A 3-year-old child with hypernatremic dehydration (serum Na 165 mEq/L) is being rehydrated. The rate of correction of sodium must not exceed which value to prevent cerebral edema during treatment?

• A 1 mEq/L per hour
• B 2 mEq/L per hour
• C 5 mEq/L per 6 hours
• D 0.5 mEq/L per hour (maximum 10–12 mEq/L per 24 hours) ✓

Explanation

In hypernatremic dehydration, the brain adapts to hypertonicity by generating organic osmolytes (idiogenic osmoles). Rapid lowering of serum sodium causes water to shift rapidly into brain cells, causing cerebral edema (seizures, herniation). The safe rate of correction is no more than 0.5 mEq/L per hour or 10–12 mEq/L per 24 hours, replacing the deficit over 48 hours. This is the critical distinction from hyponatremic dehydration correction.

Reference: Ghai Essential Pediatrics, 10th ed.

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Written and medically reviewed by the StethoPrep medical team.