[Idiopathic hypercalciuria: clinical manifestation, outcome and risk for urolithiasis in children].

OBJECTIVE

The purpose of this study was to investigate the clinical manifestations, outcome and risk factors for urolithiasis of untreated idiopathic hypercalciuria (IH) in children.

PATIENTS AND

METHODS

During a 5 year period, all children with hematuria, lower urinary tract symptoms (LUS), or abdominal pain who were observed to have IH (urinary calcium > 4 mg/kg/day) were included in the study. The relationship between some variables (age, gender, hypercalciuria subtype, and clinical features) and urolithisis was analyzed.

RESULTS

We studied 76 children with IH (9 with renal IH, 49 with absorptive IH and 18 with undetermined IH). Hematuria (46%), LUS (27.6%), lumbar pain (22%) and abdominal pain (15.7%) were the most common initial symptoms. We found a significant difference between age and clinical presentation. LUS were found more frequently in young children (46.4%) and flank pain in older patients (47.8%). Hematuria was age dependent. Eighteen (23%) patients developed urolithiasis. These 18 patients tended to be older (9.3 vs 6 years) than the other 58 children. Age at diagnosis presented a linear relationship with the development of urolithiasis (p < 0.001). Significant relative risk for urolithiasis (4.3) was found in those children who initially presented with lumbar pain. In all other parameters measured (calciuria, uricosuria, oxaluria, citraturia) and clinical characteristics analyzed, there were no statistically significant differences between those with and without stones.

CONCLUSIONS

An age-dependent clinical pattern can be established for children with hypercalciuria. Significant risk for urolithiasis accompanies those children who are diagnosed later (> 9 years) and who initially present with lumbar pain.