Abstracts

Rationale: Objective: Bone mineral density (BMD) is reduced in epilepsy and may underlie the observed increased fracture rate. Non-ambulatory patients with cerebral palsy and epilepsy have reduced BMD, although, it is not clear if normally weight bearing ambulatory patients are similarly vulnerable. We examined BMD in normally ambulatory patients with symptomatic epilepsy and compared them to patients with idiopathic epilepsy and to healthy controls.Methods: Cross-sectional study examining age & gender specific z-score total bone mineral density (z-BMD) in 116 normally ambulatory children with epilepsy between ages 6 and 18 years (79 idiopathic epilepsy and 37 symptomatic epilepsy) were compared to 36 healthy controls. Results: Idiopathic and symptomatic epilepsy were associated with lower z-BMD (0.38+1; 0.17 + 1 respectively) compared to controls (0.52 + 0.76). Patients with generalized seizures had lower z-BMD than those with partial seizures. Symptomatic generalized epilepsy was associated with the lowest z-BMD (-0.15+1.1) compared to controls (p<0.05). Increasing duration of symptomatic epilepsy, but not idiopathic epilepsy, was associated with lower z-BMD (correlation coefficient=0.1; p<0.01). Conclusions: The main findings of this study were: 1) Generally, patients with epilepsy had lower BMD compared to controls. 2) There was a differential effect on BMD by epilepsy type, with patients with symptomatic epilepsy having lower BMD compared to those with idiopathic epilepsy and controls. 3) Patients with generalized seizures had lower BMD compared to those with partial seizures. Interestingly, even patients with idiopathic generalized epilepsy had lower BMD compared to those with idiopathic partial epilepsy. 4) Importantly, the group where bone was most adversely affected were patients with symptomatic generalized epilepsy who experienced significantly lower BMD compared to controls. Both idiopathic and symptomatic epilepsy are associated with reduced BMD. Those with symptomatic epilepsy, particularly symptomatic generalized epilepsy, had the greatest reduction in BMD. These data suggests that BMD is reduced in epilepsy beyond what can be explained by lack of ambulation and may underlie the vulnerability to fractures.