Meningococcemia

Basics

Description

  • Bacterial illness caused by gram negative Neisseria Meningitidis
  • Presentation may range from mild/self-limited vs severe illness
  • Septic shock and meningitis/encephalitis are most dangerous forms
  • Chronic/occult meningococcemia possible
  • Septic arthritis and other organ manifestations
  • Acquired from close contact with an infected individual or an asymptomatic carrier

Etiology And Epidemiology

  • N. meningitidis:
    • Multiple serotypes, though 1 type is no more virulent than another
    • B, C, W are most reported in North America
    • Majority of infections caused by A, B, C, X, Y, and W135
  • Bacteria attach to and enter nasopharyngeal epithelial cells
  • Bacteria spread from the nasopharynx through the bloodstream via entry of vascular endothelium
  • Most circulating meningococci are eliminated by the spleen
  • Meningococci produce an endotoxin (lipooligosaccharide):
    • Involved in pathogenesis of the skin, adrenal manifestations, and vascular collapse
  • Human oropharynx/nasopharynx is the only reservoir
  • Carrier usually has developed immunity to serotype-specific antibody (not immune to all serotypes):
    • Age: Most common <1 yr old, 16–44, >85 yr old
    • Risk factors: Close contact, asplenia, HIV+ status, passive smoke exposure, crowded living environments, taking complement inhibitors including eculizumab, etc.
    • Consider migrant/refugee communities, especially if unvaccinated
    • Lower rate of immunity in children, and asplenic individuals
  • Most common in fall and spring
  • Increased incidence in military recruits and close living conditions
  • Epidemics—ages 5–9 yr most/earliest affected

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