Hypercalciuria in children with febrile convulsions.

BACKGROUND

The purpose of the present study was to investigate whether idiopathic hypercalciuria may be implicated in the pathogenesis of febrile convulsions.

METHODS

We studied 38 children (22 boys) with febrile convulsions (mean (+/- SD) age 3.25 +/- 1.09 years) and 45 healthy children (28 boys) of similar age who served as controls. Twenty-four hour urine calcium and phosphate, as well as serum calcium, phosphate, alkaline phosphatase and intact parathyroid hormone (PTH) concentrations were determined.

RESULTS

Hypercalciuria (urine Ca >4.0 mg/kg bodyweight per 24 h) was found in nine children with febrile convulsions (23.7%) and in three controls (6.7%). Hypercalciuric children excreted significantly more phosphate in their urine (37.0 +/- 11.6 mg/kg bodyweight per 24 h) than normocalciuric children (18.7 +/- 8.7 mg/kg bodyweight per 24 h) and controls (20.2 +/- 7.6 mg/kg bodyweight per 24 h). They also had higher serum intact PTH concentrations (49.87 +/- 15.36 pg/mL) than normocalciuric (35.39 +/- 15.67 pg/mL) and control children (28.21 +/- 14.00 pg/mL). According to the calcium-loading test, eight of nine children with hypercalciuria had the renal type of the disorder. Furthermore, hypercalciuric children had significantly more convulsive episodes (2.77 +/- 1.98) than normocalciuric children (1.86 +/- 1.24).

CONCLUSIONS

Our results suggest that renal hypercalciuria may be implicated in the pathogenesis of febrile convulsions.