Abstracts

Rationale: It has become increasingly evident that the prevalence of seizures in Multiple Sclerosis (MS) is about three times higher than in the general population. The reasoning behind this is controversial, however multiple mechanisms are suggested, including the increased identification of cortical pathology as well as increased lesion burden in MS. In addition, it seems likely that, more advanced MS, and increased burden of disease correlates with seizures and refractory epilepsy. There is little data regarding optimal treatment for this population which is important to illicit given increased prevalence of adverse reactions and medication interactions in this population. Therefore, more caution with seizure surveillance may be of greater significance than previously considered in patient sub-populations with increased lesions and progressive MS.  Methods: Out of 3339 of the patients diagnosed with multiple sclerosis at Barrow Neurological Institute outpatient setting over the past ten years, a total of ten patients were diagnosed with epilepsy. The presenting symptom, whether related to MS pathology or seizure was determined, timing between diagnosis of MS or seizures, and seizure freedom in relation to MS duration and amount of MRI lesions were all retrospectively analyzed.  Results: Out of ten patients, one was lost to follow up. Seizure freedom was defined as seizure free at last follow up. The mean follow-up was 2.39 year (range 9 months to 5 years). Five patients had an EEG, and epileptiform activity was found in 60 percent of these, all of which demonstrated multifocal discharges. Four of the nine patients were seizure free, and the remaining five continued to have seizures. Interestingly, 60 percent of those who were not seizure free developed MS symptoms prior to the seizure onset. 75 percent of those who were seizure-free developed MS after the seizure onset. Patients who were seizure-free were taking only one AED and remained seizure free for 3 to 34 years. Patients who were not seizure-free had the seizure frequency of at least 2 per year. Four of the five who were not seizure free required two AEDs with the exception of one patient on monotherapy. Regarding medication, interestingly, the newer generation AEDs were used in eight out of the nine patients, with one patient who took two first-generation AEDs in the past. Within the group that remained seizure free, the AED regimen included: 1) phenytoin 2) cerebellar stimulator and levetiracetam 3) two patients with levetiracetam monotherapy. Of the group that was not seizure free the AED regimen included: 1) two patients treated with levetiracetam and lamotrigine 2) phenytoin and valproic acid and later changed to lamotrigine and lacosamide 3) gabapentin and levetiracetam. Of of the four patients who were seizure free, one was known to have developed secondary progressive MS. Two of the five patients that were not seizure-free were diagnosed with secondary progressive MS, and of this group, all demonstrated extensive lesions on MRI.  Conclusions: The experience at our institution suggests that refractory epilepsy is more commonly associated with increased chronic and enhancing lesions verified by MRI as seen in advanced MS, particularly secondary progressive MS, and those with high lesion burden or active disease. It seems that an increased degree of surveillance and awareness of seizure risk will benefit the standard of care as patients develop more active, advanced, or longstanding MS disease. In our patient cohort, less than half of the patients were seizure free, and most were taking second generation AED rather than first generation AED. Funding: No funding