[Assessment of oxalate concentration in serum and urine of children with renal stones].

UNLABELLED

Oxalate crystals are the main component of renal stones and oxalate urolithiasis is the most common type both in adults and children. The aim of the work was the assessment of oxalate concentration in plasma and urine of children with renal stones.

MATERIAL

The examined group (I) consisted of 29 children (12.0 +/- 3.87 years) with confirmed stones in caliceal-pelvic system. The control group (C) was composed of 30 healthy children.

METHODS

The oxalate concentration in plasma and urine was measured using an enzymatic method after 3-4 days of hypooxalate diet. Children with congenital abnormalities of urinary tract were excluded. We found 1-5 stones, 0.35-1.5 in diameter.

RESULTS

In I group mean plasma oxalate concentration (4.89 +/- 1.58 micromol/l) was higher than in control group (p<0,05). However urinary oxalate concentration exceeded 95 percentile of those obtained in healthy group only in 16 (55%) children, mainly with II and III degree of urolithiasis. In children with urolithiasis we also found hypercalciuria with normal serum calcium concentration. No correlation between plasma and urinary oxalate concentration was found.

CONCLUSIONS

1. Plasma oxalate concentration in children with renal stones is higher than in healthy children. 2. Hyperoxaluria was found in 16 (55%) children with first attack of nephrolithiasis.