Abstracts

Rationale: Prevalence of seizures is higher in Multiple Sclerosis (MS) patients compared to the general population with an occurrence of 1.5% to 7.8%1. The exact mechanism of epilepsy in multiple sclerosis is unclear. There is limited information on seizure characteristics and especially seizures outcome in patients with multiple sclerosis. Few studies have noted the seizure freedom rate of around 35% in these patients2. Methods: We performed a chart review of our retrospective multiple sclerosis and epilepsy database, and collected information on seizure types, antiepileptic drug (AED) use and seizure outcomes for patients seen between 2014 and 2017. Results: We reviewed a total of 48 MS patients with epilepsy (32 African American, 16 others). Thirty-five patients were females, and 13 patients were males. Age at MS diagnosis was in the range of 16-60 years. The most common MS type was relapsing-remitting multiple sclerosis (RRMS) in 32, secondary progressive multiple sclerosis (SPMS) in 8, primary progressive MS(PPMS) in 3, a clinically isolated syndrome in 1, and four could not be categorized accurately. Twenty-two patients reported having focal to bilateral tonic-clonic seizures, six patients had only focal impaired awareness seizures, two patients had a psychogenic non-epileptic seizure (PNES), and 17 patients had unknown seizure type. EEG was available in 33 patients and with epileptiform discharges noted in 10 patients, background slowing in 17 patients, and normal EEG pattern in 6 patients. MRI showed demyelinating cortical and subcortical lesions, including temporal lobes and frontal-parietal regions. 17 out of 48 patients did not continue disease-modifying therapy for MS. 23 patients were on AED monotherapy, 22 patients were on polytherapy, while three patients did not receive AEDs. Keppra was the most commonly used AED. With available follow up of 1 - 3 years in 31 patients, only 11 patients (35%) were seizure free, and 20 patients (65%) had medically intractable seizures with documented failure of two AEDs. Seventeen patients (including two with PNES did not have long-term follow up.  Conclusions: In patients with concurrent epilepsy and MS evaluated at our center, seizure freedom rate is low. Overall only one-third of patients with epilepsy are expected to have medically intractable epilepsy, but it was noted in two-thirds of our patients. The higher rate of intractability might indicate that either MS relapse is a significant risk factor triggering seizures or AEDs in MS patients receiving disease-modifying drugs might be less efficacious due to medication interaction. Previous literature in patients with concurrent MS with epilepsy has shown seizures to be well controlled, which is contrary to our findings. Future aims include a comparison of seizure outcomes in patients with epilepsy but without MS. These findings might indicate the need for specialized epilepsy care in these group of patients and consideration of surgical management.References: - Gasparini, Sara, et al. 'Risk factors for unprovoked epileptic seizures in multiple sclerosis: a systematic review and meta-analysis.' Neurological Sciences 38.3 (2017): 399-406. - Nyquist, Paul A., Gregory D. Cascino, and Moses Rodriguez. 'Seizures in patients with multiple sclerosis seen at Mayo Clinic, Rochester, Minn, 1990-1998.' Mayo Clinic Proceedings. Vol. 76. No. 10. Elsevier, 2001. Funding: No funding