Description

• Meningococcemia is a blood-borne infection caused by Neisseria meningitidis.
• Bacteremia without meningitis: Patient is acutely ill and may have skin manifestations (rashes, petechiae, and ecchymosis) and hypotension. Bacteremia with meningitis: sudden onset of fever, nausea, vomiting, headache, decreased ability to concentrate, and myalgias
• Disease progresses rapidly (within hours).
• Skin findings and hypotension may be present.
  • A petechial rash appears as discrete lesions 1 to 2 mm in diameter; most frequently on the trunk and lower portions of the body; seen in >50% of the 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

Incidence

• The mortality rate is ~13%.
  • 11–19% of survivors suffer serious sequelae, including deafness, neurologic deficits, or limb loss.
• Disease is seasonal and peaks in December/January.
• Atypical clinical presentations include abdominal symptoms, septic arthritis, and bacteremic pneumonia.
• Peak incidence occurs in the 1st year of life; 35–40% of cases occur in children aged <5 years. A second peak occurs in adolescence.
• In 2017 (most recent CDC data), there were <350 cases of reported meningococcal disease (incidence rate of 0.18 cases per 100,000 persons) (1); most common in adolescents and young adults, followed by infants aged <1 year

Etiology and Pathophysiology

• N. meningitidis is a fastidious, aerobic, gram-negative diplococcus with at least 13 serotypes.
• N. meningitidis has an outer coat that produces disease-causing endotoxin. Virulence factors promote invasive disease.
• Humans are the only known reservoir for N. meningitidis.
• Major serogroups in the United States are B, C, Y, and W-135.
  • Serogroup B is the predominant cause of meningococcemia in children aged <1 year.
  • Serogroup C is the most common cause of meningococcal disease in the United States.
  • 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.

Genetics
Late complement component deficiency has an autosomal recessive inheritance.

Risk Factors

• Age: 3 months to 1 year
• Late complement component deficiency (C5, C6, C7, C8, or C9)
• Asplenia (1)
• Living in close quarters (e.g., household contacts, nursery/daycare, dormitories, military barracks)
• Exposure to active (and/or) passive tobacco smoke (1)

General Prevention

• Two vaccines are currently licensed for use in the United States. Each contains antigens to serogroups A, C, Y, and W-135. Neither provides immunity against serotype B, which is responsible for 1/3 of U.S. cases.
  • Meningococcal polysaccharide vaccine (MPSV-4): recommended for patients aged ≥55 years at elevated risk (1)
    • Short duration of protection: 1 to 3 years for patients aged <5 years; 3 to 5 years for adolescents and adults
    • Often used when traveling to endemic areas, college freshmen, community outbreaks
  • Meningococcal conjugate vaccine (MCV-4; MenACWY) (1):
    • Routine immunization is recommended for all children aged 11 to 18 years.
    • Immunization is recommended for those aged 2 to 55 years with increased risk for meningococcal disease.
    • Guillain-Barré syndrome has been associated with the MCV-4 vaccine.
• The FDA has licensed two serogroup B meningococcal (MenB) vaccines. The first (MenB-FHbp) is a 3-dose series. The second (MenB-4C) is a 2-dose series. Both vaccines were approved for use in persons aged 10 to 25 years. Individuals aged ≥10 years who are at increased risk for meningococcal disease due to persistent complement component deficiencies, anatomic or functional asplenia, should receive MenB vaccine.
• Protective levels of antibody are achieved ~7 to 10 days after primary immunization (2).
• CDC international travel advisory: Vaccine is required for Hajj pilgrims >2 years of age; given to travelers to sub-Saharan Africa (“meningitis belt”)