How to correct hyponatremia with a sodium level of 117 mmol/L?

Correction of Hyponatremia with Sodium Level of 117 mmol/L

For a patient with hyponatremia (sodium 117 mmol/L), the maximum correction should not exceed 8 mmol/L in 24 hours, with a calculated sodium deficit based on the formula: Desired increase in Na (mEq/L) × (0.5 × body weight in kg). 1

Assessment and Initial Management

• Evaluate volume status and serum osmolality to determine the underlying cause of hyponatremia (hypovolemic, euvolemic, or hypervolemic) 1
• Check urine sodium concentration and osmolality to help distinguish between SIADH and other causes of hyponatremia 1
• Assess symptom severity to guide treatment approach and correction rate 1

Calculation of Sodium Deficit and Correction

• For a 45 kg patient with sodium of 117 mmol/L, the sodium deficit can be calculated as follows:
  • Desired increase in Na (mEq/L) × (0.5 × body weight in kg) 1
  • For example, to increase sodium by 8 mmol/L (maximum safe correction in 24 hours): 8 × (0.5 × 45) = 180 mEq of sodium needed 1

Treatment Based on Symptom Severity

For Severe Symptoms (seizures, coma):

• Administer 3% hypertonic saline with an initial goal to correct 6 mmol/L over 6 hours or until severe symptoms resolve 1
• Bolus therapy: 2 ml/kg of 3% NaCl (maximum of three boluses) to ensure immediate and controllable rise in sodium 2
• Total correction should not exceed 8 mmol/L in 24 hours to prevent osmotic demyelination syndrome 1, 3

For Mild to Moderate Symptoms:

• For euvolemic hyponatremia (SIADH): Implement fluid restriction to 1 L/day and consider oral sodium supplementation with NaCl 100 mEq three times daily 3
• For hypovolemic hyponatremia: Discontinue diuretics and administer isotonic saline (0.9% NaCl) for volume repletion 1
• For hypervolemic hyponatremia (cirrhosis, heart failure): Implement fluid restriction to 1-1.5 L/day and consider albumin infusion for cirrhotic patients 1

Special Considerations

• Patients with advanced liver disease, alcoholism, malnutrition, or prior encephalopathy require more cautious correction (4-6 mmol/L per day) due to higher risk of osmotic demyelination syndrome 1
• For chronic hyponatremia, avoid rapid correction exceeding 1 mmol/L/hour 1
• Consider proactive desmopressin administration with hypertonic saline to prevent inadvertent overcorrection, which has been shown to reduce rates of overcorrection without significant adverse events 4

Monitoring During Treatment

• Monitor serum sodium every 2-4 hours during initial correction for severe symptoms, and every 4-6 hours after resolution of severe symptoms 1, 3
• If overcorrection occurs, consider relowering with electrolyte-free water or desmopressin 1
• Watch for signs of osmotic demyelination syndrome (dysarthria, dysphagia, oculomotor dysfunction, quadriparesis) typically occurring 2-7 days after rapid correction 1

Common Pitfalls to Avoid

• Overly rapid correction of chronic hyponatremia leading to osmotic demyelination syndrome 1
• Inadequate monitoring during active correction 1
• Using fluid restriction in cerebral salt wasting (CSW), which can worsen outcomes 1
• Failing to recognize and treat the underlying cause 1
• Using hypertonic saline in hypervolemic hyponatremia without life-threatening symptoms 1