Forensic Toxicology Practice Questions

Q: While dispatching blood and urine for chemical analysis, sodium fluoride is added as a preservative in which concentration?

100 mg/10 ml. **Explanation:** In forensic toxicology, the preservation of biological samples is critical to prevent the degradation of toxins or the post-mortem production of substances (like ethanol). **Sodium Fluoride (NaF)** is the preservative of choice for blood and urine samples. **1. Why 100 mg/10 ml is correct:** Sodium fluoride acts as an **enzyme inhibitor** (specifically inhibiting the enzyme enolase in the glycolytic pathway). This prevents RBCs and microorganisms from metabolizing glucose or producing alcohol post-sampling. The standard recommended concentration is **10 mg per 1 ml** of blood or urine. Therefore, for a standard 10 ml vial, **100 mg** is required to ensure adequate preservation and prevent putrefaction. **2. Analysis of Incorrect Options:** * **A & B (30 mg and 40 mg/10 ml):** These concentrations are too low to effectively inhibit microbial growth and enzymatic activity over the duration required for transport and chemical analysis. * **C (50 mg/ml):** This concentration is excessively high (500 mg per 10 ml). While it would preserve the sample, such high salt concentrations can interfere with certain laboratory extraction techniques and analytical instruments. **3. NEET-PG High-Yield Pearls:** * **Preservative vs. Anticoagulant:** For blood samples, Sodium Fluoride (preservative) is often used in combination with **Potassium Oxalate** (anticoagulant) in a ratio of 1:3. * **Alcohol Cases:** NaF is mandatory in suspected cases of drunkenness to prevent "neo-formation" of alcohol by *Candida albicans*. * **Vitreous Humor:** If blood is unavailable or putrefied, vitreous humor is the preferred sample for alcohol estimation; it does not strictly require NaF but it is often added. * **Saturated Saline:** Used as a preservative for **viscera** (stomach, intestines, liver, kidney) but **never** for blood or urine.

Q: Marking nut is

Semicarpus anacardium. **Explanation:** **Semicarpus anacardium**, commonly known as the **Marking Nut** (Bhilawa), is a classic irritant organic vegetable poison. It derives its name from its historical use by dhobis (washermen) to mark clothes, as the juice produces an indelible black stain when mixed with lime water. * **Why Option A is correct:** The active principles are **Bhilawanol** and **Anacardic acid**. When applied to the skin, the juice causes irritation, blisters containing acrid serum, and an eczematous rash. In forensic practice, it is frequently used to simulate "bruises" (artificial bruises) to frame innocent individuals or for self-inflicted injuries. * **Why other options are incorrect:** * **Croton tiglium:** Known as **Jamalgota**, it is a drastic purgative. Its active principle is Crotin. * **Areca catechu:** Known as **Betel nut**. It is a mild stimulant and anthelmintic, not classified as a marking nut. * **Abrus precatorius:** Known as **Ratti** or Jequirity. Its active principle is **Abrin** (a toxalbumin). It is famous for "Sui" poisoning (needle poisoning) and is highly toxic, mimicking viperine snake bite. **High-Yield Clinical Pearls for NEET-PG:** * **Artificial Bruise:** To distinguish a marking nut bruise from a true bruise, look for the presence of **vesicles** at the periphery and use a chemical test (the stain of marking nut dissolves in **alcohol** and turns **orange-red with alkali**). * **Vitriolage:** Marking nut juice is sometimes used as a substitute for mineral acids in vitriolage (throwing corrosive substances). * **Antidote:** There is no specific antidote; treatment is symptomatic (e.g., washing with soap and water or applying bland oils).

Q: Artificial bruise is commonly seen in which of the following irritant poisons?

