Urinary calcium excretion in children with vesicoureteral reflux.

BACKGROUND: Renal malformations including vesico-ureteral reflux (VUR) are associated with urolithiasis. However, studies on urinary calcium excretion in children with VUR have not been reported. This study was conducted to find out whether children with VUR have a higher prevalence of hypercalciuria and whether their family members are affected by hypercalciuria and/or urolithiasis.

METHODS: We studied the prevalence of hypercalciuria and urolithiasis in 46 children (12 males and 34 females) with VUR and in their parents.

RESULTS: Three out of 46 children had renal colic and nine out of 46 exhibited calyceal microlithiasis in the renal sonography. According to Stapleton's criteria, we found that 27 out of 46 children (58.6%) had hypercalciuria. These children were significantly shorter than children with normal calciuria and showed lower values of maximal urinary osmolality. We found no differences in urinary calcium excretion values related to the VUR grading, or to the presence or absence of renal scars, or to whether VUR was still unresolved or already resolved at the time of study. Seventeen out of 27 children with hypercalciuria (63%) had one or both parents affected by hypercalciuria, and there was a history of urolithiasis in six first-degree relatives and in four second-degree relatives (37%). Besides, 10 out of 19 children without hypercalciuria (52.6%) had one or both parents affected by hypercalciuria and there was a history of urolithiasis in three first-degree relatives and in three second-degree relatives (31.6%). Among the 27 children whose parents had hypercalciuria, four had both parents affected, 19 had only the mother affected and in four patients only the father was affected.

CONCLUSION: Our results showed that the prevalence of hypercalciuria was greater in paediatric patients with VUR than in the general population. Urolithiasis in patients with VUR had a metabolic origin. Hypercalciuria was inherited as an autosomal dominant trait although with a higher probability to be inherited from the mother.