How to treat a patient with hyponatremia?

Treatment of Hyponatremia with Serum Sodium of 3.4 mmol/L

A patient with severe hyponatremia (sodium 3.4 mmol/L) requires immediate treatment with 3% hypertonic saline to prevent life-threatening neurological complications, with a target correction of 6 mmol/L over 6 hours or until severe symptoms resolve, while ensuring total correction does not exceed 8 mmol/L in 24 hours. 1

Initial Assessment and Management

• Treatment approach should be based on symptom severity, with severe symptoms (mental status changes, seizures, coma) requiring immediate intervention 1, 2
• For severe symptomatic hyponatremia, administer 3% hypertonic saline with an initial bolus of 100-150 mL or continuous infusion 1, 3
• Calculate sodium deficit using the formula: Desired increase in Na (mEq/L) × (0.5 × ideal body weight in kg) 1
• Monitor serum sodium every 4-6 hours during initial correction to avoid overcorrection 1

Correction Rate Guidelines

• Target correction of 6 mmol/L over 6 hours or until severe symptoms resolve 1
• Never exceed correction of 8 mmol/L in 24 hours for chronic hyponatremia to prevent osmotic demyelination syndrome 1, 2
• Rapid correction >1 mmol/L/hour should only be used for severely symptomatic and/or acute hyponatremia 1

Treatment Based on Volume Status

Hypovolemic Hyponatremia

• Treat with normal saline infusions to restore volume status 2, 4
• Once volume is restored, reassess sodium levels and adjust treatment accordingly 4

Euvolemic Hyponatremia (SIADH)

• Initial management includes fluid restriction to 1 L/day 1
• Add oral sodium supplementation (NaCl 100 mEq orally three times daily) if needed 1
• Consider second-line therapies such as urea or tolvaptan if fluid restriction is ineffective 3
• High protein diet to augment solute intake 1

Hypervolemic Hyponatremia

• For patients with cirrhosis or heart failure, restrict fluid to 1-1.5 L/day 5, 1
• Address underlying cause (heart failure, cirrhosis) 2
• Discontinue diuretics if they're contributing to hyponatremia 1

Special Considerations

• For neurosurgical patients with cerebral salt wasting (CSW), volume repletion with normal saline is primary, with oral sodium supplementation added if needed 1
• Fluid restriction should be avoided in subarachnoid hemorrhage patients at risk of vasospasm 1, 5
• Fludrocortisone may be considered for hyponatremia in subarachnoid hemorrhage patients at risk of vasospasm 5, 1

Monitoring and Safety

• Monitor for hyperkalemia when using oral sodium supplements, especially in patients with renal impairment 1
• Watch for signs of overcorrection, which is more likely in severely symptomatic patients 1
• If correction is occurring too rapidly, consider administering hypotonic fluids or desmopressin to slow the rate 3
• Continue monitoring sodium levels after initial correction to ensure appropriate maintenance 1

Pharmacological Options

• For persistent euvolemic or hypervolemic hyponatremia, tolvaptan (vasopressin V2 receptor antagonist) may be considered 6, 7
• Start tolvaptan at 15 mg once daily, with possible titration to 30 mg and then 60 mg once daily 6
• Avoid fluid restriction during the first 24 hours of tolvaptan therapy to prevent overly rapid correction 6

Pitfalls to Avoid

• Overly aggressive correction leading to osmotic demyelination syndrome 5, 8
• Inadequate monitoring of serum sodium levels during correction 1
• Treating based on laboratory values alone without considering clinical symptoms 1, 2
• Failure to identify and address the underlying cause of hyponatremia 4
• Using fluid restriction in patients with cerebral salt wasting, which can worsen outcomes 1