Authors :
Presenting Author: Shruti Iyer, MD – University of Pittsburgh Medical Center
Tara Pirnia, PhD – University of Pittsburgh Medical Center
Zachary Duarte, MD – University of Pittsburgh Medical Center, Erie
Katie McFarlane, MS – University of Pittsburgh Neurology
Gabriela Pucci, MD – University of Pittsburgh Medical Center
Alex Israel, MD – University of Pittsburgh Medical Center
Danielle Carns, PsyD – University of Pittsburgh Medical Center
Carolina Cuello-Oderiz, MD – University of Pittsburgh Medical Center
Joseph Ta, MD – University of Pittsburgh Medical Center
Wesley Kerr, MD, PhD – University of Pittsburgh Department of Neurology
Rationale: Many patients with functional (nonepileptic) seizures (FS) are prescribed anti-seizure medications (ASMs) before a definitive diagnosis is made, resulting in potential medication-related side effects and delays in initiating treatment for functional seizures. However, limited evidence exists to guide decisions about which patients should discontinue ASMs and when. To inform clinical decision-making about the safe discontinuation or continuation of ASMs, we evaluated the frequency of ASM discontinuation based on the level of evidence for co-occurring epilepsy in a multidisciplinary FS clinic.
Methods: Adults with video-EEG-documented or clinically established FS, diagnosed using International League Against Epilepsy criteria, were retrospectively categorized into five levels of evidence for co-occurring epilepsy: Unlikely (no evidence), Possible (historical report), Probable (neuro-diagnostic evidence), Clinically Established (strong evidence without ictal EEG), and Documented (ictal EEG) [table]. Using a two-year period following FS diagnosis, Cox proportional hazards regression models were applied to assess whether patients with stronger evidence for co-occurring epilepsy were more likely to continue ASM prescriptions.
Results: A total of 460 adult patients with FS were included in the analysis (78% female, median age 34 years [interquartile range: 24–46]). Patients were categorized based on evidence of co-occurring epilepsy: Unlikely (62%, n = 285), Possible (12%, n = 53), Probable (16%, n = 72), Clinically Established (1.1%, n = 5), and EEG Documented (10%, n = 45). In 44% of patients with unlikely epilepsy, ASMs were stopped upon the diagnosis of FS (22%) or had never been started before diagnosis (22%). In cases with available records, 48% (56/116) of patients with unlikely epilepsy continued ASMs for more than two years after diagnosis, of whom 71% (40/56) were prescribed topiramate or lamotrigine. Compared to patients with unlikely epilepsy, those with documented or clinically established epilepsy were significantly less likely to discontinue ASMs (Hazard Ratio [HR] 0.26, p < 0.01). Patients with probable epilepsy were also less likely to discontinue ASMs compared to patients with unlikely epilepsy (HR 0.42, p < 0.01). However, patients with possible epilepsy showed no statistically significant difference in ASM discontinuation compared to those with unlikely epilepsy (HR 0.75, p = 0.20).
Conclusions:
Most patients with FS and unlikely epilepsy either never initiated ASMs, discontinued them at the time of FS diagnosis, or stopped them within two years of FS diagnosis. This suggests that discontinuing ASMs in the 62% of FS patients with no suspicion of co-occurring epilepsy is likely safe. In some cases, ASMs may have been continued for non-seizure comorbidities, such as topiramate for migraines or lamotrigine for mental health conditions. For patients with intermediate evidence of co-occurring epilepsy, such as possible or probable cases, individualized risk assessments can guide ASM discontinuation decisions.
Funding: Dr. Kerr’s research is funded by NINDS (K23NS135134) and the Susan-Spencer Clinical Research Training Scholarship by the AAN, AES, ABF, Epilepsy Foundation