What is the protocol for correcting severe hyponatremia?

Protocol for Correcting Severe Hyponatremia

For severe hyponatremia, hypertonic sodium chloride (3%) administration should be reserved for those who are severely symptomatic, with careful monitoring to prevent osmotic demyelination syndrome by limiting correction to 4-6 mEq/L per 24 hours, not exceeding 8 mEq/L in a 24-hour period. 1

Classification and Initial Assessment

Hyponatremia is defined as serum sodium <135 mEq/L, with severity categorized as:

• Mild: 126-135 mEq/L
• Moderate: 120-125 mEq/L
• Severe: <120 mEq/L 1

Additionally, assess:

• Volume status: hypovolemic, euvolemic, or hypervolemic
• Symptom severity: asymptomatic, mildly symptomatic, or severely symptomatic
• Chronicity: acute (<48 hours) or chronic (>48 hours)

Treatment Protocol Based on Severity and Symptoms

1. Severely Symptomatic Hyponatremia (Life-threatening)

Symptoms include seizures, coma, cardiorespiratory distress, abnormal and deep somnolence

• First Hour Treatment:

  • Administer 3% hypertonic saline to increase serum sodium by 5 mEq/L in the first hour 1
  • Initial bolus: 100-150 mL of 3% hypertonic saline over 10-20 minutes
  • Monitor serum sodium hourly

• Subsequent Management:

  • After initial correction, slow down to ensure total correction does not exceed 8 mEq/L in 24 hours 1
  • Continue monitoring serum sodium every 2-4 hours
  • If overcorrection occurs, consider relowering with electrolyte-free water or desmopressin 1

2. Moderate Hyponatremia (120-125 mEq/L)

• Water restriction to 1,000 mL/day
• Discontinue diuretics
• Monitor serum sodium every 6-8 hours 1

3. Severe Hyponatremia (<120 mEq/L) Without Severe Symptoms

• More severe water restriction
• Albumin infusion
• Monitor serum sodium every 4-6 hours 1

Volume-Specific Management

Hypovolemic Hyponatremia

• Discontinue diuretics and/or laxatives
• Plasma volume expansion with normal saline or 5% albumin 1
• Correct underlying cause

Hypervolemic Hyponatremia

• Water restriction (1-1.5 L/day) for those with serum sodium <125 mEq/L 1
• Discontinue or reduce diuretics if they are contributing to hyponatremia
• Consider albumin infusion in cirrhotic patients 1

Special Considerations

Liver Cirrhosis

• For hypovolemic hyponatremia: plasma volume expansion with saline solution 1
• For hypervolemic hyponatremia: fluid restriction and albumin infusion 1
• Vaptans may be considered for short-term use (≤30 days) but should be used with caution 1

Patients Awaiting Liver Transplantation

• Hypertonic saline can be considered for severe hyponatremia
• Multidisciplinary coordinated care to mitigate risk of osmotic demyelination syndrome 1

Critical Safety Parameters

• Maximum Correction Rate:

  • 4-6 mEq/L per 24 hours, not exceeding 8 mEq/L in 24 hours for chronic hyponatremia 1
  • This is especially important in high-risk patients (advanced liver disease, alcoholism, malnutrition) 1

• Warning Signs of Osmotic Demyelination Syndrome (ODS):

  • Dysarthria, mutism, dysphagia, lethargy, affective changes
  • Spastic quadriparesis, seizures, coma 2

• If Overcorrection Occurs:

  • Consider relowering sodium with electrolyte-free water
  • Consider desmopressin administration 1

Monitoring Protocol

1. Baseline serum sodium measurement
2. For severe symptomatic hyponatremia: hourly sodium measurements during initial correction
3. After initial correction: every 4-6 hours for first 24 hours
4. Daily measurements until stabilized
5. Monitor for neurological symptoms throughout treatment

Pitfalls to Avoid

• Rapid correction exceeding recommended rates, especially in chronic hyponatremia
• Failure to identify and treat underlying causes
• Inadequate monitoring during correction
• Using hypotonic fluids in hyponatremic patients
• Overlooking medication causes of hyponatremia

By following this protocol and carefully monitoring serum sodium levels and neurological status, the risk of complications such as osmotic demyelination syndrome can be minimized while effectively treating severe hyponatremia.