Inflammation: vascular permeability: practice question

A Pathology 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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Pathology · Inflammation: vascular permeability

Sample item

A farmer is stung by a wasp and develops local swelling within minutes, which subsides over about an hour. Which mechanism is responsible for the increased vascular permeability in this early response?

ALeukocyte-mediated damage to the endotheliumBHistamine-induced contraction of endothelial cells in post-capillary venulesCDirect necrosis of endothelial cells by a toxinDReduced plasma oncotic pressure from protein loss

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

The answer and the reasoning

B. Histamine-induced contraction of endothelial cells in post-capillary venules

The immediate transient response to mild injury is due to mediators such as histamine, bradykinin and leukotrienes, which cause contraction of endothelial cells and widening of gaps in venules. It appears within minutes and subsides within 30 minutes or so. Direct injury and leukocyte-mediated injury produce sustained leakage lasting hours to days.

Option by option

A. Leukocyte-mediated damage to the endothelium
Leukocyte-mediated endothelial injury is a later and prolonged mechanism involving oxygen radicals and enzymes.
B. Histamine-induced contraction of endothelial cells in post-capillary venules (correct)
Correct. Histamine acting on venules opens interendothelial gaps rapidly and briefly.
C. Direct necrosis of endothelial cells by a toxin
Direct endothelial necrosis gives immediate but sustained leakage, as in severe burns.
D. Reduced plasma oncotic pressure from protein loss
Reduced oncotic pressure causes transudates, as in nephrotic syndrome, and does not explain a rapid local reaction.

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 Pathology question

What is the answer to this Pathology question?

The best answer is B, Histamine-induced contraction of endothelial cells in post-capillary venules. The immediate transient response to mild injury is due to mediators such as histamine, bradykinin and leukotrienes, which cause contraction of endothelial cells and widening of gaps in venules.

Why is "Leukocyte-mediated damage to the endothelium" not the answer?

Leukocyte-mediated endothelial injury is a later and prolonged mechanism involving oxygen radicals and enzymes.

Why is "Direct necrosis of endothelial cells by a toxin" not the answer?

Direct endothelial necrosis gives immediate but sustained leakage, as in severe burns.

Why is "Reduced plasma oncotic pressure from protein loss" not the answer?

Reduced oncotic pressure causes transudates, as in nephrotic syndrome, and does not explain a rapid local reaction.

What concept does this question test?

It tests Inflammation: vascular permeability in Pathology. It appears within minutes and subsides within 30 minutes or so. Direct injury and leukocyte-mediated injury produce sustained leakage lasting hours to days.

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 Inflammation: vascular permeability?

Learn each disease as a bundle: cause, key histology, markers, and the clinical hallmark. Then use the flashcards and the other Pathology 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.