At what rate is sodium corrected for hyponatremia?

Sodium Correction Rate for Hyponatremia

For most patients with hyponatremia, the maximum correction rate should not exceed 8 mmol/L in 24 hours to prevent osmotic demyelination syndrome. 1

Correction Rates Based on Symptom Severity

Severe Symptomatic Hyponatremia (Seizures, Coma, Altered Mental Status)

• Administer 3% hypertonic saline with an initial target of 6 mmol/L correction over the first 6 hours or until severe symptoms resolve 1, 2
• Give 100 mL boluses of 3% sapertonic saline IV over 10 minutes, repeatable up to three times at 10-minute intervals if seizures persist 2
• After achieving 6 mmol/L correction in 6 hours, limit additional correction to only 2 mmol/L over the remaining 18 hours (total 8 mmol/L in 24 hours) 1, 2
• Monitor serum sodium every 2 hours during initial correction phase 1, 2

Asymptomatic or Mildly Symptomatic Hyponatremia

• Target correction of 4-8 mmol/L per day, not exceeding 8 mmol/L in 24 hours 1
• For chronic hyponatremia, avoid rapid correction exceeding 1 mmol/L/hour 1
• Monitor serum sodium every 4 hours after resolution of severe symptoms 1

High-Risk Populations Requiring Slower Correction

Patients with advanced liver disease, alcoholism, malnutrition, or prior encephalopathy require even more cautious correction at 4-6 mmol/L per day 1, 3

These patients have significantly higher risk of osmotic demyelination syndrome and should not exceed:

• 4-6 mmol/L per 24 hours 1
• 8 mmol/L maximum in 48 hours 1

Treatment Approach by Volume Status

Hypovolemic Hyponatremia

• Discontinue diuretics and administer isotonic saline (0.9% NaCl) for volume repletion 1
• Correction rate still limited to 8 mmol/L in 24 hours 1

Euvolemic Hyponatremia (SIADH)

• Fluid restriction to 1 L/day is the cornerstone of treatment for mild/asymptomatic cases 1, 2
• For severe symptoms: 3% hypertonic saline with careful monitoring 1
• Add oral sodium chloride 100 mEq three times daily if no response to fluid restriction 1, 2

Hypervolemic Hyponatremia (Cirrhosis, Heart Failure)

• Fluid restriction to 1-1.5 L/day for serum sodium <125 mmol/L 1
• Consider albumin infusion in cirrhotic patients 1
• Avoid hypertonic saline unless life-threatening symptoms present, as it may worsen edema and ascites 1

Critical Safety Limits

The absolute maximum correction limits to prevent osmotic demyelination syndrome are: 1, 4, 3

• 8 mmol/L in 24 hours
• 18 mmol/L in 48 hours
• 20 mmol/L in 72 hours

Managing Overcorrection

If sodium correction exceeds 8 mmol/L in 24 hours: 1

• Immediately discontinue current fluids and switch to D5W (5% dextrose in water)
• Consider administering desmopressin to slow or reverse the rapid rise
• Monitor 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 exceeding 8 mmol/L in 24 hours is the most common cause of osmotic demyelination syndrome 1
• Inadequate monitoring during active correction 1
• Using fluid restriction in cerebral salt wasting (worsens outcomes) 1, 2
• Using hypertonic saline in hypervolemic hyponatremia without life-threatening symptoms 1
• Failing to recognize high-risk patients who need slower correction (4-6 mmol/L per day) 1