ESPN 50th Annual Meeting

ESPN 2017


 
Are 1-25 vitamin D measurement useful for managing children with nephrolithiasis and/or nephrocalcinosis?
MELODIE MOSCA 2 BERTHOLET-THOMAS AURELIA 1 LEMOINE SANDRINE 1 CARLIER MARIE-CHRISTINE 1 DUBOURG LAURENCE 1 BACCHETTA JUSTINE 1

1- CENTRE DE RéFéRENCE DES MALADIES RéNALES RARES NéPHROGONES,
2- UNIVERSITé CLAUDE BERNARD LYON1, LYON, FRANCE
 
Introduction:

The measurement of calcitriol, the active form of vitamin D, can be expensive and time-consuming, and there is no clear evidence of its interest in the management of patients with nephrolithiasis (NL) and/or nephrocalcinosis (NC). The aim of this study was to study our current practice of 1-25 vitamin D3 (1-25-D) assessment in order to evaluate its interest in the initial diagnosis and follow-up of children with NL/NC.

Material and methods:

We retrospectively studied all pediatric patients having undergone at least one 1-25-D measurement in our pediatric nephrology unit between December 2014 and November 2015. Clinical, biological and radiological (ultrasounds) data were recorded.

Results:

A total of 264 measurements of 1-25-D levels were performed in 200 patients (age range 1 month to 18 years). The primary renal diseases were the following: 39% NL, 18% NC, 14% transplantation, 5% nephrotic syndrome, 3% neonatal hypercalcemia, 3% hypercalcemia, 2% rickets, 1% tubulopathy, and 15% miscellaneous.

In the 113 patients with NC or NL (mean age 6.4± 5,5 years, 73 boys), the etiology of NC/NL were the following: 27% unexplained despite extensive investigations, 15% neonatal hypercalcemia, 11% hypercalciuria without hypercalcemia, 10% urinary malformations, 9% infections, 6% nutritional mistake, 5% hypervitaminosis D, 4% hypercalcemia hypercalciuria, 4% tubulopathy, 3% hyperoxaluria, 6% miscellaneous.
1-25-D levels were found inappropriately high in 39 (35%) patients and further led to the diagnosis of CYP24A1 mutation in 3 patients and of vitamin D hypersensitivity without any identified mutation in 3 patients. Moreover, it modified the clinical management in 54 (47%) patients.

Conclusions:

Assessment of 1-25D levels modifies clinical management in 47% of patients, mainly by allowing an adaptation of native vitamin D supplementation. In 5% of pediatric patients with NC and/or NL, it also clearly improves the diagnostic strategy. It therefore seems useful in the evaluation of NC/NL in children.