Is it correct to increase sodium levels to 120 mmol/L in patients with severe symptoms of hyponatremia?

Severe Symptomatic Hyponatremia: Target Sodium of 120 mmol/L

For severe symptomatic hyponatremia (seizures, coma, altered mental status), the goal is NOT to reach 120 mmol/L, but rather to correct by 6 mmol/L over 6 hours or until symptoms resolve, with a maximum total correction of 8 mmol/L in 24 hours. 1

Critical Correction Targets for Severe Symptoms

The primary endpoint is symptom resolution, not a specific sodium level. 1 The correction strategy should be:

• Initial 6-hour target: Increase sodium by 6 mmol/L OR until severe symptoms (seizures, coma) resolve—whichever comes first 1
• 24-hour maximum: Total correction must not exceed 8 mmol/L in any 24-hour period 1, 2, 3
• If 6 mmol/L corrected in first 6 hours: Only 2 mmol/L additional correction allowed in remaining 18 hours 1

Why 120 mmol/L is NOT the Target

The concept of "leveling up to 120" is a misunderstanding of hyponatremia management. The correction is rate-limited, not level-targeted. 1 For example:

• Patient with sodium 110 mmol/L and seizures: Correct to 116 mmol/L (6 mmol/L increase) over 6 hours, then stop aggressive correction 1
• Patient with sodium 115 mmol/L and coma: Correct to 121 mmol/L (6 mmol/L increase) over 6 hours, then stop aggressive correction 1

Attempting to reach 120 mmol/L regardless of starting sodium level would cause dangerous overcorrection in many patients. 1, 2

Treatment Protocol for Severe Symptoms

Immediate Management

• Administer 3% hypertonic saline immediately 1, 4
• Give as 100 mL boluses over 10 minutes, repeatable up to 3 times at 10-minute intervals until symptoms improve 1
• Check serum sodium every 2 hours during initial correction phase 1

Monitoring Thresholds

• Stop hypertonic saline when EITHER:
  • Severe symptoms resolve (seizures stop, consciousness improves) 1
  • OR 6 mmol/L increase achieved in first 6 hours 1
  • OR 8 mmol/L total increase achieved in 24 hours 1

Risk of Osmotic Demyelination Syndrome

Overcorrection beyond 8 mmol/L in 24 hours significantly increases ODS risk. 5, 6 Recent meta-analyses show:

• Rapid correction (>8-12 mmol/L/24h) increases ODS risk 3-4 fold (RR 3.16-3.91) 5, 6
• ODS incidence with rapid correction: 0.73% vs 0.10% with controlled correction 6
• Historical data shows correction >12 mmol/L/day caused neurologic sequelae in all affected patients 3

High-Risk Populations Requiring Even Slower Correction (4-6 mmol/L/day maximum)

• Advanced liver disease 1
• Chronic alcoholism 1
• Malnutrition 1
• Prior encephalopathy 1

Common Pitfalls to Avoid

• Never target a specific sodium level like 120 mmol/L—this leads to overcorrection 1
• Never continue aggressive correction after symptoms resolve—the brain has adapted and further rapid correction is dangerous 1, 4
• Never exceed 8 mmol/L correction in 24 hours for chronic hyponatremia (>48 hours duration) 1, 2, 3
• Never use fluid restriction as initial treatment for severe symptomatic hyponatremia—this is a medical emergency requiring hypertonic saline 1

If Overcorrection Occurs

• Immediately discontinue hypertonic saline and switch to D5W (5% dextrose in water) 1
• Consider desmopressin to slow or reverse rapid sodium rise 1
• Target: bring total 24-hour correction back to ≤8 mmol/L from starting point 1

Symptom Severity Determines Urgency, Not Sodium Level

Severe symptoms (seizures, coma, respiratory distress) constitute a medical emergency regardless of absolute sodium level. 7 A patient with sodium 125 mmol/L and seizures requires the same urgent hypertonic saline treatment as one with sodium 110 mmol/L and seizures. 1, 7 The rapidity of development matters more than the absolute value—acute hyponatremia (<48 hours) causes more severe symptoms than chronic hyponatremia at identical sodium levels. 7