Seizures and epilepsy in multiple sclerosis: epidemiology and prognosis in a large tertiary referral center.

Background: Seizures and epilepsy may substantially add to the burden of disease in multiple sclerosis (MS), whereas the exact prevalence and prognosis of seizures and epilepsy in patients with MS remains largely unknown.
Objectives: We aimed to investigate the epidemiology and prognosis of seizures and epilepsy in MS.
Methods: We retrospectively analyzed a cohort of 4078 MS patients from a single tertiary referral clinic.
Results: After excluding 37 patients with unconfirmed MS and alternative seizure etiologies, we found seizures attributable to MS in 1.5% and epilepsy in 0.9% of patients. 40.4% of patients with a follow-up of at least twelve months experienced only a single seizure and 59.6% had recurring seizures. 39% of patients with recurrent seizures were considered drug-resistant, with 9.7% experiencing status epilepticus. Seizure recurrence after a first seizure depended significantly on the MS subtype and was seen more often if the first seizure occurred simultaneously with a MS relapse than in the absence of a relapse.
Conclusion: Our study shows a lower number of seizures and epilepsy in MS than previously reported. While a single seizure in MS usually has a good prognosis, relapse-associated seizures and established epilepsy in MS may not be as benign as previously assumed.