Comparative clinical characteristics of early- and adult-onset multiple sclerosis patients with seizures.

Multiple sclerosis (MS) and epilepsy are common disorders, the co-occurrence of which has been of considerable interest. This study aimed to evaluate the prevalence and clinical features of epileptic seizures in patients with definite MS including those with pediatric onset (≤16 years of age). Out of 2,300 patients with definite MS followed in our outpatient clinic, 36 with epileptic seizures were identified. In this cohort, 8 out of 146 pediatric cases had seizures. The clinical and demographic features of the patients were recorded. Multiple logistic regression model with the occurence of seizures as the dependent variable was performed to identify the risk factors for seizure occurrence in MS patients. The prevalence of epileptic seizures was 1.5% in definite MS patients, 1.3% in adult-onset (comparable to seizure prevalence in the general population) and 5.5% in pediatric MS patients (≤16 years old). Twenty-six of 36 (72%) patients with MS and epilepsy developed recurrent seizures after the first epileptic seizure. Mean annual relapse rate (p ≤ 0.001), mean expanded disability status scale (EDSS) score (p = 0.004) and the ratio of patients with pediatric onset (p = 0.01) were higher in MS patients with seizures. In the multiple logistic regression analysis, age at MS onset and EDSS at the last examination were found to be predictors of seizure occurrence. Occurrence of seizures during the clinical course of MS appears to be associated with early-onset and increased disease severity and might be coincidental in adults.