Forensic Toxicology Practice Questions

Q: The 'Hooch tragedy' was due to consumption of:

Methyl alcohol. **Explanation:** The term **'Hooch tragedy'** refers to mass poisoning events caused by the consumption of illicit, adulterated, or "country-made" liquor. The primary toxic agent in these cases is **Methyl alcohol (Methanol)**. **1. Why Methyl Alcohol is correct:** Methanol is often added to illicit liquor to increase its potency or occurs as a byproduct of improper distillation. While methanol itself is relatively non-toxic, it is metabolized in the liver by *alcohol dehydrogenase* into **Formaldehyde**, and then by *aldehyde dehydrogenase* into **Formic acid**. Formic acid is the primary toxin responsible for: * **Anion gap metabolic acidosis.** * **Ocular toxicity:** It causes retinal edema and optic nerve atrophy, leading to the characteristic "snowstorm vision" and eventual blindness. * **Putaminal necrosis:** Specific brain lesions seen on imaging. **2. Why other options are incorrect:** * **Cannabis:** A hallucinogen derived from *Cannabis sativa*. Toxicity causes tachycardia and "run amok" behavior but does not lead to the systemic metabolic crises associated with hooch. * **Ethyl alcohol:** This is standard consumable alcohol. While acute intoxication or chronic abuse causes health issues, it does not cause the rapid, mass-casualty poisoning seen in hooch tragedies unless adulterated. * **Dhatura:** A deliriant poison (containing atropine/scopolamine). It causes "Dry as a bone, Red as a beet, Blind as a bat, Mad as a hatter" symptoms, but is not a constituent of hooch. **Clinical Pearls for NEET-PG:** * **Antidote:** **Fomepizole** (inhibits alcohol dehydrogenase) is the drug of choice. Alternatively, **Ethanol** is used as it has a higher affinity for the enzyme. * **Lethal Dose:** Approximately 30–100 ml; however, as little as 10 ml can cause permanent blindness. * **Treatment:** Hemodialysis is indicated if there is significant metabolic acidosis or visual impairment.

Q: Which of the following is NOT an organophosphate pesticide?

Endrin. **Explanation:** The correct answer is **Endrin** because it belongs to the **Organochlorine** group of insecticides, not Organophosphates (OPs). 1. **Why Endrin is the correct answer:** Endrin is a chlorinated hydrocarbon (Organochlorine), similar to DDT, BHC, and Lindane. These compounds are highly lipid-soluble and act primarily by interfering with sodium-potassium channels in nerve membranes and inhibiting GABA receptors, leading to CNS overstimulation and seizures. Unlike OPs, they do not inhibit the acetylcholinesterase enzyme. 2. **Analysis of incorrect options:** * **Diazinon, Malathion, and Parathion** are all classic examples of **Organophosphates**. These compounds work by irreversibly inhibiting the enzyme **Acetylcholinesterase (AChE)**, leading to an accumulation of acetylcholine at muscarinic and nicotinic receptors (causing the "cholinergic crisis"). * *Note:* Malathion is considered one of the least toxic OPs for humans because it is rapidly detoxified by plasma esterases. **High-Yield Clinical Pearls for NEET-PG:** * **OP Poisoning Triad:** Pinpoint pupils (miosis), muscle fasciculations, and the smell of garlic (or kerosene) in the breath/vomitus. * **Management:** Atropine is the physiological antidote (reverses muscarinic effects); Pralidoxime (2-PAM) is the enzyme reactivator (must be given before "aging" of the enzyme occurs). * **Endrin Toxicity:** Known as "Plant Drin," it is highly toxic. A characteristic feature of organochlorine poisoning is the early onset of seizures without the cholinergic signs (salivation/miosis) seen in OPs.

Q: Which of the following poisons has a sweet taste and produces perioral sensation and tingling?

