Dexamethasone to prevent kidney scarring in acute pyelonephritis: a randomized clinical trial.

BACKGROUND: Urinary tract infection (UTI) is one of the most common bacterial infections in childhood and is associated with long-term complications. We aimed to assess the effect of adjuvant dexamethasone treatment on reducing kidney scarring after acute pyelonephritis (APN) in children. METHODS: Multicenter, prospective, double-blind, placebo-controlled, randomized clinical trial (RCT) where children from 1 month to 14 years of age with proven APN were randomly assigned to receive a 3-day course of either an intravenous corticosteroid (dexamethasone 0.30 mg per kg/day) twice daily or placebo. The late technetium 99 m-dimercaptosuric acid scintigraphy (> 6 months after acute episode) was performed to assess kidney scar persistence. Kidney scarring risk factors (vesicoureteral reflux, kidney congenital anomalies, or urinary tract dilatation) were also assessed. RESULTS: Ninety-one participants completed the follow-up and were finally included (dexamethasone n = 49 and placebo n = 42). Both groups had similar baseline characteristics. Twenty participants showed persistent kidney scarring after > 6 months of follow-up without differences in incidence between groups (22% and 21% in the dexamethasone and placebo groups, p = 0.907). Renal damage severity in the early DMSA (ß = 0.648, p = 0.023) and procalcitonin values (ß = 0.065 p = 0.027) significantly modulated scar development. Vesicoureteral reflux grade showed a trend towards significance (ß = 0.545, p = 0.054), but dexamethasone treatment showed no effect. CONCLUSION: Dexamethasone showed no effect on reducing the risk of scar formation in children with APN. Hence, there is no evidence for an adjuvant corticosteroid treatment recommendation in children with APN. However, the study was limited by not achieving the predicted sample size and the expected scar formation. TRIAL REGISTRATION: Clinicaltrials.gov, NCT02034851. Registered in January 14, 2014. "A higher resolution version of the Graphical abstract is available as Supplementary information."

Plasma intact fibroblast growth factor 23 level is a useful tool for diagnostic approach of renal hypophosphatemia.

BACKGROUND: Primary hypophosphatemic syndromes are a heterogeneous group of rare diseases. In recent years, fibroblast growth factor 23 (FGF23) has been postulated as a useful tool for differential diagnosis of hypophosphatemic rickets characterized by impaired renal phosphate reabsorption. This study aimed to investigate the utility of FGF23 to discriminate between X-linked hypophosphatemic rickets (XLH), an FGF23-driven disease, from other causes of renal phosphate wasting such as Fanconi syndrome (FS), a generalized dysfunction of the proximal tubule unrelated to FGF23. METHODS: Circulating levels of intact FGF23 (iFGF23) were measured in nine children with XLH receiving conventional therapy (six girls, mean ± SD age 10.8 ± 6.7 years) and nine children with secondary FS (four girls, mean ± SD age 9.9 ± 5.2 years), using an automated chemiluminescent immunoassay. Phosphate, calcium, creatinine, estimated glomerular filtration rate (eGFR), intact parathormone (iPTH), and urinary parameters were evaluated simultaneously. Maximum renal tubular threshold for phosphate reabsorption (TmP/GFR) was also estimated. RESULTS: Plasma iFGF23 concentrations in patients with XLH were significantly higher than those in the SF group: 146.2 ± 69.2 ng/L vs. 29.5 ± 15.0 ng/L (p < 0.001). Remarkably, we did not observe an overlap between XLH and FS patients. Significant hypophosphatemia (2.55 ± 0.50 mg/dL) and secondary hyperparathyroidism (iPTH 109.4 ± 58.1 ng/mL) were present in XLH patients, while FS patients showed modest hypophosphatemia (3.97 ± 0.68 mg/dL), higher TmP/GFR compared with XLH, lower eGFR and hypercalciuria. CONCLUSIONS: This study supports the value of measuring FGF23 levels as a useful tool to exclude XLH in patients with increased phosphate wasting of kidney origin. Graphical Abstract.

