Toxicological Emergencies — MCQs
A farmer with pinpoint pupils, increased secretions and urination. What is the most likely diagnosis?
A farmer presented with confusion, increased salivation, fasciculations, miosis, tachycardia and hypertension. Poison that can cause these manifestations:
Diazepam poisoning is treated by:
Best preservative for viscera in poisoning cases?
A patient presents to the emergency department with a history of ingestion of ten tablets of paracetamol. He has developed oliguria and liver function tests show deranged values. In the context of paracetamol overdose, which of the following can be used in the management of this condition?
Which of these is the best for management of methanol poisoning?
Antidote used in methyl alcohol poisoning is?
A patient presents with constricted pupils, respiratory depression, and cyanosis. What is the likely poison?
Antidote for opioid poisoning:
What is the dose of ulipristal acetate when used for emergency contraception?
Toxicological Emergencies Indian Medical PG Practice Questions and MCQs
Question 1: A farmer with pinpoint pupils, increased secretions and urination. What is the most likely diagnosis?
- A. Alcohol poisoning
- B. Organophosphate poisoning (Correct Answer)
- C. Opioid poisoning
- D. Atropine poisoning
Explanation: ***Organophosphate poisoning*** - **Pinpoint pupils (miosis)**, **increased secretions** (salivation, lacrimation, bronchial secretions), and **urination** are classic signs of cholinergic crisis caused by organophosphate toxicity [1]. - The patient's profession as a **farmer** increases the likelihood of exposure to pesticides, which often contain organophosphates [1], [2]. *Alcohol poisoning* - While alcohol poisoning can cause CNS depression, it does not typically present with **pinpoint pupils** or **increased secretions** like salivation and urination. - Common signs include **ataxia**, **slurred speech**, **nausea**, and **vomiting**. *Opioid poisoning* - Opioid poisoning also causes **pinpoint pupils** and **CNS depression**, but it typically leads to **decreased secretions** and **urinary retention**, not increased urination [2]. - **Respiratory depression** is a hallmark feature, which is not highlighted here as a primary symptom. *Atropine poisoning* - Atropine is an anticholinergic agent, meaning it would cause the opposite effects of organophosphate poisoning [2]. - Symptoms would include **dilated pupils (mydriasis)**, **dry mouth**, **decreased secretions**, and **urinary retention**.
Question 2: A farmer presented with confusion, increased salivation, fasciculations, miosis, tachycardia and hypertension. Poison that can cause these manifestations:
- A. Arsenic
- B. Opium
- C. Dhatura
- D. OPC (Correct Answer)
Explanation: ***OPC*** - The combination of **confusion**, increased salivation, **fasciculations**, **miosis**, and **tachycardia/hypertension** points towards **organophosphate poisoning (OPC)** due to excessive cholinergic stimulation. - Farmers are at high risk for OPC due to exposure to **pesticides**. *Arsenic* - **Arsenic poisoning** typically causes severe gastrointestinal symptoms such as vomiting, diarrhea, and abdominal pain, along with **garlic breath** and **neuropathy**. - It does not commonly present with prominent salivation, fasciculations, or miosis. *Opium* - **Opioid overdose** characteristically leads to **CNS depression**, **respiratory depression**, **pinpoint pupils (miosis)**, and **bradycardia** and **hypotension**. - It does not cause increased salivation, fasciculations, or tachycardia. *Dhatura* - **Dhatura poisoning** is characterized by **anticholinergic symptoms** such as **dry mouth**, dilated pupils (mydriasis), blurred vision, warm dry skin, **tachycardia**, and **agitation/delirium**. - It would not cause increased salivation, fasciculations, or miosis.
Question 3: Diazepam poisoning is treated by:
- A. Resins
- B. Hemofiltration
- C. Charcoal
- D. Flumazenil (Correct Answer)
Explanation: ***Flumazenil*** - **Flumazenil** is a **benzodiazepine receptor antagonist** that competitively binds to the benzodiazepine binding site on the GABA-A receptor, reversing the effects of diazepam. - It is used in cases of severe benzodiazepine overdose causing **respiratory depression** or **severe sedation**. *Resins* - **Resins**, such as **cholestyramine**, are typically used to bind toxins or drugs in the **gastrointestinal tract** that undergo enterohepatic recirculation. - They are generally not effective for reversing the central nervous system depression caused by a benzodiazepine overdose. *Hemofiltration* - **Hemofiltration** is a form of renal replacement therapy used to remove small and middle molecular weight substances from the blood. - While it can remove some drugs, **diazepam** is highly **lipophilic** and extensively **protein-bound**, making it poorly amenable to removal by hemofiltration. *Charcoal* - **Activated charcoal** is used to prevent the absorption of ingested toxins from the gastrointestinal tract. - It is effective when administered soon after ingestion but does not reverse the established effects of an absorbed drug like diazepam in an overdose situation.
