Metabolic features and renal outcomes of urolithiasis in children

Aim: The incidence of pediatric urolithiasis has increased over the last century because of dietary changes, metabolic abnormalities, climate change, and genitourinary abnormalities. Data on pediatric urolithiasis in non-endemic countries are limited. The aim of this study was to evaluate the clinical findings and metabolic etiology of urolithiasis in Korean children. Material and methods: The medical records of 73 Korean children who were newly diagnosed with urolithiasis from January 2010 to December 2013 were retrospectively analyzed. Evaluation of metabolic risk factors, including hypercalciuria, hyperuricosuria, hypomagnesuria, hyperoxaluria, and hypocitraturia, required analysis of 24-h urine specimens or, alternatively, for infants and toddlers, the solute-creatinine ratio in spot urine. Results: The male-to-female ratio of the included patients was 1.3:1. The median age at diagnosis was 10.1 years, and the patients were divided into two age groups with pre-school-age children (n?=?27, 37.0%) and school-age children (n?=?46, 63.0%). While flank pain was more common in school-age children, incidentally detected or urinary tract infection (UTI)-associated urolithiasis was more common in pre-school-age children. Eight patients (11.0%) had renal function deterioration associated with urolithiasis, and three patients (4.1%) progressed to chronic kidney disease. Metabolic abnormalities according to urine chemistry were found in 30 patients (41.1%), including hypercalciuria in 21.9%, hyperuricosuria in 11.0%, hypomagnesuria in 4.1%, hyperoxaluria in 1.4%, hypocitraturia in 1.4%, and cystinuria in 1.4%. Conclusion: We suggest that school-age children with renal colic and pre-school-age children with UTI should be evaluated for urolithiasis. Additionally, the evaluation for metabolic risk factors is important in order to prevent recurrence and renal insufficiency.