Clinical Reasoning: Drug Resistant Epilepsy in a 61-Year-Old Man With Abnormal MRI Brain Findings and Management With Vagal Nerve Stimulator

Abstract

A 66-year-old man with seizures that started at 61 years eventually developed drug-resistant epilepsy and was managed with medications and vagal nerve stimulation. The patient had a convulsive event at age 61, followed by recurrent events of confusion and speech arrest lasting 30-120 seconds. He underwent gadolinium enhanced MRI brain and angiogram which revealed pial enhancement in the right occipital, parietal, and posterior temporal regions with subcortical atrophy. CSF findings were unremarkable. Continuous video EEG showed electroclinical correlation for his episodes of confusion and speech arrest with recurrent brief runs of rhythmic delta from the right temporal region with evolution and spread to the entire right hemisphere. The patient tried multiple antiseizure medications including valproic acid, topiramate, phenytoin, carbamazepine, levetiracetam, brivaracetam, lamotrigine without success. He was eventually put on a combination of lacosamide, zonisamide, clonazepam, and primidone, which helped to certain extent, but the patient continued to have daily episodes and 10-12 electroclinical seizures noted on a follow-up 24-hour ambulatory EEG. Follow-up MRI brain with contrast confirmed the diagnosis. Phase II intracranial monitoring for surgical management was offered to the patient which he deferred due to risks. Vagal nerve stimulator (VNS) was also offered as a palliative therapy to which the patient agreed. Gradual titration of VNS settings over 1 year helped to achieve seizure freedom. Presentation of focal seizure with this type of atypical etiology is rare. Typically surgical management is used to achieve seizure freedom in this condition; successful management with VNS has not been reported so far.