Tetanus

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