Abstract | December 19, 2022

Atypical HSV Meningoencephalitis: Bayesian Reasoning in The Case of Normal CSF

Presenting Author: Andrew Sephien, MD, Internal Medicine Resident PGY3, Department of Internal Medicine, HCA Florida Citrus Hospital, Inverness, Fl

Coauthors: Soleil Soto, DO, Internal Medicine, PGY2, HCA Florida Citrus Hospital, Inverness, Fl; Jeffrey Jordan, MD, Internal Medicine, Program Director, HCA Florida Citrus Hospital, Inverness, Fl; Gustine Liu-Young, MD, FACP, Internal Medicine, Infectious Disease, HCA Florida Citrus Hospital, Inverness, Fl

Learning Objectives

  1. Discuss the atypical findings that may be present in HSV Encephalitis
  2. Demonstrate the utilization of Bayesian reasoning in clinical diagnosis

Introduction: Left untreated, the mortality rate of herpes simplex virus (HSV) encephalitis exceeds 70%. This emphasizes the importance of early initiation of therapy. However, cases of atypical meningoencephalitis, where lack of pleocytosis in cerebrospinal fluid (CSF) are observed at  increasing incidence, placing further importance on Bayesian reasoning in clinical diagnosis.

 

Case: Patient is a 50-year-old Caucasian female who was previously treated three weeks prior for SARS-CoV2 pneumonia complicated by methicillin-resistant staphylococcus aureus (MRSA) bacteremia and received a prolonged course of high dose corticosteroids, remdesivir, and barcitinib while requiring invasive mechanical ventilation. She was readmitted three weeks later for encephalopathy with seizure-like movements, tachycardia, and leukocytosis. Magnetic resonance imaging of the brain revealed right temporal enhancement. Lumbar puncture revealed lack of pleocytosis in CSF and patient was empirically started on intravenous (IV) acyclovir. Eventually, HSV-1 polymerase chain reaction (PCR) came back positive with varicella zoster virus  PCR was negative.

 

Final/Working Diagnosis: Atypical HSV Meningoencephalitis 

 

Management, Outcome, and Follow-up: Patient began to improve clinically with no complications and completed two weeks of IV acyclovir.

 

References:

  1. Granerod J, Crowcroft NS. The epidemiology of acute encephalitis. Neuropsychol Rehabil. 2007;17(4-5):406-428.
  2. Bewersdorf JP, Koedel U, Patzig M, et al. Challenges in HSV encephalitis: normocellular CSF, unremarkable CCT, and atypical MRI findings. Infection. 2019;47(2):267-273.
  3. Rice CM, Yadav S, Boyanton B, Subedi P, Band J. Clinical problem-solving. A creeping suspicion. N Engl J Med. 2014;371(1):68-73.
  4. Gnann JW Jr, Whitley RJ. Herpes Simplex Encephalitis: an Update. Curr Infect Dis Rep. 2017 Mar;19(3):13

 

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