Tetanus

Original article by Lily Stanley | Last updated on 7/6/2014
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Organism

Clostridium tetani=gram positive, spore forming bacteria
Incubation period; varies according to site of injury, shorter (approx. 1 week in severe disease)
 

Transmission

Spores of c.tetani live in faeces, soil and dustàcan be introduced by small break in skin/via mucosa.
**Tetanus is only infectious vaccine preventable disease that isnt contagious
 

Epidemiology

Occurs worldwide
Now almost exclusively affects those not vaccinated
more common in
  • Hot, damp climates.
  • Those who work in agriculture (manure).
  • Heroin users (spores can be found in contaminated heroin)
WHO estimates 59,000 newborns worldwide died in 2008 as a result of neonatal tetanus.
 

Pathogenesis

Spores germinate in anaerobic conditions at wound site and produce neurotoxinsàtoxins travel up peripheral nerves and cleaves the protein that allows fusion oif the synaptic vesicle with the membraneàprevents transmitter release.
 
Primarily affects inhibitory glycine or GABAàleads to less inhibition(relaxation)àincreased firingàcontraction skeletal musle.
 

Clinical features

  • Prodrome:fever, malaise, headache
  • Trismus (lock jaw)
  • Risus sardonicus (grinding expression of facial muscles)
  • Opisthotonus (arching of body with neck hyper-extension)
  • Spasms- initially induced by movement/noise but later spontaeaous.
  • Autonomic dysfuction (arrhythmias and BP fluctuations)


[image from Wikipedia]

 

Complications

Spasms may cause dysphagia or respiratory arrest
 

Diagnosis

Usually clinical - "spatula test" =clinical test for tetanus (high specificity and a high sensitivity) - touching the posterior pharyngeal wall with spatula
  • Positive= involuntary contraction of the jaw (biting down)
  • Negative= gag reflex
 

Treatment

  • Clean the wound
  • Metronidazole (clears the bacteria but has not effect on toxin)
  • Tetanus immunoglobulin IM/IV
  • Diazepam/magnesium- to prevent muscle spasm
  • May require nutiritional and ventilator support
 

Prevention

Vaccination
  • with tetanus toxoid (+booster every 10 years)
  • part of the routine DTP vaccine in children in the UK