Residual Symptoms, Recovery & Predictors of Long-term Sequalae After Autoimmune Encephalitis
Smathorn Thakolwiboon1, Emma Orozco2, Michael Gilligan1, Jeffrey Britton1, Divyanshu Dubey1, Eoin Flanagan1, Alfonso Lopez1, Cristina Valencia Sanchez1, Nicholas Zalewski1, Anastasia Zekeridou1, Sean Pittock1, Andrew McKeon1
1Neurology, Mayo Clinic, 2Neurology, University of New Mexico
Objective:

To investigate residual symptoms, recovery, and long-term sequelae in autoimmune encephalitis (AE).

Background:

Knowledge of outcomes and long-term sequelae is important for patient care and counseling in AE, but the data remain limited.

Design/Methods:

Retrospective chart review of 182 patient charts meeting definite AE criteria evaluated at the Autoimmune Neurology Clinic, Mayo Clinic (January 2006-December 2020). After the last AE attack, 143 had follow-up for ≥12-24 months and 119 had follow-up >24 months.

Results:

Antibody positivities among the 182 were: LGI1 (60), GAD65, (32), NMDA-R (25), seronegative (18), GFAP (11), CASPR2 (9), DPPX (7), ANNA1 (6), MOG (6), Ma2 (6) and other (22).  Median number of attacks was 1 (range, 1-5). After the last attack residual symptoms were: cognitive difficulties (97/143, 68%, during the initial 12-24 months; and 63/119, 53%, at the last follow-up), seizures (38/143, 27%, and 31/119, 26%), depression (27/143, 19%, and 27/119, 23%), sleep disorders (36/143, 25%, and 23/119, 19%), movement disorders (15/143, 10%, and 17/119, 14%), brainstem symptoms (18/143, 13%, and 16/119, 13%), dysautonomia (16/143, 11%, and 15/119, 13%), chronic pain (10/143, 7%, and 13/119, 11%), and fatigue (20/143, 14% and 12/119, 10%). At last follow-up, 100/119 (84%) achieved mRS≤2, which was associated with mRS<4 at attack (p=0.021) and lack of CSF pleocytosis (p=0.019). Factors associated with dementia after AE included delayed treatment (p=0.044) and neuronal nuclear/cytoplasmic antibody positivity (p=0.034). Factors associated with post-AE epilepsy were: focal to bilateral tonic-clonic seizure (p=0.023) during the attack, multiple anti-epileptic medication use (p=0.008), and medial temporal atrophy (p=0.027). Of 182 patients, 20 (11%) died, and the most common cause of death was neurological deterioration.

Conclusions:
Post-AE, diverse neurological, psychiatric and sleep problems are reported. A significant proportion of patients achieved independence in daily activities within two years post-attack. These findings and factors associated with long-term sequelae may assist in counselling at diagnosis.
10.1212/WNL.0000000000205399