From the Guidelines
Treatment of SIADH involves correcting hyponatremia and addressing the underlying cause.
Treatment Options
- Free water restriction (< 1 L/d) is a first-line treatment for asymptomatic mild SIADH and a recommended adjunct to other therapy for severe cases 1.
- Hypertonic 3% saline IV is given in life-threatening or acute symptomatic and severe (< 120 mEq/L) hyponatremia 1.
- Demeclocycline, lithium, and vasopressin 2 receptor antagonists (conivaptan, lixivaptan, tolvaptan, and satavaptan) may also be used to correct hyponatremia 1.
- Discontinuation of implicated medications and adequate oral salt intake is also recommended for the management of confirmed SIADH 1.
Considerations
- In patients with a short prognosis, strict fluid restriction may not be appropriate and should be considered in the context of their goals of care 1.
- Clinical assessment of intravascular volume status and biochemical measurements in blood and urine are essential for diagnosing and managing SIADH 1.
- Laboratory findings, such as urine osmolality, urinary sodium level, serum osmolality, and serum uric acid concentration, can help confirm the diagnosis of SIADH 1.
From the Research
Treatment Options for SIADH
- Fluid restriction is a common treatment approach for SIADH, especially for patients with mild to moderate hyponatremia 2, 3, 4, 5, 6
- Hypertonic saline solution (3%) can be used to treat acute, severe hyponatremia, especially in patients with severe symptoms such as seizures or coma 2, 3, 4, 5
- Demeclocycline can be used as an alternative to fluid restriction in patients who cannot tolerate it 2
- Loop diuretics, such as furosemide, can be used to increase urine output and correct hyponatremia 2, 3, 4, 6
- Vaptans, such as tolvaptan, are vasopressin receptor antagonists that can be used to treat SIADH, especially in patients with chronic hyponatremia 3, 4, 5, 6
- Urea can be used as an alternative to hypertonic saline solution in some cases 2, 5, 6
Treatment Algorithms
- Algorithm 1: addresses acute correction of hyponatremia posing as a medical emergency, using 3% hypertonic saline solution 3, 4
- Algorithm 2: addresses mild or moderate, non-acute hyponatremia, using fluid restriction, solute, furosemide, and tolvaptan 3, 4
Important Considerations
- The goal of treatment is to correct hyponatremia and alleviate symptoms, while avoiding overcorrection and osmotic demyelination 2, 5
- The rate of correction of hyponatremia should be limited to less than 8-10 mmol/liter per day to avoid osmotic demyelination 5
- Regular monitoring of serum sodium levels is crucial to prevent overcorrection or relapse of hyponatremia 5, 6