Pancreas: insulinoma diagnosis: practice question

A General Surgery 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 Surgery · Pancreas: insulinoma diagnosis

Sample item

A 40-year-old woman has recurrent early-morning confusion and sweating relieved by eating. During a supervised 72-hour fast she becomes symptomatic with glucose 38 mg/dL. She uses no drugs. Which result confirms insulinoma?

AHigh insulin with high C-peptide and proinsulin at the time of hypoglycaemiaBSuppressed insulin and C-peptide with high beta-hydroxybutyrateCRaised glucagon with low insulinDHigh insulin with suppressed C-peptide

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

The answer and the reasoning

A. High insulin with high C-peptide and proinsulin at the time of hypoglycaemia

Insulinoma, the commonest functional pancreatic neuroendocrine tumour, causes Whipple triad: symptoms of hypoglycaemia, documented low glucose and relief on glucose. The supervised fast shows inappropriately high insulin, C-peptide and proinsulin with low beta-hydroxybutyrate. Most tumours are solitary, small and benign, and are enucleated after localisation by CT, MRI or endoscopic ultrasound.

Option by option

A. High insulin with high C-peptide and proinsulin at the time of hypoglycaemia (correct)
Correct. Endogenous hyperinsulinism shows high insulin, C-peptide and proinsulin during hypoglycaemia.
B. Suppressed insulin and C-peptide with high beta-hydroxybutyrate
Suppressed insulin with ketones is the normal physiological response to fasting.
C. Raised glucagon with low insulin
Raised glucagon with low insulin suggests a glucagonoma, which causes hyperglycaemia.
D. High insulin with suppressed C-peptide
High insulin with low C-peptide points to exogenous insulin administration.

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.

Questions about this General Surgery question

What is the answer to this General Surgery question?

The best answer is A, High insulin with high C-peptide and proinsulin at the time of hypoglycaemia. Insulinoma, the commonest functional pancreatic neuroendocrine tumour, causes Whipple triad: symptoms of hypoglycaemia, documented low glucose and relief on glucose.

Why is "Suppressed insulin and C-peptide with high beta-hydroxybutyrate" not the answer?

Suppressed insulin with ketones is the normal physiological response to fasting.

Why is "Raised glucagon with low insulin" not the answer?

Raised glucagon with low insulin suggests a glucagonoma, which causes hyperglycaemia.

Why is "High insulin with suppressed C-peptide" not the answer?

High insulin with low C-peptide points to exogenous insulin administration.

What concept does this question test?

It tests Pancreas: insulinoma diagnosis in General Surgery. The supervised fast shows inappropriately high insulin, C-peptide and proinsulin with low beta-hydroxybutyrate. Most tumours are solitary, small and benign, and are enucleated after localisation by CT, MRI or endoscopic ultrasound.

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 Pancreas: insulinoma diagnosis?

Learn classic signs and eponyms alongside what they diagnose. Then use the flashcards and the other General Surgery 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.