Forensic Toxicology Practice Questions

Q: Which of the following is not classified as a contact poison?

Digoxin. **Digoxin** - Digoxin is a **cardiac glycoside** that acts systemically, affecting heart function through absorption, not direct contact. - It is an orally or intravenously administered medication used to treat **heart failure** and **atrial fibrillation**. *Paris green* - **Paris green** (copper(II) acetoarsenite) is an arsenic-based compound historically used as an insecticide and rodenticide, which acts upon direct contact with the target organism. - It works by disrupting **cellular respiration** and attacking enzymes vital for life processes, primarily through topical exposure. *Rotenone* - **Rotenone** is a naturally occurring insecticide derived from plant roots that acts as a contact poison as well as an ingested poison. - It works by inhibiting **mitochondrial complex I**, disrupting cellular respiration and energy production in insects and fish upon contact. *Pyrethrum* - **Pyrethrum** is a natural insecticide derived from chrysanthemum flowers, well-known for its rapid knockdown effect on insects upon direct contact. - It primarily affects the **nervous system** of insects by disrupting sodium channels, leading to paralysis and death.

Q: What type of venom is primarily produced by sea snakes?

Neurotoxic. ***Neurotoxic***- Sea snake venom is **primarily neurotoxic**, containing potent **postsynaptic neurotoxins** that block acetylcholine receptors at the neuromuscular junction [1].- The **neurotoxic component is the predominant and most immediately life-threatening** aspect, causing **descending paralysis, ptosis, respiratory failure**, and death if untreated [1].- While myotoxicity is also present, the **initial clinical presentation and main cause of mortality** is neurotoxic paralysis.*All types of venom*- While sea snake venom contains multiple components, it is **not a general combination of all venom types**.- It lacks significant **hemotoxic, cytotoxic, or cardiotoxic effects** that characterize other snake families.- The venom is specifically adapted for rapid neuromuscular paralysis of fish prey.*Hemotoxic*- **Hemotoxic venom** primarily affects blood and blood vessels, causing **coagulopathy, hemorrhage**, and tissue necrosis, commonly seen in **viper venoms**.- Sea snake venom does **not cause significant coagulation defects or bleeding** as the primary mechanism.- This is not the characteristic feature of sea snake envenomation.*Musculotoxic*- While sea snake venom **does contain myotoxins** that can cause **rhabdomyolysis and myoglobinuria**, this occurs **secondary to the neurotoxic effects** and develops over hours.- The term "**primarily produced**" refers to the **dominant and most dangerous component** - the neurotoxins that cause immediate paralysis and respiratory arrest.- Clinically, **neurotoxicity determines the acute management** (ventilatory support and antivenom), making it the primary concern despite coexisting myotoxicity.

Q: The smoky stool syndrome is seen in which poisoning?

Phosphorus. ***Phosphorus*** - **Phosphorus poisoning** can lead to severe gastrointestinal irritation, causing a characteristic diarrhea with a grey or "smoky" appearance, also known as "smoky stool syndrome." - This symptom is due to the presence of **elemental phosphorus** and its oxidative products in the stool, which produces a **luminescent/phosphorescent glow** in darkness, giving the characteristic "smoky" appearance. - This is a **pathognomonic sign** of yellow/white phosphorus poisoning. *Arsenic* - **Arsenic poisoning** primarily causes severe **gastroenteritis** with watery, "rice-water" stools, abdominal pain, and vomiting, but not typically "smoky stools." - Chronic exposure can lead to **dermatological manifestations** like hyperkeratosis and hyperpigmentation, and neurological symptoms. *Lead* - **Lead poisoning** is associated with gastrointestinal symptoms such as **colicky abdominal pain** (lead colic) and constipation, but not "smoky stools." - Other common signs include a **lead line on the gums** and neurological effects like cognitive deficits in children or peripheral neuropathy in adults. *Zinc* - **Zinc poisoning**, typically from excessive intake, can cause gastrointestinal upset including nausea, vomiting, and diarrhea. - However, it does not produce the specific "smoky stool" symptom characteristic of phosphorus poisoning.

Q: Highest cannabinoid content of cannabis is found in which part of the plant?

