Hematuria due to hyperuricosuria in children: 36-month follow-up

Hyperuricosuria (HU), defined as a urinary acid excretion higher than 95 percent of normal values, is an important lithogenic factor, accounting; for about 5-20% of recurrent hematuria in childhood. We prospectively studied 30 children (15 male, 15 female aged 3 to 13 years old) with previously undiagnosed isolated hematuria and HU for 6 to 36 months. The family history of nephrolithiasis was positive in 40%, Idiopathic hypercalciuria (IH), UCa >4 mg/kg/day, was not found initially, but was diagnosed after 6 to 24 months in 20% of the patients. The following treatments were utilized: restricted purine diet (13%), allopurinol (4%) and potassium citrate (1%). No specific treatment was given to 82% of the patients. Therapy normalized uricosuria with resolution of hematuria over 6-12 months. Thirteen percent and 6% of untreated patients developed urolithiasis after 6 and 12 months respectively. The data suggest that HU, like IH, is associated with hematuria. Furthermore, recognition of this association may prevent unnecessary, and in some cases, invasive diagnostic manoeuvres.