How to manage confusion in patients with hyponatremia?

Management of Confusion in Hyponatremia

For patients with confusion due to hyponatremia, immediately administer 3% hypertonic saline with a target correction of 6 mmol/L over 6 hours or until confusion resolves, with total correction not exceeding 8 mmol/L in 24 hours. 1

Immediate Assessment and Emergency Treatment

Confusion indicates severe symptomatic hyponatremia requiring urgent intervention—this is a medical emergency, not a condition for conservative management. 1, 2

Initial Emergency Protocol

• Administer 3% hypertonic saline immediately as 100 mL boluses over 10 minutes, which can be repeated up to three times at 10-minute intervals until confusion improves 1
• Target correction: Increase sodium by 6 mmol/L over the first 6 hours or until severe symptoms resolve 1
• Monitor serum sodium every 2 hours during initial correction phase 1
• ICU admission is recommended for close monitoring during treatment 1

Critical Safety Limits

Never exceed 8 mmol/L correction in 24 hours to prevent osmotic demyelination syndrome, which causes dysarthria, dysphagia, quadriparesis, seizures, coma, or death. 1, 3, 2 This limit is absolute and applies regardless of symptom severity.

For high-risk patients (advanced liver disease, alcoholism, malnutrition, or prior encephalopathy), use even more cautious correction rates of 4-6 mmol/L per day. 1

Post-Acute Management Based on Underlying Cause

Once confusion resolves and the patient is stabilized, treatment diverges based on volume status:

For SIADH (Euvolemic Hyponatremia)

• Fluid restriction to 1 L/day is the cornerstone of ongoing treatment 1
• If no response to fluid restriction, add oral sodium chloride 100 mEq three times daily 1
• Consider vaptans (tolvaptan 15 mg once daily) for resistant cases, but use with extreme caution due to risk of overly rapid correction 3

For Cerebral Salt Wasting (Hypovolemic)

• Continue volume and sodium replacement with isotonic or hypertonic saline 1
• Add fludrocortisone for severe symptoms or in subarachnoid hemorrhage patients 1
• Never use fluid restriction in cerebral salt wasting—this worsens outcomes 1

For Hypervolemic Hyponatremia (Heart Failure, Cirrhosis)

• Fluid restriction to 1-1.5 L/day for sodium <125 mmol/L 1
• Discontinue diuretics temporarily until sodium improves 1
• Consider albumin infusion in cirrhotic patients 1
• Avoid hypertonic saline once symptoms resolve, as it worsens edema and ascites 1

Distinguishing Key Causes in Confused Patients

The distinction between SIADH and cerebral salt wasting is critical because treatments are opposite:

SIADH characteristics: 1

• Euvolemic on exam (no edema, no orthostatic hypotension)
• Urine sodium >20-40 mmol/L
• Urine osmolality >300 mOsm/kg
• Treatment: Fluid restriction

Cerebral Salt Wasting characteristics: 1

• True hypovolemia (orthostatic hypotension, dry mucous membranes, flat neck veins)
• Urine sodium >20 mmol/L despite volume depletion
• Central venous pressure <6 cm H₂O
• Treatment: Volume and sodium replacement

Common Pitfalls to Avoid

• Never use fluid restriction as initial treatment for confusion from hyponatremia—this is a medical emergency requiring hypertonic saline 1
• Never correct chronic hyponatremia faster than 8 mmol/L in 24 hours—overcorrection risks osmotic demyelination syndrome 1, 3
• Never use fluid restriction in subarachnoid hemorrhage patients at risk of vasospasm 1
• Never attribute confusion solely to mild hyponatremia (130-135 mmol/L) without investigating other causes 2
• Inadequate monitoring during active correction can lead to osmotic demyelination syndrome 1

Monitoring Protocol

• During severe symptoms: Check serum sodium every 2 hours 1
• After symptom resolution: Check every 4 hours 1
• Watch for osmotic demyelination syndrome signs (dysarthria, dysphagia, oculomotor dysfunction, quadriparesis) typically occurring 2-7 days after rapid correction 1

Special Populations

Neurosurgical patients: Cerebral salt wasting is more common than SIADH; consider fludrocortisone and avoid fluid restriction in subarachnoid hemorrhage patients at risk for vasospasm. 1

Cirrhotic patients: Require more cautious correction (4-6 mmol/L per day) due to higher risk of osmotic demyelination; hyponatremia increases risk of hepatic encephalopathy, hepatorenal syndrome, and spontaneous bacterial peritonitis. 1