Teriparatide Therapy in a 4-Month-Old With Severe Hypoparathyroidism.

Teriparatide is a human parathyroid hormone analog approved for the treatment of osteoporosis in adult patients. Its use for hypocalcemia and hypoparathyroidism in the pediatric population is described through case reports and small case series; however, larger studies that demonstrate long-term efficacy and safety are limited. At our institution, a 4-month-old premature (gestational age: 32 weeks) infant with multiple congenital anomalies, functional athymia, and severe hypoparathyroidism and receiving calcitriol, vitamin D, and calcium carbonate supplementation was initiated on subcutaneous injection of teriparatide. During the course of treatment, her calcium carbonate, vitamin D, and calcitriol supplementation requirements substantially decreased. Teriparatide effectively increased serum ionized calcium concentrations and decreased serum phosphorus concentrations in the present case-study over a 6-month period. Teriparatide was well tolerated, and no evidence of hypercalcemia was observed throughout treatment.

Immunoglobulin A Nephropathy and Immunoglobulin A Vasculitis.

Henoch-Schönlein purpura nephritis and immunoglobulin A nephropathy are common glomerulopathies in the pediatric population that deserve special attention. In some cases the primary care provider can follow the patient but others need more intensive management. Delaying this treatment can lead to worse morbidity. This article provides information on the pathogenesis, outcomes, and follow-up strategies that will aid in the diagnosis and referral of patients at risk for kidney disease.

Early Continuous Renal Replacement Therapy Improves Nutrition Delivery in Neonates During Extracorporeal Life Support.

OBJECTIVE: Optimizing nutrition in neonatal patients as soon as possible after extracorporeal life support (ECLS) initiation is imperative as malnutrition can worsen both short- and long-term outcomes. Fluid restriction, used to manage the fluid overload that commonly complicates neonatal ECLS, severely impairs nutrition delivery. Continuous renal replacement therapy (CRRT) can be used to help manage fluid overload. We hypothesize that early CRRT utilization ameliorates the need for fluid restriction and allows providers to prescribe higher parenteral nutrition (PN) volumes leading to better nutrition delivery. DESIGN: The design of the study was a retrospective chart review, and the setting was a single, level III neonatal intensive care unit. SUBJECTS: Neonatal patients (n = 42) treated with ECLS between January 1, 2008, and December 31, 2013. INTERVENTIONS: Comparisons were made between 2 groups: neonates who received ECLS without early CRRT initiation (group 1; n = 23) and with early CRRT initiation (group 2; n = 19). MAIN OUTCOME MEASURES: The main outcome measures were goal total fluid intake, prescribed PN volume, protein, glucose infusion rate, intralipid, and kilocalories. RESULTS: Infants who received early CRRT were prescribed higher mean total fluid intake goals (group 1: 99 mL/kg/day vs. group 2: 119 mL/kg/day, P < .001) and higher mean volumes of PN (group 1: 61 mL/kg/day vs. group 2: 81 mL/kg/day, P < .001) over the first 72 hours of ECLS compared with infants who did not receive early CRRT. Early CRRT receivers also were prescribed greater mean amounts of protein during the first 72 hours of ECLS (group 1: 2.7 g/kg/day vs. group 2: 3 g/kg/day, P = 0.03). There were no significant changes noted in prescribed glucose infusion rates, intralipid, or total kilocalories. CONCLUSIONS: Institution of early CRRT in neonates on ECLS allows for administration of greater volumes of PN with improved protein delivery. This study characterizes one benefit of early CRRT initiation in neonates on ECLS and suggests these patients could experience improved nutritional outcomes.

FGF23 decreases renal NaPi-2a and NaPi-2c expression and induces hypophosphatemia in vivo predominantly via FGF receptor 1.

Fibroblast growth factor-23 (FGF23) is a phosphaturic hormone that contributes to several hypophosphatemic disorders by reducing the expression of the type II sodium-phosphate cotransporters (NaPi-2a and NaPi-2c) in the kidney proximal tubule and by reducing serum 1,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] levels. The FGF receptor(s) mediating the hypophosphatemic action of FGF23 in vivo have remained elusive. In this study, we show that proximal tubules express FGFR1, -3, and -4 but not FGFR2 mRNA. To determine which of these three FGFRs mediates FGF23's hypophosphatemic actions, we characterized phosphate homeostasis in FGFR3(-/-) and FGFR4(-/-) null mice, and in conditional FGFR1(-/-) mice, with targeted deletion of FGFR1 expression in the metanephric mesenchyme. Basal serum phosphorus levels and renal cortical brush-border membrane (BBM) NaPi-2a and NaPi-2c expression were comparable between FGFR1(-/-), FGFR3(-/-), and FGFR4(-/-) mice and their wild-type counterparts. Administration of FGF23 to FGFR3(-/-) mice induced hypophosphatemia in these mice (8.0 +/- 0.4 vs. 5.4 +/- 0.3 mg/dl; p < or = 0.001) and a decrease in renal BBM NaPi-2a and NaPi-2c protein expression. Similarly, in FGFR4(-/-) mice, administration of FGF23 caused a small but significant decrease in serum phosphorus levels (8.7 +/- 0.3 vs. 7.6 +/- 0.4 mg/dl; p < or = 0.001) and in renal BBM NaPi-2a and NaPi-2c protein abundance. In contrast, injection of FGF23 into FGFR1(-/-) mice had no effects on serum phosphorus levels (5.6 +/- 0.3 vs. 5.2 +/- 0.5 mg/dl) or BBM NaPi-2a and NaPi-2c expression. These data show that FGFR1 is the predominant receptor for the hypophosphatemic action of FGF23 in vivo, with FGFR4 likely playing a minor role.