Respiratory medicine: flow-volume loop in tracheal stenosis: 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: flow-volume loop in tracheal stenosis

Sample item

A 45-year-old woman who was intubated for 3 weeks four months ago has inspiratory stridor and exertional breathlessness. Spirometry shows a flow-volume loop with a plateau of flow on both inspiration and expiration. What type of lesion does this indicate?

ARestrictive lung diseaseBFixed upper airway obstructionCVariable intrathoracic obstructionDVariable extrathoracic obstruction

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

The answer and the reasoning

B. Fixed upper airway obstruction

A fixed narrowing, such as post-intubation tracheal stenosis, limits flow in both phases of breathing, giving a plateau in both limbs of the loop. Variable extrathoracic lesions limit inspiration only, and variable intrathoracic lesions limit expiration only.

Option by option

A. Restrictive lung disease
Restrictive disease gives a small loop with preserved shape, not a plateau.
B. Fixed upper airway obstruction (correct)
Correct. A fixed lesion limits flow in both inspiration and expiration.
C. Variable intrathoracic obstruction
A variable intrathoracic lesion flattens only the expiratory limb.
D. Variable extrathoracic obstruction
A variable extrathoracic lesion flattens only the inspiratory limb.

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, Fixed upper airway obstruction. A fixed narrowing, such as post-intubation tracheal stenosis, limits flow in both phases of breathing, giving a plateau in both limbs of the loop.

Why is "Restrictive lung disease" not the answer?

Restrictive disease gives a small loop with preserved shape, not a plateau.

Why is "Variable intrathoracic obstruction" not the answer?

A variable intrathoracic lesion flattens only the expiratory limb.

Why is "Variable extrathoracic obstruction" not the answer?

A variable extrathoracic lesion flattens only the inspiratory limb.

What concept does this question test?

It tests Respiratory medicine: flow-volume loop in tracheal stenosis in General Medicine. Variable extrathoracic lesions limit inspiration only, and variable intrathoracic lesions limit expiration only.

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 Respiratory medicine: flow-volume loop in tracheal stenosis?

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.