Abstract Details

Title Characterizing Follow Up Lumbar Punctures in Encephalitis Patients

Topic Infectious Disease

Presentation(s) P3 - Poster Session 3 (11:45 AM-12:45 PM)

Poster/Presentation
Number 10-005

Objective To evaluate the results of follow-up lumbar punctures (LP) and characteristics of encephalitis patients undergoing repeat LPs.

Background Clinical case definitions often rely on cerebrospinal fluid (CSF) results to indicate central nervous system inflammation in encephalitis, though some patients present with subtle signs of inflammation on initial LP. This study examines temporal changes in CSF results and explores the rationale behind repeating LP, aiming to identify patterns that improve diagnosis and care in encephalitis cases.

Design/Methods This retrospective study analyzes LP data from the initial hospital admissions of 627 adult encephalitis patients, including autoimmune and infectious cases, from 2002 to 2022.

Results Of 627 patients, 184 (29.3%) underwent follow-up LPs. Inflammatory markers, such as white blood cell (WBC) count, significantly decreased on repeat LP (median WBC LP1 = 38 vs. LP2 = 19, p < 0.001), with the decline becoming apparent three days after the initial LP. Patients with repeat LPs were more likely to have autoimmune encephalitis (22%) compared to those with a single LP (16%), p=0.04. Conversely, patients with a single LP were more frequently diagnosed with infectious encephalitis (48.1%) than those undergoing repeat LPs (33.7%), p<0.001. Patients with more severe clinical presentations (e.g., status epilepticus, altered mental status) and hospitalization course (e.g., prolonged admission, lower GOS score, ICU admission) were significantly more likely to undergo repeat LPs. Diagnostic uncertainty and lack of response to treatment were common reasons for repeat LPs. Notably, 93.2% of patients with a definitive diagnosis had positive findings on the initial LP, while subsequent LPs rarely provided new diagnostic information.

Conclusions Our study found that repeat LPs were more common in autoimmune and severe encephalitis cases but rarely provided additional diagnostic insights. This emphasizes the importance of the initial LP.

Authors/Disclosures
Jordan Benderoth PRESENTER	Miss Benderoth has nothing to disclose.
Ralph Habis, MD (Johns Hopkins School of Medicine)	Dr. Habis has nothing to disclose.
Merrick Garner	Ms. Garner has nothing to disclose.
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.
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.
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.

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