Overly rapid correction of hyponatremia carries risk of which condition?

• A. Cerebral edema
• B. Osmotic demyelination syndrome
• C. Seizure
• D. Hypokalemia

Answer: (B)

Rapid correction of hyponatremia is dangerous because the brain adapts to low sodium by accumulating osmolites to prevent swelling. If sodium is corrected too quickly, the extracellular environment becomes hyperosmolar relative to the brain, and water rushes out of brain cells. This rapid shift damages myelin sheaths, most notably in the central pons, leading to osmotic demyelination syndrome. That’s why gradual correction is essential (roughly no more than 8 mEq/L in 24 hours and 18 mEq/L in 48 hours, with extra caution in malnourished oralcoholic patients). Cerebral edema is a consequence of hyponatremia itself, not the rapid correction; seizures and hypokalemia aren’t the specific rapid-correction risk in the same way.