Risk of cardiovascular involvement in pediatric patients with X-linked hypophosphatemia.

OBJECTIVE: To find out if cardiovascular alterations are present in pediatric patients with X-linked hypophosphatemia (XLH). STUDY DESIGN: Multicentre prospective clinical study on pediatric patients included in the RenalTube database ( www.renaltube.com ) with genetically confirmed diagnosis of XLH by mutations in the PHEX gene. The study's protocol consisted of biochemical work-up, 24-h ambulatory blood pressure monitoring (ABPM), carotid ultrasonography, and echocardiogram. All patients were on chronic treatment with phosphate supplements and 1-hydroxy vitamin D metabolites. RESULTS: Twenty-four patients (17 females, from 1 to 17 years of age) were studied. Serum concentrations (X ± SD) of phosphate and intact parathyroid hormone were 2.66 ± 0.60 mg/dl and 58.3 ± 26.8 pg/ml, respectively. Serum fibroblast growth factor 23 (FGF23) concentration was 278.18 ± 294.45 pg/ml (normal < 60 pg/ml). Abnormally high carotid intima media thickness was found in one patient, who was obese and hypertensive as revealed by ABPM, which disclosed arterial hypertension in two other patients. Z scores for echocardiographic interventricular septum end diastole and left ventricular posterior wall end diastole were + 0.77 ± 0.77 and + 0.94 ± 0.86, respectively. Left ventricular mass index (LVMI) was 44.93 ± 19.18 g/m2.7, and four patients, in addition to the obese one, had values greater than 51 g/m2.7, indicative of left ventricular hypertrophy. There was no correlation between these echocardiographic parameters and serum FGF23 concentrations. CONCLUSIONS: XLH pediatric patients receiving conventional treatment have echocardiographic measurements of ventricular mass within normal reference values, but above the mean, and 18% have LVMI suggestive of left ventricular hypertrophy without correlation with serum FGF23 concentrations. This might indicate an increased risk of cardiovascular involvement in XLH.

Primary distal renal tubular acidosis: novel findings in patients studied by next-generation sequencing.

This corrects the article DOI: 10.1038/pr.2015.243.

Primary distal renal tubular acidosis: novel findings in patients studied by next-generation sequencing.

BACKGROUND: Primary distal renal tubular acidosis (DRTA) is a rare disease caused by loss-of-function mutations in at least three genes (ATP6V0A4, ATP6V1B1, and SLC4A1) involved in urinary distal acidification. The next-generation sequencing (NGS) technique facilitates the search for mutations in DRTA patients and helps to characterize the genetic and clinical spectrum of the disease. METHODS: Ten DRTA patients were studied. They had normal serum anion gap (AG), metabolic acidosis with simultaneous positive urinary AG, and inability to maximally acidify the urine. The exons of the three genes were sequenced in two pools by ultrasequencing. Putative mutations were confirmed by corresponding Sanger sequencing of each exon. RESULTS: We found 13 mutations in nine patients. ATP6V0A4: Intron16+2insA; p.R807Q; p.Q276fs; p.P395fs; Intron7-2T>C. ATP6V1B1: p.I386fs; p.R394Q. SLC4A1: p.V245M; p.R589C; p.R589H; p.G609A. One case was a compound heterozygous with a known mutation in ATP6V1B1 (p.G609R) and a pathogenic variation at SLC4A1 (p.E508K). One patient was negative for mutations. CONCLUSION: This study evidences that NGS is labor and cost effective for the analysis of DRTA genes. Our results show for the first time SLC4A1 gene mutations in Spanish patients and disclose that compound heterozygosity at two different genes can be responsible for DRTA.

Novel mutations associated with nephrogenic diabetes insipidus. A clinical-genetic study.

