Treatment for Hyponatremia with Sodium Level of 128 mmol/L
For a patient with a serum sodium level of 128 mmol/L, continue diuretic therapy with close monitoring of serum electrolytes. Water restriction is not recommended at this level. 1
Assessment and Classification
- Hyponatremia with sodium level of 128 mmol/L is classified as mild hyponatremia (126-135 mEq/L) 2
- Initial workup should include serum and urine osmolality, urine electrolytes, uric acid, and assessment of extracellular fluid volume status to determine the underlying cause 3
- Evaluate for hypovolemic, euvolemic, or hypervolemic status as this will guide treatment approach 3, 4
Treatment Based on Volume Status
Hypovolemic Hyponatremia
- Discontinue diuretics and administer isotonic saline (0.9% NaCl) for volume repletion 3
- Address the underlying cause of volume depletion 4
Euvolemic Hyponatremia (e.g., SIADH)
- Primary treatment is fluid restriction to 1 L/day for symptomatic cases 3
- Consider oral sodium chloride 100 mEq three times daily if needed 5
- For medication-induced hyponatremia, consider discontinuing the offending agent 4
Hypervolemic Hyponatremia (e.g., cirrhosis, heart failure)
- Implement fluid restriction to 1-1.5 L/day for moderate hyponatremia 3
- Consider albumin infusion for patients with cirrhosis 3
- Continue to treat the underlying condition (heart failure, cirrhosis) 4
Specific Recommendations Based on Sodium Level
- For serum sodium 126-135 mmol/L with normal serum creatinine: Continue diuretic therapy but monitor serum electrolytes closely. Do not restrict water. 1
- For serum sodium 121-125 mmol/L: International opinion suggests continuing diuretic therapy, but a more cautious approach may be warranted 1
- For serum sodium ≤120 mmol/L: Stop diuretics and consider volume expansion 1
Correction Rate Guidelines
- Maximum increase should not exceed 8 mmol/L in 24 hours to prevent osmotic demyelination syndrome 3, 6
- For patients with advanced liver disease, alcoholism, malnutrition, or prior encephalopathy, use more cautious correction rates (4-6 mmol/L per day) 3
- For severe symptoms (seizures, coma), correction by 6 mmol/L over 6 hours or until symptoms improve is recommended 3
Pharmacological Considerations
- Tolvaptan is indicated for clinically significant hypervolemic and euvolemic hyponatremia (serum sodium <125 mEq/L or less marked hyponatremia that is symptomatic and has resisted correction with fluid restriction) 7
- Tolvaptan should be initiated in a hospital setting where serum sodium can be closely monitored 7
- Tolvaptan is contraindicated in hypovolemic hyponatremia 7
Monitoring and Follow-up
- Monitor serum sodium levels regularly during treatment 3
- For patients on diuretics with sodium 126-135 mmol/L, continue to observe serum electrolytes 1
- Watch for signs of osmotic demyelination syndrome (dysarthria, dysphagia, altered mental status, quadriparesis) 7
Common Pitfalls to Avoid
- Overly rapid correction of chronic hyponatremia leading to osmotic demyelination syndrome 3
- Using fluid restriction in cerebral salt wasting, which can worsen outcomes 3
- Failing to recognize and treat the underlying cause 3
- Using hypertonic saline in hypervolemic hyponatremia without life-threatening symptoms 3