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Meningococcal Meningitis

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Meningococcal Meningitis, Neisseria Meningitidis, Meningococcus, Meningococcemia, Waterhouse-Friderichsen Syndrome

  • See also
  1. Bacterial Meningitis
  • Epidemiology
  1. Most common in young adults and children with bimodal peak
    1. Age under 2 years accounts for 50% of cases
    2. Also peaks in teens
  2. Incidence
    1. Among top 2 causes of Bacterial Meningitis in U.S. (other is Streptococcal Pneumoniae Meningitis)
    2. Up to 2800 cases per year per year in the U.S.
    3. One case per 100,000 people
  3. Exposure risks
    1. Sporadic cases are most common
    2. Outbreaks in close quarters (e.g. Dormitory)
  • Pathophysiology
  1. Neisseria Meningitidis
    1. Gram Negative Cocci in pairs (diplococci)
    2. Normal oral flora in 5-10% (provides carriers natural Immunity after age 2 years)
  2. Transmission
    1. Respiratory secretions passed via aerosol or contact
  3. Polysaccharide capsule surrounds Neisseria Meningitidis
    1. Resistant to Phagocytosis in the absence of Opsonins (antibodies to capsule)
    2. Capsular Polysaccharides may become Antigens for Antibody response
    3. Serogroups are defined by the specific capsular Polysaccharides (13 have been defined)
      1. Meningitis is most commonly caused by serogroups A, B, C, as well as W-135, Y
  4. Endotoxin
    1. Lipopolysaccharide Endotoxin is released from Meningococcus
    2. Triggers vascular necrosis, Petechiae, Hemorrhage and Sepsis
  5. IgA1 Protease
    1. Enzyme expressed by some pathologic Meningococcus
    2. Lyses IgA in half
  6. Pili
    1. Allow Neisseria to adhere to the nasopharynx
    2. May also act as Antigen targets for immune response
  7. Other pathogenic mechanisms
    1. Extracts iron from human Transferrin
  • Risk Factors
  1. Infants age 6 months to 2 years
    1. Vertical transmission of maternal Antibody provides protection for first few months
  2. Living in college dormitory or military barracks
    1. High rates of exposure to Meningococcus carriers with a wide variety of strains
  3. More common in white males
  4. Tobacco use or passive Tobacco exposure
  5. Recent Upper Respiratory Infection
  • Precautions
  • Presentations may be cryptic
  1. Nuchal Rigidity may be absent
  2. Severe Upper Respiratory Infection may be only initial presentation
  3. Petechiae and fever confers a 10-15% risk of Meningococcemia
  4. May present with concurrent other infections (e.g. Otitis Media, Conjunctivitis, Pneumonia)
  • Symptoms
  1. Headache
  2. Myalgias or Arthralgias
  3. Vomiting
  • Signs
  1. See Meningitis
  2. Fever
  3. Nuchal Rigidity may be absent
  4. Rash (70% of cases)
    1. Centripetal Rash (starts on distal extremities, wrists and ankles)
    2. May start with light pink maculopapular rash (may even blanch initially)
    3. Petechiae (non-blanching) are common
      1. If biopsied and cultures, petechial lesions will yield diplococci
    4. Fulminant Purpura (20% of cases)
      1. Central gun-metal gray center
  • Findings
  • Clinical Syndromes
  1. Meningococcemia
    1. Bacteremia resulting in toxic appearance, fever, chills, myalgias and petechial rash
  2. Waterhouse-Friderichsen Syndrome
    1. Fulminant Meningococcemia with bilateral adrenal Hemorrhage and Adrenal Insufficiency
    2. Presents with rapid progression within hours, Septic Shock, DIC, coma and very high mortality
  3. Bacterial Meningitis
    1. Most common presentation of Neisseria Meningitidis, typically combined with Meningococcemia
  • Labs
  1. See Bacterial Meningitis
  2. Gram Stain
    1. Neisseria Meningitidis appears as Gram Negative diplocci under microscopy
    2. Each coccus is Kidney bean shaped, with pairs facing and overlapping one another
  3. Polymerase chain reaction (PCR)
    1. Neisseria Meningitidis may be identified from body fluids (e.g. blood, CSF)
  4. Culture
    1. Blood Agar Plates ("Chocolate agar")
      1. Named for the brown coloration after agar plates are heated
      2. Neisseria grow well on blood agar
    2. Thayer-Martin VCN Media
      1. Chocolate agar with 3 antimicrobials: Vancomycin, Colistin (Polymixin), Nystatin
      2. Antimicrobials kill all Gram Negatives except Neisseria, and all Gram Positives and fungi
    3. High CO2 Environment
      1. High CO2 concentrations further selects for Neisseria growth
    4. Acid production from Maltose Metabolism
      1. Distinguishes Neisseria Meningitidis (metabolizes maltose) from N. gonorrhoeae
  • Management
  1. See Bacterial Meningitis Management
  2. If considered, obtain Lumbar Puncture and start empiric Antibiotics immediately
  3. Manage shock
    1. See Sepsis (covers fluid boluses and pressor use)
    2. Consider adding Corticosteroids to the Antibiotic regimen
      1. Meningococcus may be associated with adrenal infarction Hemorrhage
  • Complications
  1. Waterhouse-Friderichsen Syndrome
    1. Shock, Petechiae and adrenal infarction (bilateral adrenal Hemorrhage)
  • Prevention
  1. See Meningococcal Vaccine
  2. Vaccination does on confer 100% protection (misses some sub-groups)
    1. Known exposures to Meningococcal Meningitis need Antibiotic prophylaxis despite Immunization
  1. Indications
    1. Exposure from 7 days before onset of illness until 24 hours after Antibiotics initiated AND
    2. Significant exposure (treat if any concern)
      1. Household contacts (up to 800 fold increase in risk, up to 1 in 250 will be infected)
      2. Child care centers
      3. Oral secretion exposure (e.g. health care worker without adequate protection)
      4. Long-distance (>8 hours) travel next to source
  2. Prophylaxis options (pick one): Start as soon as possible (up to 14 days after exposure)
    1. Rifampin
      1. Age <1 month: 5 mg/kg orally every 12 hours for 2 days
      2. Age >1 month: 10 mg/kg (max: 600) orally every 12 hours for 2 days
      3. Adults: 600 mg orally every 12 hours for 2 days
    2. Ciprofloxacin (adults) 500 mg orally for one dose
    3. Ceftriaxone (Rocephin)
      1. Age <15 years: 125 mg IM for one dose
      2. Age >15 years: 250 mg IM for one dose
  3. References
    1. Bilukha (2005) MMWR Recomm Rep 54:1-21 [PubMed]
  • Prognosis
  1. Mortality: Approaches 14% despite treatment
  2. Serious residual morbidity approaches 19%
  • References
  1. Claudius in Herbert (2012) EM:Rap 12(11): 8
  2. Kimmel (2005) Am Fam Physician 72:2049-56 [PubMed]