How to treat hypernatremia?

Management of Hypernatremia (Sodium Level of 156)

The treatment of hypernatremia with a sodium level of 156 mmol/L requires careful fluid replacement with hypotonic fluids while ensuring a controlled correction rate of 4-6 mmol/L in the first 24 hours, not exceeding 8 mmol/L per day, to avoid neurological complications. 1, 2

Initial Assessment

• Determine the cause of hypernatremia:

  • Water deficit (most common): inadequate water intake or excessive water loss
  • Sodium excess: less common but can occur with excessive sodium intake
  • Assess volume status: hypovolemic, euvolemic, or hypervolemic

• Check for symptoms:

  • Mild: thirst, weakness, lethargy
  • Severe: altered mental status, seizures, coma

Treatment Algorithm

Step 1: Calculate the Water Deficit

• Formula: Water deficit = Total body water × [(measured Na⁺/140) - 1]
• Total body water ≈ 0.6 × weight (kg) for men; 0.5 × weight (kg) for women

Step 2: Determine Rate of Correction

• For chronic hypernatremia (>48 hours): correct at 4-6 mmol/L per 24 hours 1
• For acute hypernatremia (<48 hours): can correct more rapidly but still not exceeding 10 mmol/L per 24 hours
• Too rapid correction can lead to cerebral edema and neurological damage 3

Step 3: Select Appropriate Fluid

For hypernatremia with sodium level of 156 mmol/L:

1. Hypovolemic hypernatremia:

   • Initial treatment: isotonic saline (0.9% NaCl) to restore intravascular volume
   • Then switch to hypotonic fluids (0.45% NaCl or 5% dextrose in water) 2

2. Euvolemic hypernatremia:

   • 5% dextrose in water (D5W) or 0.45% NaCl 2
   • Oral water if patient can tolerate

3. Hypervolemic hypernatremia:

   • Loop diuretics plus 5% dextrose in water
   • Consider dialysis in severe cases with renal failure 1

Step 4: Monitor Closely

• Check serum sodium every 4-6 hours during active correction 1
• Adjust fluid rate based on sodium measurements
• Monitor neurological status for signs of cerebral edema
• Monitor fluid status and urine output

Special Considerations

• In pediatric patients, a reduction rate of 10-15 mmol/L/24h is recommended 3
• Identify and treat the underlying cause:
  • Diabetes insipidus: consider desmopressin
  • Excessive sodium intake: remove source
  • Insensible losses: replace appropriately

Common Pitfalls to Avoid

1. Overly rapid correction: Can lead to cerebral edema and neurological damage
2. Inadequate monitoring: Failure to check sodium levels frequently during correction
3. Incorrect fluid choice: Using isotonic fluids when hypotonic fluids are needed
4. Missing the underlying cause: Failing to identify and address the reason for hypernatremia
5. Underestimating insensible losses: Especially in febrile or critically ill patients

Severe Cases

In cases of extreme hypernatremia (>170 mmol/L) or severe neurological symptoms:

• Consider hemodialysis or continuous renal replacement therapy
• Consult nephrology for assistance with management 2

Remember that hypernatremia has a high mortality rate, especially when severe or when correction is improperly managed. The most important prognostic factors are the patient's age and the initial serum sodium concentration 4.