How to manage a patient with severe hyponatremia?

Management of Severe Hyponatremia (Sodium 120 mEq/L)

For severe hyponatremia (sodium <120 mEq/L), hospitalization is required with very strict fluid restriction, albumin infusion, and consideration of hypertonic saline only for life-threatening manifestations. 1

Initial Assessment and Classification

1. Determine acuity and severity:

   • Sodium 120 mEq/L classifies as moderate hyponatremia 1
   • Assess for symptoms:
     • Mild symptoms: nausea, vomiting, weakness, headache
     • Severe symptoms: delirium, confusion, impaired consciousness, ataxia, seizures 2

2. Assess volume status to determine if hyponatremia is:

   • Hypovolemic (dehydration, diuretics)
   • Euvolemic (SIADH, hypothyroidism)
   • Hypervolemic (heart failure, cirrhosis) 1, 2

Management Algorithm

For Symptomatic Severe Hyponatremia (Life-threatening symptoms)

1. Administer hypertonic (3%) saline:

   • Only for life-threatening manifestations 1
   • Goal: Increase serum sodium by 4-6 mEq/L within 1-2 hours 3
   • Critical safety limit: Do not exceed correction of 8 mEq/L in 24 hours (4-6 mEq/L for high-risk patients) 1
   • Monitor serum sodium every 4-6 hours during active correction 1

2. If overcorrection occurs:

   • Consider desmopressin to halt water diuresis 1

For Non-Life-Threatening Severe Hyponatremia

1. Very strict fluid restriction (primary approach) 1

   • Limit to <1000 mL/day

2. Volume-specific treatments:

   • Hypovolemic: Normal saline infusion 2
   • Euvolemic: Consider tolvaptan if appropriate 1, 4
   • Hypervolemic: Treat underlying cause (heart failure, cirrhosis) 2

3. For euvolemic or hypervolemic hyponatremia:

   • Consider tolvaptan (vasopressin receptor antagonist):
     • Starting dose: 15 mg once daily
     • Can increase to 30 mg after 24 hours (maximum 60 mg daily) 1, 4
     • IMPORTANT: Must be initiated in hospital setting 4
     • Do not administer for more than 30 days (risk of liver injury) 4
     • Contraindicated in hypovolemic hyponatremia 4

Critical Safety Considerations

1. Avoid overly rapid correction:

   • Maximum correction rate: 8 mEq/L in 24 hours 1
   • For high-risk patients (alcoholism, liver disease, malnutrition): 4-6 mEq/L in 24 hours 1

2. Monitor for osmotic demyelination syndrome:

   • Presents 2-7 days after rapid correction
   • Symptoms: dysarthria, dysphagia, oculomotor dysfunction 1, 4
   • Diagnosed with brain MRI 1

3. Special precautions with tolvaptan:

   • Monitor for hypernatremia 4
   • Increased risk of gastrointestinal bleeding in cirrhotic patients 1, 4
   • Patients should continue fluid intake in response to thirst 4

Monitoring

1. Serum sodium levels: Every 4-6 hours during active correction 1
2. Neurological status: Regularly assess for changes 4
3. Volume status: Ongoing assessment 1

Follow-up After Initial Stabilization

1. Identify and treat underlying cause
2. After discontinuation of tolvaptan:
   • Resume fluid restriction
   • Monitor for changes in serum sodium and volume status 4

Pitfalls to Avoid

1. Rapid correction leading to osmotic demyelination syndrome 1, 4, 3
2. Hypertonic saline in cirrhotic patients with hypervolemic hyponatremia (can worsen ascites and edema) 1
3. Inadequate monitoring during correction 1
4. Treating without determining volume status 2, 3

Remember that even mild chronic hyponatremia is associated with cognitive impairment, gait disturbances, and increased risk of falls and fractures 3, making proper management essential for improving both short and long-term outcomes.