Objective  To investigate the clinical features and prognosis of autoimmune encephalitis (AE).

  Methods  Accessing data from the electronic medical records of patients receiving care at West China Hospital, Sichuan University, China between 2013 and 2019, we conducted a retrospective study of the disease characteristics, laboratory examinations, treatment, and prognosis of AE patients. Before they were discharged, modified Rankin Scale (mRS) was used to assess the prognosis of AE patients and their mRS scores were then used to categorize patients as having good prognosis (mRS scores of 0-2) or poor prognosis (mRS scores of 3-6). Multivariate logistic regression was used to analyze risk factors associated with poor prognosis.

  Results  A total of 121 patients were included in the study. The male-to-female ratio was 1∶1.1. At the time of diagnosis, patients were mainly from the age group of young to middle-aged individuals. Among the 121 patients, 64.5% (78 patients) had anti-N-methyl D-aspartate receptor (NMDAR) encephalitis, accounting for the largest proportion. 33.1% (40 patients) first visited the Department of Psychiatry for medical assistance. 62.8% (76 patients ) showed prodromal symptoms. The common clinical manifestations of the AE patients at the time of admission included cognitive dysfunction (104 patients, 86.0%), thought disorder (90 patients, 74.4%), and altered behaviors (88 patients, 72.7%). The NMDAR antibody titers were higher in the cerebrospinal fluid (CSF) than those in the serum. Double-positive antibodies were detected in 6 patients. No abnormality was observed in the brain magnetic resonance imaging (MRI) of 42 patients (34.7%) . Electroencephalography abnormalities were observed in 71 patients (58.7%). 111 patients (91.7%) received first-line immunotherapy and 61 patients (50.4%) still had neuropsychiatric deficits when they were discharged. Multivariate logistic regression revealed that consciousness disorder (odds ratio OR=4.230, 95% confidence interval CI: 1.540-11.617; P=0.005), altered behavior (OR=2.997, 95% CI: 1.068-8.406; P=0.037) and movement disorder (OR=7.753, 95% CI: 1.446-41.578; P=0.017) were risk factors for poor clinical prognosis of AE patients.

  Conclusions  Patients with AE mainly manifest cognitive damage. Half of the patients left neuropsychiatric deficits. The relationship between CSF titers and serum titers is unparalleled. The options of immunotherapy show no difference in their influence on prognosis. Cognitive dysfunction, altered behavior and movement disorder are independent risk factors for a poor prognosis at discharge.