21st May 2025

You are asked to review a 60-year-old gentleman with a sodium of 111 mmol/L as he has become acutely confused.

You are asked to review a 60-year-old gentleman with a sodium of 111 mmol/L as he has become acutely confused. He has a background of asthma, CKD and type 2 diabetes. On assessment his observations remain stable. Blood glucose levels are 8 mmol/L. Serum osmolality is 300 mOsmol/kg. He is hypervolaemic.

Which of the following causes would most likely account for the hyponatraemia? Please select only ONE answer.