Question 4: Best preservative for viscera in poisoning cases?
- A. 10% formalin
- B. Absolute alcohol
- C. Rectified spirit (Correct Answer)
- D. Saturated saline
Explanation: ***Rectified spirit*** - **Rectified spirit** (ethanol 95%) is the best preservative for viscera in poisoning cases because it effectively preserves tissues without interfering with most toxicological analyses. - It prevents decomposition and bacterial growth while allowing for the detection of a wide range of **poisons**, including organic compounds and some volatile substances. *10% formalin* - **10% formalin** is primarily used for **histopathological examination** to preserve tissue architecture. - However, it can interfere with certain toxicological analyses and chemically alter some poisons, making their detection difficult. *Absolute alcohol* - While a good preservative, **absolute alcohol** (100% ethanol) is hygroscopic and can cause significant tissue dehydration and hardening. - It is often more expensive and less readily available than rectified spirit, and offers no significant advantage over rectified spirit for routine toxicological preservation. *Saturated saline* - **Saturated saline** is a poor choice for long-term preservation of viscera in poisoning cases. - It is not effective at preventing putrefaction and bacterial contamination, and it can dilute or leach out certain toxins from the tissues.
Question 5: A patient presents to the emergency department with a history of ingestion of ten tablets of paracetamol. He has developed oliguria and liver function tests show deranged values. In the context of paracetamol overdose, which of the following can be used in the management of this condition?
- A. N-acetylcysteine (Correct Answer)
- B. Dopamine
- C. Ursodeoxycholic acid
- D. Furosemide
Explanation: **Correct: N-acetylcysteine** - **N-acetylcysteine (NAC)** is the specific antidote for **paracetamol overdose**, working by replenishing **glutathione** stores in the liver. - Replenishing **glutathione** helps detoxify the toxic metabolite **N-acetyl-p-benzoquinone imine (NAPQI)**, preventing further **hepatic damage** and facilitating recovery in cases of **liver failure** and potential **renal damage** (oliguria). - Most effective when given within **8 hours** of ingestion, but remains beneficial even with **established hepatotoxicity** (as in this case with deranged LFTs). *Incorrect: Dopamine* - **Dopamine** is a **vasopressor** primarily used to increase **blood pressure** and **cardiac output** in conditions like **shock**. - While it might be used to support circulation in severe overdose complications, it does not directly treat the **paracetamol toxicity** itself. *Incorrect: Ursodeoxycholic acid* - **Ursodeoxycholic acid (UDCA)** is a **cholagogue** used in the management of **cholestatic liver diseases** (e.g., primary biliary cholangitis) by improving bile flow. - It has no role in the direct management of **acute liver failure** due to **paracetamol overdose**. *Incorrect: Furosemide* - **Furosemide** is a **loop diuretic** used to increase **urine output** in conditions like **fluid overload** or **heart failure**. - While **oliguria** is present, it is often a sign of **acute kidney injury** requiring supportive care, and furosemide would not address the underlying **toxic mechanism** of paracetamol.
Question 6: Which of these is the best for management of methanol poisoning?
- A. Fomepizole (Correct Answer)
- B. Naltrexone
- C. Disulfiram
- D. Acamprosate
Explanation: ***Fomepizole*** - **Fomepizole** is a competitive inhibitor of **alcohol dehydrogenase**, the enzyme responsible for metabolizing methanol into toxic metabolites like formic acid. - By inhibiting this enzyme, it prevents the formation of these toxic metabolites, thereby reducing organ damage and metabolic acidosis in methanol poisoning. *Naltrexone* - **Naltrexone** is an **opioid receptor antagonist** used in the treatment of alcohol and opioid dependence. - It does not have any direct action on the metabolism of methanol or its toxic byproducts. *Disulfiram* - **Disulfiram** inhibits **aldehyde dehydrogenase**, leading to an unpleasant reaction when alcohol is consumed (flushing, nausea, vomiting). - It is used for alcohol cessation and has no role in the management of methanol poisoning. *Acamprosate* - **Acamprosate** is a medication used to reduce alcohol cravings in individuals recovering from alcohol dependence, possibly by modulating **glutamate neurotransmission**. - It does not directly affect the metabolism of methanol or mitigate its toxic effects.
Question 7: Antidote used in methyl alcohol poisoning is?
