Why must hyponatremia correction be cautious to prevent osmotic demyelination, and what is a typical 24-hour correction cap?

• A. Rapid correction risks osmotic demyelination; cap about 6-8 mEq/L per 24 hours; adjust for chronicity.
• B. Rapid correction safe up to 20 mEq/L per 24h.
• C. Hyponatremia should be corrected to normal within 2 hours.
• D. Correction should be always with hypertonic saline regardless of level.

Answer: (A)

Correcting hyponatremia must be done slowly to protect the brain from osmotic injury. When hyponatremia develops, the brain adapts by reducing intracellular osmolytes to prevent swelling. If the serum sodium is raised too quickly, the extracellular osmolality climbs faster than the brain can readjust, pulling water out of brain cells and causing osmotic demyelination, which can be devastating. That’s why a typical safe correction limit is about 6–8 mEq/L in 24 hours, with careful adjustment based on how long the hyponatremia has been present (chronic cases are more vulnerable and require even more cautious pacing). Hypertonic saline may be used for severe symptoms, but even then you aim not to overshoot the target and you monitor closely. The other options imply correction speeds or strategies that are unsafe or inappropriate for most hyponatremia situations.