Normative values of renin and aldosterone in clinically stable preterm neonates.

BACKGROUND: There is a paucity of literature on the normative levels of plasma renin concentration (PRC) and serum aldosterone (SA) in premature neonates. This study aims to provide normative data on PRC and SA levels in preterm neonates in the first 2 weeks after birth and explore associations with maternal, perinatal, or postnatal factors. METHODS: Neonates born at 26- to 34-week gestation were recruited from two neonatal intensive care units in Canada and Australia. The direct renin assay PRC and SA were analyzed on day 1 and days 14-21 after birth to compare across categorical variables and to produce normative values. RESULTS: A total of 262 subjects were enrolled from the Canadian (29%) and Australian (71%) sites. The mean gestational age was 30 weeks, with a mean birth weight of 1457 g. The normative values of PRC and SA for neonates born between 26 + 0 and 29 + 6 weeks and 30 + 0 and 34 + 0 weeks of gestation were produced for day 1 and day 14-21 after birth. Both PRC and SA increased from day 1 to day 14-21. The more premature neonates reached a higher PRC on days 14-21 after birth but exhibited lower SA levels on day 1 after birth. When comparing gender, birth weight, and maternal risk factor categories, no statistical differences in PRC or SA were found. A small but significant decrease in PRC, but not SA, was noted for neonates with placental pathology. CONCLUSIONS: This study produced normative values of PRA and SA in clinically stable preterm neonates that can be referenced for use in clinical practice. A higher resolution version of the Graphical abstract is available as Supplementary information.

Worldwide view of nephropathic cystinosis: results from a survey from 30 countries.

BACKGROUND: Nephropathic cystinosis is a rare inherited metabolic disorder leading to progressive renal failure and extra-renal comorbidity. The prognosis relies on early adherence to cysteamine treatment and symptomatic therapies. Developing nations [DiN] experience many challenges for management of cystinosis. The aim of this study was to assess the management characteristics in DiN compared with developed nations [DeN]. METHODS: A questionnaire was sent between April 2010 and May 2011 to 87 members of the International Pediatric Nephrology Association, in 50 countries. RESULTS: A total of 213 patients were included from 41 centres in 30 nations (109 from 17 DiN and 104 from 13 DeN). 7% of DiN patients died at a median age of 5 years whereas no death was observed in DeN. DiN patients were older at the time of diagnosis. In DiN, leukocyte cystine measurement was only available in selected cases for diagnosis but never for continuous monitoring. More patients had reached end-stage renal disease in DiN (53.2 vs. 37.9%, p = 0.03), within a shorter time of evolution (8 vs. 10 yrs., p = 0.0008). The earlier the cysteamine treatment, the better the renal outcome, since the median renal survival increased up to 16.1 [12.5-/] yrs. in patients from DeN treated before the age of 2.5 years of age (p = 0.0001). However, the renal survival was not statistically different between DeN and DiN when patients initiated cysteamine after 2.5 years of age. The number of transplantations and the time from onset of ESRD to transplantation were not different in DeN and DiN. More patients were kept under maintenance dialysis in DiN (26% vs.19%, p = 0.02); 79% of patients from DiN vs. 45% in DeN underwent peritoneal dialysis. CONCLUSIONS: Major discrepancies between DiN and DeN in the management of nephropathic cystinosis remain a current concern for many patients living in countries with limited financial resources.

Is cyclophosphamide effective in patients with IgM-positive minimal change disease?

BACKGROUND: We analyzed the impact of immunoglobulin M (IgM) positivity on the relapse-free interval post completed course of cyclophosphamide (CYC) treatment in patients with steroid-dependent nephrotic syndrome (SDNS) and minimal change disease (MCD). METHODS: This was a retrospective chart review of all children who received CYC for SDNS and MCD between 1988 and 2009. Patients were divided into three groups based on kidney biopsy: MCD without immunoglobulin M (IgM) positivity (IgM-), MCD with IgM-positive immunofluorescence (IF) only (IgM+), and MCD with IgM-positive IF and electron-dense deposits on electron microscopy (IgM++). The relapse-free time interval to the first relapse post-CYC therapy or up to 48 months of follow-up (if no relapse occurred) was used for survival analysis. RESULTS: Forty children aged 1.5-12.3 years (15 were IgM-, 16 were IgM+, 9 were IgM++) received a cumulative CYC dose of 175 ± 30 mg/kg. The overall relapse-free survival time was 75 % at 12 months, 64 % at 24 months, 59 % at 36 months, and 56 % at 48 months, with no significant differences between the IgM groups (p = 0.80). CONCLUSIONS: Based on our results, we conclude that more than 50% of our SDNS patients with MCD remained relapse-free 4 years post-CYC treatment. No significant difference in the response to CYC was observed between patients with or without IgM positivity.

