Forensic Toxicology Practice Questions

Q: An 8-year-old boy, Raju, is brought to the casualty with a history of consuming something while playing outside in the playground. In the examination, there was altered sensorium, hyperpyrexia, dilated pupils. Most probable cause is -

Dhatura poisoning. ***Dhatura poisoning*** - The symptoms of **altered sensorium**, **hyperpyrexia**, and **dilated pupils** are classic signs of anticholinergic toxicity, which is characteristic of *Dhatura* (jimsonweed) poisoning. - *Dhatura* contains **atropine-like alkaloids** (hyoscine, atropine, scopolamine) that block muscarinic acetylcholine receptors, leading to these effects. *Parthenium poisoning* - *Parthenium* (carrot grass) exposure primarily causes **allergic contact dermatitis**, respiratory symptoms, and occasionally gastrointestinal issues. - It does not typically present with the acute neurological and systemic anticholinergic signs described. *Organophosphorus poisoning* - Organophosphorus poisoning leads to excessive cholinergic stimulation, manifesting as **miosis** (pinpoint pupils), **bradycardia**, salivation, lacrimation, urination, and defecation (SLUDGE syndrome). - This is distinct from the **dilated pupils** and **hyperpyrexia** seen in the patient. *Barbiturate poisoning* - Barbiturate overdose primarily causes **central nervous system depression**, leading to drowsiness, stupor, coma, respiratory depression, and hypotension. - It is not associated with **dilated pupils** or **hyperpyrexia** as primary symptoms; pupils are often normal or mildly constricted.

Q: All are features of non-poisonous snakes except

Fangs present. ***Fangs present*** * **Non-poisonous snakes** typically do **not possess fangs**. The presence of **hollow, venom-injecting fangs** is characteristic of **venomous snakes**, which use them to inject venom into prey or threats. * While non-poisonous snakes have teeth, these are generally small and uniform, designed for grasping and holding prey rather than injecting toxins. *Usually not triangular* * This statement is a **feature of non-poisonous snakes**. Their heads are typically more **rounded or oval**, rather than the distinct **triangular shape** often seen in many **venomous snakes**. * The triangular head shape in venomous snakes is associated with the presence of **venom glands** located behind the eyes, which create the characteristic widening. *Head scales are large* * This is also a **feature of non-poisonous snakes**. They typically have **large, symmetrical scales** on their heads (regular head plates), which can be a distinguishing characteristic from many venomous species. * Many venomous snakes (especially vipers) tend to have **numerous small scales** on their heads instead of large regular plates. *Belly scales are narrow and do not cover the entire breadth* * This describes a characteristic that is **typical of non-poisonous snakes**, particularly in the traditional forensic teaching context. * In contrast, many **venomous snakes** have **broad ventral scales** that span the entire width of their underside. * However, this feature should be used with caution as there are exceptions, and modern herpetology recognizes significant variation among species.

Q: Anti Snake Venin (ASV) should be given in all these situations with further lab investigations in a child presenting at 4 am except :

Severe pain abdomen but no fang marks. ***Severe pain abdomen but no fang marks*** - This is the scenario where ASV should **NOT** be given without further lab investigations - **Abdominal pain** has numerous differential diagnoses (appendicitis, peritonitis, gastroenteritis, pancreatitis, etc.) - Without clear evidence of snakebite (no fang marks), **confirmation is crucial** before administering ASV - ASV carries risks including anaphylaxis and serum sickness, so it should only be given when snakebite is confirmed or highly likely *Incorrect: External ophthalmoplegia* - External ophthalmoplegia (cranial nerve involvement) is a **classic sign of neurotoxic envenomation** - This requires **immediate ASV administration** regardless of other investigations - Delay can lead to respiratory muscle paralysis and death *Incorrect: Ptosis with head flexed without bite marks* - **Ptosis** and **head flexor weakness** are pathognomonic signs of neurotoxic envenomation (typically from kraits/cobras) - These signs mandate **immediate ASV** even without visible bite marks - Absence of bite marks occurs in ~50% of genuine snakebites (dry bites, small fangs, thick clothing) *Incorrect: Local swelling with fang marks* - **Direct evidence of envenomation** with both local signs and bite marks - Requires **immediate ASV administration** to prevent progression of local and systemic effects - No lab investigations needed before starting ASV

Q: Yellowish discoloration of the mucous membrane and teeth is produced by

Nitric acid. ***Nitric acid*** - **Nitric acid** causes **xanthoproteic reaction** with proteins, leading to a characteristic **yellow discoloration** of tissues like skin and mucous membranes. This reaction involves the nitration of aromatic amino acid residues. - This yellow staining is particularly noticeable on **teeth** and other mucosal surfaces when exposed to nitric acid. *Hydrochloric acid* - **Hydrochloric acid** is a strong acid but typically causes a more generalized **corrosive effect** with ulceration and necrosis, rather than a distinct yellow discoloration. - Its corrosive action leads to tissue damage and often a **whitish or grayish appearance** of affected areas due to coagulation necrosis. *Sulphuric acid* - **Sulphuric acid** is a dehydrating agent that causes severe **corrosion and charring** of tissues, often presenting as a **blackened or brownish-black** appearance. - It rapidly absorbs water from tissues, leading to a distinct type of chemical burn that is not characterized by yellow discoloration. *Carbolic acid* - **Carbolic acid** (phenol) causes a whitish caustic burn, followed by **reddening and blistering**. It can also have a strong anesthetic effect. - It is known for its protoplasmic corrosive action, leading to tissue coagulation and necrosis, but typically not a prominent yellow staining like nitric acid.

