Abstracts

Rationale: Anti-NMDAR encephalitis is a neuro-autoimmune syndrome in which antibodies are formed in response to a number of possible stimuli which cross react with synaptic proteins. Anti-NMDAR encephalitis most commonly presents in young adult females with fluctuating mental status, hallucinations, posturing, catatonia and purposeless movements (1-3). Seizures also present in approximately 75% of all the patients with only a few reports of status epilepticus (4). During EEG monitoring, slow activity has been the most common EEG finding in adult patients. (5) More recently,"Extreme Delta Brush" has been identified in many patients and is associated with prolonged illness (6). The goal of this study was to characterize EEG findings in children with anti-NMDAR encephalitis. Methods: Three patients that were admitted to Stony Brook University Medical Center between June 2013 and June 2014 that underwent long term video EEG montoring with a subsequent diagnosis of Anti-NMDAR encephalitis were identified. The patient demographics and EEG characteristics were tabulated. Results: Three patients with Anti-NMDA encephalitis underwent long term video EEG monitoring. The median age was 17 years and 2/3 patients were female. Pre-existing behavioral conditions were identified in 2/3 of the patients. One patient presented with seizures arising from the left hemisphere as well as an "Extreme Delta Brush" background pattern. The remaining 2 patients presented with visual and auditory hallucinations as well as behavioral changes. The EEG for these patients showed mild to moderate generalized background slowing. Normal sleep architecture was seen in 2/3 patient including the patient with seizures. No malignancies were detected in any of the patients. Conclusions: In this case series, 1/3 of patients with NMDA encephalitis also had seizures and exhibited the "Extreme Delta Brush" background pattern. Whether this pattern increases the risk for seizures in these patients is unclear. Although the "Extreme Delta Brush" pattern may correlate with anti-NMDAR encephalitis, lack of this pattern does not exclude the diagnosis.