Outcome and Sequelae of Autoimmune Encephalitis

Abstract

Autoimmune etiologies are a common cause for encephalitis. The clinical syndromes consistent with autoimmune encephalitis are both distinct and increasingly recognized, but less is known about persisting sequelae or outcomes. We searched PubMed for reports on outcomes after autoimmune encephalitis. Studies assessing validated, quantitative outcomes were included. We performed a narrative review of the published literature of outcomes after autoimmune encephalitis. We found 146 studies that produced outcomes data. The mortality rates were 6%-19% and the relapse risks were 10%-62%. Most patients achieved a good outcome based on a score on the modified Rankin Scale (mRS) of ≤2. Forty-nine studies evaluated outcomes beyond mRS; these studies investigated cognitive outcome, psychiatric sequelae, neurological deficits, global function, and quality-of-life/patient-reported outcomes using various tools at varying time points after the index hospital discharge. These more-detailed assessments revealed that most patients had persistent impairments, with frequent deficits in cognitive function, especially memory and attention. Depression and anxiety were also common. Many of these sequelae continued to improve over months or even years after the acute illness. While we found that lasting impairments were common among survivors of autoimmune encephalitis, additional research is needed to better understand the nature and impact of these sequelae. Standardized evaluation protocols are needed to improve the ability to compare outcomes across studies, guide rehabilitation strategies, and inform outcomes of interest in treatment trials as the field advances.

Keywords: autoimmune encephalitis; cognitive impairment; outcomes; patient-reported outcome.

Fig. 1. Flow diagram of included studies. AMPA, alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid; Caspr2, contactin-associated protein-like 2; DPPX, dipeptidyl-peptidase-like-protein-6; GABA-A, gamma aminobutyric acid A; GABA-B, gamma aminobutyric acid B; GAD65, glutamic acid decarboxylase-65kD; GFAP, glial fibrillary acidic protein; IgLON5, immunoglobulin-like cell adhesion molecule 5; LGI1, Leucine-rich glioma-inactivated 1; MOG, myelin oligodendrocyte glycoprotein; NMDA, N-methyl D-aspartate; R, receptor.