What is the treatment for a patient with severe hyponatremia (sodium level of 118 mEq/L), seizures, and confusion?

Treatment of Severe Hyponatremia with Seizures and Confusion

For a patient with severe hyponatremia (sodium 118 mEq/L) presenting with seizures and confusion, immediate administration of 3% hypertonic saline is required, with a target correction of 4-6 mEq/L within 1-2 hours or until severe symptoms resolve.

Initial Emergency Management

For Severe Symptomatic Hyponatremia (Seizures, Confusion)

1. Administer 3% hypertonic saline:

   • Give up to three 100 mL boluses of 3% sodium chloride solution spaced at 10-minute intervals 1
   • Target: Increase serum sodium by 4-6 mEq/L in first 1-2 hours or until severe symptoms improve 2
   • Maximum correction: 8 mEq/L in first 24 hours to prevent osmotic demyelination syndrome 2

2. Monitoring during treatment:

   • Check serum sodium levels every 2-4 hours initially during active correction 2
   • Monitor for neurological improvement
   • Adjust rate of correction based on sodium levels and symptom resolution

Post-Emergency Management

After Initial Stabilization

1. Determine the underlying cause:

   • Evaluate volume status (hypovolemic, euvolemic, or hypervolemic)
   • Check urine osmolality and sodium to differentiate causes
   • Consider medication review, especially diuretics, antidepressants, and anticonvulsants 3

2. Management based on volume status:

   • Hypovolemic hyponatremia: Administer isotonic (0.9%) saline 4
   • Euvolemic hyponatremia (e.g., SIADH): Fluid restriction (1-1.5 L/day) 1
   • Hypervolemic hyponatremia (e.g., heart failure, cirrhosis): Fluid restriction to 1,000 mL/day and possibly albumin infusion for severe cases 1

3. Consider vasopressin receptor antagonists (vaptans):

   • For persistent euvolemic or hypervolemic hyponatremia
   • Tolvaptan starting at 15 mg once daily, can be titrated up to 60 mg 5
   • Must be initiated in a hospital setting where serum sodium can be closely monitored 5
   • Avoid fluid restriction during first 24 hours of vaptan therapy 5

Monitoring and Prevention of Complications

1. Prevent overly rapid correction:

   • Do not exceed correction rate of 8 mEq/L in 24 hours 2
   • More conservative approach (4-6 mEq/L per day) for high-risk patients 2
   • Frequent monitoring of serum sodium levels is crucial

2. Watch for signs of osmotic demyelination syndrome (ODS):

   • Dysarthria, mutism, dysphagia, lethargy, affective changes
   • Spastic quadriparesis, seizures, coma 5
   • Particularly in high-risk patients (alcoholism, malnutrition, advanced liver disease) 5

Important Clinical Considerations

• Seizures and confusion with sodium of 118 mEq/L represent a medical emergency requiring immediate intervention
• Neurological symptoms correlate with severity of hyponatremia - patients with sodium <120 mEq/L are at highest risk for seizures 6
• The rate of sodium correction is as important as the absolute level - too rapid correction can cause irreversible neurological damage
• Chronic hyponatremia (>48 hours) requires more cautious correction than acute hyponatremia (<48 hours) 7, 8
• After initial emergency treatment, ongoing management should address the underlying cause of hyponatremia

Pitfalls to Avoid

• Delaying treatment in symptomatic severe hyponatremia
• Overly rapid correction leading to osmotic demyelination syndrome
• Inadequate monitoring of serum sodium during correction
• Failure to identify and treat the underlying cause
• Using hypotonic fluids in symptomatic severe hyponatremia
• Continuing diuretics in patients with hypovolemic hyponatremia