NEUROPSYCHIATRIC HALLMARKS OF ANMDARE

Objective: To determine the neuropsychiatric hallmarks of ANMDARE, as compared to patients with a negative determination of NMDAR-antibodies. Methods: A prospective, longitudinal, and comparative study was conducted, with patients admitted to the National Institute of Neurology and Neurosurgery of Mexico, who fulfilled criteria for possible autoimmune encephalitis, or showed red flags. Patients were included in a six-year period, by means of a consecutive case sampling. Clinical assessments were done before knowing NMDAR antibodies results, including a bespoke inventory to register a large scope of neuropsychiatric features, the Bush and Francis Catatonia Rating Scale, and the Confusion Assessment Method. Patients were classified according to DSM-5. CSF antibodies against the NR1 subunit of N-methyl-D-aspartate receptor were processed at Labco Nous Diagnostics, Barcelona. Results: After obtaining the CSF antibodies results in 120 consecutive cases, 80 patients were positive and classified as having a definitive ANMDARE. 40 remaining patients were negative. The most distinctive features of ANMDARE were excited catatonia, delirium with catatonic signs, manic syndrome, psychomotor agitation, aggressive behavior, seizures, movement disorders (mainly orolingual dyskinesia), and hypoventilation.