Characteristics and prognosis of LGI1 antibody encephalitis

Objectives: To investigate clinical manifestations and outcomes of patients with LGI1 autoimmune encephalitis. Methods: A total of 12 patients who were diagnosed with LGI1 autoimmune encephalitis were retrospectively analyzed between 2018 and 2022 at the Department of Neurology of the Affiliated Hospital of Xuzhou Medical University. Clinical characteristics, laboratory examinations, electroencephalograms, brain magnetic resonance images and prognosis were assessed. The clinical data were collected by searching through electronic medical records. Results: Among 12 patients, 8 were male and 4 were female. The average age at disease onset was 61.8 years (24–83). The most common clinical symptoms were seizures (n=10), cognitive dysfunction (n=8), and mental behavioral disorders (n=8). A total of 9 cases had hyponatremia. Brain MRI and electroencephalographic were abnormal in 7 patients each. All patients were treated with first line immunotherapy. Most patients responded well and 3 patients relapsed on follow-up. Conclusion: Characteristic features of LGI1 antibody encephalitis include subacute onset cognitive impairment, seizures, faciobrachial dystonic seizures (FBDS), and mental and behavioral abnormalities. Especially, FBDS and hyponatremia suggest LGI1-antibody encephalitis. Therefore, early identification and immunotherapy may prevent cognitive impairment and improve prognosis.