How should severe hyponatremia be corrected in a patient?

Management of Severe Hyponatremia (Sodium 118)

For a patient with severe hyponatremia (sodium 118), correction should be performed at a rate not exceeding 8 mEq/L in 24 hours, with careful monitoring every 2 hours to prevent osmotic demyelination syndrome. 1

Initial Assessment and Treatment Approach

For Symptomatic Severe Hyponatremia:

• If severe neurological symptoms present (seizures, coma, severe confusion):
  • Administer 3% hypertonic saline as bolus infusion
  • Target initial increase: 4-6 mEq/L within 1-2 hours until symptoms improve 1, 2
  • Critical safety principle: Do not exceed correction of 8-10 mEq/L in 24 hours 1

For Asymptomatic or Mildly Symptomatic Hyponatremia:

• Treatment based on volume status assessment:
  • Hypovolemic: Isotonic (0.9%) saline infusion
  • Euvolemic: Fluid restriction (<1 L/day)
  • Hypervolemic: Fluid restriction + treatment of underlying condition 1

Monitoring Protocol

• Check serum sodium every 2 hours in severely symptomatic patients 1
• Monitor urine output and specific gravity every 4 hours 1
• Watch for signs of water diuresis (sudden decrease in urine specific gravity ≥0.010), which can lead to overcorrection 1

Risk Factors for Overcorrection

1. Severe symptoms (38% vs 6% overcorrection rate compared to moderate symptoms) 1
2. High urine output or water diuresis 1
3. Hypovolemia that may be misinterpreted as symptomatic hyponatremia 1

Specific Management Considerations

Pharmacologic Options for Resistant Cases:

• Tolvaptan may be considered for euvolemic or hypervolemic hyponatremia, but:
  • Must be initiated in a hospital setting
  • Requires close monitoring of serum sodium
  • Risk of too rapid correction (>12 mEq/L/24 hours) can cause osmotic demyelination 3
  • Starting dose: 15 mg once daily, may increase to 30 mg after 24 hours if needed 3
  • Avoid fluid restriction during first 24 hours of tolvaptan therapy 3

Prevention of Osmotic Demyelination Syndrome:

• Patients with severe malnutrition, alcoholism, or advanced liver disease may require slower correction rates 1, 3
• If correction is proceeding too rapidly, consider:
  • Administering hypotonic fluids
  • Using desmopressin to slow correction 1

Volume Status-Based Treatment Algorithm

Volume Status	First-Line Treatment	Second-Line Treatment
Hypovolemic	Isotonic saline infusion	Discontinue diuretics if applicable
Euvolemic	Fluid restriction (<1 L/day)	Consider vasopressin antagonists under close monitoring
Hypervolemic	Fluid restriction + sodium restriction	Treat underlying condition (heart failure, cirrhosis); consider loop diuretics [1]

Important Caveats

• Avoid fluid restriction in neurosurgical patients at risk of vasospasm 1
• Patients requiring urgent intervention to raise sodium for serious neurological symptoms should not receive tolvaptan 3
• Following discontinuation of any treatment, monitor for rebound hyponatremia 1, 3
• The optimal correction rate is no more than 8 mEq/L in 24 hours, with careful monitoring to avoid overcorrection 1