This is one of the most common causes of hyponatraemia; patients produce an inappropriately concentrated urine when there is no discernible stimulus for release of antidiuretic hormone (1).
The following criteria should be fulfilled before a diagnosis of SIADH can be made:
- persistent excretion of concentrated urine with no reason for ADH release
- normal renal and adrenal function
- no oedema or hypovolaemia should be present
- (1) Hoorn EJ, van der Lubbe N, Zietse R. SIADH and hyponatraemia: why does it matter? NDT Plus. 2009;2(Suppl_3):iii5-iii11
Last reviewed 01/2018