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Snapshot
  • A 40-year-old man presrisus sardonicus seen in tetanusents to your clinic with a 3-day history of jaw discomfort and inability to open his mouth. Ten days ago he had punctured his right foot with a nail while working in his shed. He did not seek medical attention. Patient was immunized in childhood but had never received a booster dose since then. Temperature was 98.4°F (37°C) and blood pressure was 120/70 mmHg. Physical exam revealed an inability to open his mouth more than one inch as well as a puncture wound on the sole of the left foot 2.5 cm by 1 cm, with surrounding erythema. Patient was admitted and given two doses of hyperimmune tetanus immunoglobulin as well as one dose of Td booster. Intravenous metronidazole as well as diazepam was given and wound debridement was carried out.
Introduction
  • C. tetaniClassification
    • bacteria (anaerobic)
      • gram-positive bacilli
        • spore-forming
          • Clostridium
            • C. tetani
  • Pathogenesis
    • transmission
      • puncture wounds/trauma
        • requires low tissue oxygenation
      • mothers
        • incompletely removed placentas
      • neonates
        • colonization of umbilical stump
    • reservoir
      • soil
    • molecular biology
      • spores germinate in tissues and produce exotoxin
      • exotoxin travels to the CNS by retrograde axonal transport
        •  binds to ganglioside receptors
        •  cleaves SNARE protein at pre-synaptic nerve terminals
        •  blocks glycine release from Renshaw cells in spinal cord
          • glycine is  an inhibitory neurotransmitter
Presentation
  • Tetanus
    • caused by tetanospasmin toxin
      • prevents release of inhibitory neurotransmitters glycine and GABA in the spinal cord
      • the cleavage of synaptobrevin 2 halts the fusion of the vesicle with the neuronal membrane  
      • travels to CNS by retrograde axonal transport
    • tetanic (spastic) paralysis
    • risus sardonicus
    • trismus (lockjaw)
    • opisthotonus
Evaluation
  • Large gram-positive, spore-forming rods
    • "tennis racket" appearance
  • Diagnosis is clinical on the basis of history and physical exam
    • organism is not usually isolated
Differential
  • Seizure disorders
  • Meningitis
  • Trismus secondary to dental infection
  • Drug-induced dystonias
Treatment
  • Vaccine
    • made of tetanus toxoid
      • formaldehyde-inactivated
    • prevent neonatal tetanus by vaccinating women of childbearing age 
    • babies first administered vaccine at 2 months of age
  • Post-exposure
    • hyperimmune human globulin (TIG) neutralizes toxin
    • metronidazole or penicillin also given
    • spasmolytic drugs treat symptoms (e.g., diazepam)
Prognosis, Prevention, and Complications
  • Prognosis
    • worse in
      • generalized tetanus
      • extremes of age
      • poor access to intensive medical care
  • Prevention
    • universal vaccination with DTap beginning in infancy
    • booster doses are given
      • every 10 years in adults
      • third trimester of pregnancy
      • following puncture wounds if immune status uncertain
  • Complications
    • laryngospasm
    • fractures
    • respiratory failure and death
 

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