of 2 Israeli families with AME, patients who presented early maintained long-term normal kidney function, while those who presented late progressed to ESKD. Nevertheless, despite early diagnosis and management, AME is commonly associated with serious complications of the disease or its treatment.

Acute glomerulonephritis with concurrent suspected bacterial pneumonia - is it the tip of the iceberg?

BACKGROUND: Post infectious glomerulonephritis is the most common glomerulopathy in children, occurring several weeks after nephritogenic streptococcal throat or skin infection. Reports of acute glomerulonephritis (AGN) occurring during active bacterial pneumonia in children are rare. The aim of this study was to evaluate the incidence of AGN concurrent with bacterial pneumonia in children. METHODS: We reviewed records of all children admitted with a diagnosis of pneumonia to the pediatric department in a single tertiary medical center between January 2015 and April 2023. Patients with bacterial pneumonia and concurrent glomerulonephritis were included. RESULTS: Eleven (0.98%) of 1,123 patients with bacterial pneumonia had concurrent AGN. All were males with a median age of 2.7 years (range 1-13). Mean time from bacterial pneumonia onset to acute glomerulonephritis symptoms was 2.7 ± 1.5 days. Five (45%) patients had evidence of pneumococcal infection. Hypertension was found in 10 (91%) patients. Mean trough eGFR was 43.5 ± 21.4 ml/min/1.73 m2 (range 11-73). Ten patients (91%) had low C3 levels. Median urinary protein-to-creatinine ratio was 2.5 mg/mg (IQR 2.15-14.75). All patients fully recovered. Microscopic hematuria was the last finding to normalize after a median of 29.5 days (IQR 17.25-38). CONCLUSION: AGN during bacterial pneumonia may be more frequent than previously recognized. Kidney prognosis was excellent in all patients. Prospective studies are needed to evaluate the impact of this condition.

Diagnostic Utility of Exome Sequencing Among Israeli Children With Kidney Failure.

Introduction: Genetic etiologies are estimated to account for a large portion of chronic kidney diseases (CKD) in children. However, data are lacking regarding the true prevalence of monogenic etiologies stemming from an unselected population screen of children with advanced CKD. Methods: We conducted a national multicenter prospective study of all Israeli pediatric dialysis units to provide comprehensive "real-world" evidence for the genetic basis of childhood kidney failure in Israel. We performed exome sequencing and assessed the genetic diagnostic yield. Results: Between 2019 and 2022, we recruited approximately 88% (n = 79) of the children on dialysis from all 6 Israeli pediatric dialysis units. We identified genetic etiologies in 36 of 79 (45%) participants. The most common subgroup of diagnostic variants was in congenital anomalies of the kidney and urinary tract causing genes (e.g., EYA1, HNF1B, PAX2, COL4A1, and NFIA) which together explain 28% of all monogenic etiologies. This was followed by mutations in genes causing renal cystic ciliopathies (e.g., NPHP1, NPHP4, PKHD1, and BBS9), steroid-resistant nephrotic syndrome (e.g., LAGE3, NPHS1, NPHS2, LMX1B, and SMARCAL1) and tubulopathies (e.g., CTNS and AQP2). The genetic diagnostic yield was higher among Arabs compared to Jewish individuals (55% vs. 29%) and in children from consanguineous compared to nonconsanguineous families (63% vs. 29%). In 5 participants (14%) with genetic diagnoses, the molecular diagnosis did not correspond with the pre-exome diagnosis. Genetic diagnosis has a potential influence on clinical management in 27 of 36 participants (75%). Conclusion: Exome sequencing in an unbiased Israeli nationwide dialysis-treated kidney failure pediatric cohort resulted in a genetic diagnostic yield of 45% and can often affect clinical decision making.

Primary hyperoxaluria: the pediatric nephrologist's point of view.

The clinical presentation of primary hyperoxaluria in children ranges from mildly symptomatic nephrocalcinosis to very early onset end-stage kidney failure with systemic oxalosis, a devastating complication. We review the various manifestations of pediatric hyperoxaluria, treatment options for children with preserved kidney function and appropriate dialysis regimens. Liver or combined liver/kidney transplantation is currently the only definitive treatment for primary hyperoxaluria type 1, but novel RNA interference treatments offer hope for the future. Finally, we address the medical and ethical dilemmas facing pediatricians treating children with hyperoxaluria.

A multidisciplinary nephrogenetic referral clinic for children and adults-diagnostic achievements and insights.

