Emergency and critical care: paraquat poisoning oxygen: practice question

A General 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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General Medicine · Emergency and critical care: paraquat poisoning oxygen

Sample item

A farmer who drank a herbicide has ulcers in the mouth and then progressive breathlessness with pulmonary fibrosis over several days. The team avoids giving oxygen unless there is severe hypoxia. What is the reason?

AOxygen suppresses the respiratory driveBOxygen increases superoxide generation and worsens lung injuryCOxygen increases absorption of the poison from the gutDOxygen causes severe bronchospasm

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

The answer and the reasoning

B. Oxygen increases superoxide generation and worsens lung injury

Paraquat undergoes redox cycling in the lung, generating superoxide radicals. High oxygen concentrations increase this free radical injury, so oxygen is given only for severe hypoxia. Gastrointestinal decontamination with adsorbents is given early, and prognosis depends on the amount ingested.

Option by option

A. Oxygen suppresses the respiratory drive
Suppression of the respiratory drive is a concern in chronic carbon dioxide retention, not here.
B. Oxygen increases superoxide generation and worsens lung injury (correct)
Correct. Oxygen fuels radical formation from redox cycling and so worsens injury.
C. Oxygen increases absorption of the poison from the gut
Oxygen has no effect on absorption of poison from the gut.
D. Oxygen causes severe bronchospasm
Bronchospasm is not the reason, and the pulmonary injury is a fibrosing alveolitis.

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.

Questions about this General Medicine question

What is the answer to this General Medicine question?

The best answer is B, Oxygen increases superoxide generation and worsens lung injury. Paraquat undergoes redox cycling in the lung, generating superoxide radicals.

Why is "Oxygen suppresses the respiratory drive" not the answer?

Suppression of the respiratory drive is a concern in chronic carbon dioxide retention, not here.

Why is "Oxygen increases absorption of the poison from the gut" not the answer?

Oxygen has no effect on absorption of poison from the gut.

Why is "Oxygen causes severe bronchospasm" not the answer?

Bronchospasm is not the reason, and the pulmonary injury is a fibrosing alveolitis.

What concept does this question test?

It tests Emergency and critical care: paraquat poisoning oxygen in General Medicine. High oxygen concentrations increase this free radical injury, so oxygen is given only for severe hypoxia. Gastrointestinal decontamination with adsorbents is given early, and prognosis depends on the amount ingested.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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 Emergency and critical care: paraquat poisoning oxygen?

For each disease know the classic presentation, the best test, and the first-line treatment. Then use the flashcards and the other General 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.