Electrolytes: Liddle 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 · Electrolytes: Liddle syndrome

Sample item

A 19-year-old has resistant hypertension, potassium 3.0 mmol/L and metabolic alkalosis. Plasma renin and aldosterone are both suppressed. His father had early-onset hypertension. Which drug is most appropriate?

AHydrochlorothiazideBDexamethasoneCAmilorideDSpironolactone

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

The answer and the reasoning

C. Amiloride

Liddle syndrome is a gain-of-function mutation of the epithelial sodium channel, so sodium is reabsorbed without aldosterone. This gives hypertension, hypokalaemia and alkalosis with low renin and low aldosterone. Direct channel blockers such as amiloride or triamterene correct it, whereas aldosterone antagonists do not.

Option by option

A. Hydrochlorothiazide
A thiazide would worsen hypokalaemia and alkalosis.
B. Dexamethasone
Dexamethasone treats glucocorticoid-remediable aldosteronism, in which aldosterone is high.
C. Amiloride (correct)
Correct. Amiloride blocks the overactive sodium channel directly.
D. Spironolactone
Spironolactone acts through the aldosterone receptor, and aldosterone is already low, so it fails.

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 C, Amiloride. Liddle syndrome is a gain-of-function mutation of the epithelial sodium channel, so sodium is reabsorbed without aldosterone.

Why is "Hydrochlorothiazide" not the answer?

A thiazide would worsen hypokalaemia and alkalosis.

Why is "Dexamethasone" not the answer?

Dexamethasone treats glucocorticoid-remediable aldosteronism, in which aldosterone is high.

Why is "Spironolactone" not the answer?

Spironolactone acts through the aldosterone receptor, and aldosterone is already low, so it fails.

What concept does this question test?

It tests Electrolytes: Liddle syndrome in General Medicine. This gives hypertension, hypokalaemia and alkalosis with low renin and low aldosterone. Direct channel blockers such as amiloride or triamterene correct it, whereas aldosterone antagonists do not.

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 Electrolytes: Liddle 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.