In chronic hyponatremia, sodium levels drop gradually over days or weeks — and symptoms and complications are typically more moderate.

In acute hyponatremia, sodium levels drop rapidly — resulting in potentially dangerous effects, such as rapid brain swelling, which can result in coma and death.

Premenopausal women appear to be at the greatest risk of hyponatremia-related brain damage. This may be related to the effect of women's sex hormones on the body's ability to balance sodium levels.

Jul. 14, 2011