What is the effect of rapid correction of hypernatremia?

Rapid correction of hypernatremia can lead to brain swelling due to the rapid shift of water into the brain cells. Hypernatremia, characterized by an elevated sodium concentration in the blood, results in cellular dehydration as water moves out of cells to balance the osmotic gradient created by the high sodium levels. When hypernatremia is corrected too quickly, typically through the administration of hypotonic fluids or rapid dilution, the sodium concentration decreases sharply.

This sudden decrease in extracellular osmolarity causes water to flow back into cells to restore osmotic balance. The brain is particularly vulnerable to these rapid changes because it adjusts its osmotic state more slowly than other tissues. If the correction occurs too fast, the brain cells swell, leading to a condition known as cerebral edema, which can result in serious neurological complications, including headache, seizures, and in severe cases, coma or death.

A careful and gradual correction of hypernatremia is necessary to avoid these detrimental effects, highlighting the importance of closely monitoring sodium levels during treatment.