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

Objective: Determining prevalence of idiopathic hypercalciuria (IH) in primary school children of Tehran.
Material & Methods: We evaluated 778 primary school children (age 6-11, mean 9.1 years) in two steps: first (Screening test), we measured urine calcium to urine creatinine ratio (UCa/UCr) and in the second step (Definitive test), for those children who had UCa/UCr ratio more than 0.21 mg/mg we measured 24 hours urine calcium excretion. Children with secondary forms of hypercalciuria were excluded from the study. Children with idiopathic hypercalciuria were evaluated for manifestations of IH.
Findings: Among 778 children, 195 (25.1%) had UCa/UCr ratio more than 0.21 mg/mg, but from these 195 children only 128 children delivered 24 hours urine samples. Among these 128 children for whom 24 hours urine calcium measurements were done 28 children excreted more than 4mg/kg/day calcium without hypercalcemia or any other known causes of hypercalciuria and we defined them as having idiopathic hypercalciuria. If all 195 suspicious cases of IH had delivered 24-hrs urine samples we 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 and urolithiasis.

Keywords
Idiopathic hypercalciuria, Children, Urolithiasis, Hematuria, Dysuria, Urgency