Inflammation of the membranes of the brain or spinal cord, usually caused by viruses or bacteria and, rarely, fungi or parasites


  • Bacterial meningitis
    • Most common agents in children of all ages include Streptococcus pneumoniae and Neisseria meningitidis.
    • Underlying host factors, age, exposure, and geographic location alter incidence and pathogen.
  • Viral meningitis
    • Most common agent in all age groups
    • Most common isolated viruses are enteroviruses that tend to occur in outbreaks in summer and early fall.
  • Fungal meningitis
    • Cryptococcus neoformans is a budding encapsulated yeast-like organism found in soil and avian excreta; associated with immunocompromised patients (especially AIDS), rare cases in healthy children
    • Candida species occurs in immunocompromised patients and ill premature infants.
  • Tuberculous meningitis
    • Mycobacterium tuberculosis (TB) meningitis occurs in 0.5% of untreated primary TB infections.
    • Most common in children aged 6 months to 4 years
    • In ~50% of cases, miliary TB is accompanied by meningitis.


  • Haemophilus influenzae type b (Hib) vaccine has significantly reduced the incidence of meningitis and other invasive Hib infections by up to 99%.
  • 13-valent pneumococcal conjugate vaccine (PCV13) for use in all infants given at 2, 4, 6, and 12 to 15 months of age
  • Quadrivalent meningococcal vaccine for serogroups A, C, Y, and W is recommended for all patients ≥11 years of age and select at-risk populations <11 years. A booster dose is recommended for all patients who receive the first dose of the vaccine between 11 and 15 years of age.
  • Children with anatomic or functional asplenia or persistent complement deficiency should be considered for meningococcal serogroup B vaccines.


  • Bacterial
    • Cause differs depending on age:
      • <1 month old: group B Streptococcus, gram-negative pathogens (Escherichia coli, Citrobacter koseri, Cronobacter sakazakii, Serratia marcescens, and Salmonella species), Listeria monocytogenes, S. pneumoniae
      • 1 to 3 months old: group B Streptococcus, E. coli, S. pneumoniae, Hib
      • 3 months to 5 years old: S. pneumoniae, N. meningitidis, Hib
      • >5 years old: S. pneumoniae, N. meningitidis
      • Consider Hib in unvaccinated patients of any age.
  • Viral
    • Herpes simplex virus (HSV) in the neonatal population
    • Enteroviruses: ∼70 different strains that include polioviruses, coxsackie A, coxsackie B, and echoviruses. Recently discovered enteroviruses are not placed in these four groups but are numbered (e.g., enterovirus 68).
    • Other, less common: arboviruses (e.g., West Nile virus), mumps
  • Fungal
    • Fungi most commonly isolated include Candida species, Coccidioides immitis, C. neoformans, and Aspergillus species.
  • Aseptic meningitis
    • Agents not easily cultured in the viral or microbiology laboratory can cause meningitis and include Borrelia burgdorferi (Lyme disease) and Treponema pallidum (syphilis).
  • Tuberculous meningitis
  • Unusual pathogens more likely in immunocompromised patients

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