Acute disease caused by neurotoxins from the bacterium Clostridium tetani
Aetiology
C. tetani toxin
C. tetani = anaerobic gram positive with terminal spore
Risk factors
A high risk is associated with wounds contaminated with garden soil, manure or caused by rusty metals
Can also complicate ulcers, gangrene, burns, snakebites, septic abortion and poor obstetric techniques (tetanus neonatorum)
Pathophysiology
C. tetani spores found in soil, enter the body through broken skin
Incubation period - 4 days to several weeks
Toxin binds to inhibitory neurons, preventing release of inhibitory neurotransmitters → widespread activation of motor neurons and spasming of muscles throughout the body
Clinical features
Toxin-mediated generalised tetanus is the most common presentation
Descending pattern of symptoms following prodromal malaise and fever
Muscular spasms, abdominal rigidity, dysphagia, opisthotonus, trismus and 'risus sardonicus'
Can lead to aspiration pneumonia, fractures, laryngospasm (causing asphyxia) and respiratory failure