GI imaging: gallstone ileus: 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 · GI imaging: gallstone ileus

Sample item

An elderly woman with a history of gallstones has vomiting and abdominal distension. A plain abdominal film shows dilated small bowel loops, gas in the biliary tree and an ectopic calcified stone in the right lower abdomen. What is the diagnosis?

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

The answer and the reasoning

C. Gallstone ileus from a cholecystoduodenal fistula

A large gallstone erodes through the gallbladder wall into the duodenum and obstructs the distal small bowel, commonly at the ileocaecal valve. Rigler triad is small bowel obstruction, pneumobilia and an ectopic gallstone.

Option by option

  • A. Paralytic ileus after surgery

    Paralytic ileus has no ectopic stone or biliary air.

  • B. Sigmoid volvulus

    Sigmoid volvulus shows a massively dilated coffee-bean loop and no biliary gas.

  • C. Gallstone ileus from a cholecystoduodenal fistula (correct)

    Correct. Obstruction, pneumobilia and an ectopic stone form the Rigler triad of gallstone ileus.

  • D. Acute appendicitis with appendicolith

    An appendicolith would not cause biliary gas or such a dilated small bowel.

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 C, Gallstone ileus from a cholecystoduodenal fistula. A large gallstone erodes through the gallbladder wall into the duodenum and obstructs the distal small bowel, commonly at the ileocaecal valve.

Why is "Paralytic ileus after surgery" not the answer?

Paralytic ileus has no ectopic stone or biliary air.

Why is "Sigmoid volvulus" not the answer?

Sigmoid volvulus shows a massively dilated coffee-bean loop and no biliary gas.

Why is "Acute appendicitis with appendicolith" not the answer?

An appendicolith would not cause biliary gas or such a dilated small bowel.

What concept does this question test?

It tests GI imaging: gallstone ileus in Radiology. Rigler triad is small bowel obstruction, pneumobilia and an ectopic gallstone.

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 GI imaging: gallstone ileus?

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.