Aconite. **Explanation:** **Aconite** (derived from *Aconitum napellus*), also known as "Monkshood" or "Blue Rocket," is a potent neurotoxic and cardiotoxic poison. The correct answer is Aconite because of its classic clinical presentation: upon ingestion, it produces a characteristic **sweetish taste** followed by an intense **tingling and numbness (paresthesia)** of the lips, mouth, and tongue (perioral sensation). This sensation eventually spreads to the extremities and the whole body. **Why the other options are incorrect:** * **Cerbera odollam (Suicide tree):** This contains cerberin, a cardiac glycoside. While it is highly toxic, it is known for its bitter taste and primarily causes gastrointestinal distress and fatal arrhythmias without the specific perioral tingling associated with Aconite. * **Yellow Oleander (*Thevetia peruviana*):** Contains thevetin and peruvoside. It typically presents with vomiting, abdominal pain, and bradycardia. It does not produce the sweet taste or specific neurotoxic tingling sensation. * **Digitalis purpurea (Foxglove):** A source of digoxin, it primarily causes visual disturbances (xanthopsia/yellow vision), nausea, and cardiac conduction blocks. It lacks the rapid-onset perioral paresthesia characteristic of Aconite. **High-Yield Clinical Pearls for NEET-PG:** * **Active Principle:** Aconitine (activates sodium channels, leading to prolonged depolarization). * **Fatal Dose:** 1–2 grams of root; 2–5 mg of alkaloid. * **Fatal Period:** Usually 2 to 6 hours. * **Key Sign:** "Hippocratic face" (anxious, sunken eyes, cold skin) and "Waves of tingling" spreading through the body. * **Post-mortem:** No specific findings; subendocardial hemorrhages may be seen. * **Medical Use:** Used in Ayurveda (after purification) and as a liniment for neuralgia.

Q: A patient presents to the emergency department with a pinpoint pupil, salivation, lacrimation, tremors, and red tears. Plasma cholinesterase levels were 30% of normal. What is the most probable diagnosis?

Organophosphate Poisoning. **Explanation:** The clinical presentation is a classic case of **Organophosphate (OP) Poisoning**. The underlying mechanism is the irreversible inhibition of the enzyme **Acetylcholinesterase (AChE)**, leading to an accumulation of acetylcholine at muscarinic and nicotinic receptors. * **Why Option A is correct:** The symptoms follow the **DUMBELS** mnemonic (Diarrhea, Urination, Miosis, Bronchospasm, Emesis, Lacrimation, Salivation). Specifically, **"Red Tears" (Chromodacryorrhea)** is a high-yield sign caused by the accumulation of porphyrin in the Harderian glands. A **Plasma Cholinesterase level <50%** is diagnostic of significant exposure. * **Why Option B is incorrect:** Dhatura poisoning presents with anticholinergic features (the opposite of OP): dilated pupils (mydriasis), dry mouth, and hot/flushed skin ("Dry as a bone, Red as a beet"). * **Why Option C is incorrect:** While Opioids cause pinpoint pupils (miosis), they typically present with respiratory depression and coma, not the "wet" symptoms like salivation, lacrimation, or tremors. * **Why Option D is incorrect:** Pontine hemorrhage presents with pinpoint pupils and hyperpyrexia, but it lacks the systemic cholinergic signs (salivation/lacrimation) and would not show reduced cholinesterase levels. **High-Yield Clinical Pearls for NEET-PG:** * **Antidote of choice:** Atropine (to reverse muscarinic effects) and Pralidoxime/PAM (to reactivate the enzyme, effective only if given before "aging" occurs). * **Monitoring Atropinization:** Look for a heart rate >100 bpm and clearing of lung secretions (Pupillary dilation is not the best indicator). * **Smell:** OP compounds often have a characteristic **Garlic-like odor**.

Q: According to the Motor Vehicles Act, 1988, what is the punishable quantity of alcohol in the blood?

