How should we assess renal function in neonates and infants?

Abstract

Aim Review of current knowledge on assessing renal function in term and preterm neonates. Methods Literature review and analysis of own data. Results Prematurity, genetic, environmental and maternal factors may alter peak nephron endowment and life‐long renal function. Nephrogenesis continues until 34‐36 weeks of gestation, but it is altered with premature delivery. Variability of nephron endowment has a substantial impact on the clearance of renally excreted drugs. Postnatally, glomerular function rate (GFR) increases daily, doubles by two weeks, and slowly reaches full maturity at 18 months of age. Ideally, renal function biomarkers should be expressed as age‐independent z‐scores, and evidence suggests indexing these values to post‐conceptual age rather than chronological age. Newborn and maternal serum creatinine correlate tightly for more than 72 hours after delivery, rendering this biomarker unsuitable for the assessment of neonatal renal function. Cystatin C does not cross the placenta and may be the preferred biomarker in the neonate. Here, we provide preliminary data on the natural evolution of the cystatin C eGFR in infancy. Conclusion Cystatin C may be superior for GFR estimation in neonates, but the best approach to drug dosing of renally excreted drugs remains to be established.

Still trouble with serum creatinine measurements

“…Apart from the need for calibrated reference materials, new methodologies may have to be utilized to improve the lower limit of detection, and there may be a need to measure creatinine with novel methods necessary for precision at the lower limit of detection [12]. This is especially true in the most vulnerable population, prematurely born and term infants, who require accurate assessment of kidney function [13], not only for the diagnosis of acute kidney injury, but also for proper drug dosing of the over 60% renally excreted drugs [14].…”

Animal, Human, and 23Na MRI Imaging Evidence for the Negative Impact of High Dietary Salt in Children

“…There is increasing evidence that activation of the RAAS increases oxidative stress. This is important since there is a finite nephron endowment that develops until 36 weeks of gestational age [ 16 ].…”

Issue highlights

“…A review by Filler et al 6 explores the current knowledge on assessing renal function in term and preterm neonates. The authors conclude that cystatin C may be superior for estimating the glomerular function rate in neonates, but the best approach to drug doses for renally excreted drugs still needs to be established.…”