Viral meningitis

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Last reviewed: 9 Apr 2025
Last updated: 18 Feb 2025

Summary

Definition

History and exam

Key diagnostic factors

  • headache
  • nausea and vomiting
  • photophobia
  • neck stiffness
  • fever
Full details

Other diagnostic factors

  • rash
  • Kernig sign
  • Brudzinski sign
Full details

Risk factors

  • infants and young children
  • young adults
  • older people
  • summer and fall
  • exposure to mosquito or tick vector
  • unvaccinated for mumps
  • use of swimming pools and ponds
  • immunosuppression
  • exposure to rodents
Full details

Diagnostic tests

1st tests to order

  • CSF microscopy
  • CSF Gram stain
  • CSF bacterial culture
  • CSF protein
  • CSF glucose
  • CSF PCR for enteroviruses
  • CSF PCR for herpes viruses
  • HIV serology/HIV reverse transcriptase (RT)-PCR
Full details

Tests to consider

  • CT/MRI head
  • EEG
  • CSF viral culture
Full details

Emerging tests

  • CSF C-reactive protein (CRP)
  • serum and CSF procalcitonin
  • CSF lactate
Full details

Treatment algorithm

INITIAL

possible bacterial meningitis

ACUTE

confirmed viral agent, other than HSV, varicella zoster, or CMV

HSV or varicella zoster confirmed causative agent

CMV confirmed causative agent

ONGOING

recurrent viral meningitis

Contributors

Expert advisers

John Williams, MRCP, DTM&H

Consultant

The James Cook University Hospital

Middlesbrough

UK

Disclosures

JW declares that he has no competing interests.

Acknowledgements

Dr John Williams would like to gratefully acknowledge Dr David Chadwick, a previous contributor to this topic.

Disclosures

DC is an author of a reference cited in this topic.

Peer reviewers

Karen Roos, MD

John and Nancy Nelson Professor of Neurology

Indiana University School of Medicine

Indianapolis

IN

Disclosures

KR declares that she has no competing interests.

Vassiliki Syriopoulou, MD

Professor of Pediatrics

University of Athens

Aghia Sophia Children's Hospital

Athens

Greece

Disclosures

VS declares that she has no competing interests.

References

Our in-house evidence and editorial teams collaborate with international expert contributors and peer reviewers to ensure that we provide access to the most clinically relevant information possible.

Key articles

McGill F, Heyderman RS, Michael BD, et al. The UK joint specialist societies guideline on the diagnosis and management of acute meningitis and meningococcal sepsis in immunocompetent adults. J Infect. 2016 Apr;72(4):405-38.Full text  Abstract

Centers for Disease Control and Prevention. About viral meningitis. Jan 2024 [internet publication].Full text

Miller JM, Binnicker MJ, Campbell S, et al. Guide to utilization of the microbiology laboratory for diagnosis of infectious diseases: 2024 update by the Infectious Diseases Society of America (IDSA) and the American Society for Microbiology (ASM). Clin Infect Dis. 2024 Mar 5 [Epub ahead of print].Full text  Abstract

Reference articles

A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.
  • Differentials

    • Meningitis, bacterial
    • Encephalitis
    • Encephalopathy (toxic/metabolic)
    More Differentials
  • Guidelines

    • Guide to utilization of the microbiology laboratory for diagnosis of infectious diseases
    • The UK joint specialist societies guideline on the diagnosis and management of acute meningitis and meningococcal sepsis in immunocompetent adults
    More Guidelines
  • Patient information

    Meningitis and septicemia

    Lumbar puncture

    More Patient information
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