Relapses in Anti-NMDAR Encephalitis: Clinical Characterization and Predictive Features

Area of Science:

• Neurology
• Immunology
• Neuroimmunology

Background:

• Relapses occur in up to 25% of anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis patients.
• Characterizing relapses and identifying predictors is crucial for management.

Purpose of the Study:

• To clinically characterize anti-NMDAR encephalitis relapses.
• To identify predictors of relapse during the first episode.
• To evaluate the impact of immunotherapy on relapse occurrence.

Main Methods:

• Retrospective observational study.
• Analysis of 507 patients diagnosed with anti-NMDAR encephalitis between 2007 and 2022.
• Follow-up longer than 1 year.

Main Results:

• 9% of patients experienced relapses, typically monosymptomatic and less severe than the initial episode.
• CSF pleocytosis >20 cells/mL and a paraneoplastic etiology decreased relapse risk.
• Delayed immunotherapy (>30 days) and less frequent use of first- and second-line treatments were associated with higher relapse rates.

Conclusions:

• Anti-NMDAR encephalitis relapses are infrequent and generally milder.
• CSF pleocytosis and a paraneoplastic cause are protective factors against relapse.
• Prompt immunotherapy, especially rituximab, may prevent recurrent episodes.