Botulism

Basics

Description

  • Rare in the US, causing <200 cases/yr; however, has significant bioterrorism potential
  • Neuromuscular disorder caused by the botulinum neurotoxin (BoNT) produced by the clostridium species of bacteria, most commonly Clostridium botulinum.
  • Toxin blocks neuromuscular transmission in cholinergic nerve fibers
  • Symptoms occur by inhibition of acetylcholine release from presynaptic nerve membranes
  • BoNT is most toxic substance known
    • Damage is permanent
    • Recovery is slow and requires formation of new synapses sprouting from the axon
    • Death can occur 24 hr after onset of symptoms
  • Mortality:
    • Untreated: 60–70%
    • With supportive care: 3–10%
  • 6 types: Foodborne, wound, infantile (see Pediatric Considerations), iatrogenic, adult intestinal toxemia, and inhalational botulism.
  • Foodborne botulism:
    • Ingestion of home-preserved food containing BoNT
    • Onset 4 h to 10 d (typically 8–26 h)
  • Wound botulism:
    • Wounds contaminated with soil
    • Majority of US cases are from IV drug use
    • Onset 7–14 d
  • Iatrogenic botulism:
    • Counterfeit “Botox” or mishandled botulinum toxin injections
    • Onset 0–36 d after injection
  • Adult intestinal toxemia:
    • Colonization after ingestion of spores of BoNT-producing clostridia
    • Seen in adults with functional or structural GI abnormalities, the immunocompromised or those who have had prolonged antibiotic use
    • Onset unknown
  • Inhalation botulism
    • Aerosolization of toxin may have bioterrorism applications
    • Onset 24–36 hr to several d

Pediatric Considerations

  • Infantile botulism occurs from the ingestion of C. botulinum spores, which germinate in the gut and produce 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
    • Associated with weaning from breast milk, which may alter intestinal flora and increase susceptibility to clostridial infection
  • Usually presents with change in stool pattern or constipation, progressing over several d to symptoms of bulbar weakness, then descending flaccid paralysis
  • Slower onset (3–30 d) is attributed to the toxin being produced locally as opposed to being ingested in single dose
  • C. botulinum spores found in honey
    • Honey not recommended for children <1 yr

Etiology

  • 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–G:
    • Types A, B, E, and rarely F are responsible for most human cases

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