How is hypernatremia treated?

Treatment of Hypernatremia

Hypernatremia treatment should be based on the underlying cause, with careful correction of water deficit at a rate not exceeding 10 mmol/L per 24 hours to prevent neurological complications.

Assessment and Classification

Before initiating treatment, it's essential to properly evaluate the patient:

1. Confirm true hypernatremia - Exclude pseudohypernatremia and check glucose-corrected sodium concentration 1
2. Determine onset - Acute (<48 hours) or chronic (>48 hours) 1
3. Assess volume status - Categorize as hypovolemic, euvolemic, or hypervolemic 1
4. Measure urine osmolality and sodium - Helps identify the underlying cause 1

Treatment Algorithm

Step 1: Calculate Water Deficit

Water deficit (L) = Total body water × [(Current Na⁺/140) - 1]

• Total body water = 0.6 × weight (kg) for men; 0.5 × weight (kg) for women

Step 2: Determine Rate of Correction

• Acute hypernatremia (<48 hours): Can correct more rapidly but still not exceeding 1 mmol/L/hour
• Chronic hypernatremia (>48 hours): Correct at maximum rate of 10 mmol/L/24 hours 1

Step 3: Select Appropriate Fluid

Treatment depends on volume status:

Hypovolemic Hypernatremia

• Initial treatment: Isotonic saline (0.9% NaCl) to restore hemodynamic stability
• Subsequent treatment: Hypotonic fluids (0.45% saline or 5% dextrose) to correct free water deficit 2

Euvolemic Hypernatremia

• Primary treatment: Hypotonic fluids (0.45% saline or 5% dextrose)
• For diabetes insipidus: Consider desmopressin (DDAVP) for central DI or specific treatments for nephrogenic DI 1

Hypervolemic Hypernatremia

• Primary treatment: Loop diuretics plus hypotonic fluids
• Goal: Remove excess sodium while replacing free water 2

Step 4: Monitor Closely

• Check serum sodium every 2-4 hours initially, then every 4-6 hours
• Adjust fluid rate based on sodium correction rate
• Monitor for signs of cerebral edema (headache, altered mental status, seizures)

Special Considerations

Diabetes Insipidus

• Central DI: Desmopressin (DDAVP)
• Nephrogenic DI: Treat underlying cause, consider thiazide diuretics, NSAIDs, or amiloride 1

Elderly and High-Risk Patients

• More susceptible to hypernatremia due to impaired thirst mechanism
• Require closer monitoring during correction 2

Preventing Complications

• Cerebral edema: Can occur with overly rapid correction
• Seizures: More common with rapid changes in serum sodium
• Death: Associated with severe hypernatremia or complications of treatment 3

Pitfalls to Avoid

1. Overly rapid correction - Can lead to cerebral edema and neurological damage
2. Inadequate monitoring - Failure to adjust treatment based on sodium levels
3. Missing underlying causes - Treating symptoms without addressing the root cause
4. Inappropriate fluid selection - Using the wrong tonicity of fluid for the patient's volume status

While much of the evidence focuses on hyponatremia management, the principles of careful correction to prevent neurological complications apply equally to hypernatremia management. The key is to restore water balance gradually while addressing the underlying cause of sodium imbalance.