How to treat severe hyponatremia with a sodium level of 118 mmol/L?

Treatment of Severe Hyponatremia with Sodium Level of 118 mmol/L

For severe hyponatremia with a sodium level of 118 mmol/L, the treatment approach should be determined by the patient's volume status and symptom severity, with fluid restriction to 1,000 mL/day recommended for moderate hyponatremia, and more severe restriction plus albumin infusion for severe cases. 1

Initial Assessment

1. Determine the type of hyponatremia:

   • Hypovolemic (depleted fluid volume)
   • Euvolemic (normal fluid volume)
   • Hypervolemic (excess fluid volume)

2. Assess symptom severity:

   • Mild: nausea, weakness, headache
   • Severe: seizures, coma, cardiorespiratory distress, abnormal somnolence

Treatment Algorithm Based on Volume Status

For Hypovolemic Hyponatremia:

• Discontinue diuretics and/or laxatives if they are the cause 1
• Provide fluid resuscitation with 5% IV albumin or crystalloid (preferably lactated Ringer's) 1
• Correct the underlying cause of volume depletion

For Euvolemic Hyponatremia:

• Treat based on the specific underlying cause (SIADH, medications, hypothyroidism) 1
• Fluid restriction to 1,000 mL/day for moderate hyponatremia (120-125 mmol/L) 1

For Hypervolemic Hyponatremia (most common in cirrhosis):

• Fluid restriction to 1,000 mL/day 1
• Reduction or discontinuation of diuretics if appropriate 1
• Consider albumin infusion, which has shown improvement in hyponatremia in hospitalized cirrhotic patients 1

Management of Severely Symptomatic Hyponatremia

If the patient has severe symptoms (seizures, coma, cardiorespiratory distress):

• Administer 3% hypertonic saline 1
• Initial correction should aim for 5 mmol/L in the first hour to attenuate clinical symptoms 1
• Do not exceed correction rate of 8 mmol/L per day to avoid osmotic demyelination syndrome 1

Important Safety Considerations

1. Correction Rate: Too rapid correction can cause osmotic demyelination syndrome

   • Tolvaptan should only be initiated in a hospital setting where sodium can be closely monitored 2
   • Do not exceed correction of 8 mmol/L in 24 hours 1

2. Monitoring Requirements:

   • Frequent monitoring of serum electrolytes and volume status during treatment 2
   • For patients receiving tolvaptan, avoid fluid restriction during the first 24 hours 2

3. Use of Vaptans:

   • Vaptans (tolvaptan, conivaptan) can be considered for short-term treatment 1, 2
   • Safety established only for treatments lasting from one week to one month 1
   • Tolvaptan is contraindicated in hypovolemic hyponatremia 2

Special Considerations for Cirrhotic Patients

For patients with cirrhosis and hyponatremia:

• Hypertonic sodium chloride should be limited to severely symptomatic cases or patients awaiting liver transplant 1
• Albumin infusion appears to improve serum sodium concentration 1
• Vaptans should be used with caution due to concerns about long-term safety 1

Pitfalls to Avoid

1. Overly rapid correction: Can lead to osmotic demyelination syndrome, causing dysarthria, mutism, quadriparesis, seizures, or death 2

2. Inadequate monitoring: Serum sodium should be checked frequently during correction

3. Inappropriate fluid restriction: Not necessary in most cases unless sodium is <120-125 mmol/L 1

4. Prolonged vaptan use: Safety only established for short-term treatments 1

By following this structured approach based on volume status and symptom severity, hyponatremia with a sodium level of 118 mmol/L can be effectively and safely managed while minimizing the risk of complications.