Clinical Presentation of Hyperuricosuria in Children

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ntroduction: Hyperuricosuria (HU), defined as an increased uric acid excretion, has different symptoms in children and is responsible for the formation of kidney stone. This study was aimed to outline the clinical presentation and natural history of HU in children with hematuria, dysuria, discoloration of urine, and recurrent abdominal / flank pain.
Material and Methodes: In this cross sectional study, from October 2002 to May 2006, 88 children with Hyperuricosuria at Dr Sheikh Hospital, Mashhad were evaluated. Urinalysis, urine culture, 24-hour urine collection for measurement of uric acid, Calcium and Creatinine, serum evaluation for BUN, Creatinine, uric acid, Calcium, Phosphorous and Hco₃^- and renal ultrasonugeraphy were carried out done for patients. All data were recorded and analyzed with descriptive statistical methods.
Results: From 88 evaluated patients, 51% were boys and 48.8 % were girls. The mean age of children was 5.3± 1.2 years. The mean Urine Uric Acid was 13.4 mg/kg/24h and mean Urine PH was 5.3. Hematuria was not among the presenting symptoms in 41 patients. Thirty three patients had normal urinalysis at the first examination, 28 of them had microcalculi (< 3 mm in diameter) at renal ultrasonography and 12 had stones (4-13 mm). Dysuria and abdominal / flank pain were present in 22 and 17 patients, respectively. There was no microscopic hematuria in 24.3% of patients with microcalculi or stone. Family history of urolithiasis was positive in 63 of the children.
Conclusion: Hyperuricosuria has to be suspected in children with dysuria, recurrent abdominal / flank pain, discoloration of urine, and familial history of urolithiasis. The lack of hematuria is not predictive of the absence of urolithiasis.