Long-Term Effect of Nephrocalcinosis on Renal Function and Body Growth Index in Children: A Retrospective Single Center Study

Abstract

Background: Nephrocalcinosis to the presence of calcium salts within renal tissue. Infants and children are more likely to have an underlying etiology for nephrocalcinosis including inherited errors of metabolism, anatomic abnormalities of the urinary tract, renal disorders, vitamin D excess, medication and prematurity. The body growth and renal function have rarely been investigated concerning children with nephrocalcinosis (NC). Objectives: This study aimed to evaluate effect of NC on growth index and kidney function of patients according to its cause. Methods: This study was conducted on twenty-eight now 2-27-year-old patients with NC who were admitted or referred to Loghman Hakim Hospital within 2006 and 2013. The patients’ data were recorded in terms of age, gender, NC etiology, clinical presentation, GFR, standard deviation scores of height and weight, and follow-up period. Data was imported to the SPSS software version 18 and analyzed using statistical tests. Results: Mean age of the participants was 2.5 ± 2.2, ranging from 0.1 to 9.7 years. Fourteen (47%) patients were male. Mean follow-up time period was 7.1 ± 5.2, ranging from 1.0 to 20.9 years. The most common clinical presentations leading to the NC diagnosis were urinary tract infection (25%) and growth retardation among 18% of the patients. The NC was rooted in distal renal tubular acidosis (dRTA) regarding 34.5% of the subjects, idiopathic hypercalciuria (IHC) in terms of 17.2% participants, Bartter syndrome in 10.3% and other different factors in 31.1% of the participants and cause of the NC was unknown in 6.9% of the subjects. Mean glomerular filtration rate (GFR) was 75.6 ± 29.1 in presentation and 105.7 ± 21.9 ml/min/1.73m2 in follow-up (P < 0.001). There was no significant decrease in height and weight SDS from the first to last observation. Also, a significant increase of BMI was observed from first to last observation. Conclusions: Findings revealed that nephrocalcinosis has no significant effect on growth index and glomerular filtration within a long term and its impact depends on the underlying causes.