Botulism is a topic covered in the 5-Minute Emergency Consult.

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  • Rare in US, causing <200 cases/yr; however, has significant bioterrorism potential.
  • Caused by a polypeptide, heat-labile exotoxin produced by Clostridium botulinum:
    • Most potent poison known
  • Toxin blocks neuromuscular transmission in cholinergic nerve fibers.
  • Symptoms occur by inhibition of acetylcholine release from presynaptic nerve membranes:
    • Damage is permanent.
    • Recovery is by formation of new synapses through sprouting from the axon.
  • Onset: 12–72 hr after exposure; may be up to 1 wk after exposure:
    • Death can occur 24 hr after onset of symptoms.
  • Slow recovery; symptoms often persist for months
  • Mortality:
    • Untreated: 60–70%
    • With supportive care: 3–10%
  • 3 major types: Food-borne botulism, wound botulism, and infantile botulism (see “Pediatric Considerations”). Absorbed through mucosal surfaces or nonintact skin
  • Food-borne botulism:
    • Occurs by ingestion of preformed toxin; from improperly canned food, improper refrigeration
    • Conditions required for exposure:
      • Food product contaminated with C. botulinum bacilli or spores
      • Proper conditions for germination of spores exist.
      • Time and conditions permit production of toxin before eating.
      • Food not heated sufficiently to destroy botulism toxin
      • Toxin-containing food ingested by susceptible host
  • Wound botulism:
    • Clinical evidence of botulism after trauma with a resultant infected wound and no history suggestive of food-borne illness
    • Botulinum isolated in about 50%
    • Wounds usually contaminated with soil
    • Majority of US cases from IV drug use
  • Other types:
    • Adult intestinal toxemia botulism:
      • Seen in adults with functional or structural GI abnormalities, are immunocompromised or with prolonged antibiotic use
      • Predisposes to Clostridial colonization
      • May have sporadic or recurrent botulism with no known source and even after immunoglobulin treatment
    • Iatrogenic botulism:
      • Doses found in cosmetic applications are insufficient to cause systemic symptoms.
      • No known recent cases from medical use.
      • Symptoms would be expected to be classic.
    • Inhalation botulism:
      • Aerosolization of toxin may have bioterrorism applications. Last reported naturally occurring case in 1962 from the disposal of animal remains.

Pediatric Considerations
  • Infantile botulism occurs from the ingestion of C. botulinum spores, which germinate in the gut and produce the toxin.
  • Accounts for 50–76% of botulism cases
  • 90% occur in children <6 mo:
    • Associated with patient or family exposure to soil, dust, or agricultural industry.
    • May also be associated with weaning from breast milk, which may alter intestinal flora and increase susceptibility to Clostridia infection.
  • Usually presents with change in stool pattern or constipation, progressing over several days to symptoms of bulbar weakness, then descending flaccid paralysis.
  • Slower onset is attributed to the toxin being produced locally as opposed to being ingested in 1 dose.
  • C. botulinum spores found in honey:
    • Honey not recommended for children <1 yr.


  • C. botulinum is a large spore-forming, usually gram-positive, strictly anaerobic bacilli ubiquitous in nature.
  • Each strain produces antigenically distinct toxins, designated types A to G:
    • Types A, B, E, and rarely F are responsible for most human cases.

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