Viral meningitis

Last reviewed: 27 Aug 2023
Last updated: 16 Nov 2022



History and exam

Key diagnostic factors

  • headache
  • nausea and vomiting
  • photophobia
  • neck stiffness
  • fever
More key diagnostic factors

Other diagnostic factors

  • rash
  • Kernig sign
  • Brudzinski sign
Other diagnostic factors

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
More risk factors

Diagnostic investigations

1st investigations 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
More 1st investigations to order

Investigations to consider

  • CT/MRI head
  • EEG
  • CSF viral culture
More investigations to consider

Emerging tests

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

Treatment algorithm


possible bacterial meningitis


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

HSV or varicella zoster confirmed causative agent

CMV confirmed causative agent


recurrent viral meningitis



John Williams, MRCP, DTM&H
John Williams


The James Cook University Hospital




JW declares that he has no competing interests.


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




KR declares that she has no competing interests.

Vassiliki Syriopoulou, MD

Professor of Pediatrics

University of Athens

Aghia Sophia Children's Hospital




VS declares that she has no competing interests.

  • Differentials

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

    • A guide to utilization of the microbiology laboratory for diagnosis of infectious diseases: 2018 update by the Infectious Diseases Society of America and the American Society for Microbiology
    • The UK joint specialist societies guideline on the diagnosis and management of acute meningitis and meningococcal sepsis in immunocompetent adults
    More Guidelines
  • Patient leaflets

    Meningitis and septicemia

    Lumbar puncture

    More Patient leaflets
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