In hyponatremia, what signs indicate severe symptoms requiring hypertonic saline, and what is the typical hypertonic solution used?

• A. Seizures, coma, severe confusion; treat with 3% NaCl with careful rate
• B. Seizures, coma; treat with 0.9% NaCl
• C. Mild dizziness; treat with 0.45% NaCl
• D. Asymptomatic; no treatment necessary

Answer: (A)

Severe symptoms from hyponatremia reflect brain swelling and require rapid, controlled correction with hypertonic saline to reduce cerebral edema. Seizures, coma, and severe confusion signal that the brain is threatened and need urgent intervention. The typical choice is 3% sodium chloride, given in small, careful boluses (for example, 100 mL over 10 minutes) with reassessment after each dose. The goal is to raise the serum sodium by about 4-6 mEq/L in the first 6 hours, not exceeding roughly 8-10 mEq/L in 24 hours, to lower the risk of overcorrection and osmotic demyelination. Serum sodium should be checked every 2-4 hours during correction, and therapy adjusted accordingly.

Isotonic saline (0.9% NaCl) isn’t the preferred initial treatment for severe symptomatic hyponatremia because it may not produce the needed rapid rise in sodium for those neurologic signs and can be ineffective or inappropriate depending on the underlying cause. Mild or asymptomatic hyponatremia is managed more conservatively, often with fluid restriction and slower correction.