More Related Content
What's hot
What's hot (20)
Similar to Toxicology - Strychnine / strychnos nux-vomica poisoning
Similar to Toxicology - Strychnine / strychnos nux-vomica poisoning (20)
Recently uploaded
Recently uploaded (20)
Toxicology - Strychnine / strychnos nux-vomica poisoning
- 1. Strychnine poisoning Adhavan. M 2nd year MBBS IGMC&RI Puducherry
- 2. • Introduction • Properties • Active principles • Uses • Action • Metabolism • Signs & symptoms • Tetanus vs strychnine poisoning • Treatment • Post-mortem findings • Medico-legal importance
- 3. Introduction • Strychnos nux-vomica (family loganiaceae) is evergreen tree native to south-east Asia especially India and Myanmar • One of the oldest poisons known to man • Also called nux-vomica, poison nut, quaker buttons • Seeds of ripe fruit are poisonous • Unbroken seeds are not poisonous
- 4. Identification of seeds: • Flat, circular discs, 2.5×0.6 cm, concavo-convex, ash grey in colour, have a shiny surface, covered with silky hair Properties of Strychnine: • Colourless, odourless, bitter, rhombic prism shaped crystals; dissolves sparingly in water & ether, dissolves well in alcohol & benzene
- 5. Active principles • The seeds contain mainly 2 alkaloids: 1. Strychnine 2. Brucine • Seeds also contain glucoside & loganin • Alkaloids are mostly in seeds; but can also be isolated from all other parts including bark, leaves, roots • Barks, leaves and roots contain Brucine, not Strychnine
- 6. Uses • Respiratory stimulant, rodenticide, to kill stray dogs • Available as herbal remedies as purgative, appetite suppressant, nerve tonics • Adulterant in street drugs such as cocaine, heroin, amphetamines
- 7. Action • Strychnine competitively antagonises the inhibitory neurotransmitter glycine by blocking its post-synaptic uptake by brain stem & spinal cord receptors • Inhibitory effect of glycine is reduced, nerve impulses are triggered even with low levels of neurotransmitters • Without inhibitory effect the motor neurons give continuous stimuli causing constant muscle contraction called release excitation • High action in anterior horn cells/ Renshaw cells of spinal cord • GABA is not affected
- 8. Metabolism • All mucous membranes absorb Strychnine • Taken up by liver and muscles • Released later that causes convulsions on 2nd or 3rd day • 80% metabolised by liver; hepatotoxic • 20% excreted in urine and bile • Found in cadaver for 4 years
- 9. Signs and symptoms • Seen within 15 - 30 mins of ingestion of crushed seeds • Bitter taste, choking sensation in throat, stiffness of neck, face • Prodromal symptoms: restlessness, increased rigidity of muscles, muscular twitching, increased acquity of perception • Face: cyanosed, looks anxious, staring eyes, prominent eyeballs, pupils dilated, mouth filled with bloodstained froth • Risus sardonius - scornful laughter, Risus caninus - dog like laughter: seen due to raised eyebrows, bulging of eyes and contraction of jaw and facial muscles
- 10. • Convulsions: initially clonic later becomes tonic • Even slight impulses lead to high intensity convulsions • Marked convulsions of anti-gravity muscles causing Opisthotonus posture • Patient remains awake during convulsions as Strychnine doesn’t cross BBB • Spasm of abdominal muscles cause Emprosthotonus (forward bending) or Pleurosthotonus (sideways)
- 12. • Convulsions cause lactic acidosis, rhabdomyolysis and hyperthermia • Death occurs within 4-5 convulsions as patient cannot breathe • Consciousness is lost and mind is clear until death • During death, body freezes in middle of convulsions causing Cadaveric spasm
- 13. • Cause of death: ‣ Death due to medullary paralysis ‣ Asphyxia due to spasm of respiratory muscles ‣ Exhaustion from convulsions • Fatal dose: 15-50 mg or 1 crushed seed • Fatal period: 1-2 hours
- 14. S. No. Features Strychnine poisoning Tetanus 1 History of injury None Present 2 Onset Sudden in hours Gradual (days) 3 Site of action Post synaptic membrane Pre synaptic membrane 4 Trismus or lock jaw Does not start in nor especially affect jaw Starts in and affects lower jaw 5 Muscular condition Relaxed in between convulsions Rigid throughout 6 Fatal period 1-2 hrs >24 hrs 7 Chemical analysis Strychnine found No poison Strychnine poisoning Vs Tetanus
- 15. Treatment • There is no specific antidote • Supportive care with reducing external stimulus, prevention of convulsions • Control of convulsions: Put patient in dark, noise-free room. Diazepam 0.1- 0.5 mg/kg I.V. If ineffective GA like Galamine is given • Barbiturates like Phenobarbital sodium, Amytal are antidotes • Stomach wash with warm water and dil. KMnO₄. Then suspension of activated charcoal given • I.V. fluid to maintain urine output to prevent renal failure due to metabolic acidosis • Haemodialysis is ineffective
- 16. Autopsy findings • Findings are not characteristic • Rigor mortis appears early but is not necessarily prolonged • Signs of asphyxia • Extravasated blood may be found in muscles • Viscera are congested • Haemorrhages may be found in stomach, duodenum • Strychnine can be easily detected in blood, urine, gastric fluid, bile, liver and kidney samples
- 17. Medico-legal importance • Death is usually accidental due to overdose, exposure to rodenticide or children eating seeds • Suicide and homicide are rare due to its bitter taste and painful death • Used as aphrodisiac, cattle, arrow, dog and rat poison • Tolerance develops on repeated consumption • Can be detected easily even in decomposed bodies
- 18. References • Biswas G. Spinal and peripheral nerve poisons-Strychnos Nux-vomica. In: Review of Forensic Medicine and Toxicology. Third edition. Jaypee Brothers Medical Publishers (P) Ltd; 2015.p.572-574. • K.S.N. Reddy, O.P.Murthy. Spinal poisons. In: The Essentials of Forensic Medicine & Toxicology. 33rd edition. Jaypee Brothers Medical Publishers (P) Ltd. 2014.p.612-614.