BACKGROUND: Genetic kidney diseases contribute a significant portion of kidney diseases in children and young adults. Nephrogenetics is a rapidly evolving subspecialty; however, in the clinical setting, increased use of genetic testing poses implementation challenges. Consequently, we established a national nephrogenetics clinic to apply a multidisciplinary model. METHODS: Patients were referred from different pediatric or adult nephrology units across the country if their primary nephrologist suspected an undiagnosed genetic kidney disease. We determined the diagnostic rate and observed the effect of diagnosis on medical care. We also discuss the requirements of a nephrogenetics clinic in terms of logistics, recommended indications for referral, and building a multidisciplinary team. RESULTS: Over 24 months, genetic evaluation was completed for a total of 74 unrelated probands, with an age range of 10 days to 72 years. The most common phenotypes included congenital anomalies of the kidneys and urinary tract, nephrotic syndrome or unexplained proteinuria, nephrocalcinosis/nephrolithiasis, tubulopathies, and unexplained kidney failure. Over 80% of patients were referred due to clinical suspicion of an undetermined underlying genetic diagnosis. A molecular diagnosis was reached in 42/74 probands, yielding a diagnostic rate of 57%. Of these, over 71% of diagnoses were made via next generation sequencing (gene panel or exome sequencing). CONCLUSIONS: We identified a substantial fraction of genetic kidney etiologies among previously undiagnosed individuals which influenced subsequent clinical management. Our results support that nephrogenetics, a rapidly evolving field, may benefit from well-defined multidisciplinary co-management administered by a designated team of nephrologist, geneticist, and bioinformatician. A higher resolution version of the Graphical abstract is available as Supplementary information.

Association of post-transplantation anellovirus viral load with kidney transplant rejection in children.

BACKGROUND: Post-transplantation immunosuppressive therapy reduces the risk of graft rejection but raises the risk of infection and malignancy. A biomarker of the level of immunosuppression can be helpful in monitoring immunosuppressive therapy. Inverse correlation between Torque teno virus (TTV) from the Anelloviridae (AV) family load and immune competence was described in previous studies. The aim of this study was to analyze the association between AV family viruses' kinetics and the risk for graft rejection in the first year after kidney transplantation in children. METHODS: The titers of three genera (TTV, TTMDV, and TTMV) from the AV family were monitored by real-time PCR in consecutive samples from children before and after kidney transplantation. RESULTS: Twenty-one children who underwent kidney transplantation were enrolled. Five out of 21 patients experienced acute graft rejection within a year from transplantation. We found that in patients who experienced graft rejection, the median titers of TTV and total AV titers at 5-6 months post-transplantation were lower than in those who did not. Using a threshold determined by ROC analysis, significant differences in TTV and total AV load were found between patients who had or did not have graft rejection (p = 0.002 and 0.004, respectively). No association was found between the dominance of any AV genus titer and the likelihood of rejection. CONCLUSION: This pilot study suggests that children after kidney transplantation with low TTV and total AV titers 5-6 months post-transplantation are at increased risk for graft rejection within a year after transplantation. A higher resolution version of the Graphical abstract is available as Supplementary information.

Metabolic alkalosis in infants treated with peritoneal dialysis.

BACKGROUND: Acid-base balance is maintained by kidney excretion of titratable acids and bicarbonate reabsorption. Metabolic alkalosis is uncommon in dialysis-treated patients. The aim of this retrospective study was to assess the rate of metabolic alkalosis in pediatric patients treated with peritoneal dialysis. METHODS: Medical records of children treated with peritoneal dialysis in Shaare Zedek Medical Center from January 2000 to June 2021 were reviewed and compared with young adults currently treated with peritoneal dialysis. Demographic, clinical, and peritoneal dialysis characteristics were extracted from the medical records. RESULTS: Thirty chronic peritoneal dialysis patients were included in our study, seven under 2 years, 13 between 2 and 18 years, and 10 adults. 90.3% of the measurements in infants showed metabolic alkalosis compared to 32.3% in the 2-18-year group and none in the adult group. Higher size-adjusted daily exchange volume, lack of urine output, and high lactate-containing dialysate were associated with metabolic alkalosis. Alkalosis was not explained by vomiting, diuretic therapy, or carbonate-containing medications. High transport membrane, low dietary protein, and malnutrition, all previously reported explanations for metabolic alkalosis, were not found in our study. CONCLUSIONS: Metabolic alkalosis is common in infants treated with peritoneal dialysis as opposed to older children and adults. High lactate-containing dialysate is a possible explanation. Higher size-adjusted daily dialysate exchange volume, which may reflect higher bicarbonate absorption, is another independent predictor of alkalosis. Acid-base status should be closely followed in infants, and using a dialysis solution with lower bicarbonate or lactate level should be considered. A higher resolution version of the graphical abstract is available as Supplementary Information.

