Hyperuricosuria in children: Clinical presentation and natural history

Objective. Idiopathic hyperuricosuria (HU) was previously reported in only a limited number of children with hematuria. We aimed to outline the clinic al presentation and natural history of HU not only in children with hematur ia, but also in those with dysuria and/or recurrent abdominal/flank pain an d a family history of urolithiasis. Study Design. Retrospective analysis of data at diagnosis from 102 consecut ive children with HU and outcome analysis of 26 of them who were followed g reater than or equal to1 years (mean: 3.1) with no specific therapy. Results. Sixty-one participants had HU and 41 had HU + hypercalciuria. Fift y-two patients had no hematuria among the presenting symptoms, more than on e third had normal urinalysis at our first examination, one half had microc alculi (<3 mm in diameter) at renal sonography, and 12% had stones (4-18 mm ). Thirty participants of the 39 with no hematuria at our first examination (77%) showed microcalculi or calculi at renal sonography. The patients wit h microcalculi were significantly older than were those without microcalcul i. During the followup, 4 of 26 children never had hematuria and 8 had no h ematuria during most of the follow-up period. Two patients who had a calcul us at first visit and 3 who formed calculi 4 to 12 mm in diameter, after 1 to 3.5 years subsequently passed them in the urine. Conclusions. The lack of hematuria is not predictive of absence of urolithi asis. Therefore, it may be misleading to judge on the efficacy of a given t herapy only based on disappearance of hematuria. HU and hypercalciuria have to be suspected in children with dysuria and those with recurrent abdomina l/flank pain and familial history of urolithiasis, although they have no he maturia.