From Hypercalciuria to Hypocitraturia-A Shifting Trend in Pediatric Urolithiasis?

Purpose: We analyzed the metabolic abnormalities in children with urolithiasis, and the relationship between diet and hypocitraturia. Materials and Methods: A single center, retrospective analysis was conducted in all children with renal and/or ureteral calculi seen at our Multidisciplinary Stone Clinic between January 2010 and July 2011. Data at presentation were extracted from the clinical database. Results: We analyzed 63 children (37 girls) with urolithiasis with a mean age of 13.43 +/- 4.61 years. Of the 45 patients with 24-hour urinalysis, a metabolic risk factor was present in 68.9%, with hypocitraturia (58.1%) and hypercalciuria (48.3%) being the most common. Children with isolated hypocitraturia had lower urinary magnesium and potassium levels (1.06 +/- 0.62 mg/kg and 0.53 +/- 0.24 mmol/kg per day) than those with no metabolic abnormalities (1.72 +/- 0.61 mg/kg and 0.68 +/- 0.20 mmol/kg per day) (p = 0.015 and p = 0.132, respectively). Urinary citrate was positively correlated with urinary potassium (r = 0.50, p = 0.002) and urinary magnesium (r = 0.49, p = 0.001). Dietary analysis revealed a lower intake of magnesium and potassium in children with hypocitraturia (28.97% +/- 12.25% and 15.42% +/- 7.25% recommended dietary index) than in normocitraturic cases (51.06% +/- 17.51% and 45.23% +/- 29.49% recommended dietary index) (p = 0.042 and p = 0.056, respectively). Conclusions: The majority of children had an identifiable metabolic risk factor for urolithiasis, with hypocitraturia being the most common. This shift in metabolic trend may be a significant contributor to the increasing incidence in pediatric urolithiasis. Hypocitraturia appears to be dietary in origin, correlated with a low consumption of potassium and magnesium.