Hyponatremia Correction Protocol
For severe symptomatic hyponatremia (seizures, altered mental status, coma), immediately administer 3% hypertonic saline as 100-150 mL IV bolus or 2 mL/kg over 20 minutes, targeting a 4-6 mEq/L increase within 1-2 hours to reverse cerebral edema, but limit total correction to 8 mEq/L in the first 24 hours to prevent osmotic demyelination syndrome. 1, 2, 3
Severity-Based Treatment Algorithm
Severe Symptoms (Medical Emergency)
Symptoms: Seizures, coma, altered mental status, cardiorespiratory distress
Immediate Management:
- Hypertonic saline (3% NaCl): 100-150 mL IV bolus over 20 minutes 1, 3
- Target: Increase serum sodium by 4-6 mEq/L within 1-2 hours 1, 2
- Critical limit: Do NOT exceed 8 mEq/L correction in first 24 hours 1
- Monitoring: Check sodium every 2 hours 1
- Location: ICU admission required 1
Calculation for sodium deficit:
- Na deficit (mEq) = Desired increase in Na (mEq/L) × (0.5 × ideal body weight in kg) 1
Once severe symptoms resolve: Transition to mild symptom protocol immediately 1
Mild-Moderate Symptoms or Asymptomatic with Na <120 mEq/L
Symptoms: Nausea, vomiting, headache, weakness, confusion
Management:
- Hospitalization strongly recommended for sodium <120 mEq/L 4
- Check sodium every 4 hours 1
- Fluid restriction: 1-1.5 L/day 4, 1
- Target correction: 4-6 mEq/L per 24 hours 5
- Maximum limit: 8-10 mEq/L per 24 hours 5, 3, 6
Asymptomatic with Na 120-130 mEq/L
Outpatient Management:
- Fluid restriction: 1-1.5 L/day 4
- Sodium restriction: Dietary sodium limitation 4
- Discontinue or reduce diuretics and laxatives 4
- Monitor sodium daily until stable >125 mEq/L 4
Etiology-Specific Treatment
SIADH (Euvolemic)
First-line: Fluid restriction <1 L/day 1
Critical exception: Subarachnoid hemorrhage patients at risk for vasospasm should NOT be fluid restricted - use hypertonic saline instead 1
Cerebral Salt Wasting (Hypovolemic)
Treatment:
- Normal saline infusion: 50-100 mL/kg/day 1
- Oral salt supplementation: 12g/day 1
- Fludrocortisone: 0.1 mg TID for 7 days 1
- Never fluid restrict - causes cerebral infarction 1
Hypervolemic Hyponatremia (Cirrhosis, Heart Failure)
Outpatient:
Inpatient (severe or symptomatic):
- Discontinue diuretics and laxatives 4
- Fluid restriction less than urine output 4
- IV albumin for volume assessment 4
- Midodrine (oral vasoconstrictor) to improve renal perfusion 4
- 3% saline: Only for life-threatening cases or pre-transplant, use cautiously 4
- Vaptans: Reserved for short-term use in severe cases awaiting transplant due to hepatic injury risk 4
Prevention and Management of Overcorrection
High-Risk Patients for Osmotic Demyelination
- Chronic hyponatremia (>48 hours duration) 1, 5
- Severe hyponatremia (<120 mEq/L) 7
- Alcohol use disorder 7
- Malnutrition 5
Overcorrection Prevention Strategy
Desmopressin protocol (for high-risk patients):
- Administer desmopressin 1-2 mcg IV/SC every 6-8 hours concurrently with hypertonic saline 5, 8
- This prevents excessive water diuresis and inadvertent overcorrection 8
- Allows predictable, controlled correction rate 8
If overcorrection occurs:
- Immediately administer:
- Goal: Reverse overcorrection within hours 3
Monitoring Requirements
Severe Symptoms
- Sodium level every 2 hours 1
- Strict intake/output monitoring 1
- Daily weights 1
- Neurological status continuously 1
Mild Symptoms
Asymptomatic
Critical Pitfalls to Avoid
Do NOT fluid restrict in:
- Cerebral salt wasting (causes cerebral infarction) 1
- Subarachnoid hemorrhage patients (increases vasospasm risk) 1
- Hypovolemic hyponatremia of any cause 1
Do NOT correct faster than 8-10 mEq/L in 24 hours in chronic hyponatremia - this causes osmotic demyelination syndrome with permanent neurological damage including quadriparesis, locked-in syndrome, or death 1, 2, 9, 5
Do NOT use vaptans in cirrhosis except short-term pre-transplant due to hepatic injury and mortality risk 4
Rapid correction (>1 mEq/L/hour) is ONLY for: