What is the treatment for hyponatremia with a serum sodium level of 128 mmol/L?

Treatment for Hyponatremia with Serum Sodium Level of 128 mmol/L

For hyponatremia with a serum sodium level of 128 mmol/L, diuretic therapy can be safely continued while monitoring serum electrolytes, and water restriction is not recommended. 1, 2

Classification and Assessment

Hyponatremia with sodium level of 128 mmol/L falls into the moderate category (125-129 mmol/L) 2. Before initiating treatment, it's crucial to determine:

• Volume status: hypovolemic, euvolemic, or hypervolemic
• Presence of symptoms
• Rate of development (acute vs. chronic)
• Underlying cause

Treatment Algorithm Based on Severity

For Sodium Level 128 mmol/L (Moderate Hyponatremia):

1. Continue diuretic therapy if already prescribed 1

   • Monitor serum electrolytes closely
   • Do NOT implement water restriction at this level 1

2. If patient has normal serum creatinine:

   • Continue current management with regular monitoring
   • Target correction rate should be 4-6 mEq/L per day, not exceeding 8 mEq/L in 24 hours 2

3. If serum creatinine is elevated (>150 mmol/L or >120 mmol/L and rising):

   • Stop diuretics
   • Consider volume expansion with colloid or saline 1

Treatment Based on Volume Status

For Hypovolemic Hyponatremia:

• Administer normal saline infusion 3
• Address underlying cause of volume depletion

For Euvolemic Hyponatremia:

• Consider salt tablets or urea (30 g/day) 2, 3
• If SIADH is the cause, tolvaptan may be considered starting at 15 mg once daily 2, 4
  • Caution: Tolvaptan must be initiated in a hospital setting with close monitoring of serum sodium 4
  • Do not use tolvaptan for more than 30 days due to risk of liver injury 4

For Hypervolemic Hyponatremia:

• Treat underlying condition (heart failure, cirrhosis) 2, 3
• Spironolactone (starting at 100 mg, up to 400 mg) may be effective 1, 2

Monitoring and Safety Considerations

• Monitor serum sodium every 4-6 hours during active correction 2
• Avoid increasing serum sodium by >8 mEq/L in 24 hours to prevent osmotic demyelination syndrome 2, 4
• For patients at high risk of osmotic demyelination (alcoholism, malnutrition, advanced liver disease), use slower correction rates 4
• If correction occurs too rapidly, consider desmopressin to slow the rate 2

Important Pitfalls to Avoid

1. Avoid water restriction for sodium levels >126 mmol/L 1
2. Avoid overly rapid correction (>8 mEq/L in 24 hours) which can cause osmotic demyelination syndrome 2, 4
3. Do not delay treatment while pursuing diagnosis in symptomatic patients 3
4. Do not use tolvaptan in hypovolemic hyponatremia or in patients with ADPKD 4
5. Do not continue tolvaptan beyond 30 days due to risk of liver injury 4

By following this approach, you can safely and effectively manage a patient with moderate hyponatremia (sodium 128 mmol/L) while minimizing risks of complications from both the condition and its treatment.