Catatonia in patients with anti-NMDA receptor encephalitis.

AIM: There is a lack of studies related to the frequency, phenomenology, and associated features of catatonic syndrome in patients with anti-NMDA receptor encephalitis (ANMDARE). This study aimed to measure the frequency of catatonia in this condition and to delineate its particular symptoms. METHODS: A prospective study was done with all inpatients who fulfilled the criteria of definite ANMDARE admitted to the National Institute of Neurology and Neurosurgery of Mexico from January 2014 to September 2018. The Bush-Francis Catatonia Rating Scale and Braünig Catatonia Rating Scale were administered at admission. RESULTS: Fifty-eight patients were included and catatonia was diagnosed in 41 of these patients (70.6%). Immobility, staring, mutism, and posturing were the most frequent catatonic signs. Catatonia was associated with delirium, hallucinations, psychomotor agitation, generalized electroencephalography dysfunction, and previous use of antipsychotics. Mortality was present in 10% of the total sample; it was associated with status epilepticus, and was less frequent in the catatonia group. After immunotherapy, all cases showed a complete recovery from catatonic signs. CONCLUSION: This systematic assessment of catatonic syndrome shows that it is a frequent feature in patients with ANMDARE as part of a clinical pattern that includes delirium, psychomotor agitation, and hallucinations. The lack of recognition of this pattern may be a source of diagnostic and therapeutic errors, as most physicians associate catatonia with schizophrenia and affective disorders.