Which treatment is recommended if SIADH is symptomatic?

• A. Hypertonic saline
• B. Fluid restriction
• C. Observation only
• D. Diuretic therapy

Answer: (A)

When SIADH causes symptoms, the priority is to rapidly raise the serum sodium to relieve brain edema and protect neurologic function. Hypertonic saline does this by creating an osmotic gradient that pulls water out of brain cells, increasing serum sodium quickly and reducing cerebral edema.

In practice, a controlled amount of hypertonic saline (often 3% saline) is given, sometimes as a bolus, with close monitoring of the sodium level and the patient’s neurologic status. The goal is a safe initial rise in sodium (often about 4–6 mEq/L in the first few hours) while avoiding too rapid an increase, which can cause osmotic demyelination. After stabilization, management shifts to safer, longer-term strategies such as fluid restriction and treatment of the underlying cause of SIADH.

Fluid restriction alone is more for mild or chronic hyponatremia and won’t promptly address acute neurologic symptoms. Observation only would allow ongoing harm from hyponatremia, and diuretic therapy without addressing the sodium deficit won’t correct the urgent problem and can worsen volume status or electrolyte balance. Hypertonic saline directly treats the symptomatic hyponatremia and is the recommended initial treatment.