Medical Archive

Definition

Etiology and microbiology

TABLE 150-1 Structure of the Polysaccharide Capsule of Common Disease-Causing Meningococci

Meningococcal Capsular Group	Chemical Structure of Oligosaccharide	Current Disease Epidemiology
A	2-Acetamido-2-deoxy-D-mannopyranosyl phosphate	Epidemic disease mainly in sub-Saharan Africa; sporadic cases worldwide
B	?-2,8-N-acetylneuraminic acid	Sporadic cases worldwide; propensity to cause hyperendemic disease
C	?-2,9-O-acetylneuraminic acid	Small outbreaks and sporadic disease
Y	4-O-?-D-glucopyranosyl-N-acetylneuraminic acid	Sporadic disease and occasional small institutional outbreaks
W	4-O-?-D-galactopyranosyl-N-acetylneuraminic acid	Sporadic disease; outbreaks of disease associated with mass gatherings;epidemics in sub-Saharan Africa
X	(?1?4) N-acetyl-D- glucosamine-1-phosphate	Sporadic disease and large outbreaks in the meningitis belt of Africa

Meningococci metabolize glucose and maltose, produce IgA protease. 
Capsule(+), pilus(-)

GRAM : WBC ? intracellular G(-) diplococci, Ab? false negative??
Culture: gold standard. By Thayer-Martin medium
Inhibit G+ with Vancomycin / G- with  and Colistin / Fungi with Nystatin

Antigenic variation? ??? vaccine??? ???. 

Virulence factors
Pili on the capsular surface
Attachment and colonization of the nasopharynx
A, C, W, Y? ???? ?? B? ??.
IgA protease, capsular polysaccharide, lipo-oligosaccharide(endotoxin), Opa-protein(aid in endothelial attachment, and invasion)

Epidemiology

Patterns of disease

Factors associated with disease risk and susceptibility

Pathogenesis

Transmission risk

7 days prior to symptom onset ~ 24 hours after initiating appropriate antibiotic therapy.

Transmission route

1. Aerosolized droplets
2. Nasopharynx
   • Colonization using fimbriae and pili
   • Asymptomatic carrier state
3. Blood
   • ~0.2%, bacteria penetrate the epithelium and enter bloodstream.
4. Choroid plexus
5. Meninges

Clinical manifestations

• Key features distinguishing meningococcal disease from more benign illnesses
  • Severe myalgias (eg, diffuse leg pain)
  • Signs of poor perfusion reflecting myocardial depression
    • Cold hands/feet
    • Mottled skin or pallor
  • Symptoms progress rapidly over 12-24 hours -> altered mental status
• These features likely reflect the significant inflammatory response.

Rash

Petechial/purpuric rash

Meningitis

• Nonsuppurative pharyngitis
  • Rare presentation of meningococcal meningitis that may be mistaken for streptococcal or viral pharyngitis
  • Rapid disease progression (<12hrs)

Septicemia

Petechial hemorrhages and gangrene of toes

Chronic meningococcemia

Postmeningococcal reactive disease

Diagnosis

Treatment

3?? Cefa. ??? ??? 2?? Rifampin ?????

Complications

Waterhous-Friderichsen syndrome
Adrenal insufficiency, fever, DIC, shock

Prognosis

Prevention

Serotype A, C, W, Y vacine
MenACWY-CRM(Menveo), MenACWY-D(Menactra)

All patients age 11-18
2-dose series at 11-12 years, 16 years

Polysaccharide vaccines

Conjugate vaccines

Vaccines based on subcapsular antigens

Management of contacts

Antimicrobial chemophylaxis should be given to asymptomatic close contacts, regardless of vaccination status, who have had exposure during this period.

• Close contacts
  • During the 7 days before symptom onset until 24 hours after appropriate antibiotic initiation.
  • Household contacts and roommates
  • Intimate partners, caretakers, and anyone with prolonged (?8 hours) exposure.
• Regimen
  • Rifampin
  • Ceftriaxone
  • Ciprofloxacin (in adults)
  • Ideally within a day of diagnosis but up to 2 weeks.