First-line treatment for SIADH?

First-line treatment for SIADH?

• A. Fluid restriction
• B. Hypertonic saline
• C. Demeclocycline
• D. Tolvaptan

Answer: (A)

SIADH causes euvolemic hyponatremia because excess ADH makes the kidneys retain water, diluting the serum. The simplest and safest way to begin correcting this in mild, stable cases is fluid restriction. By limiting free-water intake (often around 800–1000 mL per day, tailored to the patient), the kidneys can excrete the excess water, allowing serum sodium to rise gradually toward normal. This approach directly addresses the water overload without risking too-rapid shifts in sodium. Hypertonic saline is reserved for severe or life-threatening symptoms (like seizures or coma) where a rapid but carefully controlled correction is needed. Demeclocycline and tolvaptan are options when fluid restriction alone isn’t effective or in chronic, refractory SIADH, but they carry more risks (slower onset, nephrotoxicity with demeclocycline; risk of overly rapid correction with tolvaptan) and are not used as first-line.

SIADH causes euvolemic hyponatremia because excess ADH makes the kidneys retain water, diluting the serum. The simplest and safest way to begin correcting this in mild, stable cases is fluid restriction. By limiting free-water intake (often around 800–1000 mL per day, tailored to the patient), the kidneys can excrete the excess water, allowing serum sodium to rise gradually toward normal. This approach directly addresses the water overload without risking too-rapid shifts in sodium.

Hypertonic saline is reserved for severe or life-threatening symptoms (like seizures or coma) where a rapid but carefully controlled correction is needed. Demeclocycline and tolvaptan are options when fluid restriction alone isn’t effective or in chronic, refractory SIADH, but they carry more risks (slower onset, nephrotoxicity with demeclocycline; risk of overly rapid correction with tolvaptan) and are not used as first-line.