Comparing blood culture contamination rates by different sampling methods in a paediatric emergency department.

AIM: Blood culture contamination (BCC) can cause unnecessary hospitalisations and inappropriate use of antibiotics. The aim of this study was to find risk factors associated with BCCs in children and to compare contamination rates between open and closed blood culture collection systems. METHODS: Data were prospectively collected regarding blood cultures obtained in the paediatric emergency department from February 26, 2020, to September 30, 2020, based on the method of drawing blood reported by the obtaining physician. A comparison between contaminated and non-contaminated blood cultures was performed. We also compared the composition of the contaminations in the study period to the same period in 2019. RESULTS: A total of 512 blood cultures were included, 33 (6.4%) of which were contaminated. The only parameter that was associated with an increased rate of contamination by 2.34 fold (95% CI 1.1-4.99, P = 0.028) was obtaining blood through an 'open' system, using a syringe connected to a needle in order to draw blood from an open ended needle. The proportion of contaminations originating from oral flora decreased in the study period by 44.7% as compared to the same period in the previous year (13% vs. 23.5%, P = 0.056). CONCLUSIONS: 'Open system' method, which is commonly used in paediatric emergency departments for blood culture obtainment, was associated with an increase in BCC. Adherence to blood cultures obtainment guidelines, even at the price of two different blood tests, is important in order to reduce BCC rates in children.

COVID-19 in children and young adults with kidney disease: risk factors, clinical features and serological response.

BACKGROUND: Chronic kidney disease (CKD) and kidney transplantation in adults are well-recognized risk factors for coronavirus disease 2019 (COVID-19) associated morbidity and mortality. Data on the toll of the pandemic on children and young adults with kidney disease is scarce. The aim of this study was to assess the incidence and severity of COVID-19, as well as the serological response, in this population. METHODS: Study population included all patients with CKD stage 3-5, glomerular disease treated with immunosuppression and kidney transplant recipients followed-up at a tertiary medical center, between 1.12.2020 and 15.2.2021. Data collected included PCR testing, symptoms, exposure, and socio-demographic data. Anti-SARS-CoV-2 antibodies were tested. RESULTS: A total of 197 children and 63 young adults were included, 57% were Jewish, 43% were Arab. PCR-confirmed COVID-19 incidence was 20.8%, 37% of cases were asymptomatic, three patients were hospitalized for observation, and the remainder had mild symptoms. Kidney function remained stable without treatment modification. Risk factors for infection included exposure at home (OR 15.4, 95% CI 6.9-34.2) and number of household members (OR 1.45, 95% CI 1.21-1.73). Anti-SARS-CoV-2 antibodies were detected in 61% of cases and were not associated with COVID-19 severity or immunosuppressive therapy. Three patients who did not develop antibodies had a mild recurrent infection. CONCLUSIONS: Unlike COVID-19 in adult patients with kidney disease, in our cohort of children and young adults, COVID-19 incidence was similar to the general population and all cases were mild. It may be unnecessary to impose severe restrictions on this patient population during the pandemic.

[ACUTE KIDNEY INJURY SECONDARY TO URINARY TRACT OBSTRUCTION - A RARE COMPLICATION OF CIRCUMCISION].

INTRODUCTION: Approximately a third of men worldwide and over 90% of Israeli men are circumcised. The procedure carries a low rate of complication, mainly including surgical and infectious complications. Urinary tract obstruction (UTO) is a rare complication of circumcision. AIMS: The aim of this study was to define the incidence of UTO following circumcision in the last 20 years and describe the characteristics of the affected babies. METHODS: Study participants were identified from a list consisting of all male babies aged 7-30 days treated at the Shaare Zedek Medical Center during the years 2000-2020. Files of patients with serum creatinine ≥ 1 mg/dl were reviewed. Clinical and laboratory data were collected from patients' records. RESULTS: Ten babies with acute kidney injury due to UTO after circumcision were identified. Average age at admission was 10.1 days (8-13). Only two babies had an uncomplicated postnatal course. The main findings on physical examination were distended abdomen, abdominal wall discoloration and leg edema. Average creatinine on admission was 1.76 mg/dl (1.0-3.28). Additional findings were hyperkalemia 6.2 mEq/L (4.5-7.6) and hyponatremia 125 mEq/L (118-134). All hospitalized patients developed post-obstructive diuresis. Kidney function and laboratory abnormalities completely resolved in all of our patients. There was no evidence of kidney damage in six children with long-term follow up. CONCLUSIONS: UTO with acute kidney injury is a rare severe complication of circumcision. Prompt identification and proper treatment can result in complete resolution of kidney function.

