Abstract Details

Title Distinguishing Paraneoplastic and Autoimmune Encephalitis

Topic Autoimmune Neurology

Presentation(s) P8 - Poster Session 8 (11:45 AM-12:45 PM)

Poster/Presentation
Number 1-011

Objective Compare paraneoplastic encephalitis (PE) patients to non-paraneoplastic autoimmune encephalitis (AE) patients to identify distinguishing features of PE at clinical presentation.

Background PE is an immune-mediated syndrome that is a remote consequence of a systemic immune response to cancer and can even occur years before cancer detection. The PNS-Care Score integrates phenotype, antibody risk, and cancer association to classify cases as definite, probable, or possible paraneoplastic cases. At presentation, overlap between PE and AE may delay cancer diagnosis.

Design/Methods

This retrospective multicenter study included 647 encephalitis patients across two Johns Hopkins (2006–2022) and two UTHealth institutions (2005–2023). The retrospective design enabled assessment of cancer incidence after presentation. Patients meeting PNS-Care Score criteria for probable PE were compared by demographic and clinical features to patients with AE using non-parametric tests. Variables that were statistically significant in univariate analyses were included in a multivariate logistic regression analysis.

Results Compared with AE patients (N=95), PE patients (N=30) tended to be younger (13.3% vs 30.5% >60 years; p =0.06), and were more likely to present with acute onset (<5 days, 93.1% vs 68.8%; p =0.009) and fever (46.4% vs 25.3%; p =0.04), but were less likely to have abnormal movements (33.3% vs 61.4%; p =0.03). Moreover, PE patients had stronger inflammatory activity with higher CSF leukocyte counts (median 19 [5–39] vs 8 [2–25] cells/mm³; p =0.04). In multivariate analysis, pleocytosis (>5 cells/mm³) (OR 3.3, 95% CI 1.2–9.2, p =0.023) and acute onset (OR 8.6, 95% CI 1.8–33.3, p =0.007) independently predicted PE, while fever was positively associated with PE but did not reach statistical significance (OR 2.3, 95% CI 0.9–6.1, p =0.09).

Conclusions Early inflammatory markers, including CSF pleocytosis and rapid onset of encephalitis symptoms within five days, may help distinguish PE from AE. These results support the link between a tumor related immune response and CSF inflammation.

Authors/Disclosures
Jordan Benderoth PRESENTER	Miss Benderoth has nothing to disclose.
Silvia S. Leblanc, Medical Student	Ms. Leblanc has nothing to disclose.
Roba El-Zibaoui, MD	Dr. El-Zibaoui has nothing to disclose.
Sophia Zhao, BA, BS	Miss Zhao has nothing to disclose.
Ralph Habis, MD (Johns Hopkins School of Medicine)	Dr. Habis has nothing to disclose.
Rajesh K. Gupta, MBBS (UTHealth)	Dr. Gupta has nothing to disclose.
Arun Venkatesan, MD, PhD (Johns Hopkins Hospital)	Dr. Venkatesan has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Janssen Pharmaceuticals. The institution of Dr. Venkatesan has received research support from NIH. The institution of Dr. Venkatesan has received research support from U.S. DOD.
Rodrigo Hasbun	Rodrigo Hasbun has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Biomeriaux. The institution of Rodrigo Hasbun has received research support from Biomeriaux.
John Probasco, MD, FAAN (The Johns Hopkins Hospital)	Dr. Probasco has received personal compensation in the range of $10,000-$49,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for NEJM Clinician. The institution of Dr. Probasco has received research support from Roche/Genentech.

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