Treatment Rate for Severe Hyponatremia (Sodium 120 mEq/L)
For severe hyponatremia with a sodium level of 120 mEq/L, the correction rate should be 4-6 mEq/L per 24-hour period, not exceeding 8 mEq/L in any 24-hour period to prevent osmotic demyelination syndrome. 1, 2
Initial Assessment and Treatment Approach
- Determine symptom severity - severe symptoms (seizures, coma) require more urgent correction than mild or no symptoms 2
- For severe symptomatic hyponatremia, administer 3% hypertonic saline with an initial goal to correct 6 mEq/L over 6 hours or until severe symptoms resolve 2
- For asymptomatic or mildly symptomatic patients with severe hyponatremia (<120 mEq/L), implement fluid restriction with more severe water restriction plus albumin infusion 1
- Discontinue diuretics that may be contributing to hyponatremia 1, 2
Correction Rate Guidelines
- Limit correction to 4-6 mEq/L per day, not exceeding 8 mEq/L in 24 hours for patients with severe hyponatremia (<120 mEq/L) 1
- Patients with advanced liver disease, alcoholism, malnutrition, or prior encephalopathy require even more cautious correction due to higher risk of osmotic demyelination syndrome 1, 2
- Monitor serum sodium every 2-4 hours during initial correction to avoid overcorrection 2
Treatment Based on Volume Status
- For hypovolemic hyponatremia: administer isotonic (0.9%) saline to restore intravascular volume 2, 3
- For euvolemic hyponatremia (e.g., SIADH): implement fluid restriction to 1 L/day as first-line approach 2, 4
- For hypervolemic hyponatremia (e.g., cirrhosis, heart failure): implement fluid restriction to 1-1.5 L/day and consider albumin infusion 1, 2
Prevention of Complications
- If overcorrection occurs, consider relowering with electrolyte-free water or desmopressin 1, 5
- Watch for signs of osmotic demyelination syndrome (dysarthria, dysphagia, oculomotor dysfunction, quadriparesis) typically occurring 2-7 days after rapid correction 1, 2
Special Considerations
- Hypertonic saline should be reserved for patients with severe symptoms or those with imminent liver transplantation 1
- Vasopressin receptor antagonists (vaptans) can be used for short-term treatment (≤30 days) but should be used with caution 1, 6
- Urea may be considered as an alternative treatment option in certain cases 7, 8
Common Pitfalls to Avoid
- Overly rapid correction exceeding 8 mEq/L in 24 hours can lead to osmotic demyelination syndrome 1, 2
- Inadequate monitoring during active correction can result in unintended overcorrection 2
- Using hypertonic saline in hypervolemic hyponatremia without life-threatening symptoms can worsen edema and ascites 2
- Failing to recognize and treat the underlying cause of hyponatremia 2, 4