Long-term complications of systemic oxalosis in children-a retrospective single-center cohort study.

BACKGROUND: Systemic oxalosis is a severe complication seen in primary hyperoxaluria type I patients with kidney failure. Deposition of insoluble calcium oxalate crystals in multiple organs leads to significant morbidity and mortality. METHODS: We describe a retrospective cohort of 11 patients with systemic oxalosis treated at our dialysis unit from 1982 to 1998 (group 1) and 2007-2019 (group 2). Clinical and demographic data were collected from medical records. Imaging studies were only available for patients in group 2 (n = 5). RESULTS: Median age at dialysis initiation was 6.1 months (IQR 4-21.6), 64% were male. Dialysis modality was mostly peritoneal dialysis in group 1 and daily hemodialysis in group 2. Bone disease was the first manifestation of systemic oxalosis, starting with the appearance of sclerotic bands (mean 166 days, range 1-235), followed by pathological fractures in long bones (mean 200.4 days, range 173-235 days). Advanced disease was characterized by vertebral fractures with resulting kyphosis, worsening splenomegaly, and adynamic bone disease. Two patients developed pulmonary hypertension, 4 and 8 months prior to their death. Four of 11 patients developed hypothyroidism 0-60 months after dialysis initiation. Only one patient survived after a successful liver-kidney transplantation. Four patients died after liver or liver-kidney transplantation. CONCLUSIONS: This is the first comprehensive description of the natural history of pediatric systemic oxalosis. We hope that our findings will provide basis for a quantitative severity score in future, larger studies.

First-week urine beta-2 microglobulin levels in term healthy neonates.

BACKGROUND: Beta-2 microglobulin (ß2mG) is a low-molecular-weight protein that is almost exclusively eliminated through the kidneys. It is freely filtered in the glomeruli and almost completely reabsorbed and degraded in the proximal tubules. Normal urinary ß2mG levels are very low (between 0.04 and 0.22 mg/L). No reference values are known in infants and young children. METHODS: Urinary ß2mG levels were measured in 103 healthy term neonates during the first week of life by nephelometric technology. RESULTS: The average level of urinary ß2mG was 0.65 mg/L (95% confidence interval between 0 and 10.8 mg/L). There was a minor difference between male and female neonates but it did not reach statistical significance. There was no effect of the gestational week, birth weight, or weight loss in the first week of life, on urinary ß2mG levels. CONCLUSIONS: First-week urinary ß2mG levels in healthy term infants were higher than adult levels. Incomplete maturation of kidney tubules in neonates could be a possible explanation. These can now be used in clinical practice and further studies that assess the degree of proximal tubular function in health and disease. Graphical abstract.

Mutations in HOGA1 do Not Confer a Dominant Phenotype Manifesting as Kidney Stone Disease.

PURPOSE: The etiology of calcium-oxalate kidney stone formation remains elusive. Biallelic mutations in HOGA1 are responsible for primary hyperoxaluria type 3 and result in oxalate overproduction and kidney stone disease. Our previous study showed that carriers of HOGA1 mutations have elevated urinary levels of oxalate precursors. In this study we explored the possibility that mutations in HOGA1 confer a dominant phenotype in the form of kidney stone disease or hyperoxaluria. MATERIALS AND METHODS: An observational analytic case control study was designed to determine the prevalence of pathogenic HOGA1 mutations among adults with calcium-oxalate kidney stone disease. Given the high prevalence of HOGA1 mutations among Ashkenazi Jews, this group was evaluated separately. Carrier frequency of any of the 52 reported pathogenic mutations was compared to data derived from gnomAD for the corresponding ethnic group. Sanger sequencing of HOGA1 gene was performed on DNA samples from the following groups: 60 Ashkenazi Jews and 86 nonAshkenazi calcium-oxalate stone formers, 150 subjects with low and 150 with high urinary oxalate levels. RESULTS: The carrier prevalence of pathogenic mutations among the Ashkenazi Jews was 1.7% compared to 2.8% in the corresponding control group (p=0.9 OR=0.6 95% CI 0.01-3.51). We did not detect any mutation among the nonAshkenazi study group. No correlation was detected between hyperoxaluria and HOGA1 variants. CONCLUSIONS: This study shows that mutations in HOGA1 do not confer a dominant phenotype in the form of calcium-oxalate kidney stone disease or hyperoxaluria.

