21st May 2025

You are asked to see an 80-year-old lady on the respiratory ward with new confusion.

You are asked to see an 80-year-old lady on the respiratory ward with new confusion. She has a background of small cell lung cancer. On review of her bloods, it is noted she has a sodium of 125 mmol/L.

Which of the following would suggest that the cause is most likely to be SIADH? Please select only ONE answer.