Forensic Toxicology — MCQs
On this page
Datura poisoning is characterized by:
Cadmium causes:
Rectified spirit is NOT used as preservative in case of:
Which of the following substances is a toxin but has also been historically used as a therapeutic emetic in poisoning management?
Abrus precatorius poisoning resembles which poison?
A dead body is having cadaveric lividity of bluish green color. The most likely cause of death is by poisoning due to:
The poison commonly detected in exhumed bodies is:
What is the characteristic pupil condition seen in opium poisoning?
'Phossy jaw' is seen in chronic poisoning with:
In forensic toxicology practice, capsicum seeds are most likely to be confused with:
Forensic Toxicology Indian Medical PG Practice Questions and MCQs
Question 821: Datura poisoning is characterized by:
- A. Pinpoint pupil
- B. Dilated pupil (Correct Answer)
- C. Dilated salivary gland
- D. Decreased temperature
Explanation: ***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 822: Cadmium causes:
- A. Polyneuritis
- B. Distal tubular necrosis
- C. Proximal tubular necrosis (Correct Answer)
- D. Cirrhosis
Explanation: ***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.
Question 823: Rectified spirit is NOT used as preservative in case of:
- A. Phenol (Correct Answer)
- B. Cyanide
- C. Alphos
- D. Insecticides
Explanation: ***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.
Question 824: Which of the following substances is a toxin but has also been historically used as a therapeutic emetic in poisoning management?
- A. Thallium
- B. Copper sulphate (Correct Answer)
- C. Arsenic oxide
- D. Mercuric chloride
Explanation: ***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.
Question 825: Abrus precatorius poisoning resembles which poison?
- A. Arsenic
- B. Ricin (Correct Answer)
- C. Cyanide
- D. Thallium
Explanation: ***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.
Question 826: A dead body is having cadaveric lividity of bluish green color. The most likely cause of death is by poisoning due to:
- A. Hydrogen sulfide (Correct Answer)
- B. Hydrocyanic acid
- C. Oleander
- D. Sodium nitrite
Explanation: ***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 827: The poison commonly detected in exhumed bodies is:
- A. Lead
- B. Mercury
- C. Arsenic (Correct Answer)
- D. Cadmium
Explanation: ***Arsenic*** - **Arsenic** is the most common poison detected in exhumed bodies due to its exceptional **stability** and **resistance to degradation** in decomposing tissues. - It readily binds to **keratin-rich tissues** like hair and nails, making it detectable even after long periods (years to decades). - Known as a "**persistent poison**" in forensic medicine due to its ability to resist putrefaction and remain in tissues indefinitely. *Cadmium* - While **cadmium** is a toxic heavy metal, it is not as frequently detected in exhumed bodies as arsenic due to differing toxicokinetics and post-mortem stability. - Cadmium poisoning often involves **renal and pulmonary toxicity**, and its detection post-mortem might be more challenging after significant decomposition. *Mercury* - **Mercury** can be toxic and persist in some tissues, but its detection in exhumed bodies is less common than arsenic due to its different **metabolic pathways** and **degradation patterns**. - **Elemental mercury** is poorly absorbed, and other forms like **methylmercury** can be found, but their post-mortem stability does not match arsenic's. *Lead* - **Lead** is a heavy metal that causes chronic toxicity and can be detected in bones for extended periods. However, its overall detection rate in exhumed bodies for acute poisoning is typically lower than arsenic. - Lead's clinical presentation often includes **neurological, gastrointestinal, and hematological symptoms**, but its presence in various tissues diminishes over time compared to arsenic's unique persistence.
Question 828: What is the characteristic pupil condition seen in opium poisoning?
