21st May 2025

You are asked to review a 68-year-old lady by the F1 as her bloods have shown a hyponatraemia of 121 mmol/L.

You are asked to review a 68-year-old lady by the F1 as her bloods have shown a hyponatraemia of 121 mmol/L.  Her serum osmolality is reduced at 250 mOsmol/Kg and she is noted to have a positive fluid balance of +1.5 L. 

Which of the following is not a cause of hypervolaemic hyponatraemia? Please select only ONE answer.