Endocrinology and diabetes: adrenal insufficiency: 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 · Endocrinology and diabetes: adrenal insufficiency

Sample item

A 35-year-old woman has weight loss, fatigue, postural hypotension and skin creases that are darkly pigmented. Sodium is 127 mEq/L and potassium is 5.9 mEq/L. Which test confirms the diagnosis?

A24-hour urine metanephrinesBWater deprivation testCOvernight dexamethasone suppression testDShort ACTH (synacthen) stimulation test

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

The answer and the reasoning

D. Short ACTH (synacthen) stimulation test

Hyperpigmentation with hyponatraemia and hyperkalaemia suggests primary adrenal insufficiency, where raised ACTH causes the pigmentation and aldosterone lack causes hyperkalaemia. A failure of cortisol to rise after synthetic ACTH confirms it. Tuberculosis and autoimmune adrenalitis are the leading causes.

Option by option

A. 24-hour urine metanephrines
Urine metanephrines are for phaeochromocytoma.
B. Water deprivation test
A water deprivation test assesses diabetes insipidus.
C. Overnight dexamethasone suppression test
Dexamethasone suppression is for suspected cortisol excess.
D. Short ACTH (synacthen) stimulation test (correct)
Correct. A blunted cortisol response to synacthen confirms adrenal failure.

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 Medicine question

What is the answer to this General Medicine question?

The best answer is D, Short ACTH (synacthen) stimulation test. Hyperpigmentation with hyponatraemia and hyperkalaemia suggests primary adrenal insufficiency, where raised ACTH causes the pigmentation and aldosterone lack causes hyperkalaemia.

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

Urine metanephrines are for phaeochromocytoma.

Why is "Water deprivation test" not the answer?

A water deprivation test assesses diabetes insipidus.

Why is "Overnight dexamethasone suppression test" not the answer?

Dexamethasone suppression is for suspected cortisol excess.

What concept does this question test?

It tests Endocrinology and diabetes: adrenal insufficiency in General Medicine. A failure of cortisol to rise after synthetic ACTH confirms it. Tuberculosis and autoimmune adrenalitis are the leading causes.

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 Endocrinology and diabetes: adrenal insufficiency?

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.