Abdominal and GI imaging: acute colonic pseudo-obstruction: practice question

A Radiology 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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Radiology · Abdominal and GI imaging: acute colonic pseudo-obstruction

Sample item

An elderly man develops abdominal distension after hip surgery. A plain film shows a markedly dilated caecum and right colon with gas reaching the rectum, and CT shows no transition point or mechanical lesion. What is the diagnosis?

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

The answer and the reasoning

A. Acute colonic pseudo-obstruction

Ogilvie syndrome is functional dilatation of the colon without a mechanical block, seen after surgery, trauma and critical illness. Gas through to the rectum and no transition point on CT confirm the diagnosis, and caecal diameter guides the risk of perforation.

Option by option

  • A. Acute colonic pseudo-obstruction (correct)

    Correct. Colonic dilatation with no mechanical cause is pseudo-obstruction.

  • B. Toxic megacolon

    Toxic megacolon arises in colitis with systemic toxicity and loss of haustra, not after surgery in a well patient.

  • C. Sigmoid volvulus

    Sigmoid volvulus shows a massively dilated closed loop from the pelvis, with the coffee-bean sign.

  • D. Obstructing rectosigmoid carcinoma

    A carcinoma would show a transition point with collapsed bowel distally on CT.

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 Radiology question

What is the answer to this Radiology question?

The best answer is A, Acute colonic pseudo-obstruction. Ogilvie syndrome is functional dilatation of the colon without a mechanical block, seen after surgery, trauma and critical illness.

Why is "Toxic megacolon" not the answer?

Toxic megacolon arises in colitis with systemic toxicity and loss of haustra, not after surgery in a well patient.

Why is "Sigmoid volvulus" not the answer?

Sigmoid volvulus shows a massively dilated closed loop from the pelvis, with the coffee-bean sign.

Why is "Obstructing rectosigmoid carcinoma" not the answer?

A carcinoma would show a transition point with collapsed bowel distally on CT.

What concept does this question test?

It tests Abdominal and GI imaging: acute colonic pseudo-obstruction in Radiology. Gas through to the rectum and no transition point on CT confirm the diagnosis, and caecal diameter guides the risk of perforation.

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 Abdominal and GI imaging: acute colonic pseudo-obstruction?

Learn signs with the image, and the disease they point to. Then use the flashcards and the other Radiology 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.