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Postoperative SIADH — SCE Endocrinology MCQ

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HardPituitaryPostoperative SIADHSCE Endocrinology

Seven days after pituitary surgery, a woman with postoperative SIADH has a generalised seizure and sodium 116 mmol/L. What is the immediate sodium-directed treatment?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: A — Give 150 mL 3% saline over 20 minutes then reassess

Explanation lettering: B = shown as A · A = shown as B · E = shown as C · C = shown as E

B is correct. A seizure is severe symptomatic hyponatraemia: give 150 mL 3% saline over 20 minutes, recheck sodium and symptoms and repeat boluses according to the emergency algorithm, aiming initially for about a 5 mmol/L rise. Avoid exceeding correction limits and use desmopressin with expert input if overcorrection develops. Fluid restriction is too slow, isotonic saline can fail in SIADH, and rapid normalisation risks osmotic demyelination.

Reference: https://www.endocrinology.org/media/xhrhxhxm/emergency-management-of-severe-and-moderately-severely-symptomatic-hyponatraemia-in-adult-patients-2022.pdf