This protocol addresses chronic hyponatraemia caused by syndrome of inappropriate antidiuresis (SIAD), in patients who are euvolaemic and do not present with severe or moderately severe symptoms.
The patient has chronic hyponatraemia in the setting of SIAD, with normal volume status and without severe or moderately severe neurological symptoms. Identifying and addressing the underlying cause is central to management in this population.
Management begins with removing contributing factors — non-essential fluids, medications, and other reversible triggers of hyponatraemia — alongside cause-specific treatment. In moderate or profound hyponatraemia, fluid restriction is considered a first-line measure. The rate of sodium correction must be carefully controlled to avoid overcorrection.
Full sequencing, thresholds, and detailed guidance available in the complete protocol →DOI: 10.1530/EJE-13-1020
Stop non-essential fluids, medications and other factors that can contribute to or provoke hyponatraemia (not graded).
We recommend cause-specific treatment (1D).
In moderate or profound hyponatraemia, we suggest restricting fluid intake as first-line treatment (2D).
For demeclocycline and lithium, there is some evidence of possible harm, so we advise against their use for management of any degree of chronic hyponatraemia in patients with SIAD.