Higher than normal levels of sodium in the blood, resulting from too-frequent urination, diabetes insipidus, profuse sweating, diarrhea, or other disorder.
An elevated concentration of sodium in the bloodstream. Hypernatremia is said to be present when the sodium concentration exceeds about 145 mmol/L. In the vast majority of cases, water deficits (and not salt excesses) cause relative sodium levels to rise; i.e., high serum sodium levels usually result from dehydration or fluid deprivation. Infrequently, hypernatremia results from infusions of concentrated saline.