Tetanus (& Prophylaxis)

Background

• Thanks to childhood vaccination against tetanus, tetanus is now extremely rare in the UK (only 3-8 cases/year)
• The causative organism, Clostridium tetani, is a spore-forming gram-positive obligate anaerobe which can grow in necrotic tissue, infected tissue or in foreign bodies.  There is produces tetanospasmin toxin which can spread via blood/lymph and can cause irreversible damage to neurons, causing characteristic muscle spasm/rigidity
  • Spores may be found in garden soils/manure, rusty metals
  • Incubation time can be 7-10 days

Presentation

• Classically presents with generalised (descending) tetanus
  • Trismus (lockjaw) and risus sardonicus (grimace of the face)
  • Neck stiffness/spasticity (can develop into opisthotonus- arched body with hyperextended neck)
  • Swallowing problems, abdominal rigidity and muscle spasms may also develop
• Spasms (initially reflexive, then spontaneous) can last seconds to minutes and can be painful and exhausting
  • Patients often die of complications of these e.g. exhaustion, aspiration pneumonia or asphyxia

Diagnosis is usually clinical and rarely are any investigations required for diagnosis.

Management

Tetanus

• Give human tetanus immunoglobulin first
• Debride any wounds after a few hours (risk of toxin spread)
• Benzypenicillin 600mg IV QDS is often used (metronidazole if allergic)
• IV diazepam may help control spasms, if not- consider paralysing the patient and ventilating

Tetanus prone wounds (far more common)

• These are wounds/burns sustained >6 hours before surgical treatment or on with
  • a significant degree of devitalised tissue or a puncture wound
    • especially if there has been contact with soil/manure
  • foreign bodies
  • compound fractures
  • clinical evidence of sepsis
• If the wound is high risk (i.e. deep wound or known to be contaminated with soil/manure/rust), patient should be given anti tetanus immunoglobulin
  • If the patient has not been vaccinated it is recommended that the patient also receive anti-tetanus toxoid also
• If the wound is tetanus-prone but not high risk, IM anti-toxoid (250IU/5ml/750mg) should be given
• Thorough wound debridement and cleansing is important