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.