From the Guidelines
Hyponatremia is primarily caused by an imbalance of sodium in the body, resulting from excessive water intake, inadequate sodium intake, increased water retention by the kidneys, or excessive sodium loss, with common causes including certain medications and medical conditions such as liver cirrhosis, as noted in the most recent guidelines 1.
Causes of Hyponatremia
The causes of hyponatremia can be broadly categorized into:
- Excessive water intake that dilutes sodium concentration
- Inadequate sodium intake
- Increased water retention by the kidneys, often due to the hormone vasopressin (ADH)
- Excessive sodium loss through urine, sweat, vomiting, or diarrhea Common causes include:
- Certain medications (diuretics, antidepressants, pain medications)
- Medical conditions (heart failure, kidney disease, liver cirrhosis, adrenal insufficiency, hypothyroidism, SIADH)
- Excessive water consumption during endurance exercise
- Severe vomiting or diarrhea
- Drinking too much water too quickly
Key Considerations
As highlighted in the guidelines 1, the management of hyponatremia depends on the underlying cause and severity, with treatment options ranging from fluid restriction to intravenous sodium solutions. It is crucial to correct sodium levels carefully to avoid rapid correction, which can lead to serious neurological complications like osmotic demyelination syndrome.
Recent Guidelines
The most recent guidelines 1 emphasize the importance of distinguishing between hypovolemic and hypervolemic hyponatremia, with treatment approaches tailored to the specific type and underlying cause. For hypovolemic hyponatremia, treatment involves discontinuing diuretics and providing fluid resuscitation, while hypervolemic hyponatremia requires fluid restriction, reduction or discontinuation of diuretics, and consideration of vasopressin receptor antagonists.
Conclusion Not Applicable
Instead, prioritizing the most recent and highest quality evidence 1 is essential for guiding clinical decisions on the management of hyponatremia, focusing on minimizing morbidity, mortality, and improving quality of life.
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 categorized based on the volume status of the patient. Some of the common causes include:
- Certain medications, such as diuretics 3
- Excessive alcohol consumption 4
- Very low-salt diets 4
- Excessive free water intake during exercise 4
- Syndrome of inappropriate antidiuretic hormone (SIADH) secretion 5
- Congestive heart failure 5, 6
- Liver cirrhosis 5, 6
- Renal disease 5
- Endocrine deficiencies 5
- Reset osmostat syndrome 5
- Severe burns 5
- Gastrointestinal losses 5
- Acute water overload 5
Medication-Induced Hyponatremia
Diuretics are one of the most common causes of severe hyponatremia, with thiazide diuretics being more likely to cause this condition than loop diuretics 3.
Hyponatremia in Specific Conditions
In patients with cirrhosis and portal hypertension, hyponatremia is common and is characterized by excessive renal retention of water relative to sodium due to reduced solute-free water clearance 6. The primary cause is increased release of arginine vasopressin. Hyponatremia is also associated with increased mortality in cirrhotic patients and those with end-stage liver disease (ESLD) on transplant waiting lists 6.
Other Causes
Other causes of hyponatremia include hyperglycemia, pseudohyponatremia, and the post-transurethral prostatic resection syndrome 5. The urinary sodium concentration can help in diagnosing patients with low plasma osmolality, with high urinary sodium concentration indicating renal disorders, endocrine deficiencies, reset osmostat syndrome, SIADH, and medications, and low urinary sodium concentration indicating severe burns, gastrointestinal losses, and acute water overload 5.