Q: Saturnine Gout is due to:

Chronic Lead Poisoning. ***Chronic Lead Poisoning*** - **Saturnine gout** is historically linked to **chronic lead poisoning**, as lead was associated with the Roman god Saturn. - Lead poisoning can **impair renal excretion of uric acid** and increase its production, leading to **hyperuricemia** and the formation of uric acid crystals in joints. *Chronic Mercury poisoning* - **Mercury poisoning** (Minamata disease) primarily affects the **nervous system** and kidneys, leading to neurological symptoms. - It does not specifically cause a gout-like syndrome or have the historical term "saturnine" associated with it. *Chronic Iron Poisoning* - **Chronic iron poisoning** (hemochromatosis) leads to **iron deposition** in various organs, causing organ damage. - While it can manifest with joint pain, it is distinct from gout and does not directly result in **uric acid crystal deposition**. *Chronic Arsenic Poisoning* - **Chronic arsenic poisoning** affects multiple organ systems, causing dermatological, neurological, and gastrointestinal symptoms. - It is not specifically linked to **hyperuricemia** or the development of gout.

Q: What is the active ingredient of the marking nut (Semecarpus anacardium)?

Semecarpol. ***Semecarpol*** - **Semecarpol** is a **phenolic compound** derived from the fruit of the marking nut tree (*Semecarpus anacardium*), which is responsible for its toxic and medicinal properties. - It causes **irritation**, **blistering**, and **allergic contact dermatitis** upon contact with skin. *Ricin* - **Ricin** is a **toxic protein** found in castor beans (*Ricinus communis*), not the marking nut. - It is a **potent ribosome-inactivating protein** that can be lethal if ingested, inhaled, or injected. *Croton* - **Croton** refers to a genus of plants (*Croton*) from which various compounds, including **phorbol esters**, can be extracted. - These compounds are potent **tumor promoters** and vesicants, but they are not the active ingredient of the marking nut. *Abrin* - **Abrin** is a **highly toxic protein** found in the seeds of the jequirity bean (*Abrus precatorius*), which is distinct from the marking nut. - Like ricin, abrin is a **ribosome-inactivating protein** and is extremely toxic upon exposure.

Q: Which snake's venom is most likely to cause paralysis accompanied by convulsions?

Krait. ***Krait*** - Krait venom is primarily **neurotoxic**, leading to **flaccid paralysis** due to presynaptic blockage of acetylcholine release at the neuromuscular junction. - While paralysis is the hallmark, some krait species' venom components can also cause central nervous system effects, potentially leading to **convulsions** in severe envenomation. *Vipers* - Viper venoms are predominantly **hemotoxic**, causing **coagulopathy**, tissue necrosis, and acute kidney injury. - They do not typically cause paralysis or convulsions, though some may have minor neurotoxic components. *Sea snakes* - Sea snake venoms are potent **neurotoxins** that cause **muscle paralysis** by blocking acetylcholine receptors. - However, they are less commonly associated with convulsions compared to some krait envenomations. *Cobra* - Cobra venom is also mainly **neurotoxic**, leading to **flaccid paralysis** and respiratory failure. - Unlike krait venom, cobra venom is less frequently associated with convulsions, with paralysis being the dominant neurological symptom.

Q: Scorpion venom resembles venom of -

Cobra. ***Cobra*** - Both scorpion venom and cobra venom contain **neurotoxins** that affect the nervous system, making this the closest resemblance among the given options. - Scorpion venom contains neurotoxins that act on **sodium and potassium channels**, causing neuromuscular effects, though it also produces unique **autonomic effects** (both cholinergic and adrenergic) not typical of cobra venom. - Cobra venom primarily contains **postsynaptic neurotoxins** that block acetylcholine receptors at the neuromuscular junction, causing flaccid paralysis and respiratory depression. - Among the options, cobra represents the best match due to the shared **neurotoxic** component. *Viper* - Viper venom is predominantly **hemotoxic and cytotoxic**, causing local tissue damage, bleeding, and coagulation abnormalities. - Contains enzymes like **phospholipase A2** and metalloproteases that cause vasculotoxicity and anticoagulation - completely different from scorpion venom's mechanism. *Krait* - While krait venom is also **neurotoxic**, it primarily acts at **presynaptic terminals** causing irreversible neuromuscular blockade. - The mechanism differs from scorpion venom, which acts primarily on ion channels and produces prominent autonomic manifestations not seen with krait envenomation. *All of the options* - This is incorrect because viper venom's **hemotoxic effects** are fundamentally different from scorpion venom's **neurotoxic effects**. - While both cobra and krait share neurotoxicity with scorpion venom, the closest resemblance is with **cobra** among the given options.

