Management of Severe Symptomatic Hyponatremia with Confusion
For a confused patient with sodium 122 mEq/L, immediately administer 3% hypertonic saline with a target correction of 6 mmol/L over the first 6 hours or until confusion resolves, with total correction not exceeding 8 mmol/L in 24 hours. 1
Immediate Emergency Management
This represents severe symptomatic hyponatremia requiring urgent intervention 1, 2. Confusion at this sodium level indicates cerebral edema and constitutes a medical emergency 2, 3.
Initial Treatment Protocol
- Administer 3% hypertonic saline immediately as 100 mL boluses over 10 minutes 1
- Repeat boluses up to three times at 10-minute intervals until confusion improves 1
- Target: increase sodium by 6 mmol/L in first 6 hours or until severe symptoms resolve 1, 4
- Critical safety limit: never exceed 8 mmol/L correction in 24 hours to prevent osmotic demyelination syndrome 1, 3
Intensive Monitoring Requirements
- Check serum sodium every 2 hours during initial correction phase 1
- Admit to ICU for close monitoring during active treatment 1
- After symptoms resolve, check sodium every 4 hours 1
- If you correct 6 mmol/L in the first 6 hours, only 2 mmol/L additional correction is allowed in the next 18 hours 1
Determine Underlying Cause While Treating
Do not delay treatment while pursuing diagnosis 5, but simultaneously assess volume status to guide subsequent management:
Volume Status Assessment
- Hypovolemic signs: orthostatic hypotension, dry mucous membranes, decreased skin turgor, flat neck veins 1
- Euvolemic signs: normal blood pressure, no edema, moist mucous membranes 1
- Hypervolemic signs: peripheral edema, ascites, jugular venous distention 1, 6
Essential Laboratory Tests
- Serum and urine osmolality 1, 4
- Urine sodium concentration 1, 4
- Serum uric acid (< 4 mg/dL suggests SIADH with 73-100% positive predictive value) 1
- TSH to exclude hypothyroidism 1
- Assess for medications causing hyponatremia (diuretics, SSRIs, carbamazepine, NSAIDs) 1
Post-Acute Management Based on Etiology
For SIADH (Euvolemic)
- Fluid restriction to 1 L/day once symptoms resolve 1, 7
- Add oral sodium chloride 100 mEq three times daily if no response to fluid restriction 1
- Consider vaptans (tolvaptan 15 mg daily) for persistent cases 1, 8
For Hypovolemic Hyponatremia
- Discontinue diuretics immediately 1
- Administer isotonic saline (0.9% NaCl) for volume repletion 1, 5
- Urine sodium < 30 mmol/L predicts good response to saline (71-100% positive predictive value) 1
For Hypervolemic Hyponatremia (Heart Failure, Cirrhosis)
- Fluid restriction to 1-1.5 L/day for sodium < 125 mmol/L 1, 6
- Discontinue diuretics temporarily until sodium improves 1
- Consider albumin infusion in cirrhotic patients 1
- Avoid hypertonic saline after initial emergency treatment as it worsens fluid overload 1
Special Consideration: Cerebral Salt Wasting in Neurosurgical Patients
- Never use fluid restriction - this worsens outcomes 1, 7
- Treat with volume and sodium replacement using isotonic or hypertonic saline 1
- Add fludrocortisone 0.1-0.2 mg daily for severe symptoms 1
- Distinguished from SIADH by low central venous pressure and signs of true hypovolemia 1
High-Risk Populations Requiring Slower Correction
Patients with advanced liver disease, alcoholism, malnutrition, or prior encephalopathy require even more cautious correction at 4-6 mmol/L per day (maximum 8 mmol/L in 24 hours) due to higher risk of osmotic demyelination syndrome 1, 3.
Critical Pitfalls to Avoid
- Never correct chronic hyponatremia faster than 8 mmol/L in 24 hours - this causes osmotic demyelination syndrome with devastating neurological consequences (dysarthria, dysphagia, quadriparesis) 1, 3
- Never use fluid restriction as initial treatment for confused patients - confusion indicates need for hypertonic saline, not fluid restriction 1
- Inadequate monitoring during active correction leads to overcorrection 1
- Using fluid restriction in cerebral salt wasting worsens outcomes 1, 7
Management of Overcorrection
If sodium correction exceeds 8 mmol/L in 24 hours:
- Immediately discontinue current fluids and switch to D5W (5% dextrose in water) 1
- Consider administering desmopressin to slow or reverse the rapid rise 1
- Watch for signs of osmotic demyelination syndrome typically occurring 2-7 days after rapid correction 1