Description

• Caused by Neisseria meningitidis in the blood, which results in a broad spectrum of clinical manifestations
• Bacteremia without sepsis: Meningococcal bacteremia rarely occurs without sepsis.
• Bacteremia without meningitis: Patient is acutely ill and may have skin manifestations (rashes, petechiae, and ecchymosis) and hypotension.
• Bacteremia with meningitis:
  • Predominant clinical picture of meningitis: Sudden onset of fever, nausea, vomiting, headache, decreased ability to concentrate, and myalgias
  • Disease progression is usually quite rapid with a transition from health to severe disease in a matter of hours.
  • Skin manifestations and hypotension may also be present:
    • A petechial rash appears as discrete lesions 1–2 mm in diameter, most frequently on the trunk and lower portions of the body and will be seen in >50% of patients on presentation.
    • Purpura fulminans is a severe complication of meningococcal disease and occurs in up to 25% of cases. It is characterized by acute onset of cutaneous hemorrhage and necrosis due to vascular thrombosis and disseminated intravascular coagulopathy.

Epidemiology

• The US mortality rate is 0.5–1.1/100,000, or ∼13%:
  • 11–19% of survivors suffer serious sequelae, including deafness, neurologic deficit, or limb loss.
• Disease is seasonal, with cases peaking in December and January.
• Annually, ~1,000 cases of invasive meningococcal disease occur in the US (1):
  • Among adolescents and young adults, 14–24, occurrence is 20%.
  • Among infants <1 year, occurrence is 16%.

Risk Factors

• Age: 3 months–1 year
• Late complement component deficiency (C5, C6, C7, C8, or C9)
• Asplenia (1)
• Close contacts (e.g., household, nurseries, day care, dormitories, military barracks)
• Exposure to active and passive tobacco smoke (1)

Genetics
Late complement component deficiency has an autosomal-recessive inheritance.

General Prevention

• 2 vaccines are currently licensed for use in the US. Each contains antigens to serogroups A, C, Y, and W-135. Neither provides immunity against serotype B, which is responsible for 1/3 of US cases (2):
  • Meningococcal polysaccharide vaccine (MPSV4): Recommended for patients ≥55 with elevated risk (1):
    • Duration of protection is short: 1–3 years for patients <5 years; 3–5 years for adolescents and adults (2)
    • Reasonable for patients requiring short protection such as those traveling to endemic areas, college freshmen, those experiencing community outbreaks (2)
  • Meningococcal conjugate vaccine (MCV4): Recommended for patients 2–55 (1)
• Protective levels of antibody are achieved in ∼7–10 days after primary immunization (2).
• Vaccine is recommended for all persons 11–18 and persons 19–55 at increased risk for the disease:
  • Guillain-Barré syndrome has been associated with the MCV4 vaccine, so a personal history of Guillain-Barré is a relative contraindication for receiving this vaccine.
• CDC International Travel Advisory:
  • Vaccine is required by the Government of Saudi Arabia for Hajj pilgrims >2.
  • The vaccine should be given to travelers to sub-Saharan Africa (“meningitis belt”) during dry season.

Etiology

• Neisseria meningitidis, a gram-negative diplococcus with at least 13 serotypes
• Major serogroups in the US: B, C, Y, and W-135:
  • Serogroup B is the predominant cause of meningococcemia in children <1 year.
  • Serogroup C is the most common cause of cases in the US.
  • Serogroup Y is the predominant cause of meningococcemia in the elderly (2).
• Major serogroups worldwide are A, B, C, Y, and W-135:
  • W-135 is the major cause of disease in the “meningitis belt” of sub-Saharan Africa.