General and Operative Surgery · MU Plovdiv

54. Tetanus – clinic, treatment and prevention.

Inside: 6 sections · 1 table · 17 flashcards · 6 min

Topic 54 of 77 in the MU Plovdiv syllabus for General and Operative Surgery (Medicine, Year 3). The free AceMed note covers it in 6 sections, about 874 words (6 min of reading), with 17 flashcards.

In this note

  1. Introduction
  2. Pathogenesis and clinical picture
  3. Diagnosis and differential diagnosis
  4. Treatment
  5. Prevention
  6. Complications and prognosis

Introduction

Tetanus is an acute, toxin-mediated disease of the nervous system caused by Clostridium tetani. It is almost always acquired through a wound, so it is a classic surgical infection, and it is fully preventable by vaccination. A good exam answer covers the causative agent and pathogenesis, the clinical forms and severity, diagnosis with differential diagnosis, intensive treatment including wound surgery, and prevention.

Pathogenesis and clinical picture

Clostridium tetani is a gram-positive, spore-forming, obligate anaerobic rod with a characteristic drumstick appearance. Its spores are widespread in soil, dust and animal faeces and survive for years. Disease develops when spores germinate in devitalised tissue with low oxygen tension, such as puncture wounds, crush injuries, burns, frostbite, necrotic tissue, dental infection, chronic ulcers, contaminated injections and the umbilical stump in neonates. The damage is caused by the exotoxin tetanospasmin, not by tissue invasion.

  • The toxin binds to motor nerve terminals and travels by retrograde axonal transport to the spinal cord and brainstem.
  • It cleaves synaptobrevin and blocks the release of the inhibitory transmitters glycine and GABA in the spinal cord.
  • The result is unopposed motor neuron firing, causing rigidity and painful spasms, plus autonomic overactivity from catecholamine release. Consciousness and sensation are preserved.
  • Generalised tetanus is the most common form. Localised tetanus involves only muscles near the wound and may progress. Cephalic tetanus produces cranial nerve palsies after a head or ear wound. Neonatal tetanus follows poor cord care in an unvaccinated mother.
  • The incubation period is usually 3 to 21 days; a shorter incubation period indicates a worse prognosis.
  • The first sign is usually trismus (lockjaw), followed by risus sardonicus, dysphagia and neck stiffness.
  • Spasms are triggered by light, noise or touch. Opisthotonus and board-like abdominal rigidity may develop.
  • Laryngospasm and respiratory failure are the main threats to life.
  • Autonomic signs include tachycardia, labile hypertension, sweating, fever and arrhythmias.

The severity of generalised tetanus is graded by the Ablett classification:

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