Seizures in patients with multiple sclerosis seen at Mayo Clinic, Rochester, Minn, 1990-1998

Objective: To evaluate seizure type, electroencephalographic findings, and response to antiepileptic drug (AED) treatment in patients with multiple sclerosis (MS) and coexistent seizure activity. Patients and Methods: We reviewed the medical records of all patients seen at the Mayo Clinic in Rochester, Minn, with the diagnosis of MS and seizures between 1990 and 1998. Results: During the study period, 5715 patients with MS were identified. Of these 5715 patients, 51 (0.89%) experienced seizure activity. The most common ictal behavior was a generalized tonic-clonic seizure in 35 patients (68.6%). Simple or complex partial seizures occurred in 11 patients (21.6%), and 18 patients (35.3%) had only 1 seizure episode. Focal motor status epilepticus, ie, epilepsia partialis continua, occurred in 3 patients (5.9%) and was associated with cognitive impairment. In 37 patients (72.5%), the initial seizure presentation was after the diagnosis of MS. A seizure resulted in the diagnosis of MS or occurred before the diagnosis of MS but after other symptoms or signs of demyelinating disease in 14 patients (27.4%). Electroencephalography was performed in 43 patients. Electroencephalographic findings included diffuse or localized nonspecific background slowing in 19 patients (44.2%), unilateral or bilateral frontotemporal spike discharges in 9 (20.9%), generalized atypical spike-and-wave or multifocal independent epileptiform alterations in 6 (14.0%), and normal results in 11 (25.6%). Of the 45 patients who received AED therapy, 35 (77.8%) had an excellent response, ie, they were seizure free. Five treated patients (11.1%) had an intractable seizure disorder. Conclusion: Most of the patients with MS who experienced seizure activity had a benign and transient disorder that was responsive to AED treatment or required no therapy.