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

From the Guidelines

Hyponatremia symptoms vary depending on severity and how quickly sodium levels drop, with severe cases typically producing noticeable symptoms such as seizures, decreased consciousness, coma, and in severe cases, death, as noted in the most recent guidelines 1.

Symptoms of Hyponatremia

The symptoms of hyponatremia can range from mild to severe and include:

• Headache
• Nausea
• Vomiting
• Confusion
• Fatigue
• Irritability
• Muscle weakness
• Cramps
• Spasms As the condition worsens, more serious symptoms may develop, especially in cases of acute hyponatremia, which can occur within 48 hours, as discussed in 1.

Management of Hyponatremia

The management of hyponatremia depends on the underlying cause and severity of the condition.

• In cases of hypovolemic hyponatremia, fluid resuscitation is necessary, as mentioned in 1.
• In cases of hypervolemic hyponatremia, discontinuation of intravenous fluid therapy and free water restriction should be considered, as noted in 1.
• Fluid restriction to 1–1.5 L/day should be reserved for those who are clinically hypervolaemic with severe hyponatraemia (serum sodium <125 mmol/L), as recommended in 1.
• Hypertonic sodium chloride (3%) administration should be reserved for those who are severely symptomatic with acute hyponatraemia, with careful monitoring to avoid rapid correction of serum sodium levels, as cautioned in 1 and 1.

Importance of Prompt Treatment

If you experience symptoms of hyponatremia, especially after excessive water intake, intense exercise, or while taking medications like diuretics, seek immediate medical attention as prompt treatment is essential to prevent complications, as emphasized in the guidelines 1.

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 due to too rapid correction include:
  • Dysarthria
  • Mutism
  • Dysphagia
  • Lethargy
  • Affective changes
  • Spastic quadriparesis
  • Seizures
  • Coma
  • Death 2

From the Research

Hyponatremia Symptoms

• Hyponatremia is defined by a serum sodium level of less than 135 mEq/L and can cause a range of symptoms from mild and nonspecific to severe and life-threatening 3
• Symptoms of hyponatremia can include weakness, nausea, cognitive impairment, gait disturbances, and increased rates of falls and fractures 3
• The severity of hyponatremia-induced neurological manifestation and the risk of poor outcome is mainly driven by the rapidity of serum sodium decrease 4
• Mild chronic hyponatremia is associated with cognitive impairment, gait disturbances, and increased rates of falls and fractures, while severe hyponatremia can cause seizures, coma, and even death 3, 4

Diagnosis and Treatment

• The diagnosis of hyponatremia should involve assessing the patient's fluid volume status, with categorization into hypovolemic, euvolemic, or hypervolemic hyponatremia 3
• Treatment of hyponatremia should focus on addressing the underlying cause, with options including fluid restriction, hypertonic saline, urea, and vaptans 3, 5, 6
• The use of vaptans, such as tolvaptan, can be effective in managing the syndrome of inappropriate antidiuretic hormone secretion (SIADH) and hyponatremia in patients with heart failure 5, 6
• Hypertonic saline is typically reserved for patients with severely symptomatic hyponatremia, with the goal of increasing the serum sodium level by 4-6 mEq/L within 1-2 hours 3

Management and Outcomes

• Current treatment of hyponatremia in SIADH often uses therapies with limited efficacy, with fluid restriction and isotonic saline being the most commonly chosen monotherapy treatments 6
• Despite the availability of effective therapies, most patients with SIADH are discharged from the hospital still hyponatremic 6
• The management of hyponatremia patients remains problematic, with diverse institution- and specialty-based approaches to diagnosis and treatment 7
• Clinical practice guidelines have been developed to provide a common and holistic view of the diagnostic approach and treatment of hyponatremia 7