Last reviewed: 7 Apr 2021
Last updated: 26 Jan 2021



History and exam

Key diagnostic factors

  • presence of risk factors
  • male sex
  • age <30 years
  • meningismus
  • headache
  • cranial nerve palsy
  • positive Kernig or Brudzinski sign
  • fever
  • increased head circumference (infants)
  • bulging fontanelles (infants)

Other diagnostic factors

  • neurological deficit
  • papilloedema

Risk factors

  • sinusitis
  • otitis media
  • dental procedure/infection
  • meningitis
  • recent neurosurgery
  • congenital heart disease
  • endocarditis
  • diverticular disease
  • hereditary haemorrhagic telangiectasia or arteriovenous malformation
  • diabetes mellitus
  • HIV or immunocompromise
  • intravenous drug use
  • chronic granulomatous disease
  • haemodialysis
  • birth prematurity
  • cystic fibrosis

Diagnostic investigations

1st investigations to order

  • FBC
  • serum erythrocyte sedimentation rate (ESR)
  • serum CRP
  • serum PT and PTT
  • blood culture
  • serum toxoplasma titre
  • MRI with contrast
  • CT head with and without contrast
  • ultrasound head (infants)

Investigations to consider

  • magnetic resonance spectroscopy (MRS)
  • lumbar puncture (LP) with cerebrospinal fluid (CSF) analysis
  • CT chest, abdomen, and pelvis
  • bone scan
  • mammogram

Treatment algorithm



Department of Neurosurgery

SUNY Upstate Medical University




WAH is an author of a number of references cited in this topic.

Dr Walter A. Hall would like to gratefully acknowledge Dr Peter D. Kim, a previous contributor to this topic. PDK declares that he has no competing interests.

Peer reviewersVIEW ALL

Professor and Head

Department of Neurosurgery

University of Minnesota




SH and WAH were colleagues on a faculty of the University of Minnesota between 1991 and 1997 and again between 2004 and 2006. They have coauthored articles on neurosurgical infection.

Staff Physician

Department of Neurological Sciences

Institute of Neurology C. Mondino




SR declares that she has no competing interests.

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