Corrosive Poisons — MCQs
True about acid injury to eye are all except?
Yellow discoloration of skin and mucosa is seen in poisoning with:
Gastric lavage is contraindicated in?
A body is discovered with burn marks as shown in the image, resembling a 'crocodile skin' pattern. What is the most likely cause?
Which of the following statements regarding upper gastrointestinal involvement in corrosive poisoning is true?
The poison commonly detected in exhumed bodies is:
Which type of poison is known to cause the most severe damage to body tissues upon contact or ingestion?
Which of the following statements about acid poisoning is true?
Vitreous humor is preserved in suspected poisoning with:
Gastric lavage is contraindicated in which of the following?
Corrosive Poisons Indian Medical PG Practice Questions and MCQs
Question 1: True about acid injury to eye are all except?
- A. more destructive than alkali injuries (Correct Answer)
- B. steroids are used to control inflammation
- C. makes a barrier and prevent deeper penetration
- D. glaucoma is most preventable complication following acid injury
Explanation: ***more destructive than alkali injuries*** - This statement is **false**. **Alkali burns** are generally more severe than acid burns because alkalis have **liquefactive necrosis**, which allows them to penetrate deeper into ocular tissues. - Acids cause **coagulative necrosis**, which forms a protective barrier that limits further penetration, making them typically less destructive than alkali injuries. *steroids are used to control inflammation* - **Topical corticosteroids** are commonly used in the management of ocular chemical burns, including acid injuries, to help **control inflammation** and reduce the risk of secondary complications. - However, their use must be carefully monitored due to potential side effects like increased intraocular pressure and delayed corneal healing. *makes a barrier and prevent deeper penetration* - **Acidic substances** cause **coagulative necrosis** of the superficial tissues, which creates a protective barrier of denatured proteins. - This barrier helps to prevent the acid from penetrating deeper into the ocular structures, thus often limiting the extent of damage compared to alkali burns. *glaucoma is most preventable complication following acid injury* - **Glaucoma** is indeed a significant complication of ocular acid injuries and can be prevented through **immediate copious irrigation**, control of inflammation, and monitoring of intraocular pressure. - While various complications can occur (corneal opacification, symblepharon, limbal stem cell deficiency), glaucoma prevention through early intervention and appropriate medical management is a key focus in acute management, making this statement acceptable as true.
Question 2: Yellow discoloration of skin and mucosa is seen in poisoning with:
- A. Phosphoric acid
- B. Sulphuric acid
- C. Nitric acid (Correct Answer)
- D. Nitrous oxide
Explanation: ***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.
Question 3: Gastric lavage is contraindicated in?
- A. Bicarbonate
- B. Hydrocarbons (Correct Answer)
- C. Organo-Phosphosphate poisoning
- D. PCM toxicity
Explanation: ***Hydrocarbons*** - Gastric lavage is contraindicated in **hydrocarbon poisoning** due to the high risk of **aspiration** [2]. - Aspiration of hydrocarbons can lead to severe **chemical pneumonitis**, which is often more life-threatening than the systemic toxicity from ingestion [2]. *Bicarbonate* - Ingesting a large amount of bicarbonate can cause **alkalosis** and electrolyte imbalances. - While gastric lavage is not typically the primary treatment for mild bicarbonate overdose, it is not absolutely contraindicated in cases of massive ingestion where there is a clear benefit to removing unabsorbed substance, especially if performed with proper airway protection [1], [3]. *Organo-Phosphosphate poisoning* - Gastric lavage is generally recommended for **organophosphate poisoning** if the patient presents within 1-2 hours of ingestion and is awake with an intact gag reflex, or with a protected airway [2]. - This helps remove unabsorbed poison and can reduce the systemic absorption of these highly toxic compounds. *PCM toxicity* - For **paracetamol (PCM) toxicity**, gastric lavage can be considered if the patient presents within 1-2 hours of ingestion and has ingested a potentially toxic dose, especially when activated charcoal is not immediately available or contraindicated [4]. - The primary treatment for PCM toxicity involves **N-acetylcysteine (NAC)**, but gastric emptying can play a role in reducing initial absorption [4].
