Gastroenterology: carcinoid 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: carcinoid syndrome

Sample item

A 55-year-old man has episodic facial flushing, watery diarrhoea and wheeze. CT shows an ileal mass with multiple liver metastases. Which test is the most useful to confirm the diagnosis?

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

The answer and the reasoning

C. 24-hour urinary 5-hydroxyindoleacetic acid

Serotonin from a midgut carcinoid is normally inactivated by the liver. When hepatic metastases release it directly into the hepatic veins, flushing, diarrhoea and bronchospasm result. Its metabolite 5-HIAA is raised in a 24-hour urine collection, and serotonin-rich foods should be avoided before the test.

Option by option

  • A. Serum gastrin

    Gastrin is raised in gastrinoma, which causes ulcer disease and diarrhoea, not flushing and bronchospasm.

  • B. Serum vasoactive intestinal peptide

    VIP is raised in VIPoma, which causes profuse watery diarrhoea but not an ileal mass with flushing and wheeze.

  • C. 24-hour urinary 5-hydroxyindoleacetic acid (correct)

    Correct. 5-HIAA is the urinary serotonin metabolite and confirms a secreting carcinoid.

  • D. 24-hour urinary metanephrines

    Metanephrines are raised in phaeochromocytoma, which causes sweating and hypertension rather than this 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.

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Questions about this General Medicine question

What is the answer to this General Medicine question?

The best answer is C, 24-hour urinary 5-hydroxyindoleacetic acid. Serotonin from a midgut carcinoid is normally inactivated by the liver.

Why is "Serum gastrin" not the answer?

Gastrin is raised in gastrinoma, which causes ulcer disease and diarrhoea, not flushing and bronchospasm.

Why is "Serum vasoactive intestinal peptide" not the answer?

VIP is raised in VIPoma, which causes profuse watery diarrhoea but not an ileal mass with flushing and wheeze.

Why is "24-hour urinary metanephrines" not the answer?

Metanephrines are raised in phaeochromocytoma, which causes sweating and hypertension rather than this picture.

What concept does this question test?

It tests Gastroenterology: carcinoid syndrome in General Medicine. When hepatic metastases release it directly into the hepatic veins, flushing, diarrhoea and bronchospasm result. Its metabolite 5-HIAA is raised in a 24-hour urine collection, and serotonin-rich foods should be avoided before the test.

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: carcinoid 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.