From the Research
Hypernatremia should be corrected at a rate not exceeding 1 mmol/L per hour, with a focus on addressing the underlying cause and preventing cerebral edema, as evidenced by the most recent and highest quality study 1.
Definition and Treatment
Hypernatremia is a condition characterized by elevated sodium levels in the blood, typically defined as serum sodium concentration exceeding 145 mEq/L. Treatment focuses on addressing the underlying cause while carefully correcting sodium levels.
- For mild to moderate cases (145-160 mEq/L), oral rehydration with water or hypotonic fluids is recommended.
- For severe cases (>160 mEq/L) or symptomatic patients, intravenous hypotonic fluids like 0.45% saline or 5% dextrose in water should be administered.
Correction Rate
The rate of correction depends on how quickly hypernatremia developed - acute cases (developing within 48 hours) can be corrected more rapidly than chronic cases.
- A study published in 2025 found that faster correction rates (> 0.5 mmol/L/h) may be safe and improve outcomes, particularly in patients with severe admission-related hypernatremia 1.
- However, it is essential to balance the correction rate with the risk of cerebral edema, and a rate not exceeding 1 mmol/L per hour is recommended.
Monitoring and Underlying Cause
Frequent monitoring of serum sodium, typically every 2-4 hours initially, is essential.
- The underlying cause must be addressed simultaneously, whether it's excessive water loss (through diabetes insipidus, excessive sweating, or diarrhea), inadequate water intake, or iatrogenic causes like hypertonic fluid administration.
- Hypernatremia is dangerous because it causes cellular dehydration as water moves out of cells into the hyperosmolar extracellular fluid, which can lead to brain cell shrinkage and neurological symptoms ranging from altered mental status to seizures and coma.
Recent Evidence
A systematic review and meta-analysis published in 2025 found that faster correction rates (> 0.5 mmol/L/h) overall showed no significant change in mortality, but subgroup analyses found significantly lower mortality with faster correction of hypernatremia at the time of hospital admission 1.
- Another study published in 2023 found that rapid correction (>0.5 mmol/L per hour) of hypernatremia in children was not associated with greater neurological investigation, cerebral edema, seizures, or mortality 2.