Anti-N-Methyl-D-Aspartate Receptor (anti-NMDAR) autoimmune encephalitis may go undiagnosed for some time. Patients often present first to a psychiatrist. A high index of suspicion is needed to make the diagnosis.
Psychiatric presentations may include:
(1) delirium and/or disorientation
(2) schizophrenia or other psychosis
(3) catatonia
(4) mania
(5) anxiety and/or agitation
(6) depression or bipolar disease
Additional findings include:
(1) A patient placed on a neuroleptic may present with neuroleptic malignant syndrome.
(2) extrapyramidal symptoms with only low doses of haloperidol (Bergink et al)
Diagnostic features include:
(1) variable neurologic symptoms (seizures, dyskinesia, cognitive impairment)
(2) presence of anti-NMDAR antibodies in the CSF
(3) exclusion of other diagnoses
