From the Research
Management of hypernatremia requires careful correction of elevated serum sodium levels while addressing the underlying cause, with the goal of not exceeding a sodium correction rate of 8-10 mEq/L per day to prevent cerebral edema, as recommended by the most recent and highest quality study 1.
Key Considerations
- The first step is to determine whether the patient has hypovolemic, euvolemic, or hypervolemic hypernatremia, as this guides treatment.
- For hypovolemic hypernatremia, isotonic fluid (0.9% saline) should be administered initially to restore hemodynamic stability, followed by hypotonic fluids like 0.45% saline or 5% dextrose in water, as supported by 2 and 3.
- For euvolemic or hypervolemic hypernatremia, hypotonic fluids are used from the start.
- Underlying causes must be addressed simultaneously, such as treating diabetes insipidus with desmopressin or managing hyperglycemia with insulin, as mentioned in 4 and 1.
Treatment Approach
- Calculate the free water deficit using the formula: Free water deficit = Total body water × [(measured Na⁺/desired Na⁺) - 1], where total body water is approximately 60% of body weight in men and 50% in women.
- Frequent monitoring of serum sodium (every 2-4 hours initially), urine output, and clinical status is essential to guide therapy adjustments.
- In cases of hypervolemic hypernatremia, loop diuretics like furosemide may be needed alongside free water replacement to reduce total body sodium while maintaining adequate hydration, as suggested by 2 and 3.
Important Considerations
- The rate of sodium correction should not exceed 8-10 mEq/L per day (0.33-0.42 mEq/L per hour) to prevent cerebral edema, particularly in chronic cases, as emphasized by 1 and 3.
- Close laboratory controls are important to avoid overly rapid correction of sodium concentration, which can cause osmotic demyelination syndrome, as warned by 1 and 3.