Spinal And Cardiac Poisons

Spinal and Cardiac poisons poisons are important topics for Forensic Medicine and Toxicology (FMT) preparation. Read this blog post thoroughly to understand everything you need to know about this topic and elevate your NEET PG preparation. 

Read this blog post thoroughly to understand everything you need to know about this topic and elevate your NEET PG Forensic Medicine preparation.

Spinal Poisons

Strychnine Poisoning 

Strychnine Poinsening is caused by Strychnine derived from Strychnos nuxvomica (Kuchila). It is used to kill dogs, hence called Dog-buttons. The seeds of strychnine are concavo-convex shaped. It is odorless and bitter in taste. The fatal dose is One crushed seed. Tests to identify Strychnine are: 

• Wenzel test (thuis is also used in case of Carbon monoxide (CO) Poisoning)
• Sonenshein test 

Strychnine is excitatory in action.

Mechanism of Action of Strychnine

Strychnine acts on the anterior horn cell of the spinal cord (Renshaw cells). There is complete blockade of the Ventral horn of motor neurons and postganglionic receptor site. The Effects of glycine (inhibitory neurotransmitter) are inhibited in the spinal cord and brainstem.

Thus, the overall effect is excitatory. 

Thus, this disease mimics the mechanisms of Tetanus.

Phases of Strychnine poisening

There are two phases of Strychnine poisening. They are:

1. Convulsion
   • Convulsion phase is increased in this poisoning. 
   • There may be 5-6 convulsions simultaneously.
   • Clonic convulsions are seen.
2. Relaxation 
   • Normally duration of the relaxation phase is more compared to the convulsion phase.
   • But in this poisoning, the convulsion phase is elevated.

The Cause of death in Strychnine Poisoning is respiratory muscle spasm - Asphyxia. Although the Consciousness will be retained.

Differentiation between Tetanus and Strychnine poisoning 

• In Strychnine Poisoning
  • All muscles are affected at the same time.
  • External stimuli increase the convulsions.
• In tetanus, there will be sequential muscle spasms.

Clinical Features of Strychnine poisoning

• Tonus
  • Opisthotonus
    • Hyperextension of back.
    • Most characteristic feature.
  • Emprosthotonus
    • Hyperflexion of back.
  • Pleurothotonus
    • Lateral bending 
• Spasm
  • Risus Sadonicus
    • Spasm of facial muscles.

Treatment of Strychnine poisoning

• Avoid gastric lavage as there will be convulsions. (Gastric lavage is Contraindicated in Convulsions).
• Controlling seizures
• Keeping patients away from convulsion-triggering stimuli
• Acidification of the urine 
• Antidote (to control seizures)
  • Phenobarbitone
  • Diazepam 

Postmortem Findings with Strychnine poisoning

• Rigor mortis: Early in onset and long duration 
• Postmortem Caloricity: Body temperature increases after death due to increased muscle action.
• Putrefaction: Rate of putrefaction is decreased. 
• Brain and spinal cord are to be preserved.
• Rate of putrefaction is decreased in Strychnine Poisoning.

Gelsemium Poisoning 

• It is inhibitory in action.

Cardiac Poisons

Cardiac poisoning is Caused by 

• Quinine
• Digitalis
• Oleander (yellow, white/pink)
• Nicotina tabacum
• Aconite
• Cerebra odellum

1. Aconite Poisoning

Aconite is also called blue rocket/ monks hood/ meetha zeher.

Roots of aconite are conical in shape and tapered at the end with longitudinal ridges. All parts of aconite are poisonous. Roots and seeds are the most poisonous part. Roots of Aconite are generally mistaken as Horseradish root. 

Active Principles in Aconite

• Aconitine
• Pseudaconitine
• Aconin

Mechanism of Action of Aconite

Aconite mainly acts on sodium channel (Na+ channel action). It binds to voltage-dependent sodium channels and prolongs the action leading to Excitation of sensory nerves. Sensory nerves are predominantly affected than motor nerves.

Paralyze the motor ganglia of the heart. Respiratory center is slowed. Tachycardia followed by Bradycardia is observed.

Cause of death in aconite poisoning is Cardiac arrhythmia (mostly Ventricular arrhythmia). Hyperkalemia is also seen. 

Signs and Symptoms 

• Tingling and numbness of mouth and throat (most characteristic symptom)
• Sweet taste 
• Numbness and paranesthesia of face, perioral area, and progress to all over the body.
• Weakness of four limbs
• Twitching of muscles
• Hippus sign: Alternate contraction and dilation of the pupil.
• Xanthopsia: Visual illusion of yellow color around objects.
• Hypotension, tachycardia, ventricular ectopic, cardiac arrhythmia with AV block

Fatal Dose of Aconite

1-2 gms of the root is fatal.

