What is the treatment for hypernatremia?

Treatment of Hypernatremia

The treatment of hypernatremia should focus on gradual correction using hypotonic fluids with a target correction rate of no more than 8 mmol/L per 24 hours to prevent cerebral edema. 1

Diagnostic Approach

Before initiating treatment, determine the underlying cause and volume status:

• Volume status assessment:

  • Hypovolemic: Decreased skin turgor, dry mucous membranes, orthostatic hypotension, tachycardia
  • Euvolemic: Normal vital signs but signs of dehydration
  • Hypervolemic: Edema, ascites, elevated jugular venous pressure

• Laboratory assessment:

  • Serum and urine osmolality
  • Urine sodium concentration
  • Calculate free water deficit: Water deficit (L) = 0.6 × body weight (kg) × [(current Na⁺/140) - 1] 1

Treatment Algorithm

Step 1: Address Volume Status

• Hypovolemic hypernatremia:

  • Begin with isotonic saline (0.9% NaCl) to restore hemodynamic stability
  • Once hemodynamically stable, switch to hypotonic fluids (0.45% saline or D5W) 1

• Euvolemic hypernatremia:

  • Administer hypotonic fluids (0.45% saline or D5W)
  • Consider adding desmopressin if diabetes insipidus is suspected 1

• Hypervolemic hypernatremia:

  • Loop diuretics combined with hypotonic fluid replacement
  • Monitor for signs of volume overload 1

Step 2: Calculate Correction Rate

• Acute hypernatremia (< 48 hours):

  • Can be corrected more rapidly, but still not exceeding 10 mmol/L in 24 hours 1

• Chronic hypernatremia (> 48 hours):

  • Correct at a maximum rate of 8 mmol/L per 24 hours
  • For high-risk patients (alcoholism, malnutrition, liver disease), use a lower correction rate of 4-6 mmol/L per day 1

Step 3: Monitor and Adjust

• Check serum sodium every 4-6 hours during active correction
• More frequent monitoring (every 2 hours) in severe cases
• Adjust therapy by slowing or pausing correction if sodium decreases too rapidly
• Monitor neurological status, vital signs, and fluid input/output 1

Special Considerations

Diabetes Insipidus

• If central or nephrogenic diabetes insipidus is suspected:
  • Central: Consider desmopressin administration
  • Nephrogenic: Address underlying cause, consider thiazide diuretics 1

Prevention of Complications

• Rapid correction can lead to cerebral edema, seizures, and permanent neurological damage
• If correction exceeds 8 mmol/L in 24 hours, consider administration of hypotonic fluids or desmopressin to prevent complications 1

Medication Considerations

• Vaptans are contraindicated in hypernatremia as they promote free water excretion
• Review and adjust medications that may contribute to hypernatremia 1

Common Pitfalls to Avoid

• Overly rapid correction: Can cause cerebral edema and neurological damage
• Inadequate monitoring: Failure to check serum sodium frequently during correction
• Inappropriate fluid selection: Using isotonic fluids throughout treatment when hypotonic fluids are needed
• Ignoring underlying cause: Failing to address the root cause of hypernatremia

By following this structured approach to hypernatremia management, you can effectively correct sodium levels while minimizing the risk of complications. The key is to identify the underlying cause, ensure appropriate fluid selection based on volume status, and maintain a careful correction rate with regular monitoring.