Q: Active principle of oleander plant is:

Oleandrin. ***Oleandrin*** - **Oleandrin** is a highly toxic **cardiac glycoside** found in all parts of the oleander plant (*Nerium oleander*). - It exerts its effects by inhibiting the **Na+/K+-ATPase pump**, similar to digoxin, leading to cardiotoxicity. *Atropine* - **Atropine** is an anticholinergic alkaloid derived from plants like *Atropa belladonna* (deadly nightshade), not oleander. - It blocks **muscarinic acetylcholine receptors**, causing effects such as pupil dilation, dry mouth, and increased heart rate. *Cannabinol* - **Cannabinol (CBN)** is a cannabinoid found in the *Cannabis* plant, formed from the degradation of THC. - It has psychoactive properties, but is not present in oleander. *Semicarpol* - **Semicarpol** is a chemical compound found in plants like *Anacardium occidentale* (cashew tree) and *Rhus semialata*. - It is not an active principle of the oleander plant.

Q: Datura poisoning is characterized by:

Dilated pupil. ***Dilated pupil*** - **Datura poisoning** is characterized by **anticholinergic symptoms**, including **mydriasis** (dilated pupils) due to the blockade of muscarinic receptors in the iris. - The classic mnemonic "hot as a hare, blind as a bat, dry as a bone, red as a beet, mad as a hatter" highlights the systemic effects, with "blind as a bat" specifically referring to **dilated pupils** and blurred vision. *Pinpoint pupil* - **Pinpoint pupils** (miosis) are typically associated with **opioid toxicity** or **cholinergic poisoning**, which are opposite to the effects of datura. - Datura acts as an **antimuscarinic agent**, preventing acetylcholine from constricting the pupil. *Dilated salivary gland* - **Datura poisoning** causes **dry mouth** due to the inhibition of salivary gland secretions, as it blocks muscarinic receptors responsible for glandular activity. - Therefore, a **dilated salivary gland** (implying increased activity or size) is not a characteristic feature; rather, there is a significant reduction in salivation. *Decreased temperature* - **Datura poisoning** typically leads to **hyperthermia** (increased body temperature) due to the inhibition of sweating, which impairs the body's ability to dissipate heat. - **Decreased temperature** would be an atypical finding and is more commonly seen in conditions like hypothermia or specific intoxications that depress thermoregulation.

Question 1

An 8-year-old boy, Raju, is brought to the casualty with a history of consuming something while playing outside in the playground. In the examination, there was altered sensorium, hyperpyrexia, dilated pupils. Most probable cause is -

Accepted Answer

Dhatura poisoning

Answer

Parthenium poisoning

Answer

Organophosphorus poisoning

Answer

Barbiturate poisoning

Question 2

All are features of non-poisonous snakes except

Accepted Answer

Fangs present

Answer

Usually not triangular

Answer

Head scales are large

Answer

Belly scales are narrow and do not cover the entire breadth

Question 3

Anti Snake Venin (ASV) should be given in all these situations with further lab investigations in a child presenting at 4 am except :

Accepted Answer

Severe pain abdomen but no fang marks

Answer

External ophthalmoplegia

Answer

Local swelling with fang marks

Answer

Ptosis with head flexed without bite marks

Question 4

Yellowish discoloration of the mucous membrane and teeth is produced by

Accepted Answer

Nitric acid

Answer

Hydrochloric acid

Answer

Sulphuric acid

Answer

Carbolic acid

Question 5

Saturnine Gout is due to:

Accepted Answer

Chronic Lead Poisoning

Answer

Chronic Mercury poisoning

Answer

Chronic Iron Poisoning

Answer

Chronic Arsenic Poisoning

Question 6

What is the active ingredient of the marking nut (Semecarpus anacardium)?

Accepted Answer

Semecarpol

Answer

Ricin

Answer

Croton

Answer

Abrin

Question 7

Which snake's venom is most likely to cause paralysis accompanied by convulsions?

Accepted Answer

Krait

Answer

Vipers

Answer

Sea snakes

Answer

Cobra

Question 8

Scorpion venom resembles venom of -

Accepted Answer

Cobra

Answer

Viper

Answer

Krait

Answer

All of the options

Question 9

Active principle of oleander plant is:

Accepted Answer

Oleandrin

Answer

Atropine

Answer

Cannabinol

Answer

Semicarpol

Question 10

Datura poisoning is characterized by:

Accepted Answer

Dilated pupil

Answer

Pinpoint pupil

Answer

Dilated salivary gland

Answer

Decreased temperature

Forensic Toxicology — MCQs

Forensic Toxicology — MCQs

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