The predictive utility of prior positive urine culture in children with recurrent urinary tract infections.

Urinary tract infections can cause renal damage if not treated promptly. The aim of this study was to examine if prior urine cultures can predict antibiotic susceptibility profile in a subsequent culture, in children with recurrent urinary tract infections. The medical records of all children with at least two episodes of urinary tract infection between 1999-2015 that occurred 2 weeks to 1 year apart were reviewed. Pathogen identity and antibiogram were compared between the two cultures for every patient. One hundred sixty-one cases of recurrent urinary tract infections were identified. Seventy-seven (48%) pairs of cultures grew the same pathogen. However, of these, 31 had an altered biogram. In 53% of the culture pairs, the pathogen in the second culture had a similar or better antibiotic susceptibility profile. We found no statistically significant correlation between the elapsed time between the two cultures and the probability of similar susceptibility profile between them. There was no correlation between antibiogram change and any of the demographic characteristics, including a history of renal transplantation and taking antibiotic prophylactic treatment.Conclusions: Antibiotic susceptibility profile of the pathogen in a prior urinary tract infection did not predict antibiotic susceptibility profile in a subsequent urinary tract infection in our study.What is Known:• Children with urinary tract infections often have recurrent infections.• Clinicians often use prior urine cultures to choose empirical antibiotic treatment in subsequent infections.What is New:• In only 50% of the cases, a subsequent urinary tract infection grows the same pathogen as the 1st urinary tract infection.• Even in cultures with the same pathogen growth, antibiogram is often different.

Early puberty in end stage renal failure and renal transplant recipients.

Background Delayed puberty and hypogonadism are common in children with chronic kidney disease and in renal transplant recipients, but precocious puberty has rarely been reported in these populations. We describe six girls with precocious and/or early-onset, rapidly progressive puberty before and following renal transplantation. Methods Of 112 children under the age of 18 years (67 boys, 45 girls) who received renal transplants between 2010 and 2018, six girls presented with precocious or rapidly progressive early puberty at ages 6-7/12, 7-2/12, 7-4/12, 8, 8-8/12 and 8-11/12 years. Clinical evaluation included measurements of height, weight, body mass index (BMI), Tanner staging and bone age assessment. Gonadotropin responses to intravenous gonadotropin releasing hormone (GnRH) or intramuscular triptorelin acetate were determined. Results Tanner breast stage 3 was noted at 2-6 years following renal transplantation in five girls, four with preserved kidney function. One girl began puberty before renal transplantation. Peak luteinizing hormone (LH) and follicular stimulating hormone (FSH) levels were 6.5, 20.2, 7.83, 19.1, 9 and 2.2 mIU/mL and 13, 8.3, 8.01, 7.5, 8.1 and 7.7 mIU/mL, respectively. Treatment with an intramuscular slow-release formulation of triptorelin acetate every 4 weeks slowed progression of breast development. Conclusions Although delayed puberty is more common in children with renal disease, precocious puberty can also be seen. Evaluation of growth and puberty by a pediatric endocrinologist should be part of the routine care for all children following kidney transplantation.

Eosinophilia in a peritoneal dialysis patient: Answers.

Icodextrin is a starch-derived glucose polymer used in peritoneal dialysis dialysate to treat volume overload by increasing ultrafiltration in patients with end-stage renal disease. Reported adverse reactions to icodextrin are mild and rare and mainly consist of skin rash that resolves spontaneously after discontinuation of treatment. We describe a young patient with extreme eosinophilia that appeared with the use of icodextrin, disappeared after its discontinuation, and reappeared after a rechallenge with the drug. The eosinophilia was not associated with peritonitis, was asymptomatic, and fully resolved after discontinuation of the drug. Severe eosinophilia can potentially cause tissue damage in several organs, which would indicate that blood eosinophil count is recommended in routine complete blood counts while icodextrin peritoneal dialysis is being administered.