- A. Mydriasis
- B. Miosis (Correct Answer)
- C. No change
- D. Irregular
Explanation: ***Miosis*** - **Opioids** stimulate mu-opioid receptors in the brainstem, leading to increased parasympathetic outflow to the **oculomotor nerve**. - This stimulation causes constriction of the **pupillary sphincter muscle**, resulting in pinpoint pupils. *Mydriasis* - **Mydriasis** (dilated pupils) is typically caused by anticholinergic agents, sympathetic stimulation, or certain stimulants, which are not characteristic of opium poisoning. - While dilated pupils can occur in severe terminal hypoxia due to brainstem damage, this is not the initial or characteristic presentation of opioid toxicity. *No change* - **Opioid poisoning** reliably causes a distinct pupillary response, making "no change" an incorrect option for characteristic presentation. - The pupillary response is a crucial diagnostic sign for opioid intoxication. *Irregular* - **Irregular pupils** (dyscoria) are usually associated with direct ocular trauma, neurological conditions affecting specific parts of the iris, or certain inflammatory conditions of the eye. - This is not a typical finding in **opioid toxicity**, which causes symmetrically constricted pupils.
Question 829: 'Phossy jaw' is seen in chronic poisoning with:
- A. Arsenic
- B. Phosphorus (Correct Answer)
- C. Thallium
- D. Datura
Explanation: ***Phosphorus*** - **"Phossy jaw"** refers to the severe osteonecrosis of the jaw, historically seen in workers exposed to **white or yellow phosphorus**, particularly in the matchstick industry. - Exposure to **elemental phosphorus** leads to the destruction of bone tissue, infection, and eventually necrosis of the jawbone. *Arsenic* - Chronic arsenic poisoning primarily affects the **skin (hyperkeratosis, hyperpigmentation)**, and multiple organ systems. - It is not associated with **osteonecrosis of the jaw**. *Thallium* - Thallium poisoning is characterized by **alopecia**, **neuropathy**, and gastrointestinal symptoms. - It does not cause **"phossy jaw"**. *Datura* - Datura refers to a genus of plants containing **tropane alkaloids**, which cause anticholinergic toxidrome. - Symptoms include **dilated pupils**, dry mouth, hallucinations, and tachycardia, not jaw necrosis.
Question 830: In forensic toxicology practice, capsicum seeds are most likely to be confused with:
- A. Dhatura (Correct Answer)
- B. Ricinus
- C. Opium
- D. Strychnine
Explanation: ***Dhatura*** - The seeds of both **capsicum** (chili pepper) and **Dhatura (Datura)** species are small, kidney-shaped, and often light brown to black, making them visually similar. - This resemblance poses a significant challenge in forensic investigations, especially in cases of suspected poisoning where plant material analysis is crucial. *Ricinus* - **Ricinus communis** (castor bean) seeds are typically larger, oval, and distinctly mottled with a glossy, hard coat, which differs significantly from the appearance of capsicum seeds. - The seeds also contain a prominent **caruncle** at one end, a feature absent in capsicum seeds. *Opium* - Opium itself is the dried latex from the **poppy capsule**, not a seed; **poppy seeds** are the seeds of the same plant (*Papaver somniferum*) but do not contain significant opium alkaloids. - Poppy seeds are very small, kidney-shaped, and typically dark blue-grey to black, which may show some resemblance to certain capsicum seed varieties. - However, poppy seeds are generally much smaller and have a characteristic dark color, which can differentiate them from the more varied colors of capsicum seeds. *Strychnine* - **Strychnine** is an alkaloid, not a plant seed, and is typically encountered as a white crystalline powder or in tablet form. - While it is derived from the **Strychnos nux-vomica** tree, the actual seeds of this plant are disc-shaped, flat, and covered in fine, silky hairs, making them easily distinguishable from capsicum seeds.
Practice by Chapter
General Principles of Toxicology
Practice Questions
Corrosive Poisons
Practice Questions
Metallic Poisons
Practice Questions
Non-Metallic Poisons
Practice Questions
Organic Irritant Poisons
Practice Questions
Neurotic Poisons
Practice Questions
Cardiac Poisons
Practice Questions
Asphyxiant Poisons
Practice Questions
Food Poisoning
Practice Questions
Drug Abuse and Dependence
Practice Questions
Analytical Toxicology Methods
Practice Questions
Interpretation of Toxicology Results
Practice Questions
Want unlimited practice?
Get full access to all questions, explanations, and performance tracking.
Start For Free