DESCRIPTION

Inflammation of the tissues surrounding the brain or spinal cord, usually caused by viruses or bacteria; rarely, fungi or parasites

EPIDEMIOLOGY

• Viral meningitis
  • Most common agent in all age groups
  • Enteroviruses are the most common isolated viruses and tend to occur in outbreaks in summer and early fall.
• 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.
• Fungal meningitis
  • Rare cases in healthy children
  • Cryptococcus neoformans is a budding encapsulated yeast-like organism found in soil and avian excreta; associated with immunocompromised patients
  • 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.

ETIOLOGY

• 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
• 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, Haemophilus influenzae type b (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.
• 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

GENERAL PREVENTION

• Hib vaccine has significantly reduced the incidence of meningitis and other invasive Hib infections by up to 99%.
• 13-valent, 15-valent, or 20-valent pneumococcal conjugate vaccine (PCV13, PCV15, or PCV20, respectively) for use in all infants given at 2, 4, 6, and 12 to 15 months of age; vaccination started with PCV13 may be completed with PCV15 or PCV20.
• Quadrivalent meningococcal conjugate vaccine for serogroups A, C, Y, and W-135 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. At-risk populations should receive multiple doses per specific product dosage recommendations and age.
• Children with anatomic or functional asplenia or persistent complement deficiency should be considered for meningococcal serogroup B vaccines and 23-valent pneumococcal polysaccharide vaccine (PPSV23) after complete of the PCV13 series.