A case of poisoning was brought to the casualty, a gastric lavage was done, and the lavage turned black when it was heated after being treated with silver nitrate. The poisoning is most likely to have been due to which of the following?

Question

Image below highlights jugular foramen. Which of the following structures do not pass through the marked structure “A”?

Answer 1

The clue in this question is a specific chemical test, silver nitrate added to gastric lavage fluid turns black on heating. This test detects a particular gas, so let's work out which poison releases that gas.

Tik-20: This name is loosely linked with phosphide type poisons in general use, but it is not the compound the silver nitrate blackening test is classically tied to in toxicology teaching.
Celfos: This is a well known trade name for aluminium phosphide, a solid pesticide that releases phosphine gas on contact with moisture or stomach acid. Phosphine is a strong reducing agent, and it reduces silver nitrate to metallic silver on heating, turning the mixture black, exactly the finding described.
Malathion: An organophosphate insecticide that blocks acetylcholinesterase, causing salivation, small pupils and muscle twitching, it does not release phosphine, so it will not blacken silver nitrate.
Parathion: Another organophosphate with the same cholinergic mechanism as malathion, and again no phosphine gas is released, so this test would stay negative.

The correct option is Celfos, since aluminium phosphide is the compound whose phosphine gas gives this specific silver nitrate blackening reaction on heating.

Let's summarize:

Silver nitrate turning black on heating is a test for phosphine gas, released from metal phosphide poisons.
Malathion and parathion are organophosphates that act through a different mechanism, cholinesterase inhibition, and do not give this test.

So the poisoning here is most likely due to Celfos, an aluminium phosphide compound.

Answer 2

The clue in this question is a specific chemical test, silver nitrate added to gastric lavage fluid turns black on heating. This test detects a particular gas, so let's work out which poison releases that gas.

Tik-20: This name is loosely linked with phosphide type poisons in general use, but it is not the compound the silver nitrate blackening test is classically tied to in toxicology teaching.
Celfos: This is a well known trade name for aluminium phosphide, a solid pesticide that releases phosphine gas on contact with moisture or stomach acid. Phosphine is a strong reducing agent, and it reduces silver nitrate to metallic silver on heating, turning the mixture black, exactly the finding described.
Malathion: An organophosphate insecticide that blocks acetylcholinesterase, causing salivation, small pupils and muscle twitching, it does not release phosphine, so it will not blacken silver nitrate.
Parathion: Another organophosphate with the same cholinergic mechanism as malathion, and again no phosphine gas is released, so this test would stay negative.

The correct option is Celfos, since aluminium phosphide is the compound whose phosphine gas gives this specific silver nitrate blackening reaction on heating.

Let's summarize:

Silver nitrate turning black on heating is a test for phosphine gas, released from metal phosphide poisons.
Malathion and parathion are organophosphates that act through a different mechanism, cholinesterase inhibition, and do not give this test.

So the poisoning here is most likely due to Celfos, an aluminium phosphide compound.

A case of poisoning was brought to the casualty, a gastric lavage was done, and the lavage turned black when it was heated after being treated with silver nitrate. The poisoning is most likely to have been due to which of the following?

Show Hint

The Correct Option is B

Solution and Explanation

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