From the Guidelines
Low sodium levels, or hyponatremia, are clinically significant because they can lead to serious neurological symptoms and complications, and treatment should be guided by the severity, cause, and rate of development, with the goal of raising serum sodium by 4-6 mEq/L in the first 24 hours, not to exceed 8 mEq/L per 24-hour period, as recommended by the American Association for the Study of Liver Diseases in 2021 1.
Clinical Significance of Hyponatremia
Hyponatremia can cause a range of symptoms, from mild headaches and confusion to severe seizures, coma, and death. The treatment of hyponatremia depends on the underlying cause, severity, and rate of development.
- For mild cases (130-134 mEq/L), restricting fluid intake to 1-1.5 liters daily may be sufficient.
- For moderate to severe cases, intravenous sodium chloride solution (0.9% or 3% depending on severity) may be required.
- In acute severe hyponatremia with neurological symptoms, 3% hypertonic saline is administered at 100-150 mL over 10-20 minutes, which can be repeated until symptoms improve.
Treatment Guidelines
The American Association for the Study of Liver Diseases recommends the following treatment guidelines for hyponatremia in patients with cirrhosis:
- Mild hyponatremia (Na 126-135 mEq/L) does not require specific management apart from monitoring and water restriction.
- Water restriction to 1,000 mL/day and cessation of diuretics is recommended for moderate hyponatremia (120-125 mEq/L).
- A more severe restriction of water intake with albumin infusion is recommended for severe hyponatremia (<120 mEq/L).
- The use of vasopressin receptor antagonists can raise serum sodium during treatment, but should be used with caution only for a short term (≤30 days) 1.
Monitoring and Correction
Sodium levels should be monitored every 2-4 hours during correction, and the correction rate should not exceed 8-10 mEq/L in 24 hours to prevent osmotic demyelination syndrome. Underlying causes such as medications (diuretics, antidepressants), SIADH, heart failure, liver disease, or adrenal insufficiency must be addressed 1.
Recent Guidelines
Recent guidelines from the American College of Cardiology Foundation/American Heart Association recommend the use of vasopressin antagonists in patients hospitalized with volume overload, including heart failure, who have persistent severe hyponatremia and are at risk for or having active cognitive symptoms despite water restriction and maximization of guideline-directed medical therapy 1.
From the FDA Drug Label
Tolvaptan tablets are indicated for the treatment of clinically significant hypervolemic and euvolemic hyponatremia (serum sodium <125 mEq/L or less marked hyponatremia that is symptomatic and has resisted correction with fluid restriction) Osmotic demyelination syndrome is a risk associated with too rapid correction of hyponatremia (e.g., > 12 mEq/L/24 hours). Osmotic demyelination results in dysarthria, mutism, dysphagia, lethargy, affective changes, spastic quadriparesis, seizures, coma or death.
The clinical significance of low sodium levels is that it can cause symptomatic hyponatremia, which may lead to serious neurological symptoms.
- Hyponatremia is defined as a serum sodium level <125 mEq/L.
- Rapid correction of hyponatremia can cause osmotic demyelination syndrome, resulting in severe neurologic sequelae, including dysarthria, mutism, dysphagia, lethargy, affective changes, spastic quadriparesis, seizures, coma, or death 2.
From the Research
Clinical Significance of Low Sodium Levels
The clinical significance of low sodium levels, also known as hyponatremia, is a complex electrolyte disorder that can have severe consequences on the human body.
- Hyponatremia is defined by a serum sodium level of less than 135 mEq/L and affects approximately 5% of adults and 35% of hospitalized patients 3.
- It is associated with increased hospital stay and mortality, even in mild cases 3.
- Symptoms and signs of hyponatremia range from mild and nonspecific (such as weakness or nausea) to severe and life-threatening (such as seizures or coma) 3.
Causes and Consequences of Hyponatremia
Hyponatremia can result from various causes, including:
- Water retention 3
- Syndrome of inappropriate antidiuresis 4, 5
- Heart failure 3, 4
- Cirrhosis 4
- The condition can lead to cognitive impairment, gait disturbances, and increased rates of falls and fractures 3.
- Hyponatremia is also a secondary cause of osteoporosis 3.
Treatment Options for Hyponatremia
Treatment options for hyponatremia include:
- Treating the underlying cause 3
- Urea and vaptans for the syndrome of inappropriate antidiuresis and hyponatremia in patients with heart failure 3, 4
- Hypertonic saline for severely symptomatic hyponatremia 3, 6
- Vasopressin receptor antagonists, which provide a promising treatment for hyponatremia by targeting its most common mechanism, namely, increased vasopressin activity 5, 7.