What are the symptoms of hyponatremia (low sodium levels)?

From the Guidelines

Hyponatremia symptoms vary depending on severity and how quickly sodium levels drop, and patients with severe symptoms, especially those with imminent liver transplant, should be treated with hypertonic sodium chloride administration to improve hyponatremia at the cost of worsening fluid overload, as recommended by the most recent guidelines 1.

Symptoms of Hyponatremia

The symptoms of hyponatremia include:

• Nausea
• Headache
• Confusion
• Fatigue
• Muscle weakness
• Cramps
• Irritability In more severe cases, patients may experience seizures, coma, or even death. Early symptoms are often nonspecific and can include lethargy, dizziness, and general malaise. As sodium levels continue to drop below 125 mEq/L, neurological symptoms become more prominent due to brain cell swelling caused by water moving into cells.

Management of Hyponatremia

According to the guidelines, the management of hyponatremia depends on the severity and cause of the condition. For patients with mild hyponatremia (Na 126-135 mEq/L) in cirrhosis without symptoms, no specific management is required apart from monitoring and water restriction 1. However, for patients with severe hyponatremia (<120 mEq/L), a more severe restriction of water intake with albumin infusion is recommended. The use of vasopressin receptor antagonists can raise serum sodium during treatment, but they should be used with caution only for a short term (≤30 days) 1.

Treatment of Severe Hyponatremia

For patients with severe hyponatremia, especially those with imminent liver transplant, hypertonic sodium chloride administration may be considered to improve hyponatremia at the cost of worsening fluid overload, as recommended by the most recent guidelines 1. However, this treatment requires close attention to prevent rapid increase in serum sodium and the risk of developing central pontine myelinolysis. The goal rate of increase of serum sodium is 4-6 mEq/L per 24-hour period, not to exceed 8 mEq/L per 24-hour period to ameliorate the risk of osmotic demyelination syndrome 1.

Key Considerations

When treating hyponatremia, it is essential to consider the following:

• The severity and cause of the condition
• The presence of symptoms and the risk of complications
• The need for close monitoring and adjustment of treatment
• The potential risks and benefits of different treatment options, including hypertonic sodium chloride administration and vasopressin receptor antagonists.

From the FDA Drug Label

The usual starting dose for tolvaptan tablets is 15 mg administered once daily without regard to meals. Increase the dose to 30 mg once daily, after at least 24 hours, to a maximum of 60 mg once daily, as needed to achieve the desired level of serum sodium. Patients should be in a hospital for initiation and re-initiation of therapy to evaluate the therapeutic response and because too rapid correction of hyponatremia can cause osmotic demyelination resulting in dysarthria, mutism, dysphagia, lethargy, affective changes, spastic quadriparesis, seizures, coma and death

• Hyponatremia symptoms that can occur with too rapid correction include:
  • Dysarthria
  • Mutism
  • Dysphagia
  • Lethargy
  • Affective changes
  • Spastic quadriparesis
  • Seizures
  • Coma
  • Death 2

From the Research

Hyponatremia Symptoms

• Mild symptoms of hyponatremia include nausea, vomiting, weakness, headache, and mild neurocognitive deficits 3
• Severe symptoms of hyponatremia include delirium, confusion, impaired consciousness, ataxia, seizures, and, rarely, brain herniation and death 3
• Symptom severity depends on the rapidity of development, duration, and severity of hyponatremia 4
• Mild chronic hyponatremia is associated with cognitive impairment, gait disturbances, and increased rates of falls and fractures 4
• Hyponatremia can cause osteoporosis, with patients having a higher rate of new fractures over a mean follow-up of 7.4 years 4

Classification of Hyponatremia

• Hyponatremia can be classified as mild (130-134 mEq/L), moderate (125-129 mEq/L), or severe (<125 mEq/L) 3
• Hyponatremia can also be classified based on fluid volume status: hypovolemic, euvolemic, or hypervolemic 3, 4

Treatment of Hyponatremia

• Treatment of hyponatremia depends on the underlying cause and fluid volume status 3, 4
• Hypovolemic hyponatremia is treated with normal saline infusions 3
• Euvolemic hyponatremia is treated with fluid restriction, salt tablets, or intravenous vaptans 3
• Hypervolemic hyponatremia is treated primarily by managing the underlying cause and free water restriction 3
• Severely symptomatic hyponatremia is treated with bolus hypertonic saline to reverse hyponatremic encephalopathy 4