Diphtheria

Original article by Lily Stanley | Last updated on 27/9/2016
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Organism

Cornynebacterium diptheriae
Incubation; 2-5 days
 

Transmission

Droplet spread – from nasopharynx of case or carrier.
 

Epidemiology

  • Death rate is 10%(higher in children under 5 and adults over 40).
  • Immunity (natural/vaccine-induced) does not prevent carriage.
  • Up to 5% healthy population in endemic areas test positive from pharyngeal cultures.
  • Largely been eradicated in the developed countries through vaccination programmes.
 

Pathogenesis

Organism usually infects the epithelium of the skin and the mucosa of the upper respiratory tract (classically tonsils and pharynx)
  • inflammation of tissues
  • Bacteria secrete exotoxin which interferes with cell protein synthesis(àtissue necrosis) and call interfere with local neurological supply of palate and hypopharynx(àparalysis)
  • build-up of inflammatory cells, necrotic epithelial cells, and bacteria debrisà form the characteristic adherent gray/black, tough, fiber-like covering( pseudomembrane).
  • Inflammation, pseudomembrane formation and paralysis can combine to result in Airway obstruction
  • systemic spread of the toxin in the bloodstream  can injure  the kidneys, heart, and brain.


[image from Illnois Department of Public Health, courtesy of US Centers for Disease Prevention and Control]

Diagnosis

Culture from throat or nasal swabs (toxin studies must be performed)
**do not delay treatment to wait for diagnosis
 

Treatment

Penicillin/erythromycin
Isolation
Cardiac monitor
 

Prevention

DTP (diphtheria–pertussistetanus) vaccination is recommended for all school-age children.