How to correct hyponatremia in a hospitalized patient?

Management of Hyponatremia in Hospitalized Patients

The correction of hyponatremia in hospitalized patients should not exceed 8 mmol/L per 24-hour period to prevent osmotic demyelination syndrome, with initial correction of 4-6 mmol/L in the first 24 hours being the safest approach. 1

Assessment and Classification

First, determine the severity of hyponatremia:

• Mild: 130-135 mEq/L
• Moderate: 125-129 mEq/L
• Severe: <125 mEq/L 1

Next, assess the patient's volume status to guide treatment:

• Hypovolemic (depleted)
• Euvolemic (normal)
• Hypervolemic (fluid overloaded) 1

Treatment Algorithm Based on Clinical Presentation

For Severely Symptomatic Patients (seizures, coma, severe neurological symptoms)

1. Administer 3% hypertonic saline to increase sodium by 4-6 mmol/L within 1-2 hours 1
2. Monitor serum sodium every 2-4 hours during active correction 1
3. Slow correction once symptoms improve to stay within the 8 mmol/L per 24-hour limit 1

For Asymptomatic or Mildly Symptomatic Patients

Hypovolemic Hyponatremia:

• Administer isotonic saline or 5% albumin for volume repletion 1
• Discontinue diuretics if applicable 1

Euvolemic Hyponatremia:

• Implement fluid restriction (<1 L/day) 1
• Consider tolvaptan for persistent cases (must be initiated in hospital setting) 2

Hypervolemic Hyponatremia (e.g., cirrhosis, heart failure):

• Implement fluid restriction (<1 L/day) 1
• For patients with cirrhosis, manage based on sodium levels:
  • 126-135 mmol/L: continue diuretics with close monitoring
  • 121-125 mmol/L: consider stopping diuretics
  • ≤120 mmol/L: stop diuretics and consider volume expansion 1

Special Considerations for Tolvaptan Use

If using tolvaptan (for euvolemic or hypervolemic hyponatremia):

1. Must initiate in hospital setting where sodium can be closely monitored 2
2. Start with 15 mg once daily
3. May increase to 30 mg after 24 hours, and up to 60 mg daily as needed
4. Do not administer for more than 30 days due to risk of liver injury
5. Avoid fluid restriction during first 24 hours of therapy 2

Important Precautions

• Monitor sodium levels every 2-4 hours during active correction 1
• Avoid exceeding correction rate of 8 mmol/L per 24 hours to prevent osmotic demyelination syndrome 1
• High-risk patients (alcoholism, malnutrition, advanced liver disease, chronic hyponatremia) require more cautious correction 1
• Watch for neurological symptoms (dysarthria, dysphagia, altered mental status) that may indicate osmotic demyelination 1
• Fluid restriction is not necessary in most patients with cirrhosis and ascites 3
• Chronic hyponatremia in cirrhotic patients is seldom morbid; rapid correction with hypertonic saline can lead to more complications than the hyponatremia itself 3

After Correction

• Following discontinuation of tolvaptan, resume fluid restriction and monitor sodium and volume status 2
• Continue monitoring for 48-72 hours after achieving target sodium levels to ensure stability

Common Pitfalls to Avoid

1. Correcting too rapidly (>8 mmol/L/24 hours), which can cause osmotic demyelination syndrome 1
2. Failing to identify the underlying cause of hyponatremia, which is essential for effective treatment 4
3. Restricting fluids in all patients - not necessary for most patients with cirrhosis 3
4. Using tolvaptan without proper monitoring - must be initiated in hospital setting 2
5. Continuing diuretics in patients with severe hyponatremia (≤120 mmol/L) 1

By following these evidence-based guidelines, you can safely and effectively manage hyponatremia in hospitalized patients while minimizing the risk of complications.