From the Guidelines
Hyponatremia is primarily caused by excessive water intake, inadequate water excretion, or sodium loss, and can be categorized based on volume status into hypovolemic, euvolemic, and hypervolemic types. The causes of hyponatremia can be further divided into:
- Excessive water intake, such as in psychogenic polydipsia or during prolonged exercise
- Inadequate water excretion, such as in heart failure, cirrhosis, or kidney disease
- Sodium loss, such as in vomiting, diarrhea, or certain kidney disorders
- Medications, particularly thiazide diuretics, SSRIs, carbamazepine, and NSAIDs
- Endocrine disorders, such as adrenal insufficiency and hypothyroidism
- Pseudohyponatremia, which can occur with high levels of lipids or proteins 1.
According to the most recent and highest quality study, the management of hyponatremia requires identifying and addressing the underlying cause, with careful attention to the rate of sodium correction to prevent complications like osmotic demyelination syndrome 1. The study also notes that fluid restriction may be helpful in preventing further decrease in serum sodium levels, but it is seldom effective in improving natremia.
Some key points to consider in the management of hyponatremia include:
- Hypovolemic hyponatremia requires plasma volume expansion with saline solution and correction of the causative factor
- Hypervolemic hyponatremia requires attainment of a negative water balance, which can be achieved through fluid restriction or the use of vasopressin antagonists
- Hypertonic sodium chloride administration may be considered in severely symptomatic hyponatremia, but should be used with caution to avoid central pontine myelinolysis
- Albumin infusion may improve serum sodium concentration, but more information is needed 1.
Overall, the management of hyponatremia requires a careful and individualized approach, taking into account the underlying cause and the patient's volume status, as well as the potential risks and benefits of different treatment strategies.
From the FDA Drug Label
resulting from a variety of underlying causes (heart failure, liver cirrhosis, syndrome of inappropriate antidiuretic hormone [SIADH] and others) The causes of hyponatremia include:
- Heart failure
- Liver cirrhosis
- Syndrome of inappropriate antidiuretic hormone (SIADH)
- Other underlying causes 2
From the Research
Causes of Hyponatremia
The causes of hyponatremia can be classified based on the volume status of the patient, which includes:
- Hypovolemic hyponatremia, caused by severe burns, gastrointestinal losses, and acute water overload 3
- Euvolemic hyponatremia, caused by the syndrome of inappropriate antidiuretic hormone (SIADH) secretion, medications, and certain medical conditions 3, 4
- Hypervolemic hyponatremia, caused by congestive heart failure, liver cirrhosis, and renal disease 3, 5, 6
Medication-Related Causes
Certain medications can cause hyponatremia, including:
- Thiazide diuretics, which can cause hyponatremia in elderly individuals, especially those with certain risk factors such as heart failure, liver disease, or malignancy 7
- Non-steroidal anti-inflammatory drugs, selective serotonin re-uptake inhibitors, and tricyclic antidepressants, which can increase the risk of thiazide-associated hyponatremia 7
Other Causes
Other causes of hyponatremia include: