Forensic Toxicology Practice Questions

Q: Knockout drops are:

Chloral hydrate. ***Chloral hydrate*** - **Chloral hydrate** is a sedative-hypnotic substance historically used as "knockout drops" due to its quick action in inducing sleep or unconsciousness. - Its use has largely been replaced by safer alternatives due to its narrow therapeutic index and potential for respiratory depression and cardiac arrhythmias. *Kerosene* - **Kerosene** is a flammable hydrocarbon liquid primarily used as fuel or solvent, not as a sedative or hypnotic agent. - Ingestion of kerosene is highly toxic and can cause chemical pneumonitis and gastrointestinal irritation. *Paraldehyde* - **Paraldehyde** is an older sedative and hypnotic drug, but it is not typically referred to as "knockout drops." - It has a very pungent odor and taste, which would make surreptitious administration difficult, and is generally avoided in modern medical practice. *Turpentine* - **Turpentine** is a distillate of pine resin used as a solvent or cleaner, and historically as a liniment or anthelminthic. - It is highly toxic if ingested and can cause severe gastrointestinal distress, kidney damage, and central nervous system depression, but it is not a sedative-hypnotic.

Q: Yellow discoloration of skin and mucosa is seen in poisoning with:

Nitric acid. ***Nitric acid*** - **Nitric acid** causes a characteristic **yellow discoloration** of the skin and mucous membranes due to the formation of **xanthoproteic acid**. - This reaction occurs when nitric acid comes into contact with proteins, nitrating the aromatic amino acids (tyrosine, tryptophan, and phenylalanine). *Phosphoric acid* - **Phosphoric acid** burns, if severe, can cause skin irritation with redness and blistering, but typically do not result in a distinct yellow discoloration. - While corrosive, its mechanism of tissue damage differs from nitric acid's specific reaction with proteins. *Sulphuric acid* - **Sulphuric acid** is a potent dehydrating agent and corrosive acid that causes severe burns, often appearing **black or brown (eschar)** due to tissue coagulation and carbonization. - It does not produce the specific yellow discoloration seen with nitric acid. *Nitrous oxide* - **Nitrous oxide** is an inhalational anesthetic and analgesic, and its overdose can lead to **hypoxia**, dizziness, and potential bone marrow suppression with chronic abuse. - It does not cause any form of skin or mucosal discoloration; its effects are systemic and neurological.

Q: Green colored urine is seen after ingestion of:

Phenol. ***Phenol*** - Ingestion of **phenol** can lead to green-colored urine due to the formation of oxidation products, such as **hydroquinone** and **catechol**, which are excreted in the urine. - The green discoloration is a distinct toxicological sign associated with systemic phenol absorption. *Organophosphorus* - **Organophosphorus** poisoning primarily causes cholinergic symptoms like miosis, bradycardia, bronchorrhea, and muscle fasciculations. - It does not typically lead to a change in urine color; the urine usually remains clear or amber. *Copper sulphate* - **Copper sulfate** poisoning can cause symptoms like vomiting, abdominal pain, diarrhea, and potentially kidney damage. - While it can cause renal dysfunction, it does not typically result in green urine discoloration. *Cyanide* - **Cyanide** poisoning is characterized by rapid onset of symptoms affecting the cardiovascular, respiratory, and central nervous systems, leading to cellular hypoxia. - Urine color is not a characteristic feature of cyanide poisoning; it usually remains normal or slightly discolored due to other complications like rhabdomyolysis in severe cases.

Q: Acts both as poison and antidote:

Copper sulfate. ***Copper sulfate*** - **Copper sulfate** acts both as a **poison and antidote**, demonstrating dual properties. - In **large doses**, it is toxic, causing **gastrointestinal distress**, **hepatotoxicity**, **nephrotoxicity**, and potentially death. - Historically, it was used in **small controlled doses as an emetic** (to induce vomiting) in cases of poisoning, acting as an antidote by expelling ingested toxins. - **Note**: Its use as an emetic is now **outdated** due to safety concerns, but it remains the classic example of a substance with both toxic and therapeutic properties. *Mercuric chloride* - **Mercuric chloride** is a highly toxic compound acting primarily as a **corrosive poison**, causing severe damage to the **gastrointestinal tract** and kidneys. - It does not possess any antidote properties and requires aggressive **chelation therapy** for treatment. *Silver chloride* - **Silver chloride** is of **low toxicity** due to its insolubility in water and biological fluids. - While chronic exposure can cause **argyria** (bluish skin discoloration), it has no antidote properties. *Thallium arsenate* - **Thallium arsenate** contains two highly toxic elements (**thallium** and **arsenic**), both potent poisons affecting multiple organ systems. - Used in **pesticides** and **rodenticides** due to its toxicity, it has no beneficial or antidote properties.

Q: Which of the following is used in the second-line management of strychnine poisoning?

Barbiturates. ***Barbiturates*** - As a **second-line treatment**, barbiturates like phenobarbital are used to control **refractory seizures** and muscle spasms in strychnine poisoning when benzodiazepines are insufficient. - They enhance the effect of **GABA**, leading to central nervous system depression and muscle relaxation. *Physostigmine* - This is an **acetylcholinesterase inhibitor** and is primarily used to reverse the anticholinergic effects of certain poisonings, not strychnine. - It would worsen seizures by increasing **acetylcholine**, which can cause tremors and convulsions. *Naloxone* - Naloxone is an **opioid antagonist** used to reverse opioid overdose, which presents with respiratory depression and pinpoint pupils. - It has no role in treating strychnine poisoning, which primarily causes **muscle spasms** and seizures. *Diazepam* - Diazepam, a **benzodiazepine**, is the **first-line treatment** for seizures and muscle spasms in strychnine poisoning. - It works by enhancing the effects of **GABA** at the GABA-A receptor, thereby reducing neuronal excitability.

Q: Which of the following snakes is most commonly associated with hematologic abnormalities following envenomation?

Viper. ***Correct Answer: Viper*** - **Viper venom** contains **hemotoxic components** including **metalloproteinases** and **serine proteinases** that directly activate clotting factors - This leads to **consumptive coagulopathy** characterized by **thrombocytopenia**, **hypofibrinogenemia**, and prolonged coagulation times - Clinical manifestations include spontaneous **bleeding**, **ecchymoses**, **hemorrhage** at the bite site, and in severe cases, **disseminated intravascular coagulation (DIC)** - Viper envenomation is the **classic cause** of hematologic abnormalities among snake bites *Incorrect: Sea snake* - Sea snake venoms are primarily **neurotoxic** and **myotoxic**, causing paralysis and muscle damage - While they can cause **rhabdomyolysis** and subsequent **renal failure**, significant primary hematologic abnormalities are not their hallmark feature *Incorrect: Krait* - Krait venom is predominantly **neurotoxic**, leading to **flaccid paralysis** and **respiratory failure** - Does not typically cause the significant widespread **coagulopathies** seen with viper envenomation *Incorrect: Cobra* - Cobra venom primarily contains **neurotoxins** and **cytotoxins**, causing **paralysis**, **tissue necrosis**, and localized pain - While some cobras can cause minor local bleeding, they do not generally induce the severe and systemic **hematologic abnormalities** characteristic of viper bites

Q: Pica is associated with poisoning:

Lead. ***Lead*** - **Pica**, the craving and consumption of non-food items, is a common symptom of **lead poisoning**, especially in children. - This behavior can lead to further ingestion of lead-containing substances, creating a vicious cycle of exposure. *Arsenic* - **Arsenic poisoning** primarily affects the skin, nervous system, and gastrointestinal tract, causing symptoms like **skin lesions**, neuropathy, and diarrhea. - While various neurological symptoms can occur, **pica** is not a characteristic feature of chronic arsenic exposure. *Phosphorus* - **Phosphorus poisoning** is typically associated with gastrointestinal irritation, liver damage, and cardiovascular effects, often from ingestion of pesticides or fireworks. - It does not commonly present with **pica** as a primary symptom. *Mercury* - **Mercury poisoning** manifests with neurological and psychiatric symptoms such as **tremors**, memory loss, and personality changes (**erethism**). - Pica is not a typical manifestation, although central nervous system effects can cause a range of behavioral changes.

Q: Capsaicin-induced contact dermatitis (chili pepper hands) occurs due to:

Capsicum. ***Capsicum*** - **Capsaicin** is the active component found in **chili peppers** (genus *Capsicum*), which causes the burning sensation and can lead to contact dermatitis. - This irritant leads to the release of **substance P**, a neuropeptide involved in pain transmission, resulting in the characteristic burning and redness. *Dhatura* - **Dhatura** (*Datura* species) contains **tropane alkaloids** such as scopolamine and atropine, which have anticholinergic effects, not irritant contact dermatitis. - Exposure typically leads to symptoms like **dilated pupils**, dry mouth, tachycardia, and central nervous system effects. *Abrus precatorius* - **Abrus precatorius** (rosary pea) contains **abrin**, a highly toxic plant protein that inhibits protein synthesis. - While contact can cause irritation, severe effects are usually associated with ingestion, leading to **haemorrhagic gastroenteritis** and multi-organ failure. *Strychnine* - **Strychnine** is an alkaloid primarily found in *Strychnos nux-vomica* and acts as a **neurotoxin**, blocking glycine receptors in the spinal cord and brainstem. - Poisoning causes severe **muscle spasms** and convulsions, not an irritant contact dermatitis.

Q: Magnan's symptom is seen in:

Cocaine. ***Cocaine*** - **Magnan's symptom**, also known as **formication**, is a tactile hallucination where an individual perceives insects crawling under their skin, commonly associated with chronic cocaine use. - This symptom is a manifestation of **cocaine-induced psychosis** or severe intoxication, leading to paranoid delusions and abnormal sensory experiences. *Datura* - **Datura** intoxication primarily causes anticholinergic effects, such as **dry mouth**, **dilated pupils**, confusion, and visual hallucinations, but not typically Magnan's symptom. - The hallucinations associated with Datura are often described as vivid and florid, but distinct from the tactile formication seen with cocaine. *Cannabis* - **Cannabis** use can induce altered perceptions, euphoria, anxiety, and sometimes paranoia, but it is not typically associated with tactile hallucinations like Magnan's symptom. - While high doses can lead to psychotic-like symptoms, **formication** is not a characteristic feature of cannabis intoxication. *Opium* - **Opium** and other opioids primarily cause central nervous system depression, leading to euphoria, sedation, pinpoint pupils, and respiratory depression. - Opioid use is not linked to tactile hallucinations such as **formication** or Magnan's symptom.

Q: Dilated pupil with coma is seen in which poisoning?

Dhatura. ***Dhatura*** - **Dhatura poisoning** is characterized by an **anticholinergic toxidrome**, leading to symptoms like **dilated pupils (mydriasis)**, dry mouth, flushed skin, tachycardia, and altered mental status progressing to coma. - The dilated pupils are a direct result of the **muscarinic receptor blockade** in the eye, preventing parasympathetic innervation. *Opium* - **Opium poisoning** typically causes **pinpoint pupils (miosis)**, respiratory depression, and central nervous system depression leading to coma. - This effect is due to the **opioid agonists** stimulating mu-opioid receptors. *Mushroom* - Mushroom poisoning can present with various toxidromes depending on the species; however, some muscarine-containing species can cause **miosis** (pinpoint pupils), salivation, and bradycardia, while others may cause delirium or hepatic failure. - **Dilated pupils** are not a characteristic feature of the more common deadly mushroom poisonings that lead to coma. *Pilocarpine* - **Pilocarpine** is a **direct cholinergic agonist** that stimulates muscarinic receptors and typically causes **miosis (constricted pupils)**, increased secretions, and bradycardia. - It would not lead to dilated pupils or coma in the manner described.

Question 1

Knockout drops are:

Accepted Answer

Chloral hydrate

Answer

Kerosene

Answer

Paraldehyde

Answer

Turpentine

Question 2

Yellow discoloration of skin and mucosa is seen in poisoning with:

Accepted Answer

Nitric acid

Answer

Phosphoric acid

Answer

Sulphuric acid

Answer

Nitrous oxide

Question 3

Green colored urine is seen after ingestion of:

Accepted Answer

Phenol

Answer

Organophosphorus

Answer

Copper sulphate

Answer

Cyanide

Question 4

Acts both as poison and antidote:

Accepted Answer

Copper sulfate

Answer

Mercuric chloride

Answer

Silver chloride

Answer

Thallium arsenate

Question 5

Which of the following is used in the second-line management of strychnine poisoning?

Accepted Answer

Barbiturates

Answer

Physostigmine

Answer

Naloxone

Answer

Diazepam

Question 6

Which of the following snakes is most commonly associated with hematologic abnormalities following envenomation?

Accepted Answer

Viper

Answer

Sea snake

Answer

Krait

Answer

Cobra

Question 7

Pica is associated with poisoning:

Accepted Answer

Lead

Answer

Arsenic

Answer

Phosphorus

Answer

Mercury

Question 8

Capsaicin-induced contact dermatitis (chili pepper hands) occurs due to:

Accepted Answer

Capsicum

Answer

Dhatura

Answer

Abrus precatorius

Answer

Strychnine

Question 9

Magnan's symptom is seen in:

Accepted Answer

Cocaine

Answer

Datura

Answer

Cannabis

Answer

Opium

Question 10

Dilated pupil with coma is seen in which poisoning?

Accepted Answer

Dhatura

Answer

Opium

Answer

Mushroom

Answer

Pilocarpine

Forensic Toxicology — MCQs

Forensic Toxicology — MCQs

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