Abstract Details

Title Suspected Autoimmune Encephalitis in Hospitalized Adults: Diagnostic Yield and Predictors

Topic Autoimmune Neurology

Presentation(s) P9 - Poster Session 9 (5:00 PM-6:00 PM)

Poster/Presentation
Number 1-007

Objective

To compare clinical and paraclinical features between hospitalized adults with expert-confirmed autoimmune encephalitis (AE) and those with suspected AE, but alternative final diagnoses, to identify predictors of AE.

Background

AE commonly presents with subacute neuropsychiatric symptoms, but remains challenging to diagnose. Neural autoantibodies can support the diagnosis, yet their importance depends on clinical context and they may require expert interpretation.

Design/Methods

We conducted a retrospective cohort study at Mass General Brigham, including consecutive adult inpatients for whom a serum autoimmune encephalopathy panel was ordered, either directly or on recommendation by neurology (November 2020–March 2022). Expert reviewers adjudicated final diagnoses. Among patients with any positive autoantibody result, positive predictive values (PPVs) for serum and CSF neural autoantibody panels were estimated for expert-confirmed AE. Group comparisons between AE and non-AE were performed, and predictors of AE were assessed using Firth’s penalized logistic regression.

Results

Among 269 patients included in the study, 20 (7.4%) had expert-confirmed AE and 249 had alternative final diagnoses. Compared with non-AE, AE cases more often had subacute cognitive decline (85% vs 48.6%, p<0.01), new onset seizure (55% vs 12.4%, p<0.01), malignancy within 5 years (40% vs 20.5%, p=0.05), inflammatory CSF (61.1% vs 32.1%, p=0.02), and an abnormal brain MRI (30% vs 5.6%, p<0.01). Among seropositive patients, the PPV for expert-confirmed AE was 10.3% for serum and 80% for CSF. In multivariable models, cognitive decline, seizures, malignancy, inflammatory CSF, and CSF autoantibody positivity independently predicted AE, whereas abnormal brain MRI and serum autoantibody positivity did not.

Conclusions

In hospitalized adults evaluated for suspected AE, expert-confirmed AE was uncommon, yet exhibited a coherent clinical/paraclinical profile. Subacute cognitive decline, new onset seizures, malignancy within 5 years, and inflammatory CSF support an AE diagnosis. Serum autoantibody results merit cautious interpretation; CSF autoantibody testing should be pursued in clinically suspicious cases.

Authors/Disclosures
Yoji Hoshina, MD (University of Utah Health) PRESENTER	Dr. Hoshina has nothing to disclose.
Giovanna Manzano, MD	Dr. Manzano has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Gilead Sciences. Dr. Manzano has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for InfuCare Rx.
Joao Vitor Mahler, MD	Dr. Mahler has received research support from The Sumaira Foundation.
Samuel J. Steuart	Mr. Steuart has nothing to disclose.
Bruna Leles Vieira de Souza, MD (Work)	Miss Leles Vieira de Souza has nothing to disclose.
Prashanth Rajarajan, MD, PhD (Brigham and Women's Hospital)	Dr. Rajarajan has nothing to disclose.
Rachel Rodin, MD, PhD	Dr. Rodin has nothing to disclose.
Leigh Rettenmaier, MD	Dr. Rettenmaier has nothing to disclose.
Caleb R. McEntire, MD (MGH-Brigham Neurology)	Dr. McEntire has nothing to disclose.
Ahmad Mashlah, MBBS (Mass General Brigham)	Dr. Mashlah has nothing to disclose.
Philippe-Antoine Bilodeau, MD (Massachusetts General Hospital)	Dr. Bilodeau has or had stock in Roche. The institution of Dr. Bilodeau has received research support from Alexion Pharmaceuticals. The institution of Dr. Bilodeau has received research support from Department of Defense. Dr. Bilodeau has received research support from Canadian Institutes of Health Research. The institution of Dr. Bilodeau has received research support from Ann Theodore Foundation. Dr. Bilodeau has received research support from The MOG Project.
Ahya S. Ali, MD (Westchester Medical Center)	Dr. Ali has nothing to disclose.
Leah L. Wibecan, MD, MPH	Dr. Wibecan has nothing to disclose.
Wesley Kerr, MD, PhD (University of Pittsburgh)	Dr. Kerr has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for SK Life Science. Dr. Kerr has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Biohaven Pharmaceuticals. Dr. Kerr has received personal compensation in the range of $500-$4,999 for serving as a Consultant for UCB. Dr. Kerr has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Neurelis. Dr. Kerr has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for QurAlis. Dr. Kerr has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Biohaven Pharmaceuticals. Dr. Kerr has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Epilepsia. The institution of Dr. Kerr has received research support from NINDS. The institution of Dr. Kerr has received research support from American Epilepsy Society. The institution of Dr. Kerr has received research support from American Academy of Neurology. The institution of Dr. Kerr has received research support from SK Life Science. The institution of Dr. Kerr has received research support from Biohaven Pharmaceuticals. Dr. Kerr has received publishing royalties from a publication relating to health care.
Jenny Linnoila, MD, PhD (University Neurology Associates, UPMC)	Dr. Linnoila has received personal compensation in the range of $10,000-$49,999 for serving as a expert respondent on autoimmune encephalitis with U.S. government/DHHS/Vaccine Injury Compensation Program.