USMLE

Clostridium tetani

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Bacteria - Gram Positive
  1. Staph aureus: Overview
  2. Staph aureus: Presentation
  3. Methicillin-Resistant Staph aureus (MRSA)
  4. Staph saprophyticus
  5. Strep pneumoniae: Overview
  6. Strep pneumoniae: Presentation
  7. Strep viridans
  8. Strep pyogenes: Overview
  9. Strep pyogenes: Presentation
  10. Strep agalactiae
  11. Strep bovis
  12. Enterococcus
  13. Bacillus anthracis
  14. Bacillus cereus
  15. Clostridium tetani
  16. Clostridium perfringens
  17. Clostridium botulinum
  18. Clostridium difficile
  19. Corynebacterium diphtheriae
  20. Listeria monocytogenes
  21. Nocardia
  22. Actinomyces

Clostridium tetani 

  • Characteristics
    • Common to all bacteria in Clostridia family
    • Gram + rods
    • Obligate anaerobic
    • Spore-forming
  • Produces tetanospasmin (toxin)
    • Blocks release of GABA and glycine (inhibitory neurotransmitters) in spinal neurons that regulate motor neurons
      • Removal of inhibition causes increased muscle activation (spasms)
  • Exposure
    • Trauma (piercing/puncture wound)
      • Occurs in people who have not be vaccinated
  • Presentation: tetanus
    • trismus (lockjaw)
    • sardonic smile
      • Also called risus sardonicus (raised eyebrows and open grin)
    • muscle spasms
      • Includes opisthotonos (spasms of spinal extensors)
    • irritability
    • neonatal tetanus 
      • colonization of the umbilical stump in neonates born to unvaccinated mothers
      • inability to suck or cry after day 2 of life
  • Treatment
    • Prevent with tetanus toxoid vaccine
      • Elicits humoral (antibody) immunity to tetanus toxin (tetanospasmin)
      • More common in developing countries due to low rates of vaccination 
    • Antitoxin +/- vaccine booster
      • For patients with contaminated or dirty wounds 
    • Antibiotics
    • Benzodiazepines (diazepam) for muscle spasms
    • Wound debridement