BackgroundBartter and Gitelman syndromes are autosomal recessive disorders of renal tubular salt handling. Due to their rarity, limited long-term data are available to inform prognosis and management.MethodsLong-term longitudinal data were analysed for 45 children with pathogenic variants in SLC12A1 (n = 8), KCNJ1 (n = 8), CLCNKB (n = 17), BSND (n = 2) and SLC12A3 (n = 10) seen at a single centre between 1984 and 2014. Median follow-up was 8.9 [interquartile range (IQR) 0.7–18.1] years.ResultsPolyhydramnios and prematurity were seen in children with SLC12A1 and KCNJ1 mutations. Patients with CLCNKB mutations had the lowest serum potassium and serum magnesium and the highest serum bicarbonate levels. Fractional excretion of chloride was >0.5% in all patients prior to supplementation. Nephrocalcinosis at presentation was present in the majority of patients with SLC12A1 and KCNJ1 mutations, while it was only present in one patient with CLCNKB and not in SLC12A3 or BSND mutations. Growth was impaired, but within the normal range (median height standard deviation score −1.2 at the last follow-up). Impaired estimated glomerular filtration rate (eGFR <90 mL/min/1.73 m2) at the last follow-up was seen predominantly with SLC12A1 [71 mL/min/1.73 m2 (IQR 46–74)] and KCNJ1 [62 mL/min/1.73 m2 (IQR 48–72)] mutations. Pathological albuminuria was detected in 31/45 children.ConclusionsPatients with Bartter and Gitelman syndromes had a satisfactory prognosis during childhood. However, decreased eGFR and pathologic proteinuria was evident in a large number of these patients, highlighting the need to monitor glomerular as well as tubular function. Electrolyte abnormalities were most severe in CLCNKB mutations both at presentation and during follow-up. Fractional excretion of chloride prior to supplementation is a useful screening investigation in children with hypokalaemic alkalosis to establish renal salt wasting.

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ObjectiveRituximab is an effective treatment for children with steroid dependent or frequently relapsing nephrotic syndrome. The optimum dosing schedule for rituximab has not been established. We hypothesized that a single low dose of 375 mg/m2 would have comparable outcomes to higher doses in reducing the frequency of relapse and time to B cell reconstitution.MethodsWe conducted a multicenter retrospective observational cohort study of children with steroid-sensitive frequently relapsing nephrotic syndrome. Data were extracted from clinical records including the dates of diagnosis, treatment, relapses, the use of concomitant immunosuppression, and lymphocyte subset profiling. Patients treated earlier received variable doses of rituximab, although typically two doses of 750 mg/m2. Later, patients received the current regimen of a single dose of 375 mg/m2. The primary outcome was an absence of clinically confirmed relapse 12 months following rituximab administration. Secondary outcomes were median time to relapse, probability of being relapse-free at 6 and 24 months and time to reconstitution of CD19+ B cells.ResultsSixty patients received 143 courses of rituximab. Seven different dosing regimen strategies were used, ranging between 375 and 750 mg/m2 per dose, with administration of 1–4 doses. There was no significant difference in event-free survival at 12 months between dosing strategies. The median time to reconstitution of B cells was not significantly different between groups.ConclusionsUse of a single low-dose regimen of rituximab in the management of frequently relapsing nephrotic syndrome does not affect the probability of relapse at 12 months or time to B cell reconstitution compared to a conventional higher dose.Electronic supplementary materialThe online version of this article (10.1007/s00467-018-4172-3) contains supplementary material, which is available to authorized users.

Tablets are safer, more convenient and cheaper than liquid medications. Children and young people (CYP) often remain on liquids due to habit, reluctance to change or staff and parents’ lack of knowledge about switching to tablets. We describe a quality improvement project to train staff and embed a system of converting eligible children to tablet medication. A series of tests of change were made including training, making kit available, publicity and developing team protocols. In 3 months, 21 out of 25 eligible CYP were successfully converted with added benefit of saving £46 588 per year. Switching children to tablets is simple but requires whole team engagement, culture change of expectations and available resources.

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Aims: To describe the demographics of the paediatric RRT population under the age of 16 years in the UK and to analyse changes in demography with time. Methods: Data were collected from all 13 paediatric renal centres within the UK. A series of cross-sectional and longitudinal analyses were performed to describe the demographics of paediatric RRT patients. Results: A total of 856 children and young people under 18 with ERF were receiving treatment at paediatric nephrology centres in 2011. At the census date, 80.1% had a functioning transplant, 10.5% were receiving peritoneal dialysis (PD) and 9.4% were receiving haemodialysis (HD). In patients aged <16 years the prevalence of ERF was 56.8 pmarp and the incidence 8.3 pmarp. Analysis of trends over the last 15 years shows that both incidence and prevalence are increasing. A third of the prevalent patients had one or more reported comorbidities. At transfer to adult services, 86% of patients had a functioning renal transplant. Pre-emptive transplantation was seen to occur in 31% of children starting RRT under 16 years, with lower rates seen in girls and ethnic minorities. Survival in childhood amongst children starting RRT was the lowest in those aged less than 2 years. Conclusions: The data provided in this report show increasing trends over 15 years in the incidence and prevalence of established renal failure. This is important for the planning of the provision of care for children needing renal replacement therapy. Further research is required to understand the gender and ethnic differences in pre-emptive transplantation rates and the reduced survival amongst children aged less than 2 years.

Background Primary nephrogenic diabetes insipidus (NDI) is a rare disorder and little is known about treatment practices and long-term outcome. Methods Paediatric and adult nephrologists contacted through European professional organizations entered data in an online form. Results Data were collected on 315 patients (22 countries, male 84%, adults 35%). Mutation testing had been performed in 270 (86%); pathogenic variants were identified in 258 (96%). The median (range) age at diagnosis was 0.6 (0.0–60) years and at last follow-up 14.0 (0.1–70) years. In adults, height was normal with a mean (standard deviation) score of −0.39 (±1.0), yet there was increased prevalence of obesity (body mass index &gt;30 kg/m2; 41% versus 16% European average; P &lt; 0.001). There was also increased prevalence of chronic kidney disease (CKD) Stage ≥2 in children (32%) and adults (48%). Evidence of flow uropathy was present in 38%. A higher proportion of children than adults (85% versus 54%; P &lt; 0.001) received medications to reduce urine output. Patients ≥25 years were less likely to have a university degree than the European average (21% versus 35%; P = 0.003) but full-time employment was similar. Mental health problems, predominantly attention-deficit hyperactivity disorder (16%), were reported in 36% of patients. Conclusion This large NDI cohort shows an overall favourable outcome with normal adult height and only mild to moderate CKD in most. Yet, while full-time employment was similar to the European average, educational achievement was lower, and more than half had urological and/or mental health problems.

The prevalence of patients classified as overweight or obese in the UK paediatric renal cohort is high pre-transplantation and rises subsequently. Those at risk can be identified by an unhealthy BMI pre-transplantation and will require timely intervention with close monitoring in the subsequent post-transplantation period.