Objective: To precisely describe the initial psychiatric presentation of patients with anti-NMDA receptor (NMDAR) antibodies encephalitis (anti-NMDAR encephalitis) to identify potential clues enhancing its early diagnosis.
Methods: We retrospectively studied the French Reference Centre medical records of every adult patient with anti-NMDAR encephalitis to specify the patients' initial psychiatric symptoms leading to hospitalization in a psychiatric department and the reasons underlying the diagnosis of anti-NMDAR encephalitis.
Results: The medical records of 111 adult patients were reviewed. Psychiatric features were the initial presentation in 65 patients (59%). Among them, several psychiatric manifestations were observed, including visual and auditory hallucinations (n = 26, 40%), depression (n = 15, 23%), mania (n = 5, 8%), acute schizoaffective episode (n = 15, 23%), and eating disorder or addiction (n = 4; 6%). Forty-five patients (40% of total cohort) were first hospitalized in a psychiatric institution (91% women), with a median duration of stay of 9 days (range 0.25-239 days). Among them, 24 patients (53%) had associated discreet neurologic signs at the first evaluation, while 17 additional patients (38%) developed neurologic signs within a few days. Twenty-one patients (47%) were transferred to a medical unit for a suspicion of antipsychotic intolerance characterized by high temperature, muscle rigidity, mutism or coma, and biological results suggesting rhabdomyolysis.
Conclusions: Several psychiatric presentations were observed in patients with anti-NMDAR encephalitis, although none was specific; however, patients, mostly women, also had discreet neurologic signs that should be carefully assessed as well as signs of antipsychotic intolerance that should raise suspicion for anti-NMDAR encephalitis.