What is the treatment for hypernatremia?

Treatment of Hypernatremia

Primary Treatment Approach

The cornerstone of hypernatremia treatment is replacing free water deficits with hypotonic fluids (such as D5W or 0.45% saline), while addressing the underlying cause and carefully controlling the rate of correction to prevent cerebral edema. 1, 2, 3

Correction Rate Guidelines

The rate of sodium correction is critical and depends on the acuity of hypernatremia:

Acute Hypernatremia (<24-48 hours)

• Rapid correction is safe and improves prognosis by preventing cellular dehydration effects 3
• Can correct more quickly without risk of cerebral edema 2, 3
• Hemodialysis is an effective option for rapidly normalizing severe acute hypernatremia 2

Chronic Hypernatremia (>48 hours)

• Maximum correction rate: 8-10 mmol/L per 24 hours (approximately 0.4 mmol/L/hour) 2, 3
• Slower correction prevents osmotic demyelination syndrome and cerebral edema 2, 4
• Close laboratory monitoring every 2-4 hours during active correction is essential 2

Common pitfall: Overly rapid correction of chronic hypernatremia can cause devastating neurological complications including seizures and cerebral edema, similar to the risks seen with rapid hyponatremia correction 2, 4

Treatment Based on Volume Status

Hypovolemic Hypernatremia (Most Common)

• Results from renal or extrarenal water losses exceeding sodium losses 3
• Treatment: Hypotonic fluids (0.45% saline initially, then D5W) to restore volume and correct sodium 1, 3
• Replace ongoing losses in addition to correcting the deficit 4

Euvolemic Hypernatremia (Diabetes Insipidus)

• Central diabetes insipidus: Administer desmopressin (Minirin) plus free water replacement 2, 3
• Nephrogenic diabetes insipidus: Address underlying cause (discontinue lithium, correct hypokalemia) and provide free water 3
• Distinguish between central and nephrogenic forms through clinical history and urine osmolality testing 3

Hypervolemic Hypernatremia (Rare)

• Acute form: Usually iatrogenic from hypertonic saline or sodium bicarbonate administration 3
• Chronic form: May indicate primary hyperaldosteronism 3
• Treatment: Loop diuretics to promote sodium excretion plus free water replacement 5

Fluid Selection and Administration

• D5W (5% dextrose in water): Provides pure free water replacement, ideal for correcting water deficit 1, 4
• 0.45% saline (half-normal saline): Hypotonic solution useful when volume repletion is also needed 1
• Avoid isotonic or hypertonic solutions as they will worsen hypernatremia 1

Special Considerations in Critical Care

• Hospital-acquired hypernatremia is often iatrogenic from inadequate water prescription and is therefore preventable 4, 5
• Critically ill patients with impaired consciousness cannot regulate water balance through thirst, making physician management crucial 5
• Hypernatremia is an independent risk factor for increased mortality in ICU patients 5
• When initiating renal replacement therapy in patients with chronic hypernatremia, adjust dialysate to prevent rapid sodium drops 2

Clinical Monitoring

• Check serum sodium every 2-4 hours during active correction 2
• Monitor for neurological symptoms: confusion, altered consciousness, seizures 1, 3
• Assess volume status and urine osmolality to guide ongoing management 3, 5
• Calculate free water deficit to guide total replacement needs 1

Key principle: The severity of symptoms and rapidity of development should guide the aggressiveness of correction, but chronic hypernatremia always requires slow, controlled correction regardless of symptom severity 2, 3, 4