Background: Approximately 25% of encephalitis
cases in North America are immune mediated. For most forms of autoimmune
encephalitis (AIE), risk of relapse is unclear and little evidence exists to
guide which patients have the highest risk and whether standard treatments
reduce this risk. Our objective was to determine the factors associated with
AIE relapse. Methods: We performed a chart review
consisting of patients with AIE presenting to the Calgary Neuro-Immunology
Clinic and Tom Baker Cancer Centre between 2015 and 2020. Predictors of
relapse were determined with use of t-test. Results:
Outcome data was assessable in 39/40 patients, 17/39 (44%) patients
relapsed. Seropositive patients and those with abnormal CSF were more likely
to relapse, although neither reached statistical significance (p=0.12,
0.059). Patients with longer duration of steroid and steroid sparing
treatment prior to relapse, and those on steroids at the time of relapse,
had milder relapses (p=0.024, 0.026, 0.047). There was no difference in
steroid or steroid sparing treatment use at 3, 6, and 12 months between
groups. Conclusions: Risk of relapse in AIE is high
(44%), with most relapses occurring in the first 3 years. Continuous
immunosuppression lessens the severity of relapse, although our study did
not confirm it reduced the occurrence of relapse.