engleski

Calcium oxalate urolithiasis in children: urinary promoters/inhibitors and role of their ratios

Introduction: The role of urine calcium as promoter in calcium oxalate urolithiasis is well established. Seldom used calcium/citrate ratio is ac- knowledged a as risk factor for calcium /oxalate urolithiasis. Diagnostic criteria for determination of inclination towards idiopathic calcium oxa- late (CaOx) urolithiasis based on biochemical urine parameters are not sufficiently well defined in children. The aim of this study was to deter- mine the risk of CaOx urolithiasis in children from concentrations of calcium, oxalate, citrate, glycosaminoglycans in urine and their ratios, all standardized in respect to creatinine. Material and methods: We collected and analyzed 24-h urine samples of children with CaOx urolithiasis ( n = 61) and compared with urine sam- ples of matched control group of healthy children ( n =25). Results: The study has showed that all stone formers have higher excre- tion of calcium (mmol/mmol creatinine), calcium/citrate (mol/mmol) and oxalate/(citrate × glycosaminoglycans) ratio (mol Ox × mol cr)/(mol Cit × g GAGs). ROC analysis of these variables gave criteria (> 0.28 ; > 1.07 ; > 0.08 respectively) for distinguishing stone formers from healthy children. Biochemical urine parameters and their ratios (calcium, calcium citrate and oxalate/(citrate × glycosaminoglycans) enable one to discrim- inate idiopathic calcium oxalate stone formers from healthy children. Oxalate/(citrate × glycosaminoglycans) ratio per se can serve as indepen- dent risk for stone formation. Conclusions: The values of calcium and citrate in clinically and geneti- cally proven idiopathic calcium oxalate urolithiasis makes calcium/citrate ratio useful for diagnostic purposes in such stone formers. Rarely used calcium independent oxalate/(citrate x glycosaminglycans) ratio serves as the second best high specificity marker for idiopathic calcium oxalate urolithiasis. Using biochemical urine parameters and their ratios such as calcium, calcium/citrate and oxalate/(citrate × glycosaminoglycans) en- ables one to determine diagnostic criteria towards idiopathic calcium oxalate urolithiasis in children.

calcium oxalate urolithiasis, children

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