Resin. ***Resin*** - The **resin** (often called **kief** or hashish when processed) is a sticky, viscous substance produced by glandular trichomes, which are most abundant on the female cannabis flower. - This resin contains the highest concentration of **cannabinoids**, including **THC** (tetrahydrocannabinol), which is responsible for the plant's psychoactive effects. *Root* - The **root** of the cannabis plant contains very minimal amounts of cannabinoids. - Its primary function is in nutrient and water absorption, and anchoring the plant. *Seed* - **Cannabis seeds** are rich in oils, proteins, and omega fatty acids, but they contain negligible amounts of psychoactive cannabinoids. - They are primarily used for cultivation or as a nutritional food source (hemp seeds). *Stem* - The **stem** of the cannabis plant mainly consists of fibrous material and woody tissue. - While it may contain trace amounts of cannabinoids, the concentration is significantly lower compared to the resinous parts.

Q: Which of the following statements about acid poisoning is true?

Vitriolage refers to the act of throwing acid on someone.. **Vitriolage refers to the act of throwing acid on someone.** - **Vitriolage** is a specific term used to describe the act of **assaulting someone by throwing acid** on them, often leading to severe burns and disfigurement. - This practice has historical and social significance, highlighting the destructive nature of acid attacks. *The greatest damage occurs along the lesser curvature of the stomach.* - The greatest damage from acid ingestion typically occurs along the **greater curvature** of the stomach and at the **pylorus**, where the corrosive agent tends to pool. - The **lesser curvature** is generally less affected due to its anatomical position and the rapid passage of material. *The type of acid ingested does not determine the chance of perforation.* - The **type and concentration of acid ingested significantly determine the chance of perforation**. Stronger acids, like **sulfuric acid**, are more likely to cause severe deep tissue damage and perforation. - The quantity ingested and the duration of contact also play crucial roles in the extent of injury. *Corrosives cause coagulative necrosis, but this is not the primary concern in acid poisoning.* - While corrosives do indeed cause **coagulative necrosis**, this **is a primary and immediate concern in acid poisoning**, as it leads to widespread tissue damage, stricture formation, and potential perforation. - The widespread denaturation of proteins and cellular death caused by coagulative necrosis is the immediate and most critical pathology.

Q: Which of the following statements about cocaine metabolite testing is correct?

Measures benzoylecgonine levels. ***Measures benzoylecgonine levels*** - Cocaine metabolite testing primarily looks for **benzoylecgonine**, which is the main inactive metabolite of cocaine produced in the body. - This metabolite has a significantly longer detection window than cocaine itself, making it a reliable indicator of recent use. *Only detects cocaine use within 24 hours* - This statement is incorrect because **benzoylecgonine** can be detected in urine for up to 2-4 days, and in hair for much longer, depending on the testing method. - The rapid elimination of cocaine itself (half-life of 0.5-1.5 hours) means it is usually undetectable in urine within 6-12 hours, but its metabolite persists. *Measures cocaine concentration in blood* - While cocaine can be measured in blood, typical drug screening tests, particularly urine drug screens, focus on detecting its **metabolites** rather than the parent drug. - Measuring cocaine concentration directly in blood is often done to assess acute intoxication or impairment, not usually for routine screening for past use. *None of the options* - This is incorrect because the first option, "Measures benzoylecgonine levels," correctly describes the primary method of cocaine metabolite testing.

Q: Nux vomica seeds contain 2 alkaloids, strychnine and which other alkaloid?

Brucine. ***Brucine*** - **Nux vomica seeds** (Strychnos nux-vomica) are known to contain two primary alkaloids: **strychnine** and **brucine**. - **Brucine** is structurally similar to strychnine but is generally less toxic and contributes to the bitter taste of the seeds. *Hyoscine* - **Hyoscine** (scopolamine) is an alkaloid found in plants like **deadly nightshade** (Atropa belladonna) and **Datura**. - It is known for its **anticholinergic** properties and is not a primary alkaloid of Nux vomica. *Hyoscyamine* - **Hyoscyamine** is another **tropane alkaloid** found in plants such as **henbane** (Hyoscyamus niger) and **deadly nightshade**. - It also exhibits **anticholinergic** effects and is not associated with Nux vomica seeds. *Atropine* - **Atropine** is a well-known **tropane alkaloid** found in plants of the **Solanaceae family**, like **Atropa belladonna**. - It is used as a potent **anticholinergic** agent and is not a constituent of Nux vomica.

Q: Which of the following statements about dhatura seeds is incorrect?

Yellow brown. ***Yellow brown*** - Dhatura seeds are typically **dark brown** or **blackish-brown**, not yellow-brown. - This is the **INCORRECT statement** - the characteristic dark coloration is a key identifying feature. - Yellow-brown coloration would suggest different plant seeds. *Kidney shaped* - Dhatura seeds are accurately described as **kidney-shaped** (reniform). - This flattened, curved morphology is a consistent and important identifying feature. - Approximately 3-4 mm in size with characteristic curvature. *Odourless* - The seeds are generally **odourless** when intact. - The characteristic pungent smell of Dhatura comes from other plant parts (leaves, flowers) when crushed. - This is a correct statement about dhatura seeds. *Convex smooth surface* - Dhatura seeds have a **reticulated (net-like) or finely pitted surface**, though it may appear relatively smooth to the naked eye. - The surface shows characteristic **honeycomb-like reticulation** under magnification. - While this option could be debated, "yellow brown" is the more clearly incorrect statement.