UNLABELLED: Molecular diagnosis is a useful diagnostic tool in primary nephrogenic diabetes insipidus (NDI), an inherited disease characterized by renal inability to concentrate urine. The AVPR2 and AQP2 genes were screened for mutations in a cohort of 25 patients with clinical diagnosis of NDI. Patients presented with dehydration, polyuria-polydipsia, failure to thrive (mean ± SD; Z-height -1.9 ± 2.1 and Z-weight -2.4 ± 1.7), severe hypernatremia (mean ± SD; Na 150 ± 10 mEq/L), increased plasma osmolality (mean ± SD; 311 ± 18 mOsm/Kg), but normal glomerular filtration rate. Genetic diagnosis revealed that 24 male patients were hemizygous for 17 different putative disease-causing mutations in the AVPR2 gene (each one in a different family). Of those, nine had not been previously reported, and eight were recurrent. Moreover, we found those same AVPR2 changes in 12 relatives who were heterozygous carriers. Further, in one female patient, AVPR2 gene study turned out to be negative and she was found to be homozygous for the novel AQP2 p.Ala86Val alteration. CONCLUSION: Genetic analysis presumably confirmed the diagnosis of nephrogenic diabetes insipidus in every patient of the studied cohort. We emphasize that we detected a high presence (50 %) of heterozygous females with clinical NDI symptoms. WHAT IS KNOWN: • In most cases (90 %), inherited nephrogenic diabetes insipidus (NDI) is an X-linked disease, caused by mutations in the AVPR2 gene. • In rare occasions (10 %), it is caused by mutations in the AQP2 gene. What is new: • In this study, we report 10 novel mutations associated with NDI. • We have detected a high presence (50 %) of heterozygous carriers with clinical NDI symptoms.

Long-term eculizumab improves clinical outcomes in atypical hemolytic uremic syndrome.

BACKGROUND: Atypical hemolytic uremic syndrome (aHUS) is a rare genetic disorder caused by chronic uncontrolled complement activation. CASE-DIAGNOSIS/TREATMENT: We present a 4-year-old girl with aHUS who had multiple severe clinical manifestations of thrombotic microangiopathy (TMA) including acute kidney injury, dilated cardiomyopathy, and cardiorespiratory arrest. She was managed with intensive plasma exchange and hemodialysis, which could not halt the progression of TMA. The initial single dose of eculizumab only temporarily improved the clinical symptoms of TMA. Sustained improvement of renal, hematological, and cardiac values were only achieved upon institution of chronic treatment with eculizumab. During long-term treatment with eculizumab (>2.5 years), she has had no further clinical manifestations of TMA, and required neither plasma exchange nor hemodialysis. CONCLUSION: Chronic eculizumab treatment was associated with control of complement-mediated TMA and sustained long-term improvement in renal and cardiac function.

Phenotypic characterization of X-linked hypophosphatemia in pediatric Spanish population.

BACKGROUND: X-linked hypophosphatemia (XLH) is a hereditary rare disease caused by loss-of-function mutations in PHEX gene leading tohypophosphatemia and high renal loss of phosphate. Rickets and growth retardation are the major manifestations of XLH in children, but there is a broad phenotypic variability. Few publications have reported large series of patients. Current data on the clinical spectrum of the disease, the correlation with the underlying gene mutations, and the long-term outcome of patients on conventional treatment are needed, particularly because of the recent availability of new specific medications to treat XLH. RESULTS: The RenalTube database was used to retrospectively analyze 48 Spanish patients (15 men) from 39 different families, ranging from 3 months to 8 years and 2 months of age at the time of diagnosis (median age of 2.0 years), and with XLH confirmed by genetic analysis. Bone deformities, radiological signs of active rickets and growth retardation were the most common findings at diagnosis. Mean (± SEM) height was - 1.89 ± 0.19 SDS and 55% (22/40) of patients had height SDS below-2. All cases had hypophosphatemia, serum phosphate being - 2.81 ± 0.11 SDS. Clinical manifestations and severity of the disease were similar in both genders. No genotype-phenotype correlation was found. Conventional treatment did not attenuate growth retardation after a median follow up of 7.42 years (IQR = 11.26; n = 26 patients) and failed to normalize serum concentrations of phosphate. Eleven patients had mild hyperparathyroidism and 8 patients nephrocalcinosis. CONCLUSIONS: This study shows that growth retardation and rickets were the most prevalent clinical manifestations at diagnosis in a large series of Spanish pediatric patients with XLH confirmed by mutations in the PHEX gene. Traditional treatment with phosphate and vitamin D supplements did not improve height or corrected hypophosphatemia and was associated with a risk of hyperparathyroidism and nephrocalcinosis. The severity of the disease was similar in males and females.

