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Last reviewed: 16 Mar 2025
Last updated: 31 Jan 2023

Summary

Definition

History and exam

Key diagnostic factors

  • fever
  • vomiting/nausea
  • irritable/unsettled
  • headache
  • altered mental state
  • neck stiffness
  • photophobia
  • seizures
  • focal neurological deficit
  • rash
  • shock
  • raised intracranial pressure
  • back rigidity
  • bulging fontanelle
  • Kernig’s sign
  • Brudzinski’s sign
  • apnoea
  • presence of risk factors

Other diagnostic factors

  • lethargy
  • ill appearance
  • refusing food/drink
  • muscle ache/joint pain
  • respiratory symptoms or breathing difficulty
  • chills/shivering
  • diarrhoea, abdominal pain/distension
  • sore throat, coryza, or other ear, nose, and throat symptoms/signs

Risk factors

  • age <2 years
  • incomplete immunisation
  • immunocompromising conditions
  • cranial structural defects
  • medical devices
  • perinatal period
  • exposure to pathogens
  • contiguous infection
  • crowding

Diagnostic investigations

1st investigations to order

  • blood gas (including lactate)
  • blood glucose
  • FBC
  • serum CRP, procalcitonin
  • coagulation screen
  • blood cultures
  • serum PCR for Neisseria meningitidis
  • urea, electrolytes, and creatinine
  • LFTs
  • cross-match
  • CSF white blood cell count and examination
  • CSF total protein concentration
  • CSF glucose concentration
  • CSF microscopy, Gram stain, culture, and sensitivities
  • CSF PCR for Neisseria meningitidis and Streptococcus pneumoniae

Investigations to consider

  • cranial CT
  • MRI
  • immune testing

Treatment algorithm

Contributors

Expert advisers

Emre Basatemur, MRCPCH, PhD

Consultant in Paediatric Emergency Medicine

The Royal London Hospital

London

UK

Disclosures

EB declares that he has no competing interests.

Peer reviewers

Kavita Sethi, MBBS, MD Microbiology, DTM&H, FRCPath

Lead Clinician and Consultant Microbiologist

Leeds Teaching Hospitals NHS Trust

Leeds

UK

Disclosures

KS developed educational material for the Royal College of Pathologists, and received sponsorship to attend the European Congress of Clinical Microbiology and Infectious Diseases (ECCMID).

Editors

Annabel Sidwell

Section Editor, BMJ Best Practice

Disclosures

AS declares that she has no competing interests.

Tannaz Aliabadi-Oglesby

Lead Section Editor, BMJ Best Practice

Disclosures

TAO declares that she has no competing interests.

Adam Mitchell

Drug Editor, BMJ Best Practice

Disclosures

AM declares that he has no competing interests.

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