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Bacterial meningitis

Last reviewed: 1 Nov 2023
Last updated: 25 Oct 2023



History and exam

Key diagnostic factors

  • headache
  • neck stiffness
  • fever
  • altered mental status
  • confusion
  • photophobia
  • vomiting
  • seizures
  • hypothermia (infants)
  • irritability (infants)
  • lethargy (infants)
  • poor feeding (infants)
  • apnea (infants)
  • focal neurologic deficit
  • abnormal eye movement
  • facial palsy
  • balance problems/hearing impairment
  • bulging fontanel in infants
More key diagnostic factors

Other diagnostic factors

  • high-pitched cry (infants)
  • rash
  • papilledema
  • Kernig sign
  • Brudzinski sign
Other diagnostic factors

Risk factors

  • age ≤5 or ≥65 years
  • crowding
  • exposure to pathogens
  • nonimmunized infants
  • immunodeficiency
  • cancer
  • asplenia/hyposplenic state
  • cranial anatomic defects
  • cochlear implants
  • contiguous infection
  • smoking
More risk factors

Diagnostic investigations

1st investigations to order

  • cerebrospinal fluid (CSF) cell count and differential
  • CSF protein
  • CSF glucose
  • CSF Gram stain
  • CSF culture
  • antigen detection in CSF
  • blood culture
  • CBC and differential
  • CRP
  • electrolytes, calcium (Ca), magnesium (Mg), glucose
  • coagulation profile (prothrombin time, INR, activated PTT, fibrinogen, fibrin degradation products)
  • CT head
  • polymerase chain reaction (PCR)
More 1st investigations to order

Investigations to consider

  • MRI head
  • serum procalcitonin
More investigations to consider

Treatment algorithm





confirmed infection: Streptococcus pneumoniae

confirmed infection: Haemophilus influenzae

confirmed infection: Streptococcus agalactiae (group B streptococci)

confirmed infection: Escherichia coli and other gram-negative Enterobacteriaceae

confirmed infection: Listeria monocytogenes

confirmed infection: Staphylococcus aureus

confirmed infection: Staphylococcus epidermidis

confirmed infection: Pseudomonas aeruginosa

confirmed infection: Enterococcus species

confirmed infection: Acinetobacter species

confirmed infection: Neisseria meningitidis



A. Marceline Tutu van Furth, MD, PhD, MBA
A. Marceline Tutu van Furth

Professor in Pediatric Infectious Diseases

Department of Pediatric infectious Diseases and Immunology, AI&II

Amsterdam UMC, Vrije Universiteit Amsterdam


The Netherlands


AMTvF declares that she has no competing interests.

Omaima El Tahir, MD

PhD Candidate

Department of Pediatric infectious Diseases and Immunology, AI&II

Amsterdam UMC, Vrije Universiteit Amsterdam


The Netherlands


OET declares that she has no competing interests.

Peer reviewers

Guy Thwaites, MA, MBBS, PhD, MRCP, FRCPath

Wellcome Trust Clinical Research Fellow

Centre for Molecular Microbiology and Infection

Imperial College London




GT declares that he has no competing interests.

Wendy Ziai, MD, MPH

Assistant Professor

Neurology, Neurosurgery, and Anesthesiology and Critical Care Medicine

The Johns Hopkins University




WZ declares that she has no competing interests.

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