Q: Which type of poisoning is most commonly associated with motor weakness without sensory loss?

Lead poisoning. ***Lead poisoning*** - **Lead poisoning** is classically associated with **motor neuropathy**, leading to weakness (e.g., foot drop or wrist drop) without significant sensory changes. - Lead interferes with neuronal function and peripheral nerve myelination, primarily affecting **motor axons**. *Arsenic poisoning* - **Arsenic poisoning** typically causes a **sensorimotor polyneuropathy**, meaning both sensory and motor nerves are affected. - Patients often present with symptoms like **paresthesias**, numbness, and burning pain, in addition to weakness. *Cannabis poisoning* - **Cannabis poisoning** primarily affects the central nervous system, leading to altered mental status, impaired coordination, and cardiovascular effects. - It does not typically cause specific **motor weakness** or neuropathy. *Cocaine poisoning* - **Cocaine poisoning** is known for its stimulant effects, causing cardiovascular complications (e.g., arrhythmias, myocardial infarction), seizures, and hyperthermia. - It does not commonly result in isolated **motor weakness** as a primary neurological manifestation.

Q: What is the active ingredient of marking nut?

Semecarpol. ***Semecarpol*** - **Semecarpol** is the **active ingredient** responsible for the vesicant and irritant properties of the marking nut (*Semecarpus anacardium*). - It is a **phenol derivative** found in the fruit's pericarp and can cause severe skin blistering upon contact. *Crotin* - **Crotin** is a toxic albumin found in **croton seeds** (*Croton tiglium*), not marking nut. - Croton oil contains **phorbol esters** which cause severe purgative effects and irritation. *Abrin* - **Abrin** is an extremely potent **toxin** found in the seeds of the **rosary pea** (*Abrus precatorius*). - It is a **ribosome-inactivating protein**, similar to ricin, and is not associated with marking nut. *None of the options* - This option is incorrect because **Semecarpol** is the known active ingredient of marking nut.

Question 1

Which of the following is not classified as a contact poison?

Accepted Answer

Digoxin

Answer

Paris green

Answer

Rotenone

Answer

Pyrethrum

Question 2

What type of venom is primarily produced by sea snakes?

Accepted Answer

Neurotoxic

Answer

All types of venom

Answer

Hemotoxic

Answer

Musculotoxic

Question 3

The smoky stool syndrome is seen in which poisoning?

Accepted Answer

Phosphorus

Answer

Lead

Answer

Zinc

Answer

Arsenic

Question 4

Highest cannabinoid content of cannabis is found in which part of the plant?

Accepted Answer

Resin

Answer

Root

Answer

Seed

Answer

Stem

Question 5

Which of the following statements about acid poisoning is true?

Accepted Answer

Vitriolage refers to the act of throwing acid on someone.

Answer

The greatest damage occurs along the lesser curvature of the stomach.

Answer

The type of acid ingested does not determine the chance of perforation.

Answer

Corrosives cause coagulative necrosis, but this is not the primary concern in acid poisoning.

Question 6

Which of the following statements about cocaine metabolite testing is correct?

Accepted Answer

Measures benzoylecgonine levels

Answer

Only detects cocaine use within 24 hours

Answer

Measures cocaine concentration in blood

Answer

None of the options

Question 7

Nux vomica seeds contain 2 alkaloids, strychnine and which other alkaloid?

Accepted Answer

Brucine

Answer

Hyoscine

Answer

Hyoscyamine

Answer

Atropine

Question 8

Which of the following statements about dhatura seeds is incorrect?

Accepted Answer

Yellow brown

Answer

Kidney shaped

Answer

Odourless

Answer

Convex smooth surface

Question 9

Which type of poisoning is most commonly associated with motor weakness without sensory loss?

Accepted Answer

Lead poisoning

Answer

Cannabis poisoning

Answer

Arsenic poisoning

Answer

Cocaine poisoning

Question 10

What is the active ingredient of marking nut?

Accepted Answer

Semecarpol

Answer

Crotin

Answer

Abrin

Answer

None of the options

Forensic Toxicology — MCQs

Forensic Toxicology — MCQs

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