Critical care: correction of chronic hyponatraemia: practice question

A Anaesthesia 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.

Try it

Anaesthesia · Critical care: correction of chronic hyponatraemia

Sample item

A patient with chronic hyponatraemia of 112 mmol/L has seizures. After a 3 percent saline bolus, what is the maximum safe correction in 24 hours?

A8 to 10 mmol/LBNo limit appliesC30 mmol/LD20 mmol/L

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

The answer and the reasoning

A. 8 to 10 mmol/L

Rapid correction of chronic hyponatraemia can cause osmotic demyelination with quadriparesis and locked-in syndrome. Severe symptoms are treated with hypertonic saline to raise sodium by a few mmol/L, but the total rise should not exceed 8 to 10 mmol/L per 24 hours. Sodium is checked every few hours.

Option by option

A. 8 to 10 mmol/L (correct)
Correct. A limit of 8 to 10 mmol/L in 24 hours protects against demyelination.
B. No limit applies
A limit exists because of the demyelination risk.
C. 30 mmol/L
A rise of 30 mmol/L risks severe neurological injury.
D. 20 mmol/L
A rise of 20 mmol/L is dangerously rapid.

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 Anaesthesia question

What is the answer to this Anaesthesia question?

The best answer is A, 8 to 10 mmol/L. Rapid correction of chronic hyponatraemia can cause osmotic demyelination with quadriparesis and locked-in syndrome.

Why is "No limit applies" not the answer?

A limit exists because of the demyelination risk.

Why is "30 mmol/L" not the answer?

A rise of 30 mmol/L risks severe neurological injury.

Why is "20 mmol/L" not the answer?

A rise of 20 mmol/L is dangerously rapid.

What concept does this question test?

It tests Critical care: correction of chronic hyponatraemia in Anaesthesia. Severe symptoms are treated with hypertonic saline to raise sodium by a few mmol/L, but the total rise should not exceed 8 to 10 mmol/L per 24 hours. Sodium is checked every few hours.

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 Critical care: correction of chronic hyponatraemia?

Make a table of each agent, its key advantage and its main side effect. Then use the flashcards and the other Anaesthesia 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.