- A. Alpha methyl dopa
- B. Fomepizole (Correct Answer)
- C. Acetyl cysteine
- D. EDTA
Explanation: ***Fomepizole*** - **Fomepizole** acts as a competitive inhibitor of **alcohol dehydrogenase**, preventing the metabolism of **methanol** into toxic metabolites like **formic acid**. - This prevents the accumulation of highly toxic substances responsible for the metabolic acidosis, visual disturbances, and organ damage seen in **methanol poisoning**. *Alpha methyl dopa* - **Alpha-methyl dopa** is an antihypertensive drug that primarily acts as a central alpha-2 adrenergic agonist, reducing sympathetic outflow. - It is not used in the management of **methanol poisoning** and has no role in inhibiting alcohol metabolism. *Acetyl cysteine* - **Acetylcysteine** is primarily used as an antidote for **acetaminophen (paracetamol) overdose**, where it replenishes glutathione stores, and as a mucolytic agent. - It does not inhibit the metabolism of **methanol** nor does it have any direct therapeutic effect in **methanol poisoning**. *EDTA* - **EDTA (Ethylenediaminetetraacetic acid)** is a chelating agent used to treat **heavy metal poisoning**, such as lead poisoning. - It binds to metal ions, facilitating their excretion from the body, but has no role in the management of **methanol poisoning**.
Question 8: A patient presents with constricted pupils, respiratory depression, and cyanosis. What is the likely poison?
- A. Opium (Correct Answer)
- B. Anticholinergic
- C. Cyanide Poisoning
- D. Arsenic Poisoning
Explanation: ***Opium*** - **Opioid toxicity** classically presents with the triad of **miosis** (constricted pupils), **respiratory depression**, and **CNS depression**, which aligns with the patient's symptoms. - **Cyanosis** is a direct consequence of severe respiratory depression leading to hypoxemia. *Anticholinergic* - Anticholinergic toxidrome typically presents with **dilated pupils (mydriasis)**, **dry skin and mucous membranes**, and **tachycardia**, which are opposite to the patient's presentation. - Respiratory depression is not a primary feature of anticholinergic poisoning; rather, patients may exhibit agitation or delirium. *Cyanide Poisoning* - Cyanide poisoning primarily affects cellular respiration, leading to a rapid onset of symptoms like **headache**, **confusion**, **tachycardia**, and **metabolic acidosis**. - While it can cause respiratory distress, **pupils are typically normal or dilated**, and the characteristic smell of bitter almonds may be present. *Arsenic Poisoning* - Acute arsenic poisoning manifests with severe **gastrointestinal symptoms** (nausea, vomiting, diarrhea), **cardiovascular collapse**, and **neurological symptoms** like altered mental status. - It does not typically cause constricted pupils or primary respiratory depression as seen in this case.
Question 9: Antidote for opioid poisoning:
- A. Pethidine
- B. Flumazenil
- C. Naloxone (Correct Answer)
- D. Physostigmine
Explanation: ***Naloxone*** - **Naloxone** is a pure **opioid antagonist** that reverses the effects of opioid overdose by competing for and binding to opioid receptors. - It is crucial in emergent situations to restore **respiratory drive** and consciousness in patients with opioid-induced respiratory depression. *Pethidine* - **Pethidine** is an **opioid analgesic** itself, primarily used for pain management, and would worsen opioid poisoning. - It works by binding to opioid receptors, leading to centrally mediated pain relief, making it contraindicated in overdose. *Flumazenil* - **Flumazenil** is an antagonist for **benzodiazepines**, used to reverse their sedative and respiratory depressant effects. - It has no effect on opioid receptors and would not be effective in treating opioid poisoning. *Physostigmine* - **Physostigmine** is a **cholinesterase inhibitor** used to reverse anticholinergic toxicity. - It increases acetylcholine levels at the synapse and is not indicated for opioid overdose.
Question 10: What is the dose of ulipristal acetate when used for emergency contraception?
- A. 30mg (Correct Answer)
- B. 300 mg
- C. 300 µg
- D. 30 µg
Explanation: ***30mg*** - The standard dose of **ulipristal acetate** for emergency contraception is a single 30 mg tablet. - This dosage effectively delays or inhibits **ovulation**, making it an effective post-coital contraceptive method. - Ulipristal acetate can be used up to **120 hours (5 days)** after unprotected intercourse, though it is most effective when taken as soon as possible. *300 mg* - A dose of 300 mg of **ulipristal acetate** is significantly higher than the standard therapeutic dose for emergency contraception. - Such a high dose would likely lead to increased side effects and is not recommended for this indication. *300 µg* - A dose of 300 µg (0.3 mg) of **ulipristal acetate** is too low to be effective for emergency contraception. - This dose would not provide sufficient **hormonal inhibition** to prevent ovulation or implantation. *30 µg* - A dose of 30 µg (0.03 mg) of **ulipristal acetate** is also too low for effective emergency contraception. - The efficacy of emergency contraception relies on specific hormonal levels, which this dose would not achieve.
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