Question 4: A body is discovered with burn marks as shown in the image, resembling a 'crocodile skin' pattern. What is the most likely cause?
- A. Chemical burns
- B. High voltage electrical burns (Correct Answer)
- C. Scald burns
- D. Radiation burns
Explanation: ***High voltage electrical burns*** - **High voltage electrical burns** can cause severe damage, including charring and deep tissue necrosis, which can result in a contracted, leathery skin appearance often described as **"crocodile skin"** or **alligator hide**. - The alternating current (AC) associated with high voltage can lead to muscle tetany, causing the victim to clench onto the source, prolonging exposure and increasing the severity of damage and the characteristic burn pattern. *Chemical burns* - Chemical burns result from exposure to corrosive substances and typically manifest as **discoloration**, **blistering**, or **deep tissue damage** depending on the agent and duration of contact. - While severe, chemical burns usually do not produce the specific "crocodile skin" pattern of extensive charring and contraction seen with high voltage electricity. *Scald burns* - Scald burns are caused by hot liquids or steam and commonly result in **blistering**, **redness**, and superficial to partial-thickness skin damage without the deep tissue charring. - The pattern of injury would typically be distinct from the described "crocodile skin," often showing flowing or splash patterns. *Radiation burns* - Radiation burns occur due to exposure to high doses of radiation and can lead to **erythema**, **blistering**, and **skin breakdown** over time. - These burns develop progressively and often have a characteristic delayed presentation and pattern related to the radiation field, not the immediate charring seen with electrical injuries.
Question 5: Which of the following statements regarding upper gastrointestinal involvement in corrosive poisoning is true?
- A. With alkali, involvement of the esophagus is more than the stomach. (Correct Answer)
- B. With alkali, there is more superficial injury than with acids.
- C. With acids, there is deeper tissue penetration than with alkalis.
- D. With acids, involvement of the stomach is more than the esophagus.
Explanation: ***With alkali, involvement of the esophagus is more than the stomach.*** - **Alkali ingestion** causes **liquefactive necrosis**, which breaks down tissue structure and allows deeper penetration into esophageal mucosa. - The **esophagus** is the primary site of injury due to prolonged contact time as alkalis tend to adhere to mucosal surfaces and cause more extensive damage. *With acids, involvement of the stomach is more than the esophagus.* - **Acids** primarily affect the **esophagus** due to rapid transit through the GI tract, not the stomach. - The contact time with **gastric mucosa** is often brief unless there is significant pylorospasm, making esophageal involvement predominant. *With alkali, there is more superficial injury than with acids.* - **Alkalis** cause **liquefactive necrosis** leading to deeper tissue penetration compared to acids. - **Acids** cause **coagulative necrosis** with protective eschar formation, making alkali injuries deeper and more extensive. *With acids, there is deeper tissue penetration than with alkalis.* - **Acids** cause **coagulative necrosis** with protective eschar formation that limits deeper tissue penetration. - **Alkalis** cause **liquefactive necrosis** allowing deeper and more widespread tissue damage than acids.
Question 6: 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 7: Which type of poison is known to cause the most severe damage to body tissues upon contact or ingestion?
