Respiratory medicine: acetazolamide at altitude: 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 · Respiratory medicine: acetazolamide at altitude

Sample item

A mountaineer who had severe headache and nausea on a previous ascent is advised acetazolamide before a trek to 4,000 m. How does it help prevent acute mountain sickness?

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

The answer and the reasoning

A. Causes a metabolic acidosis that stimulates ventilation

Acetazolamide inhibits carbonic anhydrase, causing a bicarbonate diuresis and mild metabolic acidosis that increases ventilatory drive, which improves oxygenation and speeds acclimatisation. Slow ascent remains the most important preventive measure.

Option by option

  • A. Causes a metabolic acidosis that stimulates ventilation (correct)

    Correct. The induced acidosis drives ventilation and improves acclimatisation.

  • B. Reduces cerebral oedema by osmotic action

    Osmotic reduction of cerebral oedema is the action of mannitol, not acetazolamide.

  • C. Dilates the pulmonary arteries directly

    Pulmonary vasodilation is the action of nifedipine in pulmonary oedema, not acetazolamide.

  • D. Raises haemoglobin oxygen affinity

    Raising haemoglobin affinity would reduce tissue oxygen delivery, and this is not its action.

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 General Medicine question

What is the answer to this General Medicine question?

The best answer is A, Causes a metabolic acidosis that stimulates ventilation. Acetazolamide inhibits carbonic anhydrase, causing a bicarbonate diuresis and mild metabolic acidosis that increases ventilatory drive, which improves oxygenation and speeds acclimatisation.

Why is "Reduces cerebral oedema by osmotic action" not the answer?

Osmotic reduction of cerebral oedema is the action of mannitol, not acetazolamide.

Why is "Dilates the pulmonary arteries directly" not the answer?

Pulmonary vasodilation is the action of nifedipine in pulmonary oedema, not acetazolamide.

Why is "Raises haemoglobin oxygen affinity" not the answer?

Raising haemoglobin affinity would reduce tissue oxygen delivery, and this is not its action.

What concept does this question test?

It tests Respiratory medicine: acetazolamide at altitude in General Medicine. Slow ascent remains the most important preventive measure.

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 Respiratory medicine: acetazolamide at altitude?

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.