Abstracts

Rationale: GAD65  (glutamic acid decarboxylase antibody) positive Autoimmune Limbic Encephalitis is a rare condition that affects the medial temporal lobe. It is important to accurately recognize this condition as treatment can be very effective. Methods: We present 2 patients who were eventually diagnosed with this condition and who had very different presentations Treatment was successful although anti-epileptic drugs (AEDs) were still required after immunotherapy. Results: Case 1: 24 y/o female who presented after having multiple complex partial seizures with and without generalization. Video EEG showed independent, right and left temporal lobe prolonged seizures, consistent with non-convulsive status epilepticus. Brain MRI and cerebral spinal fluid (CSF) were normal. Serology was positive for GAD65. Patient failed 5 AEDs and was put in pharmacological coma. Administration of steroids and IVIG resulted in initial minimal improvement, she did respond to a combination of Cytoxan (cyclophosphamide)  and Rituxan (rituximab)    Currently, she is on 4 AEDs and having only occasional seizures. Brain MRI four months after onset shows bilateral hippocampal volume reduction, no abnormal signal.  Case 2: 64 y/o female with history of temporal lobe epilepsy, presented after AVM brain surgery with acute psychosis. Video EEG showed no evidence of ongoing seizures at presentation. Due to persistent new psychiatric symptoms, a CSF and serum paraneoplastic  work up was conducted.  Serum was positive for GAD 65 antibodies. She received Cytoxan and Rituxan, followed by IVIg  (intravenous immunoglobulin)  due to blood cells count drop. Clinically she improved in terms of her epilepsy and her abnormal psychiatric symptoms. Currently she is on 3 AEDs. Conclusions: Limbic Encephalitis can be the result of different conditions (paraneoplastic or autoimmune). It is important to recognize the underlying pathology since required treatment is very different. These two cases reveal significant challenges in reaching the correct diagnosis since the clinical presentations differed considerably as well as the difficulties in managing limbic encephalitis acutely and chronically.  They also underscore the importance of being aware of this potentially reversible medical emergency (GAD65).  Funding: None