Very low-molecular-mass fragments of albumin in the plasma of patients with focal segmental glomerulosclerosis.

BACKGROUND: Primary focal segmental glomerulosclerosis (FSGS) is a glomerular disease that frequently does not respond to treatment and progresses to kidney failure. FSGS can be of either genetic origin, caused by mutations in slit diaphragm proteins, such as podocin, or idiopathic origin of unknown cause. STUDY DESIGN: Case series. SETTING & PARTICIPANTS: Children with FSGS (aged 3-18 years); 15 with idiopathic and 11 with genetic forms of FSGS. PREDICTOR: Genetic versus idiopathic forms. OUTCOMES & MEASUREMENTS: Differentially expressed proteins in the plasma proteome, detected using 2-dimensional electrophoresis and identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, Western blot, and liquid chromatography electron spray ionization tandem mass spectrometry for fragmentation and identification of the peptides. RESULTS: We found 3 very low-molecular-mass (9.2, 6.9, and 4.7 kDa; isoelectric point, 5.7) spots that were present in pooled samples from patients with genetic FSGS, but missing in patients with idiopathic FSGS and healthy individuals. Spots were identified using mass spectrometry as fragments of albumin, 2 of them apparently containing peptides from both C- and N-terminal parts of the whole protein. Proteomic analyses were carried out on all genetic patients individually; of these, 10 of 11 patients had > or =1 albumin fragment detected in the pool. We did not find an evident relationship between type of mutation or clinical status of patients and albumin fragments observed. LIMITATIONS: Very low-molecular-weight albumin fragments also can be produced by other diseases. CONCLUSIONS: We describe for the first time the presence of very low-molecular-mass albumin fragments in plasma of patients with FSGS with podocyte protein mutations that are absent in patients with idiopathic FSGS or healthy individuals. Additional studies are necessary to determine whether these fragments could be potential biomarkers to distinguish between genetic and idiopathic forms of FSGS.

Complement Activation and Thrombotic Microangiopathies.

BACKGROUND AND OBJECTIVES: Atypical hemolytic uremic syndrome is a form of thrombotic microangiopathy caused by dysregulation of the alternative complement pathway. There is evidence showing complement activation in other thrombotic microangiopathies. The aim of this study was to evaluate complement activation in different thrombotic microangiopathies and to monitor treatment response. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Complement activation was assessed by exposing endothelial cells to sera or activated-patient plasma-citrated plasma mixed with a control sera pool (1:1)-to analyze C5b-9 deposits by immunofluorescence. Patients with atypical hemolytic uremic syndrome (n=34) at different stages of the disease, HELLP syndrome (a pregnancy complication characterized by hemolysis, elevated liver enzymes, and low platelet count) or severe preeclampsia (n=10), and malignant hypertension (n=5) were included. RESULTS: Acute phase atypical hemolytic uremic syndrome-activated plasma induced an increased C5b-9 deposition on endothelial cells. Standard and lower doses of eculizumab inhibited C5b-9 deposition in all patients with atypical hemolytic uremic syndrome, except in two who showed partial remission and clinical relapse. Significant fibrin formation was observed together with C5b-9 deposition. Results obtained using activated-plasma samples were more marked and reproducible than those obtained with sera. C5b-9 deposition was also increased with samples from patients with HELLP (all cases) and preeclampsia (90%) at disease onset. This increase was sustained in those with HELLP after 40 days, and levels normalized in patients with both HELLP and preeclampsia after 6-9 months. Complement activation in those with malignant hypertension was at control levels. CONCLUSIONS: The proposed methodology identifies complement overactivation in patients with atypical hemolytic uremic syndrome at acute phase and in other diseases such as HELLP syndrome and preeclampsia. Moreover, it is sensitive enough to individually assess the efficiency of the C5 inhibition treatment.

