What is the treatment for hyponatremia?

Treatment of Hyponatremia

The treatment of hyponatremia should be based on symptom severity, volume status, and onset timing, with correction rates not exceeding 8 mmol/L in 24 hours to prevent osmotic demyelination syndrome. 1

Initial Assessment and Classification

• Evaluate volume status (hypovolemic, euvolemic, or hypervolemic) and serum osmolality to determine the underlying cause of hyponatremia 1
• Check urine osmolality and sodium concentration to differentiate between various causes (SIADH, cerebral salt wasting, etc.) 1
• Assess symptom severity to guide treatment approach and correction rate 1

Treatment Based on Symptom Severity

Severe Symptomatic Hyponatremia (seizures, coma)

• Administer 3% hypertonic saline with an initial goal to correct 6 mmol/L over 6 hours or until severe symptoms resolve 1, 2
• Total correction should not exceed 8 mmol/L in 24 hours to prevent osmotic demyelination syndrome 1, 3
• Monitor serum sodium every 2 hours during initial correction 1
• Consider ICU admission for close monitoring 1

Mild/Asymptomatic Hyponatremia

• For euvolemic hyponatremia (SIADH): Implement fluid restriction to 1 L/day as first-line treatment 1, 3
• For persistent cases, add oral sodium chloride 100 mEq three times daily 2
• Consider high protein diet to augment solute intake 2
• Monitor serum sodium every 4-6 hours during initial correction 2

Treatment Based on Volume Status

Hypovolemic Hyponatremia

• Discontinue diuretics and administer isotonic saline (0.9% NaCl) for volume repletion 1, 4
• For severe dehydration with neurological symptoms, consider hypertonic saline with careful monitoring 1

Euvolemic Hyponatremia (SIADH)

• Fluid restriction to 1 L/day for mild/asymptomatic cases 1, 3
• For resistant cases, consider pharmacological options:
  • Oral sodium chloride 100 mEq three times daily 2
  • Tolvaptan (vasopressin receptor antagonist) for clinically significant hyponatremia resistant to fluid restriction 1, 5
  • Urea as an alternative second-line therapy 6
  • Demeclocycline for persistent cases 3, 7

Hypervolemic Hyponatremia (cirrhosis, heart failure)

• Implement fluid restriction to 1-1.5 L/day for serum sodium <125 mmol/L 1, 2
• Consider albumin infusion for patients with cirrhosis 1
• Avoid hypertonic saline unless life-threatening symptoms are present 1

Correction Rate Guidelines

• Maximum increase of 8 mmol/L in 24 hours to prevent osmotic demyelination syndrome 1, 8
• For patients with advanced liver disease, alcoholism, malnutrition, or prior encephalopathy: more cautious correction (4-6 mmol/L per day) 1
• For chronic hyponatremia, avoid rapid correction exceeding 1 mmol/L/hour 1
• If overcorrection occurs, consider relowering with electrolyte-free water or desmopressin 1, 6

Special Considerations

Cerebral Salt Wasting (CSW)

• Treatment focuses on volume and sodium replacement, not fluid restriction 1
• For severe symptoms, administer 3% hypertonic saline and consider fludrocortisone 1

Liver Disease

• Patients with cirrhosis require more cautious correction (4-6 mmol/L per day) 1
• Hyponatremia in cirrhosis reflects worsening hemodynamic status and increases risk for complications 1

Common Pitfalls to Avoid

• Overly rapid correction of chronic hyponatremia leading to osmotic demyelination syndrome 1, 9
• Inadequate monitoring during active correction 1
• Using fluid restriction in cerebral salt wasting 1
• Failing to recognize and treat the underlying cause 1, 3
• Using hypertonic saline in hypervolemic hyponatremia without life-threatening symptoms 1

Monitoring and Follow-up

• For severe symptoms: monitor serum sodium every 2 hours during initial correction 1
• For mild/moderate symptoms: monitor every 4-6 hours 2
• Watch for signs of osmotic demyelination syndrome (dysarthria, dysphagia, oculomotor dysfunction, quadriparesis) typically occurring 2-7 days after rapid correction 1