Altered Mental Status in the Emergency Department – When to Consider Anti-LGI-1 Encephalitis: Case Report

INTRODUCTION: Anti-leucine-rich glioma inactivated-1 (LGI-1) is one of few antibodies implicated in limbic encephalitis, a syndrome that can result in permanent neurological symptoms if left untreated. CASE REPORT: We present a patient with dystonic seizures, progressive cognitive decline, psychiatric symptoms and short-term memory loss, and mild hyponatremia diagnosed with anti-LGI-1 antibody limbic encephalitis. CONCLUSION: There are few reports in the emergency medicine community describing anti-LGI-1 antibody limbic encephalitis. Delay in diagnosis can risk irreversible limbic damage. Therefore, it is important for the emergency physician to be aware of anti-LGI-1 antibody limbic encephalitis when presented with adult-onset seizures and altered mental status of unknown etiology.