Inflammation: kinin system and hereditary angioedema: 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.

Try it

Pathology · Inflammation: kinin system and hereditary angioedema

Sample item

A 22-year-old woman has recurrent episodes of non-pitting facial and laryngeal swelling and colicky abdominal pain without urticaria. Her father had similar symptoms, and serum C4 is low even between attacks. Antihistamines and adrenaline give no relief. Which mediator is chiefly responsible for the swelling?

ABradykininBTumour necrosis factorCHistamineDC5a anaphylatoxin

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

The answer and the reasoning

A. Bradykinin

Hereditary angioedema is due to C1 esterase inhibitor deficiency, which allows unchecked activation of the kallikrein-kinin system and excess bradykinin. Bradykinin increases vascular permeability and causes swelling without itch or urticaria. The poor response to antihistamines and adrenaline distinguishes it from allergic angioedema. ACE inhibitors may cause similar swelling by impairing bradykinin breakdown.

Option by option

A. Bradykinin (correct)
Correct. Excess bradykinin from loss of C1 inhibitor control causes the swelling.
B. Tumour necrosis factor
Tumour necrosis factor causes systemic inflammatory effects such as fever, not episodic angioedema.
C. Histamine
Histamine mediates allergic angioedema, which comes with urticaria and responds to antihistamines and adrenaline.
D. C5a anaphylatoxin
C5a is an anaphylatoxin released in complement activation, but the lack of C1 inhibitor does not cause its overproduction.

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 A, Bradykinin. Hereditary angioedema is due to C1 esterase inhibitor deficiency, which allows unchecked activation of the kallikrein-kinin system and excess bradykinin.

Why is "Tumour necrosis factor" not the answer?

Tumour necrosis factor causes systemic inflammatory effects such as fever, not episodic angioedema.

Why is "Histamine" not the answer?

Histamine mediates allergic angioedema, which comes with urticaria and responds to antihistamines and adrenaline.

Why is "C5a anaphylatoxin" not the answer?

C5a is an anaphylatoxin released in complement activation, but the lack of C1 inhibitor does not cause its overproduction.

What concept does this question test?

It tests Inflammation: kinin system and hereditary angioedema in Pathology. Bradykinin increases vascular permeability and causes swelling without itch or urticaria. The poor response to antihistamines and adrenaline distinguishes it from allergic angioedema. ACE inhibitors may cause similar swelling by impairing bradykinin breakdown.

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: kinin system and hereditary angioedema?

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.