Semicarpus anacardium. **Explanation:** **Semicarpus anacardium** (Marking Nut or *Bhilawa*) is a potent vegetable irritant. The juice of the nut contains **Anacardic acid** and **Bhilawanol**, which are highly corrosive to the skin. It is frequently used to create **artificial bruises** (factitious injuries) for the purpose of bringing false charges of assault. The juice produces a lesion that mimics a contusion but can be distinguished by specific features: it is associated with **vesication** (blisters), contains acrid serum, and the surrounding skin shows signs of itching and eczema. Unlike a true bruise, it does not follow the typical color changes (red $\rightarrow$ blue $\rightarrow$ brown $\rightarrow$ yellow) and the juice can be detected chemically by the **KOH test** (turning the juice pink/red). **Analysis of Incorrect Options:** * **Strychnos nux vomica:** A spinal poison containing strychnine. It causes tetanic convulsions and opisthotonus, not skin irritation or artificial bruises. * **Abrus precatorius (Ratti):** While it is a vegetable irritant, it is typically used for "suis" (needles) to kill cattle or humans via parenteral injection. It causes local edema and necrosis at the injection site rather than a bruise-like lesion. * **Capsicum annum:** A contact irritant (chilli) that causes a burning sensation and erythema, but it is not the classic agent described for creating deceptive artificial bruises in forensic practice. **High-Yield Clinical Pearls for NEET-PG:** * **Antidote for Semicarpus:** Local application of coconut oil or ghee. * **Differentiation:** A true bruise is sub-epidermal; an artificial bruise is purely epidermal/surface-level. * **Other agents for artificial bruises:** *Calotropis* and *Plumbago rosea* (Lal Chitra) are also used. * **Chemical Test:** Semicarpus juice turns **brownish-black** on exposure to air but yields a **bright red color** with alcoholic potash (KOH).

Q: Which of the following is NOT an active principal found in Calotropis?

Bhilawanol. **Explanation:** The question asks to identify the substance that is **not** an active principle of *Calotropis* (Madar). **1. Why Bhilawanol is the correct answer:** **Bhilawanol** (specifically Bhilawanol A and B) is the active irritant principle found in **Semecarpus anacardium** (Marking Nut/Bhilawa), not *Calotropis*. It is a catechol derivative that causes severe blistering and dermatitis upon contact with the skin. **2. Analysis of Incorrect Options (Active Principles of Calotropis):** *Calotropis procera* and *Calotropis gigantea* contain potent **cardiac glycosides** in their milky white sap (latex). * **A. Calotoxin:** A primary cardiac glycoside found in the latex. * **B. Calactin:** Another specific cardiac glycoside that acts similarly to Digitalis. * **C. Uscharin:** A potent sulfur-containing cardiac glycoside found in the plant. * *Note:* Other principles include **Calotropin** and **Gigantin**. **3. Clinical Pearls for NEET-PG:** * **Classification:** *Calotropis* is classified as an **Irritant Organic (Vegetable) poison**, but its systemic action is primarily **cardiotoxic** (Digitalis-like action). * **Medical Importance:** It is commonly used as an **abortifacient** (applied via an 'abortion stick') and for **infanticide**. * **Post-mortem Finding:** A characteristic finding in *Calotropis* poisoning is **dilated pupils** and stomatitis, along with GI irritation. * **Marking Nut (Bhilawanol) Tip:** The juice of the Marking Nut is used by malingerers to produce **artificial bruises** (distinguished from real bruises by the presence of acrid serum and absence of color changes).

Q: What is the meaning of the term 'vitriolage'?

Vitriol throwing. **Explanation:** **Vitriolage** refers to the act of throwing a corrosive substance (strong acids or alkalis) onto a person with the intent to disfigure, maim, or cause grievous hurt. The term is derived from ‘Blue Vitriol’ (Copper Sulphate) or ‘Oil of Vitriol’ (Concentrated Sulphuric Acid), which was historically the most common agent used. * **Why Option C is Correct:** Vitriolage is legally defined as the deliberate act of throwing corrosive chemicals. It is typically motivated by jealousy, revenge, or domestic disputes. Sulphuric acid is the most common agent, followed by Nitric acid (Aqua fortis) and Hydrochloric acid (Muriatic acid). * **Why Options A & B are Incorrect:** While vitriol can be used for suicide or murder, these are not the definitions of the term "vitriolage." Ingesting acid for suicide is rare due to the intense pain, and using it for murder is uncommon as it usually causes disfigurement rather than immediate death. * **Why Option D is Incorrect:** Perforation of the stomach by H2SO4 is a clinical complication of acid ingestion (often resulting in a "charred" or "blackened" stomach), but it is not the definition of the act itself. **High-Yield NEET-PG Pearls:** 1. **Legal Aspect:** Under the Indian Penal Code, vitriolage is dealt with under **Sections 326A** (causing grievous hurt by use of acid) and **326B** (attempting to throw acid). 2. **Clinical Presentation:** It causes **coagulative necrosis**, leading to deep, trickling burns (running down marks) and permanent scarring (keloids). 3. **Eye Involvement:** The most serious complication is permanent blindness due to corneal opacification. 4. **Antidote:** Immediate irrigation with large amounts of water is the gold standard for management. Do not use weak bases for neutralization as the exothermic reaction can worsen the burn.

