Management of Hypernatremia
The management of hypernatremia should focus on correcting the free water deficit at an appropriate rate based on the acuity of onset, with hypotonic fluids as the mainstay of treatment while addressing the underlying cause. 1
Assessment and Classification
- Evaluate volume status to determine if hypernatremia is hypovolemic, euvolemic, or hypervolemic 1
- Assess duration of hypernatremia: acute (<48 hours) vs. chronic (>48 hours) 2
- Measure serum and urine osmolality, urine electrolytes, and acid-base status to help determine the underlying cause 1
- Check hematocrit and blood urea nitrogen to assess hydration status 1
Treatment Approach Based on Volume Status
Hypovolemic Hypernatremia
- Administer hypotonic fluids to replace free water deficit; avoid isotonic saline as initial therapy, especially in patients with nephrogenic diabetes insipidus 1
- Calculate fluid deficit and replace gradually to avoid rapid correction 1
Euvolemic Hypernatremia
- Often seen in diabetes insipidus (central or nephrogenic) 2
- For central diabetes insipidus, consider desmopressin (Minirin) 3
- A low salt diet (<6 g/day) and protein restriction (<1 g/kg/day) may be beneficial 1
Hypervolemic Hypernatremia
- Focus on attaining negative water balance 1
- In cirrhosis, discontinue intravenous fluid therapy and implement free water restriction 1
- In heart failure, sodium and fluid restriction is recommended, limiting fluid intake to around 2 L/day 1
Correction Rate Guidelines
- For chronic hypernatremia (>48 hours), reduce sodium at a rate of 10-15 mmol/L/24 hours 1
- For acute hypernatremia (<24 hours), more rapid correction is safer, but still monitor closely 2, 3
- Avoid correcting chronic hypernatremia too rapidly to prevent cerebral edema, seizures, and neurological injury 1, 3
Special Considerations for Specific Populations
- In heart failure patients with persistent severe hypernatremia and cognitive symptoms, vasopressin antagonists (tolvaptan, conivaptan) may be considered for short-term use 1
- For patients with cirrhosis, evaluate for hypovolemic vs. hypervolemic state and treat accordingly 1
Monitoring During Treatment
- Regular monitoring of serum sodium, potassium, chloride, and bicarbonate levels is essential 1
- Assess renal function and urine osmolality throughout treatment 1
- Calculate and track fluid and electrolyte balance 1
Common Pitfalls to Avoid
- Correcting chronic hypernatremia too rapidly (>10-15 mmol/L/24 hours) can lead to cerebral edema 1, 2
- Using isotonic saline as initial therapy for hypovolemic hypernatremia, especially in nephrogenic diabetes insipidus 1
- Failing to identify and address the underlying cause of hypernatremia 4
- Inadequate monitoring during active correction 1
Treatment of Severe Hypernatremia
- For severe symptomatic hypernatremia, consider hemodialysis for rapid normalization if hypernatremia is acute (<24 hours) 3
- For chronic severe hypernatremia, maintain the slower correction rate of 10-15 mmol/L/24 hours 1, 2
- Hospitalize patients with severe hypernatremia for close monitoring during treatment 4