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Thiazide-associated hyponatraemia — SCE Geriatric Medicine MCQ

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HardPolypharmacyThiazide-associated hyponatraemiaSCE Geriatric Medicine

An 84-year-old woman is admitted with a fall and new confusion. She takes sertraline, bendroflumethiazide, ramipril, omeprazole, zopiclone and solifenacin. Sodium is 119 mmol/L, serum osmolality is low, urine osmolality is 560 mOsm/kg and urine sodium is 62 mmol/L; CT head is unremarkable. She has no oedema and creatinine is close to baseline. Which medication should be reviewed/stopped first?

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Correct answer: E — Bendroflumethiazide

Severe hypotonic hyponatraemia in an older person taking a thiazide is highly suggestive of thiazide-associated hyponatraemia, particularly with falls and delirium. Sertraline can contribute through SIADH, but thiazides are a classic high-risk and readily reversible cause, so they should be stopped and sodium corrected safely. Omeprazole and ramipril are less likely to explain this biochemical pattern. The pearl is to treat hyponatraemia as a falls and cognitive risk factor, not simply a laboratory abnormality.

Reference: BNF; NICE NG56; STOPP/START v3