Asphyxial deaths: arterial gas embolism in divers: 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 · Asphyxial deaths: arterial gas embolism in divers

Sample item

A trainee scuba diver panics and rises rapidly to the surface while holding his breath. On reaching the surface he collapses with right hemiparesis and aphasia. What is the mechanism?

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

The answer and the reasoning

D. Alveolar rupture with air entering the pulmonary veins

Air in the lungs expands as the pressure falls on ascent. If the breath is held, the alveoli rupture and gas enters the pulmonary veins and left heart, from which it reaches the brain as arterial gas embolism. Onset is within minutes of surfacing, and treatment is recompression.

Option by option

  • A. Nitrogen narcosis impairing judgement

    Narcosis occurs at depth and clears on ascent, with no focal deficit.

  • B. Nitrogen bubbles forming in the joints

    Joint bubbles cause the bends, with pain after a delay rather than sudden stroke-like signs on surfacing.

  • C. Seizures from oxygen toxicity

    Oxygen toxicity causes seizures, not focal hemiparesis with aphasia.

  • D. Alveolar rupture with air entering the pulmonary veins (correct)

    Correct. Pulmonary barotrauma lets air pass to the brain through the arterial circulation.

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 D, Alveolar rupture with air entering the pulmonary veins. Air in the lungs expands as the pressure falls on ascent.

Why is "Nitrogen narcosis impairing judgement" not the answer?

Narcosis occurs at depth and clears on ascent, with no focal deficit.

Why is "Nitrogen bubbles forming in the joints" not the answer?

Joint bubbles cause the bends, with pain after a delay rather than sudden stroke-like signs on surfacing.

Why is "Seizures from oxygen toxicity" not the answer?

Oxygen toxicity causes seizures, not focal hemiparesis with aphasia.

What concept does this question test?

It tests Asphyxial deaths: arterial gas embolism in divers in Forensic Medicine. If the breath is held, the alveoli rupture and gas enters the pulmonary veins and left heart, from which it reaches the brain as arterial gas embolism. Onset is within minutes of surfacing, and treatment is recompression.

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 Asphyxial deaths: arterial gas embolism in divers?

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.