What are the treatments for hypernatremia and hyponatremia?

Treatment of Hyponatremia and Hypernatremia

Hyponatremia Management

The treatment of hyponatremia depends critically on symptom severity and volume status, with the overriding principle being to never exceed 8 mmol/L correction in 24 hours to prevent osmotic demyelination syndrome. 1

Initial Assessment

• Classify severity: mild (130-134 mmol/L), moderate (125-129 mmol/L), severe (<125 mmol/L) 2
• Determine volume status through physical examination: assess for orthostatic hypotension, dry mucous membranes, skin turgor (hypovolemic); jugular venous distention, peripheral edema, ascites (hypervolemic); or absence of these findings (euvolemic) 1
• Obtain serum and urine osmolality, urine sodium, and urine electrolytes 1
• Assess symptom severity: mild symptoms include nausea, vomiting, headache; severe symptoms include seizures, coma, confusion, impaired consciousness 1, 2

Treatment Based on Symptom Severity

Severe Symptomatic Hyponatremia (Seizures, Coma, Altered Mental Status)

Administer 3% hypertonic saline immediately with a target correction of 6 mmol/L over 6 hours or until severe symptoms resolve. 1

• Give 100 mL boluses of 3% saline over 10 minutes, repeatable up to three times at 10-minute intervals until symptoms improve 1
• Total correction must not exceed 8 mmol/L in 24 hours 1, 2
• Monitor serum sodium every 2 hours during initial correction 1
• Consider ICU admission for close monitoring 1

Asymptomatic or Mildly Symptomatic Hyponatremia

Treatment depends on volume status:

Hypovolemic Hyponatremia:

• Discontinue diuretics immediately 1
• Administer isotonic saline (0.9% NaCl) for volume repletion 1
• Correction rate should not exceed 8 mmol/L in 24 hours 1

Euvolemic Hyponatremia (SIADH):

• Fluid restriction to 1 L/day is the cornerstone of treatment 1
• If no response to fluid restriction, add oral sodium chloride 100 mEq three times daily 1
• For resistant cases, consider urea, demeclocycline, lithium, or loop diuretics 1
• Vasopressin receptor antagonists (tolvaptan 15 mg daily, titrated to 30-60 mg) may be used for clinically significant hyponatremia resistant to fluid restriction 1, 3

Hypervolemic Hyponatremia (Cirrhosis, Heart Failure):

• Implement fluid restriction to 1-1.5 L/day for serum sodium <125 mmol/L 1
• Discontinue diuretics temporarily if sodium <125 mmol/L 1
• Consider albumin infusion in cirrhotic patients 1
• Avoid hypertonic saline unless life-threatening symptoms are present, as it may worsen edema and ascites 1
• Tolvaptan may be considered if hyponatremia persists despite fluid restriction and maximization of guideline-directed medical therapy, but use with extreme caution in cirrhosis due to higher risk of gastrointestinal bleeding (10% vs 2% placebo) 1, 3

Special Populations Requiring Cautious Correction

Patients with advanced liver disease, alcoholism, malnutrition, or prior encephalopathy require even more cautious correction at 4-6 mmol/L per day, not exceeding 8 mmol/L in 24 hours. 1

Neurosurgical Patients: Critical Distinction Between SIADH and Cerebral Salt Wasting (CSW)

In neurosurgical patients, cerebral salt wasting is more common than SIADH and requires fundamentally different treatment. 1

CSW Treatment:

• Volume and sodium replacement with isotonic or hypertonic saline (NOT fluid restriction) 1
• For severe symptoms: 3% hypertonic saline plus fludrocortisone in ICU 1
• Hydrocortisone may prevent natriuresis in subarachnoid hemorrhage patients 1
• Fluid restriction in CSW worsens outcomes 1

Subarachnoid Hemorrhage Patients at Risk for Vasospasm:

• Do NOT treat with fluid restriction 1
• Consider fludrocortisone to prevent vasospasm 1

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 in serum sodium 1
• Target reduction to bring total 24-hour correction to no more than 8 mmol/L from starting point 1
• Watch for signs of osmotic demyelination syndrome (dysarthria, dysphagia, oculomotor dysfunction, quadriparesis) typically occurring 2-7 days after rapid correction 1

Common Pitfalls to Avoid

• Overly rapid correction exceeding 8 mmol/L in 24 hours leading to osmotic demyelination syndrome 1
• Inadequate monitoring during active correction 1
• Using fluid restriction in cerebral salt wasting 1
• Failing to recognize and treat the underlying cause 1
• Using hypertonic saline in hypervolemic hyponatremia without life-threatening symptoms 1
• Ignoring mild hyponatremia (130-135 mmol/L) as clinically insignificant, as it increases fall risk and mortality 1

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Hypernatremia Management

Hypernatremia treatment focuses on addressing the underlying etiology and correcting the fluid deficit with hypotonic fluid replacement when sodium is severely elevated or patients are symptomatic. 2

Initial Assessment

• Mild hypernatremia is often caused by dehydration from impaired thirst mechanism or lack of water access 2
• Consider diabetes insipidus as a potential cause 2
• In patients with liver disease or cirrhosis, hypernatremia may indicate worsening hemodynamic status 1

Treatment Approach

• Address the underlying etiology first 2
• Correct fluid deficit with hypotonic fluid replacement when intravenous fluids are required 2
• Use D5W as the primary fluid for free water replacement 1
• Reduce sodium at a rate of 10-15 mmol/L per 24 hours to prevent neurological complications 1
• Correction rates faster than 48-72 hours for severe hypernatremia have been associated with increased risk of pontine myelinolysis 1

Special Considerations

• Patients with renal concentrating defects (e.g., nephrogenic diabetes insipidus) require hypotonic fluid replacement and can develop hypernatremia if given isotonic fluids 1
• In some clinical protocols for cerebral edema management, sodium levels of 150-155 mmol/L may be deliberately targeted 1