Treatment of Aconite Poisoning

• Gastric lavage with warm saline.
• Atropine for AV block.
• Supportive treatment 
• Correction of hyperkalemia 

Medicolegal Importance of Aconite

• Accidental poisoning by horseradish root 
• One of the ideal homicidal poisonings.
• It mimics natural cardiac arrhythmia.
• Destroyed by putrefaction. 

2. Oleander Poisoning

Oleander has two varieties which are of significance

1. Yellow Oleander 
2. Pink Oleander 

Yellow Oleander/Cerebra Thevetia/Peela Kaner

• Bell shaped flower
• All parts : Poisonous
• Active Principles
  • Cerebrin, Thevotoxin, Nerifolin

Pink Oleander/Nerium Odorum/White Oleander/Pink Kaner

• Active Principles
  • Oleandrin
  • Nerin
  • Folineri
  • Rosagenin

Mechanism of action 

 similar to digitalis

• Inhibition of Na+-K+ ATPase :
  • Bradyarrhythmia ® heart-block
  • Tachycardia ® Fibrillations
  • AV block
  • Hyperkalemia

To read about the types of oleander, sign up to the prepladder app and watch the videos from the subject forensic medicine taught by our esteemed faculty.

Treatment of Oleander Poisoning 

Gastric lavage with warm saline is the first step in management. Antidote- Digibind (same as that of Digitalis) is given. Digibind binds to the Fab end of the antibody. For AV block - Atropine is administered and for hyperkalemia - Dextrose and Insulin is given.

3. Digitalis Poisoning

Digitalis purpurea is also called purple Fox glove is known to cause digitalis poisoning.

Mechanism of action of Digitalis Poisoning

Inhibition of Sodium-potassium ATPase channel

Treatment of Digitalis Poisoning

Treatment is same as Oleander poisoning.

4. Cerebra Odellum

Cerebra Odellum is also known as Suicidal tree.

Active Principles of the suicidal tree

• Cerberin
• Cerebroside
• Odolin
• Odolotoxin

Treatment of Cerebra Odellum poisoning

BHIST regime

5. Nicotine 

Nicotine is the most common substance abused in India.

And that is everything you need to know about Spinal and Cardiac Poisons for your FMT paper. For more informative and interesting blog posts to upgrade your NEET PG preparation, download the PrepLadder App and keep following our blog. 

Important Points to remember

• Strychnine (Spinal poison )inhibits the Renshaw cells.
• Renshaw cells control muscle contraction.
• Renshaw cells inhibited: Clonic convulsion.
• Cardiac poison Kaner: Inhibits Na+-K+ ATPase.
• Antidote for oleander : Digibind
• Antidote for aconite: Atropine.
• Cerebra oddolam :Suicide tree.
• Digitalis purpurea /Purple Fox glove.
• Yellow oleander: Cerebra thevetia/Peela kaner.

Frequently asked Questions:

Q: What is the most common illicit substance in India?

Answer: Cannabis

Q: What is the most common substance abused in india?

Answer: Nicotine

Q: what is the treatment of  Cerebra Odellum poisoning?

Answer: BHIST regime

Q: What is the fatal dose of aconite?

Answer: The Fatal Dose of Aconite is 1-2 gms of the root.

Important MCQs

Q. Choose the incorrect statement regarding the following:

1. Causes AV block
2. Atropine is the antidote
3. Only root is poisonous
4. Blue rocket

Ans. 3

Q. Cerberin and Thevetin are found in:

1. White oleander
2. Yellow oleander
3. Calotropis
4. Plumnago rosea

Ans. 2

Q. In a rural community, A 45-year-old man is brought to the emergency room by his family. They describe sudden and severe muscle spasms, jaw stiffness, and generalized convulsions, as shown in the image that started shortly after he consumed a liquid. The family suspects accidental poisoning. What of the following is the reason for this condition?

1. Phosphorus
2. Snake venom
3. Strychnine
4. Arsenic

Ans. 3

Q. Which of the following is not true about the poisoning caused by the seeds shown below?

1. Pleurosthotonus
2. Post mortem caloricity
3. Uncrushed seeds will not lead to poisoning
4. Inhibits neurotransmitter glycine effect at the pre-synaptic receptor

Ans. 4

Q. A 32–year–old woman presents to the ER with a history of ingestion of crushed plant seed shown in the picture. Crushed plant seed, as shown in the picture . She was treated with stomach wash and activated charcoal. Which of the following is not caused by this?

1. Bradycardia
2. Tachycardia
3. Miosis
4. Hyperkalemia

Ans. 3

Q. A 28-year-old male patient was found unconscious in his backyard, the leaves of a plant similar to the one shown below were found scattered around him. He is now presenting with symptoms of nausea, vomiting, abdominal pain, diarrhea, and irregular heart rate. Identify the plant given below likely responsible for these symptoms?

1. Yellow oleander
2. Ricinus communis
3. Datura
4. Papaver somniferum

Ans. 1

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