Anti-N-methyl-D-aspartate Receptor Encephalitis: Characteristics and Rapid Diagnostic Approach in the Emergency Department

Abstract

Background Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is a common type of autoimmune encephalitis. Patients with this condition are frequently very ill but are often misdiagnosed in the Emergency Department (ED). The objective of this study was to analyze the clinical characteristics of anti-NMDAR patients in the ED and to identify any associations with a diagnosis of anti-NMDAR encephalitis.MethodsWe performed a retrospective analysis of a prospectively obtained cohort of ED patients from May 2011 to December 2017. We identified patients diagnosed with anti-NMDAR encephalitis in this cohort and extracted key patient characteristics and clinical data, including patient gender, age, presentation, modified Rank Score (m-RS), laboratory test results, significant treatments, and mortality.Results87 patients with anti-NMDAR encephalitis were identified. 54 (62.1%) were female, 23 (26.4%) were <18 years old, 14 (16.1%) had teratoma, and 45 (51.7%) had an m-RS ≥4. Fever, altered mental status, and seizures were the most common symptoms, with a >50% incidence of each symptom in the cohort. The sensitivity of CSF oligoclonal band (OB) testing was 78.9%. 22 (25.3%) were admitted to the ICU, 20 (23.0%) patients were intubated, but only one patient died (1.1%). 47 (54.0%) were misdiagnosed prior to ED arrival. All patients underwent immunotherapy as first-line treatment for anti-NMDAR encephalitis.ConclusionsA majority of anti-NMDAR encephalitis patients presenting to the ED were female and were likely to be misdiagnosed prior to arrival. Patients with symptoms of fever, altered mental status, and seizures need a lumbar puncture, including CSF OB testing, for definitive diagnosis.

A juvenile mouse model of anti-N-methyl-D-aspartate receptor encephalitis by active immunization

“…Anti-N-methyl-D-aspartate receptor encephalitis was first identified in 2007 by the discovery of antibodies against neuronal cell-surface NMDARs (Dalmau et al, 2007(Dalmau et al, , 2008. To date, anti-NMDAR encephalitis is the most common autoimmune encephalitis (AE), accounting for about 80% of all confirmed cases (Guan et al, 2016;Xu et al, 2022). Other antibody-mediated AE are associated with antibodies against neuronal cell-surface proteins, ion channels, or other receptors such as the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) (Zhang et al, 2021;Seery et al, 2022).…”