- A. Irritant poison
- B. Corrosive poison (Correct Answer)
- C. Alcohol
- D. Opioid
Explanation: ***Corrosive poison*** - **Corrosive poisons** cause severe damage by acting directly on tissues, leading to **chemical burns**, protein denaturation, and cell death. - They produce immediate and visible destruction upon contact, such as perforation of the esophagus or stomach, which is typically more severe than irritation. *Irritant poison* - **Irritant poisons** cause inflammation and redness but generally do not lead to the same extent of tissue destruction as corrosives. - While they can cause discomfort and damage, their effects are usually concentrated on the superficial layers of tissue. *Alcohol* - **Alcohol (ethanol)** primarily acts as a central nervous system depressant and can cause organ damage over time with chronic use, but its immediate tissue-damaging effects are not as severe as corrosives. - Acute alcohol intoxication primarily affects neurological and systemic functions, not direct tissue corrosion. *Opioid* - **Opioids** primarily exert their toxic effects by binding to opioid receptors in the brain, causing respiratory depression, sedation, and a decreased level of consciousness. - They do not cause direct, severe tissue damage upon contact or ingestion in the way corrosive substances do.
Question 8: Which of the following statements about acid poisoning is true?
- A. The greatest damage occurs along the lesser curvature of the stomach.
- B. Vitriolage refers to the act of throwing acid on someone. (Correct Answer)
- C. The type of acid ingested does not determine the chance of perforation.
- D. Corrosives cause coagulative necrosis, but this is not the primary concern in acid poisoning.
Explanation: **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.
Question 9: Vitreous humor is preserved in suspected poisoning with:
- A. Cyanide
- B. Morphine
- C. Alcohol (Correct Answer)
- D. Carbon monoxide
Explanation: ***Alcohol*** - **Vitreous humor** is an ideal sample for postmortem alcohol analysis due to its **sequestration** from other body fluids, which minimizes postmortem production or degradation of alcohol. - Its **avascular nature** and **slow diffusion** rates ensure that the alcohol concentration in the vitreous humor closely reflects the ante-mortem blood alcohol concentration. *Cyanide* - Sampling **vitreous humor** is generally not the primary choice for detecting cyanide because cyanide is rapidly absorbed and metabolized, making its detection more reliable in other tissues. - Cyanide can degrade in biological samples, and its concentration in the vitreous humor may not accurately reflect the lethal dose or recent exposure. *Morphine* - While **vitreous humor** can be used for opiate detection, **blood and urine** are generally preferred for initial screening and quantitative analysis of morphine. - Morphine undergoes metabolism during its elimination, and its distribution into the vitreous humor might not always accurately reflect the **pharmacodynamics** or precise time of exposure compared to blood. *Carbon monoxide* - **Carbon monoxide (CO) poisoning** is primarily diagnosed by measuring **carboxyhemoglobin levels** in blood, as CO binds avidly to hemoglobin. - The vitreous humor is not a suitable sample for detecting carbon monoxide or carboxyhemoglobin as it lacks red blood cells and hemoglobin, which are the targets of CO toxicity.
Question 10: Gastric lavage is contraindicated in which of the following?
- A. Organophosphorus Poisoning
- B. Dhatura poisoning
- C. Arsenic poisoning
- D. Kerosene poisoning (Correct Answer)
Explanation: ***Kerosene poisoning*** - Gastric lavage is contraindicated in **kerosene poisoning** due to the high risk of **aspiration pneumonitis**. - Kerosene is a **hydrocarbon**, and aspiration of even small amounts can cause severe lung damage. *Arsenic poisoning* - **Gastric lavage** can be performed in arsenic poisoning, especially if the ingestion occurred recently, to remove unabsorbed toxin. - Activated charcoal is less effective for arsenic, making lavage a more relevant intervention in acute settings. *Organophosphorus Poisoning* - Gastric lavage is generally recommended within an hour of ingestion for **organophosphorus poisoning** to remove the toxic substance. - This helps reduce systemic absorption and mitigate the severe **cholinergic crisis** caused by these agents. *Dhatura poisoning* - **Gastric lavage** is indicated in dhatura poisoning, particularly if presenting within a few hours of ingestion, to remove unabsorbed **atropine-like alkaloids**. - This helps in reducing the **anticholinergic effects** and improving patient outcomes.
Want unlimited practice?
Get full access to all questions, explanations, and performance tracking.
Start For Free