DESCRIPTION

A systemic infection caused by the relatively fastidious gram-negative diplococcus Neisseria meningitidis. Despite treatment with appropriate antibiotics, this disease may have a fulminant course (i.e., significant complications within hours of presentation) with a high likelihood of mortality.

EPIDEMIOLOGY

• The rates of meningococcal disease in the United States have been declining since the 1990s. In 2015, there were 375 cases with an annual incidence of 0.18 cases per 100,000.
• In North America, infants and children are most often affected, with a secondary peak occurring in adolescents, who are the population predominantly responsible for disease carriage. Indeed, it has been shown that 23.7% of adolescents carry meningococcus in their nasopharynx.
• The disease occurs most commonly in winter and spring months.
• Increased disease activity may follow an influenza A outbreak.
• 13 serogroups have been described on the basis of capsular polysaccharide antigens.
  • In the United States, serogroup B causes approximately 60% of cases in children <5 years of age.
  • Serogroups C, Y, or W cause approximately 2/3 cases of meningococcal disease among persons 11 years old and older.

RISK-FACTORS

• Patients with asplenia, deficiencies of properdin C3, or a terminal complement component (C5 to C9), and HIV are at increased risk for invasive and recurrent disease.
• People who take eculizumab for treatment of atypical hemolytic uremic syndrome or paroxysmal nocturnal hemoglobinuria are also at increased risk.
• Other risk groups include microbiologists who are routinely exposed to isolates of N. meningitidis, military recruits, college students living in residence halls, and those traveling to a country where meningococcal disease is endemic.
• Organism virulence factors, such as differences in the bacterial cell wall lipopolysaccharide, play a role in disease severity. Less virulent organisms are more likely in chronic meningococcemia, which has a favorable prognosis.

GENERAL-PREVENTION

• Exposed contacts, including household, day care, and nursery school, should receive the following:
  • Rifampin, 10 mg/kg (maximum 600 mg) PO q12h for 4 doses
  • Contacts <1 month of age should receive rifampin 5 mg/kg PO q12h for 4 doses.
  • Alternatively, ceftriaxone is also effective prophylaxis for contacts ≤15 years of age; a single dose of 125 mg IM is recommended.
  • For contacts >15 years old, ceftriaxone 250 mg IM is recommended. Its safety profile is preferred for pregnant women.
• Medical personnel should receive prophylaxis only if they had close contact with respiratory secretions.
• Vaccines for types A, B, C, W, and Y are available and produce an immune response in 10 to 14 days.
• A tetravalent conjugate meningococcal vaccine, MCV4, is licensed for use in people in the age range of 2 to 55 years. It is recommended in all unimmunized 11- to 12-year-old adolescents, with a booster dose at age 16 years.
• Serotype B vaccine was recently approved by the U.S. Food and Drug Administration (FDA) and is licensed for use in people 10 to 25 years of age. The Centers for Disease Control and Prevention (CDC) recommends that:
  • All adolescents and young adults aged 16 to 23 years may be vaccinated, ideally at aged 16 to 18 years, to give protection during this stage of increased risk.
  • Certain adolescents and young adults should receive this vaccine. This includes those identified at increased risk at times of an outbreak and those with medical conditions, including complement deficiencies and functional or anatomic asplenia.
• The CDC continues to recommend routine adolescent immunization with the exception of persons with a history of Guillain-Barré syndrome (GBS) who are not in a high-risk group for invasive meningococcal disease. An updated fact sheet on GBS and MCV4 is available at: https://www.cdc.gov/vaccinesafety/concerns/history/gbs-menactra-faqs.html. Two large studies published in 2012 did not support an association between GBS and MCV4 vaccination.

PATHOPHYSIOLOGY

• Fulminant disease is signified by diffuse microvascular damage and disseminated intravascular coagulation (DIC); see “Diagnosis” section.
• Death results from effects of endotoxic shock, including circulatory collapse and myocardial dysfunction.

ETIOLOGY

• Colonization and infection of the upper respiratory tract occurs after inhalation of, or direct contact with, the organism, usually in oral secretions.
• Disseminated disease occurs when the organism penetrates the nasal mucosa and enters the bloodstream, where it replicates.

ASSOCIATED-CONDITIONS

• Terminal complement deficiencies
• Asplenia
• HIV disease