How do you correct hypernatremia (elevated sodium levels)?

Management of Hypernatremia

The correction of hypernatremia requires administration of hypotonic fluids to replace free water deficit, with the rate of correction determined by the chronicity of the condition to prevent neurological complications. 1

Initial Assessment

• Evaluate volume status (hypovolemic, euvolemic, or hypervolemic) to guide appropriate treatment strategy 1, 2
• Assess duration of hypernatremia (acute <48 hours vs. chronic >48 hours) as this determines safe correction rate 3, 2
• Check for neurological symptoms (confusion, altered mental status, coma) which may indicate severity 3, 4
• Measure serum electrolytes, acid-base status, and calculate fluid balance 1

Treatment Based on Volume Status

Hypovolemic Hypernatremia

• Administer hypotonic fluids (not isotonic saline) as initial therapy to replace both volume and free water deficit 1, 4
• For severe volume depletion, may begin with isotonic fluids briefly to stabilize hemodynamics before switching to hypotonic solutions 4, 2
• Calculate free water deficit using formula: Free water deficit = Total body water × [(current sodium/desired sodium) - 1] 5

Euvolemic Hypernatremia

• Provide hypotonic fluids (D5W or 0.45% saline) to replace free water deficit 1, 2
• For central diabetes insipidus, consider desmopressin (Minirin) administration 3, 2
• For nephrogenic diabetes insipidus, address underlying cause and consider thiazide diuretics 2

Hypervolemic Hypernatremia

• Focus on achieving negative water balance through diuretics 1
• Implement sodium and fluid restriction 1
• Consider hemodialysis for severe cases with fluid overload 3, 6

Correction Rate Guidelines

• For acute hypernatremia (<48 hours): Correction can be more rapid, but still monitor closely 3, 2
• For chronic hypernatremia (>48 hours): Reduce sodium by no more than 8-10 mmol/L/day 3, 2
• For severe cases: Consider a reduction rate of 10-15 mmol/L/24 hours 1
• Calculate hourly correction rate: no more than 0.4-0.5 mmol/L/hour for chronic cases 2

Fluid Selection and Administration

• D5W (5% dextrose in water) is ideal for free water replacement 4, 5
• Half-normal saline (0.45% NaCl) can be used when some sodium replacement is also needed 4, 5
• Calculate fluid volume needed using formulas that account for current sodium level, desired sodium level, and total body water 5

Monitoring During Correction

• Check serum sodium levels every 2-4 hours initially, then every 4-6 hours once stabilized 1, 6
• Monitor neurological status for signs of cerebral edema (headache, nausea, seizures) which may indicate too-rapid correction 1, 3
• Assess urine output and electrolyte content to adjust ongoing fluid therapy 5

Special Considerations

• For patients with heart failure and hypernatremia, limit fluid intake to around 2 L/day 1
• In cirrhotic patients with hypernatremia, evaluate for hypovolemic vs. hypervolemic state before treatment 1
• For patients on renal replacement therapy with chronic hypernatremia, adjust dialysate sodium to prevent rapid drops in serum sodium 3, 6
• Consider vasopressin antagonists (tolvaptan, conivaptan) for short-term use in heart failure patients with persistent severe hypernatremia 1

Common Pitfalls to Avoid

• Correcting chronic hypernatremia too rapidly, which can lead to cerebral edema, seizures, and neurological injury 1, 3
• Using isotonic saline as initial therapy for hypernatremia, which may worsen the condition 1, 4
• Failing to address the underlying cause of hypernatremia 4, 2
• Inadequate monitoring during correction 1, 6

Remember that the primary goal in treating hypernatremia is the restoration of plasma tonicity while preventing neurological complications from either the condition itself or its treatment 2.