Catatonia in N-methyl-d-aspartate receptor antibody encephalitis: Phenomenological characteristics from a systematic review of case reports

Abstract

Objective: To ascertain the phenomenological characterisation of catatonia in N-methyl-d-aspartate receptor antibody encephalitis (NMDAr-AbE).

Methods: A systematic review of case reports was undertaken in accordance with PRISMA guidelines. Case reports of NMDAr-AbE containing sufficient information on the cases' clinical presentation and meeting the study's inclusion criteria were selected. Cases were searched for clinical data in keeping with core catatonic signs by applying the screening instrument of the Bush-Francis Catatonia Rating Scale. When two or more core signs were ascertained catatonia was considered to be present.

Results: 2645 records were identified through the database search. Following screening and application of eligibility/inclusion criteria 139 articles were selected reporting on 189 individual subjects. Catatonia was present in 60% of these cases. The most prevalent signs were immobility/stupor (70%), mutism (67%), excitement (50%), posturing/catalepsy (34%), stereotypies (31%), and rigidity (30%). Immobility/stupor and excitement co-occurred in the same patient in 33% of cases.

Conclusion: The phenomenological profile of catatonia in this sample of cases of NMDAr-AbE was characterised by a preponderance of signs in the hypokinetic spectrum. However, excitement often co-occurred in these patients suggesting that fluctuations in catatonic semiology may be frequent.

Keywords: Catatonia; NMDAr encephalitis; Phenomenology.