Poor phenotype-genotype association in a large series of patients with Type III Bartter syndrome.

INTRODUCTION: Type III Bartter syndrome (BS) is an autosomal recessive renal tubule disorder caused by loss-of-function mutations in the CLCNKB gene, which encodes the chloride channel protein ClC-Kb. In this study, we carried out a complete clinical and genetic characterization in a cohort of 30 patients, one of the largest series described. By comparing with other published populations, and considering that 80% of our patients presented the p.Ala204Thr Spanish founder mutation presumably associated with a common phenotype, we aimed to test the hypothesis that allelic differences could explain the wide phenotypic variability observed in patients with type III BS. METHODS: Clinical data were retrieved from the referral centers. The exon regions and flanking intronic sequences of the CLCNKB gene were screened for mutations by polymerase chain reaction (PCR) followed by direct Sanger sequencing. Presence of gross deletions or duplications in the region was checked for by MLPA and QMPSF analyses. RESULTS: Polyuria, polydipsia and dehydration were the main common symptoms. Metabolic alkalosis and hypokalemia of renal origin were detected in all patients at diagnosis. Calciuria levels were variable: hypercalciuria was detected in 31% of patients, while 23% had hypocalciuria. Nephrocalcinosis was diagnosed in 20% of the cohort. Two novel CLCNKB mutations were identified: a small homozygous deletion (c.753delG) in one patient and a small deletion (c.1026delC) in another. The latter was present in compound heterozygosis with the already previously described p.Glu442Gly mutation. No phenotypic association was obtained regarding the genotype. CONCLUSION: A poor correlation was found between a specific type of mutation in the CLCNKB gene and type III BS phenotype. Importantly, two CLCNKB mutations not previously described were found in our cohort.

Terapia secuencial parenteral oral en infecciones moderadas y severas / Oral parenteral sequential therapy in severs and moderats infection

Se realizó un estudio retrospectivo comparativo con dos grupos independientes de historias clinicas de pacientes que fueron ingresados en el Hospital Pediátrico "Dr. Elías Toro", con el objeto del evaluar la efectividad y seguridad de TSPO pra el manejo de infecciones bactrianas moderadas y severas. Como grupo de estudio se seleccionaron ochenta y seis (86) historias clínicas de pacientes en el servicio de enfermedades infectocontagiosas entre enero de 1994 y agosto de 1996. Estos pacientes recibieron al ingreso terapia parenteral y al estabilizarse sus condiciones generales eran cambiados a vía oral. El grupo control estuvo constituido por ochenta y seis (86) historias clínicas de pacientes que ingresaron a dicho centro entre enero de 1992 y diciembre de 1993 y recibieron el curso completo del antibiótico por vía parenteral. Ambos grupos presentaban características similares tanto en número, edad, sexo y diagnóstico, observándose una disminución significativa del promedio de estancia hospitalaria en los pacientes del grupo estudio con terapia secuencial parenteral oral. Se obtuvo una reducción de los días de hospitalización para los pacientes con neumonías con derrame del 54 por ciento, en celulitis periorbitarias 58 por ciento, en varicela impetiginizada 35 por ciento, en celulitis de tronco y extremidades 41 por ciento y en otras infeciones 37 por ciento, con respecto al grupo control. Esta redución fue estadísticamente significativa según la prueba de significancia de t de Student para muestras independientes (p<0,05) y con una tasa específica de fracaso, nula para cada enfermedad. Consideramos a la TSPO, una alternativa de tratamiento válida, eficaz, y segura para el manejo de infecciones moderadas y severas