30 mg in 100 ml of blood. **Explanation:** The correct answer is **30 mg in 100 ml of blood**. This limit is defined under **Section 185 of the Motor Vehicles Act, 1988**, which governs the legal threshold for "Driving by a drunken person or by a person under the influence of drugs." **Why Option A is Correct:** According to the Act, any person driving or attempting to drive a motor vehicle who has, in his blood, alcohol exceeding **30 mg per 100 ml** (detected by a breath analyzer or blood test) is considered legally intoxicated. At this level (0.03% BAC), the central nervous system begins to experience mild impairment in judgment, coordination, and reaction time, significantly increasing the risk of accidents. **Why Options B, C, and D are Incorrect:** Options B (20 mg), C (10 mg), and D (15 mg) are below the statutory limit defined by Indian law. While any amount of alcohol can affect cognitive functions, the legal "punishable" threshold is specifically set at 30 mg/100 ml to account for physiological variations and to provide a standardized legal benchmark for prosecution. **High-Yield Clinical Pearls for NEET-PG:** * **Widmark’s Formula:** Used to estimate the amount of alcohol ingested based on blood alcohol concentration (BAC). * **McEwen’s Sign:** A clinical sign of alcohol intoxication where the pupils are contracted but dilate on painful stimuli (slapping the cheek), then contract again. * **Metabolism:** Alcohol is metabolized primarily by the liver (Alcohol Dehydrogenase) at a constant rate of approximately **15 mg/100 ml per hour** (Zero-order kinetics). * **Sampling:** In living subjects, sodium fluoride (100 mg) and potassium oxalate (30 mg) are used as preservatives for 10 ml of blood to prevent glycolysis and neo-formation of alcohol.

Q: Ganja is obtained from which part of the Cannabis plant?

Flowering tops. **Explanation:** The correct answer is **C. Flowering tops**. Cannabis sativa (Indian Hemp) contains various psychoactive preparations derived from different parts of the plant. **Ganja** specifically refers to the dried, unfertilized flowering or fruiting tops of the female plant. These parts contain the highest concentration of the psychoactive alkaloid **Delta-9-Tetrahydrocannabinol (THC)**, which is responsible for its euphoric and hallucinogenic effects. **Analysis of Options:** * **A & B (Dried/Fresh leaves):** These are used to prepare **Bhang**. Bhang consists of the dried or fresh leaves and stems of the plant. It is the least potent form of cannabis because the leaves contain significantly lower concentrations of THC compared to the flowering tops. * **D (Roots):** The roots of the Cannabis plant contain negligible amounts of THC and are not used for psychoactive preparations in forensic toxicology. **High-Yield Clinical Pearls for NEET-PG:** * **Charas (Hashish):** The most potent form; it is the resinous exudate collected from the leaves and flowering tops. * **Active Principle:** Delta-9-THC. * **Run Amok:** A state of selective violence/homicidal mania seen in chronic cannabis users (often associated with Ganja). * **Flashbacks:** Users may experience "Echo Psychosis," where effects recur long after the drug has left the system. * **Legal Aspect:** Under the NDPS Act, Bhang is often excluded from the definition of "cannabis," whereas Ganja and Charas are strictly regulated.

Q: All of the following poisons are dialyzable except?

Copper sulphate. The dialyzability of a toxin depends on specific physicochemical properties: low molecular weight, low volume of distribution ($V_d$), low protein binding, and high water solubility. **Why Copper Sulphate is the Correct Answer:** Copper sulphate is **not dialyzable** because it is highly corrosive and causes significant systemic toxicity by binding extensively to proteins and tissues. It has a **large volume of distribution** and causes severe intravascular hemolysis and multi-organ failure [1]. Management primarily involves gastric lavage (if early), supportive care, and specific chelation therapy with **D-Penicillamine** or Dimercaprol (BAL), rather than extracorporeal removal [1]. **Analysis of Incorrect Options:** * **Ethylene Glycol & Methanol:** These are low-molecular-weight alcohols with small volumes of distribution and negligible protein binding. Hemodialysis is the gold standard for rapidly removing both the parent compounds and their toxic metabolites (glycolic acid and formic acid). * **Barbiturates:** Long-acting barbiturates (like Phenobarbital) have low protein binding and low $V_d$, making them highly amenable to removal via hemodialysis or hemoperfusion. **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for Dialyzable Poisons (STUMBLED):** **S**alicylates, **T**heophylline, **U**remia, **M**ethanol, **B**arbiturates (long-acting), **L**ithium, **E**thylene glycol, **D**epakote (Valproate). * **Non-dialyzable poisons:** Usually have a high $V_d$ (>1 L/kg). Examples include Digoxin, Benzodiazepines, Opioids, Tricyclic Antidepressants (TCAs), and Organophosphates. * **Copper Sulphate specific:** Look for the classic triad of **blue-green vomitus**, superficial GI erosions, and **acute intravascular hemolysis** (leading to jaundice and hemoglobinuria) [1].

