Gastroenterology: Zollinger-Ellison syndrome: 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: Zollinger-Ellison syndrome

Sample item

A 38-year-old man has recurrent ulcers in the duodenum and proximal jejunum with chronic diarrhoea. Fasting serum gastrin is 450 pg/mL (normal below 100) and basal gastric pH is 1.4. Which test best confirms the diagnosis?

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

The answer and the reasoning

D. Intravenous secretin test showing a paradoxical rise in serum gastrin

A gastrinoma secretes gastrin autonomously, so acid output is high and the gastric pH is below 2. Secretin normally inhibits G-cell gastrin release, but in a gastrinoma it causes a paradoxical rise of 120 pg/mL or more. Gastrinomas are linked to MEN1 in a minority of cases.

Option by option

  • A. Serum calcitonin level

    Calcitonin is a marker of medullary thyroid carcinoma and does not identify a gastrinoma.

  • B. Serum chromogranin A alone

    Chromogranin A is raised in many neuroendocrine tumours and by acid suppression, so it is not specific for gastrinoma.

  • C. Urea breath test

    A breath test detects H. pylori, which does not explain multiple jejunal ulcers with diarrhoea and a very low gastric pH.

  • D. Intravenous secretin test showing a paradoxical rise in serum gastrin (correct)

    Correct. A paradoxical gastrin rise after secretin is the confirmatory provocative test.

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, Intravenous secretin test showing a paradoxical rise in serum gastrin. A gastrinoma secretes gastrin autonomously, so acid output is high and the gastric pH is below 2.

Why is "Serum calcitonin level" not the answer?

Calcitonin is a marker of medullary thyroid carcinoma and does not identify a gastrinoma.

Why is "Serum chromogranin A alone" not the answer?

Chromogranin A is raised in many neuroendocrine tumours and by acid suppression, so it is not specific for gastrinoma.

Why is "Urea breath test" not the answer?

A breath test detects H. pylori, which does not explain multiple jejunal ulcers with diarrhoea and a very low gastric pH.

What concept does this question test?

It tests Gastroenterology: Zollinger-Ellison syndrome in General Medicine. Secretin normally inhibits G-cell gastrin release, but in a gastrinoma it causes a paradoxical rise of 120 pg/mL or more. Gastrinomas are linked to MEN1 in a minority of cases.

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 Gastroenterology: Zollinger-Ellison syndrome?

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.