Long-Term Follow-Up of Non-Paraneoplastic Autoimmune Encephalitis: A Canadian Single-Center Experience

Area of Science:

• Neuroimmunology
• Neurology
• Autoimmune Diseases

Background:

• Autoimmune encephalitides (AIE) are increasingly recognized causes of encephalitis.
• Diagnosis and acute management of AIE are established, but long-term outcomes and management strategies remain less understood.
• This study addresses the limited data on chronic management and relapse predictors in AIE.

Purpose of the Study:

• To review long-term management and outcomes of patients with non-paraneoplastic autoimmune encephalitides.
• To determine the incidence of relapses in AIE subtypes and identify potential predictors.
• To evaluate the impact of chronic immunotherapy on relapse risk and severity.

Main Methods:

• A retrospective chart review of non-paraneoplastic AIE patients from 2015-2020.
• Assessment of relapse severity using the Clinical Assessment Scale in Autoimmune Encephalitis (CASE).
• Descriptive analysis and t-tests were employed to analyze variables.

Main Results:

• The cohort experienced a mean relapse rate of 46%, with most relapses (76%) occurring within 3 years.
• Time to treatment initiation at relapse was significantly shorter than at initial presentation (p = 0.0015).
• Patients on immunotherapy at relapse had milder relapses (p = 0.0035), though overall relapse risk was not impacted.

Conclusions:

• Relapse is a significant concern in AIE, with a 46% incidence in the cohort, particularly within the first three years.
• Long-term follow-up is crucial for enabling earlier treatment and reducing relapse severity.
• Further research is needed to determine which AIE patients would benefit most from chronic immunotherapy.