A level of sodium in the blood that is higher than usual.

Hypernatremia can happen due to drinking too little water or taking in too much sodium. Another risk factor is dehydration from things such as diarrhea, vomiting, serious burns or use of certain diuretics.

The main symptom of hypernatremia is thirst. Other symptoms may include fatigue, muscle spasms or confusion. Without treatment, brain cells may shrink. This can lead to a coma.

Hypernatremia treatment involves receiving fluids by mouth or through a needle in a vein, also called an IV. If a health condition is found to cause hypernatremia, it also is treated.