A 65-year-old woman is admitted with acute confusion. She recently started Fluoxetine. Blood tests show: Sodium 118 mmol/L. Serum osmolality 250 mOsm/...

Question

A 65-year-old woman is admitted with acute confusion. She recently started Fluoxetine. Blood tests show: Sodium 118 mmol/L. Serum osmolality 250 mOsm/kg, Urine osmolality 400 mOsm/kg, Urine sodium 50 mmol/L. She appears euvolaemic. What is the most likely cause of her hyponatraemia?

Accepted Answer

Syndrome of Inappropriate ADH secretion (SIADH) secondary to Fluoxetine

Answer

Addison's disease

Answer

Dehydration

Answer

Diuretic use

Answer

Heart failure

mrcp part 1 MCQ (SBA): SIADH / Hyponatraemia

A 65-year-old woman is admitted with acute confusion. She recently started Fluoxetine. Blood tests show: Sodium 118 mmol/L. Serum osmolality 250 mOsm/kg, Urine osmolality 400 mOsm/kg, Urine sodium 50 mmol/L. She appears euvolaemic. What is the most likely cause of her hyponatraemia?