How to manage hyponatremia?

Management of Hyponatremia

The management of hyponatremia should be based on the severity, chronicity, and volume status of the patient, with fluid restriction to 1,000 mL/day recommended for moderate hyponatremia (120-125 mEq/L) and more severe fluid restriction with albumin infusion for severe hyponatremia (<120 mEq/L).

Classification and Assessment

Hyponatremia is classified based on severity:

• Mild: 126-135 mEq/L (or 130-135 mEq/L) 1
• Moderate: 120-125 mEq/L (or 125-129 mEq/L) 2, 1
• Severe: <120 mEq/L (or <125 mEq/L) 2, 1

Volume status assessment is crucial for proper management:

• Hypovolemic: Signs of dehydration, hypotension, tachycardia
• Euvolemic: Normal volume status
• Hypervolemic: Edema, ascites, jugular venous distension 1

Treatment Algorithm Based on Volume Status

1. Hypovolemic Hyponatremia

• First-line treatment: Fluid resuscitation with isotonic saline or 5% albumin 1
• Discontinue diuretics and/or laxatives 2
• Monitor serum sodium every 2-4 hours during active correction 1

2. Euvolemic Hyponatremia

• Identify and treat underlying cause (e.g., SIADH, medications, hypothyroidism, adrenal insufficiency) 2
• For mild hyponatremia: Generally no fluid restriction needed 1
• For moderate hyponatremia (120-125 mEq/L): Fluid restriction to 1,000 mL/day 2
• For severe hyponatremia (<120 mEq/L): More severe fluid restriction plus albumin infusion 2

3. Hypervolemic Hyponatremia (Common in Cirrhosis)

• Fluid restriction (<1 L/day) 1
• Maintain sodium restriction (5-6.5 g/day) 1
• Consider temporary discontinuation of diuretics if sodium remains <125 mmol/L 1
• Albumin infusion may improve hyponatremia in hospitalized cirrhotic patients 2

Management of Severe Symptomatic Hyponatremia

For patients with severe symptoms (confusion, seizures, coma):

• Administer 3% hypertonic saline 3, 4
• Limit correction to 8-10 mmol/L in 24 hours and 18 mmol/L in 48 hours 1
• Monitor serum sodium every 2-4 hours during correction 1
• Avoid overcorrection to prevent osmotic demyelination syndrome (ODS) 2, 1

Special Considerations in Cirrhosis

Hyponatremia in cirrhosis requires special attention:

• Patients with serum Na ≤130 mEq/L have increased risk of hepatic encephalopathy, hepatorenal syndrome, and spontaneous bacterial peritonitis 2
• Even mild hyponatremia (131-135 mEq/L) increases risk of complications 2
• Avoid vaptans in patients with liver disease due to increased risk of gastrointestinal bleeding (10% vs 2% in placebo) 5

Monitoring and Prevention of Complications

• Regular monitoring of serum sodium every 2-4 hours during active correction 1
• Limit correction to 8-10 mmol/L in 24 hours and 18 mmol/L in 48 hours 1
• For high-risk patients (advanced liver disease, alcoholism, malnutrition, hypokalemia), limit correction to 4-6 mEq/L per 24 hours 1
• Watch for signs of hypernatremia during treatment, which occurred in 1.7% of patients receiving tolvaptan vs 0.8% with placebo 5

Pitfalls to Avoid

1. Overly rapid correction: Can lead to osmotic demyelination syndrome, especially in chronic hyponatremia 4
2. Inadequate monitoring: Serum sodium should be checked every 2-4 hours during active correction 1
3. Using vaptans in liver disease: Increased risk of gastrointestinal bleeding (10% vs 2%) 5
4. Focusing solely on hyponatremia without addressing underlying causes: Always identify and treat the primary condition 1
5. Neglecting to assess volume status: Treatment differs significantly based on whether the patient is hypovolemic, euvolemic, or hypervolemic 1

By following this algorithmic approach based on severity and volume status, hyponatremia can be managed effectively while minimizing the risk of complications.