Which of the following describes SIADH treatment options?

• A. Fluid restriction alone
• B. Treat the cause, fluid restriction and diuretics, correct hyponatremia with hypertonic saline if needed, and use ADH antagonists like Conivaptan and Tolvaptan
• C. Immediate vasopressin infusion
• D. High-volume intravenous fluids

Answer: (B)

In SIADH, excess ADH causes the kidneys to retain water, leading to hyponatremia with euvolemia. Management aims to remove the excess water while addressing the underlying cause and preventing rapid sodium correction. The best approach combines several strategies: fluid restriction to limit free water intake; treat the underlying cause driving ADH secretion; use diuretics (usually loop diuretics) to promote free-water excretion once volume status is stable; correct hyponatremia with hypertonic saline if there are severe symptoms or very low sodium, but only with careful monitoring to avoid rapid shifts; and consider vasopressin receptor antagonists like conivaptan or tolvaptan to promote aquaresis when fluid restriction alone is insufficient or hyponatremia persists. Safety is key—monitor serum sodium closely and avoid overcorrection, since too rapid a rise can cause osmotic demyelination. This combined strategy reflects the multifaceted management needed to address the pathophysiology of SIADH rather than relying on any single intervention.