In an adult middle‑aged patient with chronic hyponatremia (serum sodium <120 mEq/L) without life‑threatening neurological symptoms but with risk factors such as malnutrition, alcoholism, liver disease, or severe hypokalaemia, how should the sodium be corrected to prevent osmotic demyelination syndrome?

Sodium Correction in Chronic Hyponatremia with Risk Factors

Maximum Correction Rate

In patients with chronic hyponatremia (<120 mEq/L) and risk factors such as malnutrition, alcoholism, liver disease, or severe hypokalemia, limit sodium correction to 4-6 mEq/L per day, with an absolute maximum of 8 mEq/L in any 24-hour period. 1, 2

This conservative target is critical because these high-risk patients have a substantially elevated risk of osmotic demyelination syndrome (ODS), occurring in approximately 0.5-1.5% of cases even with careful correction. 1

Risk Stratification

High-Risk Features Requiring Slower Correction (4-6 mEq/L per day maximum)

• Advanced liver disease or cirrhosis 1, 2
• Chronic alcoholism or alcohol use disorder 1, 3
• Malnutrition or poor dietary intake 1, 3
• Severe hypokalemia 1, 3
• Initial serum sodium <115 mEq/L 3
• Hypophosphatemia 2
• Hypoglycemia 2
• Low cholesterol 2
• Prior hepatic encephalopathy 1, 2

The presence of even one of these factors mandates the slower 4-6 mEq/L per day correction rate. 1, 2

Correction Protocol

Initial 24 Hours

• Target correction of 4-6 mEq/L in the first 24 hours 1, 2
• Check serum sodium every 2 hours during active correction 1
• Never exceed 8 mEq/L total rise in any 24-hour period 1, 2, 4

Subsequent Days

• Continue limiting correction to 4-6 mEq/L per day until sodium reaches 125-130 mEq/L 1
• Monitor sodium every 4-6 hours after the first 24 hours 1
• Do not aim for normonatremia acutely; target is 125-130 mEq/L 1

Treatment Approach Based on Volume Status

Hypovolemic Hyponatremia

• Administer isotonic saline (0.9% NaCl) for volume repletion 1
• Initial rate: 15-20 mL/kg/h, then 4-14 mL/kg/h based on response 1
• In cirrhotic patients, consider albumin infusion (8 g per liter of ascites removed) alongside saline 1

Euvolemic Hyponatremia (SIADH)

• Implement fluid restriction to 1 L/day as first-line therapy 1
• Add oral sodium chloride 100 mEq three times daily if no response to fluid restriction 1
• For severe symptoms, use 3% hypertonic saline with target correction of 6 mEq/L over 6 hours 1

Hypervolemic Hyponatremia (Cirrhosis, Heart Failure)

• Implement fluid restriction to 1-1.5 L/day for sodium <125 mEq/L 1
• Temporarily discontinue diuretics until sodium improves 1
• Consider albumin infusion in cirrhotic patients 1
• Avoid hypertonic saline unless life-threatening symptoms present 1, 2

Management of Overcorrection

If sodium rises more than 8 mEq/L in 24 hours, immediate intervention is required: 1, 2, 5

• Immediately discontinue current fluids and switch to D5W (5% dextrose in water) 1, 5
• Administer desmopressin to slow or reverse the rapid rise 1, 5
• Target is to bring the total 24-hour correction back to ≤8 mEq/L from baseline 1, 5
• Re-lowering should be initiated as quickly as possible after onset of neurologic symptoms 5

Recognition of Osmotic Demyelination Syndrome

ODS typically presents 2-7 days after rapid correction with: 1, 2

• Dysarthria (difficulty speaking)
• Dysphagia (difficulty swallowing)
• Oculomotor dysfunction (eye movement abnormalities)
• Quadriparesis (weakness in all four limbs)

Confirm diagnosis with brain MRI showing hyperintense lesions in pons and extrapontine areas on T2-weighted imaging. 4, 5

Critical Pitfalls to Avoid

• Never correct chronic hyponatremia faster than 8 mEq/L in 24 hours 1, 2, 4
• Never use the standard 10-12 mEq/L limit in high-risk patients; use 4-6 mEq/L instead 1, 3
• Never fail to check sodium every 2 hours during initial correction 1, 2
• Never use fluid restriction in cerebral salt wasting, as this worsens outcomes 1, 2
• Never use hypertonic saline in hypervolemic hyponatremia without life-threatening symptoms 1, 2

Special Considerations

Patients with Serum Sodium <115 mEq/L

These patients are at exceptionally high risk and require even more cautious correction: 3

• Limit correction to <8 mEq/L in 24 hours, ideally 4-6 mEq/L 3
• ODS can occur despite adherence to guidelines in this population 3, 6
• Consider thiamine supplementation (500 mg IV three times daily) before any glucose-containing fluids 3

Alcoholic Patients

• Administer thiamine 500 mg IV three times daily before any glucose-containing fluids to prevent Wernicke's encephalopathy 1
• Provide multivitamin supplementation including B-complex, folate, and B12 1
• These patients have the highest risk of ODS even with appropriate correction rates 3

Cirrhotic Patients

• Correction rate of 4-6 mEq/L per day is mandatory 1
• Avoid hypertonic saline as it may worsen ascites and edema 1
• Sodium restriction (not fluid restriction) results in weight loss as fluid follows sodium 1

Evidence Quality Note

The 8 mEq/L per 24-hour limit is supported by multiple guidelines and case reports demonstrating ODS with faster correction. 1, 2, 4, 7 However, recent meta-analysis shows ODS can occur even with correction ≤10 mEq/L per day in high-risk patients, particularly those with sodium <115 mEq/L, reinforcing the need for the more conservative 4-6 mEq/L target in this population. 3, 7