Last reviewed: 28 Sep 2021
Last updated: 30 Sep 2021

Summary

Definition

History and exam

Key diagnostic factors

  • presence of risk factors
  • headache
  • photophobia
  • neck stiffness
  • fever
  • nausea and vomiting

Other diagnostic factors

  • rash
  • Kernig's sign
  • Brudzinski's sign

Risk factors

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

Diagnostic investigations

1st investigations to order

  • blood cultures
  • FBC and differential
  • C-reactive protein (CRP)
  • serum urea, creatinine, and electrolytes
  • blood gases
  • blood glucose
  • CSF microscopy
  • CSF Gram stain
  • CSF bacterial culture
  • CSF protein
  • CSF glucose
  • CSF lactate
  • CSF, stool and throat swab PCR for viral pathogens
  • HIV serology/HIV reverse transcriptase (RT)-PCR

Treatment algorithm

Contributors

Expert advisers

John Williams, MRCP, DTM&H

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

Peer reviewers

Alex Alexiou, MBBS, BSc, DCH, FRCEM, Dip IMC RCSEd

Consultant in Emergency Medicine

Royal London Hospital

Consultant, Physician Response Unit

Barts Health NHS Trust/London Air Ambulance

London

UK

Disclosures

AA declares that he has no competing interests.

Fiona McGill, MRCP, DTMH, DipHIVMed

Clinical Lecturer

Institute of Infection and Global Health

University of Liverpool

Liverpool

UK

Disclosures

FM is on the Meningitis Research Foundation’s Medical Advisory Group, has lectured on national and international events on meningitis and has developed a review for ‘clinical medicine’ on viral meningitis and encephalitis.

Editors

Tannaz Aliabadi-Oglesby,

Lead Section Editor, BMJ Best Practice

Disclosures

TAO declares that she has no competing interests.

Rachel Wheeler,

Lead Section Editor, BMJ Best Practice

Disclosures

RW declares that she has no competing interests.

Adam Mitchell,

Drug Editor, BMJ Best Practice

Disclosures

AM declares that he has no competing interests.

Julie Costello,

Comorbidities Editor, BMJ Best Practice

Disclosures

JC declares that she has no competing interests.

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