What is the treatment for hypernatremia (elevated sodium levels)?

Treatment of Hypernatremia

The treatment of hypernatremia requires careful administration of hypotonic fluids to correct the free water deficit, with correction rates not exceeding 8-10 mmol/L per day for chronic hypernatremia to prevent neurological complications. 1

Initial Assessment and Classification

• Hypernatremia is defined as serum sodium concentration >145 mEq/L and indicates a decrease in total body water relative to sodium 2
• Determine the acuity of hypernatremia: acute (<48 hours) vs. chronic (>48 hours), as this affects the rate of correction 1
• Assess volume status to classify hypernatremia as hypervolemic, euvolemic, or hypovolemic 3
• Evaluate for underlying causes such as impaired thirst mechanism, diabetes insipidus, excessive water losses, or excessive sodium intake 4, 2

Treatment Approach Based on Duration

For Acute Hypernatremia (<48 hours)

• More rapid correction is acceptable for acute hypernatremia 1
• Hemodialysis is an effective option to rapidly normalize serum sodium levels in acute cases 1

For Chronic Hypernatremia (>48 hours)

• Limit correction rate to 8-10 mmol/L per day to prevent cerebral edema 1, 2
• Calculate free water deficit to guide replacement therapy 2

Treatment Based on Volume Status

Hypovolemic Hypernatremia

• Initial treatment with isotonic saline to restore intravascular volume 3
• Follow with hypotonic fluids (0.45% saline or 5% dextrose in water) to correct free water deficit 4, 2

Euvolemic Hypernatremia

• Administer hypotonic fluids (0.45% saline or 5% dextrose in water) to replace free water deficit 2, 3
• For diabetes insipidus, consider desmopressin (DDAVP) administration 1

Hypervolemic Hypernatremia

• Loop diuretics combined with hypotonic fluid replacement to remove excess sodium while providing free water 3
• Consider hemodialysis for severe cases with volume overload 1

Calculating Free Water Deficit

• Free water deficit (in liters) = Total body water × [(Current serum Na⁺/140) - 1] 2
• Total body water is approximately 60% of body weight in kg for men and 50% for women 2
• This calculation provides an estimate for initial therapy, but frequent monitoring is essential 2

Monitoring During Treatment

• Check serum sodium levels every 2-4 hours initially, then every 4-6 hours once stabilized 2
• Monitor for signs of cerebral edema (headache, nausea, vomiting, altered mental status, seizures) 4, 2
• Adjust fluid therapy based on serial sodium measurements 2

Special Considerations

• Patients with neurological symptoms require more careful monitoring during correction 4
• Elderly patients and those with comorbidities may have altered total body water percentages, requiring adjustment of calculations 2
• Patients with renal impairment may need more careful fluid management and possibly dialysis 1, 2

Common Pitfalls to Avoid

• Overly rapid correction of chronic hypernatremia leading to cerebral edema 1, 2
• Inadequate monitoring during active correction 2
• Failing to address the underlying cause of hypernatremia 4, 2
• Using sodium-containing fluids inappropriately in hypervolemic hypernatremia 3