Q: Nausea, vomiting, blue line on gums, wrist/foot drops, pallor, and colic are manifestations of poisoning due to which of the following?

Inorganic lead. **Explanation:** The clinical presentation described is a classic case of **Inorganic Lead Poisoning** (Plumbism). Lead interferes with heme synthesis and affects multiple organ systems, leading to the following characteristic features: * **Gastrointestinal:** Severe abdominal pain known as **Lead Colic** and constipation. * **Neuromuscular:** Peripheral neuropathy primarily affecting motor nerves, leading to paralysis of extensor muscles, resulting in **Wrist drop** and **Foot drop**. * **Hematological:** Microcytic hypochromic anemia (causing **pallor**) and characteristic **basophilic stippling** of RBCs. * **Burtonian Line:** A distinctive **blue-purplish line on the gums** due to the reaction of lead with sulfur-producing bacteria. **Why other options are incorrect:** * **Mercury:** Poisoning typically presents with tremors (Danbury tremor), erethism (behavioral changes), and gingivitis, but not wrist drop or lead colic. * **Arsenic:** Acute poisoning causes "rice-water" stools; chronic exposure leads to hyperpigmentation (raindrop pigmentation) and hyperkeratosis of palms/soles. * **Organic Lead:** Primarily targets the **Central Nervous System**, causing encephalopathy, insomnia, and delusions, rather than the peripheral nerves or gastrointestinal symptoms seen with inorganic lead. **High-Yield Clinical Pearls for NEET-PG:** * **Screening Test:** Coproporphyrin in urine (sensitive but not specific). * **Best Diagnostic Test:** Blood Lead Levels (BLL). * **Treatment of Choice:** Calcium disodium EDTA, Penicillamine, or Succimer (DMSA). * **Radiology:** "Lead lines" (increased density) at the metaphysis of long bones in children.

Question 1

Which of the following is not a phase of organophosphorus poisoning?

Accepted Answer

Late onset proximal myopathy

Answer

Acute cholinergic phase

Answer

Intermediate syndrome

Answer

OPC induced delayed polyneuropathy

Question 2

The 'Hooch tragedy' was due to consumption of:

Accepted Answer

Methyl alcohol

Answer

Cannabis

Answer

Ethyl alcohol

Answer

Dhatura

Question 3

Which of the following is NOT an organophosphate pesticide?

Accepted Answer

Endrin

Answer

Diazinon

Answer

Malathion

Answer

Parathion

Question 4

Which of the following poisons has a sweet taste and produces perioral sensation and tingling?

Accepted Answer

Aconite

Answer

Cerbera odollam

Answer

Yellow oleander

Answer

Digitalis purpurea

Question 5

A patient presents to the emergency department with a pinpoint pupil, salivation, lacrimation, tremors, and red tears. Plasma cholinesterase levels were 30% of normal. What is the most probable diagnosis?

Accepted Answer

Organophosphate Poisoning

Answer

Dhatura Poisoning

Answer

Opioid Poisoning

Answer

Pontine hemorrhage

Question 6

According to the Motor Vehicles Act, 1988, what is the punishable quantity of alcohol in the blood?

Accepted Answer

30 mg in 100 ml of blood

Answer

20 mg in 100 ml of blood

Answer

10 mg in 100 ml of blood

Answer

15 mg in 100 ml of blood

Question 7

Ganja is obtained from which part of the Cannabis plant?

Accepted Answer

Flowering tops

Answer

Dried leaves

Answer

Fresh leaves

Answer

Roots

Question 8

All of the following poisons are dialyzable except?

Accepted Answer

Copper sulphate

Answer

Ethylene glycol

Answer

Methanol

Answer

Barbiturates

Question 9

What is the fatal level of ethanol in blood?

Accepted Answer

300-400 mg/dL

Answer

100-200 mg/dL

Answer

200-300 mg/dL

Answer

> 500 mg/dL

Question 10

Nausea, vomiting, blue line on gums, wrist/foot drops, pallor, and colic are manifestations of poisoning due to which of the following?

Accepted Answer

Inorganic lead

Answer

Mercury

Answer

Arsenic

Answer

Organic lead

Forensic Toxicology — MCQs

Forensic Toxicology — MCQs

On this page

Practice by Chapter

Want unlimited practice?