Abstracts

Rationale: Objective: The purpose of this work is to follow up on long-term response in seizure control to carbamazepine (CBZ) in children with localization-related epilepsy. Methods: Methods: Longer term response to CBZ treatment was examined in 100 consecutive children with newly diagnosed partial epilepsy. Subjects were enrolled from the New Onset Seizure Clinic at Cincinnati Children's Hospital. A retrospective medical records review and telephone questionnaire was undertaken. Logistic regression was used to compare responders and non-responders. Results: Results: Long-term follow up was obtained on 75 children (75%), with minimum of 2-years and median of 7.3 years from the initiation of CBZ. The 25 patients lost to follow up were not different in sex, age, age at seizure onset, age at CBZ initiation, pretreatment duration, or epilepsy type (all p-values > 0.05). The long-term seizure outcome of the 75 subjects is outlined in Figure 1. Of 41 CBZ initial responders (seizure free at 1 year), 36 (88%) remained seizure free at a mean duration of 4.8 years (SD 2.7) and 20 (49%) patients were able to discontinue CBZ and remained seizure free at a mean duration of 5.7 years (SD1.8). Five (12%) did not maintain seizure freedom at 2 year-follow up. The mean age of seizure onset in sustained responders and non-sustained responders were 6.2 (SD 3.7) and 11 (SD 3.0) years. The mean age of CBZ initiation in sustained responders and non-sustained responders were 7.4 (SD 3.0) and 12.3 (SD 3.5) years. Sustained responders were on average younger (OR = 0.75; 95% CI = (0.58, 0.99), p = 0.04) and initiated CBZ sooner (OR = 0.72; 95% CI = (0.54, 0.96), p = 0.02). Of 34 initial non-responders (not seizure free at 1 year), 19 (56%) subsequently became seizure free after one year. Of these 19 patients, 4 continued on CBZ monotherapy despite initial non-responsiveness and 15 switched to different anti-seizure medications. Of these 15 patients, 9 (60%) became seizure on second anti-seizure medication, 3 (20%) became seizure on third anti-seizure medication, 2 (13%) became seizure free on fourth anti-seizure medication and 1 patient became seizure free after undergoing epilepsy surgery. Sixteen patients were able to discontinue anti-seizure medication with a mean seizure free duration of 5.4 years (SD + 2.1). Fifteen patients (44%) of the initial non-responders group continued to have uncontrolled seizures. Conclusions: Conclusions: This study suggests that the majority of patients who initially respond to CBZ monotherapy will remain seizure free at 2-year follow up with the probability of discontinuation of the medication. Earlier age at seizure onset and age at CBZ therapy initiation are associated with sustained efficacy. Over half of the patients initially not responsive to CBZ eventually achieve seizure freedom on different anti-seizure medications, with the majority becoming seizure free on their second anti-seizure medication. The probability of achieving seizure freedom decreases significantly after failing a second anti-seizure medication.