Forensic Toxicology Practice Questions

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.

Q: Cadmium causes:

Proximal tubular necrosis. ***Proximal tubular necrosis*** - **Cadmium** preferentially accumulates in the **renal proximal tubules**, leading to direct cellular damage and necrosis. - This toxicity is a hallmark of chronic cadmium exposure, impairing the kidney's ability to reabsorb essential substances. *Polyneuritis* - **Polyneuritis** is a condition of widespread inflammation of multiple peripheral nerves, often associated with toxins like **lead** or certain medications, but not specifically cadmium. - Its primary manifestation involves sensory and motor deficits in the limbs, which is not characteristic of cadmium poisoning. *Distal tubular necrosis* - While cadmium affects the kidneys, its primary site of toxicity is the **proximal tubule**, not the distal tubule. - Different toxins or conditions, such as **ethylene glycol** overdose, are more likely to cause distal tubular necrosis. *Cirrhosis* - **Cirrhosis** is advanced scarring of the liver and is primarily associated with chronic alcohol abuse, viral hepatitis, or fatty liver disease. - Cadmium accumulation can have some hepatic effects but does not typically lead to significant cirrhosis as its main manifestation.

Q: Rectified spirit is NOT used as preservative in case of:

Phenol. ***Phenol*** - Rectified spirit is **NOT used** for preserving specimens containing **phenol** because phenol is a **volatile poison**. - When mixed with alcohol, phenol can **evaporate** or undergo chemical interactions, leading to loss of the poison and inaccurate toxicological analysis. - Due to this **chemical incompatibility**, phenol specimens should be preserved by **refrigeration without chemical preservatives** or in specific non-alcoholic media. *Cyanide* - Rectified spirit is commonly used as a preservative for specimens involving **cyanide** poisoning cases. - It helps in preventing putrefaction while the specimen is awaiting toxicological analysis. *Alphos* - **Alphos** (aluminum phosphide) poisoning cases often require tissue or organ preservation. - Rectified spirit can be used to preserve tissues, facilitating subsequent analysis for phosphine gas or its metabolites. *Insecticides* - In cases involving **insecticide** poisoning, rectified spirit is a standard preservative for biological samples. - It helps maintain the integrity of the sample, allowing for accurate detection and quantification of various insecticide compounds.

Q: Which of the following substances is a toxin but has also been historically used as a therapeutic emetic in poisoning management?

Copper sulphate. ***Copper sulphate*** - **Copper sulphate** is a **potent toxin** that causes gastrointestinal irritation, hemolysis, hepatotoxicity, and acute renal failure upon ingestion. - It was **historically used as an emetic** to induce vomiting in certain poisoning cases for gastric decontamination, though this practice has been largely abandoned due to its own significant toxicity and the availability of safer alternatives. - This represents its dual nature: a poison itself, yet paradoxically used in poisoning management (not as an antidote, but as a gastric evacuant). *Thallium* - **Thallium** is a highly toxic heavy metal causing severe multi-organ failure, alopecia, peripheral neuropathy, and potentially fatal systemic toxicity. - It has **no therapeutic use** in poisoning management and is purely a toxicological concern. *Arsenic oxide* - **Arsenic oxide** (arsenic trioxide) is a well-known carcinogen and potent cellular poison that disrupts oxidative phosphorylation. - While it has modern therapeutic use in acute promyelocytic leukemia, it has **never been used in poisoning management** as an emetic or therapeutic agent. *Mercuric chloride* - **Mercuric chloride** is highly corrosive and causes severe gastrointestinal burns, acute tubular necrosis, and systemic mercury toxicity. - It is a **potent toxin with no therapeutic application** in poisoning management.

Q: Abrus precatorius poisoning resembles which poison?

