Isolated Nocturnal Occurrence of Orofacial Dyskinesias in N-methyl-D-aspartate Receptor Encephalitis-A New Diagnostic Clue

Abstract

Background: The syndrome of anti-N-methyl-D-aspartate receptor encephalitis is classically associated with a combination of limbic dysfunction, dysautonomia, central hypoventilation and movement disorders. On clinical grounds, the diagnosis is often supported by the presence of generalized dyskinesias in a patient with encephalopathy and catatonic signs. Orofacial dyskinesias have been recognized as characteristic of the disorder but can be absent in some patients. Pure psychiatric syndromes without movement disorders have also been described.

Methods and results: The authors describe 2 male patients who presented with prominent neuropsychiatric symptoms without movement disorders during wakefulness but isolated orofacial dyskinesias during sleep. In 1 patient, this observation supported the early introduction of immunotherapy; and, in both patients, the clinical outcome was excellent.

Conclusions: Careful history and nocturnal examination may reveal orofacial dyskinesias in patients with N-methyl-D-aspartate receptor encephalitis who have apparent pure psychiatric manifestations.

Keywords: N‐methyl‐D‐aspartate (NMDA) receptor encephalitis; autoimmune encephalitis; orofacial dyskinesias.