Anti‐NMDA receptor encephalitis: clinical characteristics, predictors of outcome and the knowledge gap in southwest China

Background and purpose The aim was to analyse the clinical profiles and outcomes of patients with anti‐ N ‐methyl‐ d ‐aspartate receptor (anti‐ NMDAR ) encephalitis in China. Methods A retrospective study of anti‐ NMDAR encephalitis in China was performed between June 2011 and June 2014. The clinical characteristics and predictors of poor outcome were determined. Results A total of 51 patients with a definitive diagnosis of anti‐ NMDAR encephalitis were included in this study. Four of them were surgically confirmed to have a neoplasm. Thirty‐two patients, amongst whom 24 were female, presented with psychiatric disorder as the initial symptom, whereas 14 patients, of whom nine were male, presented with seizure as the initial symptom ( P = 0.011). Twenty‐nine patients (56.86%) were initially misdiagnosed with psychosis, viral encephalitis or other diseases, and 58.8% of the patients experienced at least one type of complication. It typically took 3 weeks before these patients were admitted to our hospital and another 2 weeks before the correct diagnosis was made. Forty‐one patients (80%) reached a good outcome; 10 patients (20%) had a poor outcome. Older age, extended hospital stay, memory deficits, decreased consciousness, central hypoventilation, complications and abnormal cerebrospinal fluid results were associated with poor outcome ( P < 0.05). Conclusions Female patients more frequently initially present with psychiatric disorder but male patients more frequently initially present with seizure. Patients with anti‐ NMDAR encephalitis in China have a lower incidence of neoplasm. Nevertheless, this study reveals several challenges in treating anti‐ NMDAR encephalitis in China that may contribute to poor outcome.