Toxin

Strychnine Poisoning

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Strychnine Poisoning, Strychnine

  • Background
  1. Strychnine tree (Strychnos nux vomica) is a tree native to Southwest Asia and Northern Australia
  2. Strychnine seeds contain an alkaloid toxin used to kill rodents
  3. Strychnine is also found in some products consumed by humans
    1. Ma Qian Zi (Chinese herbal)
    2. Salang Chai Nut (Cambodian herbal)
    3. Contaminant in production of street drugs (e.g. Cocaine, Amphetamine or Heroin)
    4. Historically used in barbiturate Overdose
  • Pharmacokinetics
  1. Lethal dose 1-2 mg/kg (or 50-100 mg)
  2. Onset of activity: <15 to 60 minutes from ingestion
  3. Elimination half life: 10-16 hours
  4. Volume of distribution (large): 13 L/kg
  • Mechanism
  1. Strychnine competitively blocks glycine
  2. Glycine is an inhibitory neurotransmitter
    1. Results in Neuronal disinhibition and increased excitability (esp. in spinal column)
  • Signs
  1. Constitutional
    1. Agitation
    2. Anxiety
  2. Neuromuscular (primary effects, Tetanus-like reaction)
    1. Painful, severe muscle spasms, rigidity, cramps with minimal triggers
    2. Hypersensitivity to external stimuli
    3. Nystagmus
    4. Dysphagia
    5. Opisthotonos (arched back)
    6. Risus Sardonicus (Sardonic Grinning)
    7. Trismus (lock jaw)
  3. Cardiopulmonary
    1. Tachypnea (may progress to apnea)
  • Labs
  1. Serum Electrolytes (including Serum Potassium)
  2. Renal Function tests
  3. Creatinine phosphokinase
  • Differential Diagnosis
  1. See Tetanus
  • Management
  1. ABC Management with Endotracheal Intubation as needed
  2. Gastrointestinal Decontamination with Activated Charcoal
    1. Indicated if ingestion within prior 1 hour
  3. Decrease muscle contractions, hyperthermia
    1. Reduce patient movement, stimulation
    2. Benzodiazepines
    3. Consider intubation, sedation and paralysis
  • References
  1. Otter and Tomaszewski (2019) Crit Dec Emerg Med 33(3): 28
  2. Leikin (1996) Poisoning and Toxicology, Lexi-comp, p.1016-7