Clostridium botulinum neurotoxin (Botulism)


The diagnosis is by clinical features supported by neurophysiology and confirmed by toxin testing

Clinical features:

Types: Wound botulism, infant botulism, food botulism,
Descending weakness (ocular opthalmoplegia then pharyngeal then limbs)
Loss of pupil accommodation, constipation, ileus
Reflexes reduced or absent
Normal sensation

Findings on investigations:


  • RNST at 20 and 50 Hz: incremental response.
  • CMAP: low amplitude
  • Sensory conduction: Normal
  • EMG, motor unit action potentials MUAP: short duration, low amplitude
  • SFEMG single fibre EMG: increased jitter and blocking

Toxin testing for confirmation:

  • Serum botulinum toxin
  • Food botulinum toxin assay
  • Stool: toxin, in infants consider organism culture


Consider respiratory support
Trivalent antitoxin ABE. Note: current antitoxin is made in horses and associated serum sickness. Usually not needed in infants
Guanidine hydrochloride
Inform health authorities
Wound botulism:

  • Penicillin
  • Surgical debridement

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