How do you treat hypernatremia?

Treatment of Hypernatremia

The treatment of hypernatremia should focus on correcting water deficit at a controlled rate, with the goal of decreasing serum sodium by no more than 8-10 mmol/L in 24 hours to prevent neurological complications. 1, 2

Assessment and Classification

Before initiating treatment, classify hypernatremia based on:

1. Duration:

   • Acute (<48 hours)
   • Chronic (>48 hours)

2. Volume status:

   • Hypovolemic hypernatremia (most common)
   • Euvolemic hypernatremia
   • Hypervolemic hypernatremia

3. Severity:

   • Mild
   • Moderate
   • Severe

Treatment Algorithm Based on Volume Status

1. Hypovolemic Hypernatremia

• First step: Restore intravascular volume with isotonic fluids (0.9% saline) until hemodynamic stability is achieved 1
• Second step: Switch to hypotonic fluids (0.45% saline or D5W) to address free water deficit 3
• Calculation of water deficit: Water deficit (L) = 0.6 × body weight (kg) × [(current Na⁺/140) - 1]

2. Euvolemic Hypernatremia

• Most commonly caused by diabetes insipidus (central or nephrogenic)
• Central diabetes insipidus: Administer desmopressin (DDAVP) 2
• Nephrogenic diabetes insipidus: Address underlying cause (discontinue offending medications, correct hypokalemia)
• Provide hypotonic fluids (D5W) to replace free water deficit 3

3. Hypervolemic Hypernatremia

• Rare condition caused by excessive sodium intake or primary hyperaldosteronism 1
• Treatment: Remove excess sodium through diuresis
• Consider loop diuretics with hypotonic fluid replacement
• In severe cases, hemodialysis may be necessary 2

Correction Rate Guidelines

• For chronic hypernatremia (>48 hours):

  • Decrease serum sodium by no more than 8-10 mmol/L/day 1, 2
  • Too rapid correction can lead to cerebral edema

• For acute hypernatremia (<24 hours):

  • Can correct more rapidly at 1 mmol/L/hour in the first 6-8 hours 3
  • Hemodialysis is an option for rapid correction in severe cases 2

Monitoring During Treatment

• Check serum sodium levels every 2-4 hours initially
• Monitor fluid intake/output
• Assess neurological status regularly
• Adjust fluid therapy based on sodium correction rate

Special Considerations

• Elderly patients: More susceptible to hypernatremia due to impaired thirst mechanism
• Psychiatric patients: May develop hypernatremia due to abnormal thirst sensation or reduced oral intake 3
• Critically ill patients: Higher mortality associated with hypernatremia

Pitfalls to Avoid

• Overcorrection: Can lead to cerebral edema and neurological complications
• Undercorrection: May prolong symptoms and increase morbidity
• Failure to identify and treat underlying cause: Essential for preventing recurrence
• Inappropriate fluid choice: Using isotonic fluids alone will not correct hypernatremia effectively

Remember that the treatment approach must be tailored to the specific cause of hypernatremia, with careful attention to the correction rate to prevent neurological complications.