Expanding the clinical spectrum of autosomal-recessive renal tubular dysgenesis: Two siblings with neonatal survival and review of the literature.

BACKGROUND: Autosomal-recessive renal tubular dysgenesis (AR-RTD) is a rare genetic disorder caused by defects in the renin-angiotensin system that manifests as fetal anuria leading to oligohydramnios and Potter sequence. Although the most common outcome is neonatal death from renal failure, pulmonary hypoplasia, and/or refractory arterial hypotension; several cases have been reported that describe survival past the neonatal period. METHODS: Herein, we report the first family with biallelic ACE variants and more than one affected child surviving past the neonatal period, as well as provide a review of the previously reported 18 cases with better outcomes. RESULTS: While both siblings with identical compound heterozygous ACE variants have received different treatments, neither required renal replacement therapy. We show that both vasopressin and fludrocortisone in the neonatal period may provide survival advantages, though outcomes may also be dependent on the type of gene variant, as well as other factors. CONCLUSION: While AR-RTD is most often a lethal disease in the neonatal period, it is not universally so. A better understanding of the factors affecting survival will help to guide prognostication and medical decision-making.

Hypercalciuria as a cause of genital bleeding in a 6-year-old girl.

STUDY OBJECTIVE: To document an unusual cause of genital bleeding in a 6-year-old girl. DESIGN: Case report. SETTING: Outpatient pediatric gynecology clinic in a tertiary care hospital. RESULTS: Clinical presentation of a case of genital bleeding secondary to hypercalciuria in a 6-year-old female. Gynecologic investigations were negative. There were hematuria on urinalysis and an elevated calcium-to-creatinine ratio on initial presentation; however, no evidence of urolithiasis was found on ultrasound. In the context of negative investigations and persistent episodes of bleeding, the hypercalciuria was treated with hydrochlorothiazide. Normalization of calciuria was associated with the end of genital bleeding episodes. CONCLUSION: Hypercalciuria with microcrystals and urethral irritation should be considered as part of the differential diagnosis for genital bleeding in girls.

Patients with autosomal dominant polycystic kidney disease hyperfiltrate early in their disease.

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) ranks among the most common genetic disorders. The development of end-stage renal failure usually is after the fourth decade of life. Angiotensin-converting enzyme (ACE) inhibitors often are used as agents to slow the progression of renal failure, although their effectiveness and starting point in ADPKD remain unclear. METHODS: We measured technetium 99m diethylenetriamine pentaacetic acid glomerular filtration rate (GFR) and serum cystatin C (Cys-C) levels in 18 children with ADPKD and 41 control patients. Data are given as mean +/- SD. Mean age was 9.8 +/- 5.9 years, mean height was 137.5 +/- 34.3 cm, and mean weight was 39.2 +/- 22.8 kg in the ADPKD group, not significantly different from controls, with an average age of 10.4 +/- 4.9 years, height of 138.0 +/- 26.1 cm, and weight of 38.0 +/- 16.8 kg. RESULTS: Mean serum creatinine levels did not differ between the ADPKD (0.6 +/- 0.2 mg/dL [51.1 +/- 20.4 micromol/L]) and control groups (0.7 +/- 0.2 mg/dL [59.8 +/- 15.3 micromol/L]; P = 0.19). Mean GFR was 142 +/- 33.2 mL/min/1.73 m2 in the ADPKD group, significantly greater than that in controls (110 +/- 12 mL/min/1.73 m2; P < 0.0001). Mean Cys-C level for the ADPKD group was 0.71 +/- 0.11 mg/L, significantly lower than that of controls (0.81 +/- 0.12 mg/L; P = 0.0011). No patient with ADPKD had hypertension, and only 1 patient had minimal microalbuminuria. Although renal length on ultrasound was significantly increased, there was no correlation between renal length and GFR or number of cysts. CONCLUSION: Therefore, the high GFR measurements represent early hyperfiltration in children and adolescents with ADPKD, which may give a rationale to start ACE inhibitor therapy.