General physiology: lymphatic obstruction and oedema: practice question

A Physiology 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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Physiology · General physiology: lymphatic obstruction and oedema

Sample item

A 40-year-old man from a filariasis-endemic area has gross swelling of the left leg. Aspirated interstitial fluid has a high protein concentration. Which mechanism best explains the persistent swelling?

AIncreased capillary permeability from local histamine releaseBBlocked lymphatic return, so filtered fluid and interstitial protein accumulate and raise interstitial oncotic pressureCLow plasma albumin lowering capillary oncotic pressureDRaised capillary hydrostatic pressure from venous valve incompetence

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

The answer and the reasoning

B. Blocked lymphatic return, so filtered fluid and interstitial protein accumulate and raise interstitial oncotic pressure

Lymphatics return about 2 to 4 L of fluid and all filtered plasma protein to the circulation each day. When they are obstructed, protein cannot be cleared; interstitial oncotic pressure rises, drawing more fluid out and producing protein-rich, progressively fibrotic oedema.

Option by option

A. Increased capillary permeability from local histamine release
Histamine-type permeability changes produce transient oedema such as urticaria, not chronic limb swelling.
B. Blocked lymphatic return, so filtered fluid and interstitial protein accumulate and raise interstitial oncotic pressure (correct)
Correct. Failure of lymphatic clearance traps protein and fluid.
C. Low plasma albumin lowering capillary oncotic pressure
Hypoalbuminaemia produces protein-poor oedema, as in nephrotic syndrome or cirrhosis.
D. Raised capillary hydrostatic pressure from venous valve incompetence
Venous hypertension raises hydrostatic pressure but gives lower-protein oedema and does not match a filarial picture.

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 Physiology question

What is the answer to this Physiology question?

The best answer is B, Blocked lymphatic return, so filtered fluid and interstitial protein accumulate and raise interstitial oncotic pressure. Lymphatics return about 2 to 4 L of fluid and all filtered plasma protein to the circulation each day.

Why is "Increased capillary permeability from local histamine release" not the answer?

Histamine-type permeability changes produce transient oedema such as urticaria, not chronic limb swelling.

Why is "Low plasma albumin lowering capillary oncotic pressure" not the answer?

Hypoalbuminaemia produces protein-poor oedema, as in nephrotic syndrome or cirrhosis.

Why is "Raised capillary hydrostatic pressure from venous valve incompetence" not the answer?

Venous hypertension raises hydrostatic pressure but gives lower-protein oedema and does not match a filarial picture.

What concept does this question test?

It tests General physiology: lymphatic obstruction and oedema in Physiology. When they are obstructed, protein cannot be cleared; interstitial oncotic pressure rises, drawing more fluid out and producing protein-rich, progressively fibrotic oedema.

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 General physiology: lymphatic obstruction and oedema?

For each system, sketch the key graph (pressure–volume loop, oxygen dissociation curve, nephron handling) and explain it aloud. Then use the flashcards and the other Physiology 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.