Abstracts

Rationale: The phenotypic expression of autoimmune epilepsy is very variable, which can delay its diagnosis and treatment. Moreover, there is scarceness of data on treatment responses of autoimmune cases of epilepsia partialis continua (EPC), especially those associated to GAD-65 antibodies. We hereby report a case of autoimmune EPC associated with type 1 diabetes and alopecia universalis. Methods: Case report. Results: A 19 year-old gentleman with alopecia universalis since 1 year old and type 1 diabetes since age of 9 presented with right visual field pallinopsia and continuous semi-rhythmic myoclonic activity of the right side of his tongue which spread to right eyelid, lower face, and hand. Brain MRI revealed discrete non-enhancing FLAIR signal hyperintensities affecting primarily the left frontal and occipital cortical regions, but also the right frontal lobe (Figure 1A-B). EEG revealed generalized theta slowing without epileptiform activity. Extensive work up was unrevealing, except for serum GAD-65 Ab level of 74.7 nmol/L and 92.5 nmol/L on different samples, CSF GAD-65 Ab of 0.8 nmol/l and serum TPO Ab of 390 nmol/L. AIRE gene testing was normal. Patient had mild transitory improvement with a 5-day course of IV methylprednisolone 1g daily. He was transitioned to prednisone 60 mg daily and completed a 4-day course of IVIG. Fifth dose was not given due new myoclonic activity of the left lower extremity. AED regimen was adjusted to Lacosamide 200 mg daily, Keppra 2g tid, Phenytoin 200 mg bid, Oxcarbazepine 450 mg bid, and Clonazepam 2 mg bid, with no significant response. A 5-day course of plasma exchange was initiated. After Day 2, myoclonic activity started to improve. Patient was discharged on Prednisone 60 mg and AED regimen above. Five days after hospital discharge, EPC resolved completely. Prednisone was gradually tapered after a month. Repeat MRI after 2 months showed nearly complete resolution of previously described imaging changes (Figure 1C). Patient remained seizure free after Prednisone taper at follow-up after 3 months. Conclusions: To our knowledge this is the first case of EPC in the setting of type I diabetes and alopecia. EPC has only rarely been described in association with GAD-65 antibodies, which usually presents with temporal lobe seizures and limbic encephalopathy. Patients with GAD-65 autoimmunity, a cytoplasmic antigen, tend to respond poorly to immunotherapy with IVIG or plasma exchange in comparison to patients with antibodies targeting membrane surface antigens. This response could have been due to the possibility that GAD-65 and TPO antibodies are only markers of autoimmunity and coexist with other neural antigen antibodies that have not been identified. Encephalopathy and seizures associated with TPO antibodies alone usually respond to steroids, which was not the case in this patient. Our case corroborates a previous report of GAD-65 autoimmunity-associated EPC with successful response to a combined approach with plasma exchange. Clinical trials are needed to evaluate the efficacy of plasma exchange for the treatment of GAD-65 autoimmunity presenting with EPC. Funding: Not applicable.