Toxicology: paraquat: practice question

A Forensic Medicine question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Forensic Medicine · Toxicology: paraquat

Sample item

A farmer who swallowed a green weedicide has oral ulcers, vomiting and rising creatinine. A bedside urine test turns blue after adding sodium dithionite in alkaline solution. Which poison is confirmed?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. Paraquat

Paraquat urine is turned blue by alkaline sodium dithionite, a rapid test that indicates ingestion. Paraquat causes oropharyngeal ulceration, renal and hepatic injury and progressive pulmonary fibrosis through generation of reactive oxygen species. Early adsorption with Fuller's earth or charcoal and avoidance of unnecessary oxygen are part of management.

Option by option

  • A. Aluminium phosphide

    Aluminium phosphide gives phosphine gas with a garlic odour and shock rather than this test result.

  • B. Paraquat (correct)

    Correct. The dithionite test turns paraquat urine blue.

  • C. Endosulfan

    Endosulfan produces seizures, and the dithionite test is not used for it.

  • D. Organophosphate

    Organophosphates cause cholinergic features, and the test would be negative.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Forensic Medicine question

What is the answer to this Forensic Medicine question?

The best answer is B, Paraquat. Paraquat urine is turned blue by alkaline sodium dithionite, a rapid test that indicates ingestion.

Why is "Aluminium phosphide" not the answer?

Aluminium phosphide gives phosphine gas with a garlic odour and shock rather than this test result.

Why is "Endosulfan" not the answer?

Endosulfan produces seizures, and the dithionite test is not used for it.

Why is "Organophosphate" not the answer?

Organophosphates cause cholinergic features, and the test would be negative.

What concept does this question test?

It tests Toxicology: paraquat in Forensic Medicine. Paraquat causes oropharyngeal ulceration, renal and hepatic injury and progressive pulmonary fibrosis through generation of reactive oxygen species. Early adsorption with Fuller's earth or charcoal and avoidance of unnecessary oxygen are part of management.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Toxicology: paraquat?

Learn postmortem changes with their timelines, and toxicology as poison, sign, test and antidote. Then use the flashcards and the other Forensic Medicine questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.