Gastroenterology and hepatology: gallstone ileus: practice question

A General Medicine 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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General Medicine · Gastroenterology and hepatology: gallstone ileus

Sample item

A 75-year-old woman with previous gallstone attacks has 3 days of vomiting and colicky abdominal pain. A radiograph shows dilated small bowel loops and gas in the biliary tree. What is the most likely mechanism?

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

The answer and the reasoning

D. A large gallstone eroded into the duodenum and obstructed the terminal ileum

A large gallstone erodes through the gallbladder wall into the duodenum, forming a cholecystoenteric fistula, and lodges in the narrow terminal ileum. Small bowel obstruction with pneumobilia and an ectopic gallstone make up Rigler triad.

Option by option

  • A. Carcinoma of the caecum

    A caecal carcinoma would cause large bowel obstruction and not biliary air.

  • B. An adhesion band from previous surgery

    Adhesional obstruction would not explain gas in the biliary tree.

  • C. A strangulated femoral hernia

    A strangulated hernia would be seen on examination and does not cause biliary gas.

  • D. A large gallstone eroded into the duodenum and obstructed the terminal ileum (correct)

    Correct. A stone passing through a fistula into the bowel obstructs the terminal ileum and explains the biliary air.

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 General Medicine question

What is the answer to this General Medicine question?

The best answer is D, A large gallstone eroded into the duodenum and obstructed the terminal ileum. A large gallstone erodes through the gallbladder wall into the duodenum, forming a cholecystoenteric fistula, and lodges in the narrow terminal ileum.

Why is "Carcinoma of the caecum" not the answer?

A caecal carcinoma would cause large bowel obstruction and not biliary air.

Why is "An adhesion band from previous surgery" not the answer?

Adhesional obstruction would not explain gas in the biliary tree.

Why is "A strangulated femoral hernia" not the answer?

A strangulated hernia would be seen on examination and does not cause biliary gas.

What concept does this question test?

It tests Gastroenterology and hepatology: gallstone ileus in General Medicine. Small bowel obstruction with pneumobilia and an ectopic gallstone make up Rigler triad.

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 Gastroenterology and hepatology: gallstone ileus?

For each disease know the classic presentation, the best test, and the first-line treatment. Then use the flashcards and the other General Medicine 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.