Q: What is the treatment of choice for a scorpion bite?

Anti-venom. **Explanation:** The treatment of choice for a scorpion sting (specifically from the clinically significant *Mesobuthus tamulus* or Indian Red Scorpion) is **Scorpion Antivenom (SAV)**. The underlying medical concept is the neutralization of circulating toxins [1]. Scorpion venom contains complex neurotoxins that cause a massive release of endogenous catecholamines (a "sympathetic storm"). Administering antivenom early neutralizes the venom before it can bind to sodium channels, preventing severe systemic manifestations like pulmonary edema and myocardial dysfunction. **Analysis of Incorrect Options:** * **B. Insulin:** While high-dose insulin euglycemia therapy is used in some calcium channel blocker toxicities, it has no role in neutralizing scorpion venom. However, hyperglycemia is a common finding in scorpion stings due to the catecholamine surge. * **C. Steroids:** There is no evidence that steroids improve outcomes in scorpion envenomation. They do not neutralize the toxin or counteract the autonomic effects. * **D. Atropine:** This is **contraindicated** in scorpion stings. While it may reduce secretions, it blocks the parasympathetic system, further exacerbating the dangerous tachycardia and hypertension caused by the sympathetic storm. **High-Yield Clinical Pearls for NEET-PG:** * **Prazosin:** This is the **pharmacological drug of choice** to counteract the alpha-receptor-mediated effects (hypertension and pulmonary edema). It acts as a physiological antagonist to the venom's effects. * **Grading:** Most stings are managed with Prazosin; Antivenom is specifically indicated for severe systemic envenomation (Grade III/IV) [1]. * **Avoid:** Atropine and ACE inhibitors should be avoided. * **Mechanism of Death:** The most common cause of death following a scorpion sting is **acute pulmonary edema** and cardiogenic shock.

Question 1

While dispatching blood and urine for chemical analysis, sodium fluoride is added as a preservative in which concentration?

Accepted Answer

100 mg/10 ml

Answer

30 mg/10 ml

Answer

40 mg/10 ml

Answer

50 mg/ml

Question 2

Marking nut is

Accepted Answer

Semicarpus anacardium

Answer

Croton tiglium

Answer

Areca catechu

Answer

Abrus precatorius

Question 3

Artificial bruise is commonly seen in which of the following irritant poisons?

Accepted Answer

Semicarpus anacardium

Answer

Strychnos nux vomica

Answer

Abrus precatorius

Answer

Capsicum annum

Question 4

Which of the following is true about strychnine poisoning?

Accepted Answer

All muscles are affected at the same time.

Answer

The shoulder girdle is affected first.

Answer

The pelvic girdle is affected first.

Answer

None of the above.

Question 5

Which of the following is NOT an active principal found in Calotropis?

Accepted Answer

Bhilawanol

Answer

Calotoxin

Answer

Calactin

Answer

Uscharin

Question 6

Which of the following is true for the preservation of liver in case of poisoning, except?

Accepted Answer

Liver is stored as a whole in a container

Answer

500 grams of liver is preserved in adults

Answer

Whole liver is preserved in infants

Answer

Gall bladder is also included in paracetamol poisoning

Question 7

Gastric lavage is contraindicated in which of the following poisoning scenarios? 1. Kerosene poisoning 2. Organo-phosphorus poisoning 3. Corrosive poisoning 4. Iron poisoning

Accepted Answer

1 and 3 only

Answer

1 only

Answer

2 and 4 only

Answer

1, 2, 3 and 4

Question 8

What is the meaning of the term 'vitriolage'?

Accepted Answer

Vitriol throwing

Answer

Using vitriol for suicide

Answer

Using vitriol for murder

Answer

Perforation of stomach caused by H2SO4

Question 9

What is the treatment of choice for a scorpion bite?

Accepted Answer

Anti-venom

Answer

Insulin

Answer

Steroids

Answer

Atropine

Question 10

Delicate, brown or black pigmented non-carious plaque found on the enamel at the cervical margin of the tooth is:

Accepted Answer

Mesenteric line

Answer

Burtonian line

Answer

Argyria

Answer

Bismuth line

Forensic Toxicology — MCQs

Forensic Toxicology — MCQs

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