Ricin. ***Ricin*** - The toxic protein in *Abrus precatorius* seeds, **abrin**, is structurally and functionally similar to **ricin** from *Ricinus communis* seeds. - Both abrin and ricin are **ribosome-inactivating proteins**, leading to similar clinical presentations of multi-organ failure. *Arsenic* - Arsenic poisoning primarily affects the GI tract, cardiovascular system, and nervous system, causing symptoms like **rice-water stools** and **garlic odor** on breath. - It works through enzyme inhibition, specifically targeting **pyruvate dehydrogenase**, unlike the ribosome-inactivating mechanism of abrin. *Cyanide* - Cyanide poisoning rapidly impairs **cellular respiration** by inhibiting cytochrome c oxidase, leading to cellular hypoxia and lactic acidosis. - Clinical features include **rapid onset of symptoms**, bright red venous blood, and **almond odor**, which are distinct from abrin poisoning. *Thallium* - Thallium poisoning is characterized by **neurological symptoms** (e.g., severe peripheral neuropathy), **alopecia**, and gastrointestinal distress. - It interferes with potassium channels and ATPase pumps, a different mechanism of toxicity compared to abrin.

Q: A dead body is having cadaveric lividity of bluish green color. The most likely cause of death is by poisoning due to:

Hydrogen sulfide. ***Hydrogen sulfide*** - **Hydrogen sulfide poisoning** classically causes a **bluish-green cadaveric lividity** due to the formation of sulfhemoglobin. - This distinct discoloration is a key indicator often noted during post-mortem examination in cases of hydrogen sulfide exposure. *Hydrocyanic acid* - **Hydrocyanic acid poisoning** typically leads to a **cherry-red lividity** due to the inhibition of cytochrome oxidase, preventing tissue oxygen utilization, which is different from the bluish-green color described. - The bright red color results from the persistence of oxygenated hemoglobin in the venous blood. *Oleander* - **Oleander poisoning** affects the heart, causing **cardiac arrhythmias** and bradycardia, but does not typically produce a characteristic or distinct cadaveric discoloration like the bluish-green hue. - Lividity would generally be a more typical reddish-purple, consistent with simple hypostasis. *Sodium nitrite* - **Sodium nitrite poisoning** causes **methemoglobinemia**, leading to a characteristic **chocolate-brown or grayish-blue lividity** due to the oxidation of hemoglobin, which differs from the specific bluish-green described. - This change is due to the formation of methemoglobin, which cannot carry oxygen effectively.

Question 1

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

Accepted Answer

Semecarpol

Answer

Ricin

Answer

Croton

Answer

Abrin

Question 2

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

Accepted Answer

Krait

Answer

Vipers

Answer

Sea snakes

Answer

Cobra

Question 3

Scorpion venom resembles venom of -

Accepted Answer

Cobra

Answer

Viper

Answer

Krait

Answer

All of the options

Question 4

Active principle of oleander plant is:

Accepted Answer

Oleandrin

Answer

Atropine

Answer

Cannabinol

Answer

Semicarpol

Question 5

Datura poisoning is characterized by:

Accepted Answer

Dilated pupil

Answer

Pinpoint pupil

Answer

Dilated salivary gland

Answer

Decreased temperature

Question 6

Cadmium causes:

Accepted Answer

Proximal tubular necrosis

Answer

Polyneuritis

Answer

Distal tubular necrosis

Answer

Cirrhosis

Question 7

Rectified spirit is NOT used as preservative in case of:

Accepted Answer

Phenol

Answer

Cyanide

Answer

Alphos

Answer

Insecticides

Question 8

Which of the following substances is a toxin but has also been historically used as a therapeutic emetic in poisoning management?

Accepted Answer

Copper sulphate

Answer

Thallium

Answer

Arsenic oxide

Answer

Mercuric chloride

Question 9

Abrus precatorius poisoning resembles which poison?

Accepted Answer

Ricin

Answer

Arsenic

Answer

Cyanide

Answer

Thallium

Question 10

A dead body is having cadaveric lividity of bluish green color. The most likely cause of death is by poisoning due to:

Accepted Answer

Hydrogen sulfide

Answer

Hydrocyanic acid

Answer

Oleander

Answer

Sodium nitrite

Forensic Toxicology — MCQs

Forensic Toxicology — MCQs

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