Prevalence and Symptoms of Idiopathic Hypercalciuria in Primary School Children of Tehran

Objective: Determining prevalence of idiopathic hypercalciuria (IH) in primary school children ofTehran.Material Methods: We evaluated 778 primary school children (age 6-11, mean 9.1 years) in twosteps: first (Screening test), we measured urine calcium to urine creatinine ratio (UCa/UCr) and in thesecond step (Definitive test), for those children who had UCa/UCr ratio more than 0.21 mg/mg wemeasured 24 hours urine calcium excretion. Children with secondary forms of hypercalciuria wereexcluded from the study. Children with idiopathic hypercalciuria were evaluated for manifestations ofIH.Findings: Among 778 children, 195 (25.1%) had UCa/UCr ratio more than 0.21 mg/mg, but fromthese 195 children only 128 children delivered 24 hours urine samples. Among these 128 children forwhom 24 hours urine calcium measurements were done 28 children excreted more than 4mg/kg/daycalcium without hypercalcemia or any other known causes of hypercalciuria and we defined them ashaving idiopathic hypercalciuria. If all 195 suspicious cases of IH had delivered 24-hrs urine sampleswe would have 42 cases of IH.Conclusion: Prevalence of IH in our children was 5.4% and its manifestations were: hematuria,dysuria, recurrent abdominal pain, urinary incontinence, urgency, urinary tract infections andurolithiasis.