Electroclinical insights into autoimmune epilepsy

Chronic autoimmune epilepsy is an increasingly recognised entity however its clinical and electrographic features remain poorly understood. We present a case undergoing diagnostic Stereo-electroencephalography implantation that was found to have a multifocal perisylvian epilepsy with unique electrographic features and is now seizure free with immunotherapy. The patient had antibody negative refractory perisylvian epilepsy and underwent implantation of the perisylvian-temporal networks. Immunomodulatory treatment was administered during SEEG. SEEG demonstrated a multifocal perisylvian epilepsy with strong involvement of the posterior insula. There was almost continuous spiking seen interictally from multiple foci within the right hemisphere and independent seizures were generated from 5 locations. After treatment with intravenous methylprednisone and immunoglobulin during SEEG, spiking and seizures terminated while still off anti-seizure medications. The patient remains seizure free on immunotherapy. This case highlights the importance of considering autoimmunity in the differential diagnosis of refractory epilepsy, especially perisylvian epilepsy. It also highlights the need to define a clinical phenotype associated with autoantibodies in epilepsy, as there are likely many cases who are not positive for one of the commercially available tests. This case also provides insights into the possible features of an electroclinical syndrome associated with autoimmunity. •Stereo EEG is a valuable investigation in the presurgical diagnosis and management of epilepsy•It also provides insights into neural connectivity and has the potential to provide insights into autoimmune epilepsy•Little is known about chronic autoimmune epilepsy and there are potentially cases progressing inappropriately to surgery•Understanding the autoimmune electroclinical syndrome may provide pathophysiologic insights into autoimmune epileptogenesis•Improving our understanding will ensure patients receive the most appropriate treatment for their epilepsy