Abstracts

RATIONALE: Patients with MS can have a variety of symptoms that are manifestations of their disease. Seizures are thought to occur more frequently in patients with MS than in the general population with estimated incidences ranging from one to ten percent. Seizures in these patients are thought to result from plaques that abut the cortex and often enhance on gadolinium MRI scans. Some patients who present with a history of seizures can be found to have non-epileptic events. It is not clear how frequently non-epileptic events occur in patients with MS.
METHODS: This is a retrospective chart review that included patients with a diagnosis of MS and a history of seizures who had defined electroclinical syndromes based on routine EEG, prolonged EEG, and or video-EEG monitoring.
RESULTS: We identified 36 patients (27 females) with a diagnosis of MS and a history of seizures. 21 patients (15 females) were found to have epileptic seizures. The remaining 15 (12 females) had non-epileptic events. Among the 21 patients with epileptic seizures, 7 had generalized epilepsy, 1 had right frontal lobe epilepsy, 4 had right or left temporal lobe epilepsy and 2 had bilateral temporal lobe epilepsy. Among the 2 patients with parieto-occipital lobe epilesy, one patient had no prior history of seizures and was found to have an abnormal EEG prior to entering a drug study. One patient had multifocal epilepsy and the remaining 4 patients had focal epilepsy not further definable. We also observed PLEDS in 2 patients, both of whom had end-stage MS with other complicating factors. Non-epileptic events were the presenting symptom in 2 patients with MS. Almost all of our patients with focal epileptic seizures had other symptoms of MS prior to the onset of their seizures. However, 5 out of 7 patients with generalized epilepsy developed seizures prior to developing other symptoms of MS. MRI enhancing lesions were seen in 8 out of 21 patients with epileptic seizures and only 1 out of 15 patients with non-epileptic events.
CONCLUSIONS: Epileptic and non-epileptic seizures contribute to the clinical manifestations of MS. This study describes a variety of epileptic syndromes that can be seen in patients with MS including non-epileptic events. Non-epileptic events should also be considered in the differential diagnosis in patients who have MS and seizures. Previous studies may have over estimated the incidence of seizures in MS by including patients with non-epileptic events as well as generalized epilepsy whose etiology may be genetic and unrelated to MS. The presence of MRI enhancing lesions appear to occur more frequently in patients with epileptic seizures than those who had non-epileptic events. Whether MRI enhancement can be used as a crude measure to help differentiate these two groups of patients would require further studies.