What is the treatment for hypernatremia?

Treatment of Hypernatremia

Primary Treatment Approach

For hypernatremia, administer hypotonic fluids to replace the free water deficit, with a target correction rate of 10-15 mmol/L per 24 hours to avoid cerebral edema and neurological complications. 1

---

Initial Assessment and Volume Status Determination

Before initiating treatment, determine the patient's volume status as this guides fluid selection:

• Hypovolemic hypernatremia: Most common presentation, resulting from water loss exceeding sodium loss (renal or extrarenal losses) 2
• Euvolemic hypernatremia: Typically indicates diabetes insipidus (central or nephrogenic) 2
• Hypervolemic hypernatremia: Usually iatrogenic from excessive sodium administration (hypertonic saline, sodium bicarbonate) or primary hyperaldosteronism 2

Assess for neurological symptoms including confusion, altered consciousness, seizures, and evaluate thirst mechanism (impaired in elderly or neurologically compromised patients) 3, 2

---

Fluid Replacement Strategy

For Hypovolemic Hypernatremia

Administer hypotonic fluids as first-line therapy to replace free water deficit. 1 Specifically:

• Avoid isotonic saline as initial therapy, especially in patients with nephrogenic diabetes insipidus, as this can worsen hypernatremia 1
• Use hypotonic solutions (0.45% saline or 5% dextrose in water) for free water replacement 3, 2
• Calculate the free water deficit to guide replacement volume 1

For Euvolemic Hypernatremia (Diabetes Insipidus)

• Provide hypotonic fluid replacement for free water deficit 1
• For central diabetes insipidus: Consider desmopressin (Minirin) administration 4
• For nephrogenic diabetes insipidus: Hypotonic fluids are essential; avoid isotonic saline 1

For Hypervolemic Hypernatremia

• Focus on attaining negative water balance 1
• Address underlying cause (discontinue hypertonic solutions, treat hyperaldosteronism) 2

---

Correction Rate Guidelines

Chronic Hypernatremia (>48 hours duration)

Limit correction to 10-15 mmol/L per 24 hours (approximately 0.4 mmol/L per hour) to prevent cerebral edema. 1, 2, 4

• Correcting chronic hypernatremia too rapidly can lead to cerebral edema, seizures, and neurological injury 1
• Close laboratory monitoring is essential during correction 4
• Maximum reduction should not exceed 8-10 mmol/L per day in some protocols 4

Acute Hypernatremia (<24 hours duration)

• Rapid correction improves prognosis by preventing cellular dehydration effects 2
• More aggressive correction is safer when hypernatremia developed acutely 2
• For severe acute cases, hemodialysis is an effective option to rapidly normalize sodium levels 4

---

Special Population Considerations

Heart Failure Patients

• Implement sodium and fluid restriction 1
• Limit fluid intake to approximately 2 L/day for most hospitalized patients 1
• Consider stricter fluid restriction for diuretic-resistant or significantly hypernatremic patients 1
• For persistent severe hypernatremia with cognitive symptoms, vasopressin antagonists (tolvaptan, conivaptan) may be considered for short-term use 1

Cirrhosis Patients

• Evaluate for hypovolemic versus hypervolemic state 1
• For hypovolemic hypernatremia: Provide fluid resuscitation with hypotonic solutions 1
• For hypervolemic hypernatremia: Discontinue intravenous fluid therapy and implement free water restriction 1
• Focus on attaining negative water balance in hypervolemic states 1

---

Dietary Management

For patients with euvolemic hypernatremia:

• Low salt diet (<6 g/day) may be beneficial 1
• Protein restriction (<1 g/kg/day) may be considered 1

---

Monitoring Requirements

Regular monitoring during treatment is essential:

• Serum sodium, potassium, chloride, and bicarbonate levels 1
• Renal function assessment 1
• Urine osmolality 1
• Neurological status for signs of cerebral edema (if correcting too rapidly) or ongoing dehydration 1, 2

---

Common Pitfalls to Avoid

• Using isotonic saline in hypovolemic hypernatremia with nephrogenic diabetes insipidus - this worsens the condition 1
• Correcting chronic hypernatremia too rapidly - leads to cerebral edema and seizures 1
• Inadequate free water replacement - perpetuates cellular dehydration 2, 5
• Failing to identify and treat underlying cause - particularly diabetes insipidus or medication-induced causes 2
• Initiating renal replacement therapy without considering correction rate - can cause rapid sodium drops in chronic hypernatremia 4