Strychnine poisoning

nux vomicaStrychnine (Kuchila) is an alkaloid prepared from the seeds of Nux vomica tree. It is a colorless crystal with bitter taste (hence not ideal as homicidal poison). It is used to kill ‘pests’, from earthworms to dogs. There is no justification for its continued use or even manufacture, as it has no longer any place in medical treatment (used in past as respiratory stimulant) and its use in barbaric killing of animals in unjustifiable.

A. Absorption:

  • All mucous membranes
  • Much taken by liver and muscles and released in blood to produce convulsion in 2nd-3rd day

B. Action:

Blocks ventral horn motor neurone postganglionic receptor sites in spinal cord and prevents the effects of inhibitory neurotransmitter glycine

C. Clinical features:

Symptoms usually begin 5-10 minutes after ingestion. The clinical features mimic tetanus with sense of suffocation, twitching of muscles, followed by tetanic convulsions and opisthotonus, each lasting half to two minutes. Consciousness is not lost and mind remains clear till death. However, it can be differentiated from tetanus:

Trait Strychnine poisoning Tetanus
History No history of injury History of injury
Onset Sudden Gradual
Convulsions All muscles of a body at a time All muscles not affected
Lower jaw Doesn’t start in; nor especially affect the jaw Usually starts in; especially affects lower jaw
Muscular condition Between fits, muscles are fully relaxed Between fits, muscles are slightly rigid
Fatal period 1-2 hours >24 hours
Chemical Strychnine found No poison

D. Treatment:

  1. Supportive treatment as in Tetanus
  2. Potassium permanganate stomach wash
  3. Charcoal
  4. Urine acidification

E. Fatal dose: 50 -100 mg (1 crushed seed)

F. Fatal period: 1-2 hours

G. Cause of death: Respiratory exhaustion and failure

H. Manner of poisoning:

  1. Accidental: medicinal overdose, mistake, children
  2. Homicide
  3. Rarely suicide
  4. Cattle poison (arrow poison)
  5. Aphrodisiac

I. Autopsy:

  1. Hands usually clenched; feet arched and inverted
  2. Hemorrhage into traumatized muscle and tendon insertion
  3. Early appearance of rigor mortis
  4. Congestion of brain, spinal cord and lungs
  5. Empty heart
  6. Subperitoneal gastric hemorrhage, ecchymoses

J. Test:

Injection of solution into the dorsal lymph sac of frog produces tetanic convulsi

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