First-Line Treatment of Syndrome of Inappropriate Antidiuretic Hormone Secretion
This protocol covers first-line management of mild-to-moderate SIADH, addressing the key clinical steps toward safe correction of plasma osmolality and serum sodium.
Treatment Approach
Initial management centres on a structured restriction of fluid intake — specific thresholds, dietary considerations, and concurrent medication guidance are defined in the complete protocol.
Treatment Goals
A significant increase in plasma osmolality and a rise in serum sodium toward a stable target value, reassessed at 24–48 hours. Once the target serum sodium threshold is reached, the risk of CNS complications of hyponatraemia is substantially reduced.
References
DOI: 10.1016/j.amjmed.2013.07.006
- For most other cases of mild-to-moderate SIADH, fluid restriction represents the cheapest and least toxic therapy and has generally been the treatment of choice despite the almost complete lack of a supportive evidence base.
- Generally, discretionary (ie, nonfood) fluids should be limited to 500 mL/d below the average daily urine volume.
- Only fluid, not sodium or protein intake, should be restricted.
- At the time that fluid restriction is first initiated, any drugs known to be associated with SIADH should be discontinued or changed.
- Several days of restriction are usually necessary before a significant increase in plasma osmolality occurs.
- Once the serum [Na+] has reached 125 mmol/L, the risk of CNS complications of hyponatremia is low.
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