Metabolic Risk Factors in Pediatric and Adult Calcium Oxalate Urinary Stone Formers: Is There Any Difference?

Abstract

Objectives: Urolithiasis in children is recognized with an increasing frequency, while exact etiological factors remain to be determined. The aim of this study is to compare the metabolic risk factors and saturation of urine in pediatric and adult calcium oxalate (Ca-Ox) stone formers. Methods: A total of 33 pediatric (mean age: 6.8 ± 3.1 years) and 120 adult patients (mean age: 39.7 ± 5.7 years), with documented Ca-Ox urinary stone disease, underwent a comprehensive metabolic evaluation at our institution. Beside a broad serum analysis, concentrations of calcium, oxalate, magnesium, uric acid and citrate were measured in 24-hour collected urine. Saturation of urine was calculated by Marshall-Robertson’s nomograms. Results: Hypocitraturia, observed in 60.6%, and hypomagnesuria, detected in 39.4%, but not hypercalciuria, were the most common metabolic risk factors in the pediatric group. In adults, hypercalciuria still represented one of the major metabolic risk factors, detected in 44.1%, although hypocitraturia, observed in 45.8%, was the most prevalent metabolic risk factor, as it was in the pediatric group. Pediatric cases had significantly (p < 0.05) higher prevalence of hypocitraturia, hypomagnesuria and supersaturated urine when compared to adults. Metabolic abnormalities could be detected in a high percentage (82%) of primary and recurrent pediatric Ca-Ox stone formers, but not in primary adult stone formers. Conclusions: Metabolic risk factors significantly differ in pediatric and adult Ca-Ox stone formers. Hypocitraturia and hypomagnesuria seem to play a major role in stone formation, and metabolic abnormalities can be detected in a significant percentage of both primary and recurrent pediatric stone formers. Thus, a comprehensive metabolic evaluation is of utmost importance for all children with Ca-Ox stones.

A Comparison between Clinical and Metabolic Features of Renal Calyceal Microlithiasis and Overt Urolithiasis in Different Pediatric Age Groups

“…Hypocitraturia was the main metabolic abnormality in older children and adolescents with urolithiasis, which is in accordance with other global studies [9,14,15,22,23,24]. Kovacevic et al [23] indicated that there is a shift from hypercalciuria to hypocitraturia as the predominant metabolic abnormality in pediatric urolithiasis.…”

“…This may be one of the reasons for the recent increase in the incidence of urolithiasis in children, due to the important inhibitory effect of citrate on stone formation [23]. It is believed that dietary habits in older children, mainly diets containing high sodium and animal protein with low fruit and vegetables and environmental factors such as soil properties, play a key role in the lower citrate excretion in the urine [14,19,23,24]. …”

An Update on the Changing Epidemiology and Metabolic Risk Factors in Pediatric Kidney Stone Disease

“…In children, urinary magnesium excretion decreases with age when adjusted for creatinine excretion or body weight (33). A group from Turkey found that hypomagnesuria was more commonly associated with nephrolithiasis in children than in adults (57). Stone-forming children have a higher urinary calcium-to-magnesium ratio than nonstone-forming children, and children with recurrent stones have a higher calcium-to-magnesium ratio than solitary SFs (40).…”

Investigação de nefrolitíase no Oeste do Paraná

“…In this study, such change was observed in 23.5% of the metabolic disorders. Tefekli et al 35 referred to hypocitraturia as the most prevalent metabolic risk factor in children and adults with renal lithiasis (60.6%). Since the etiology of hypocitraturia is multifactorial and directly related to the consumption of animal protein, promoting acid overload, its incidence varies in the different studied regions 36 .…”