From the Guidelines
Low sodium (hyponatremia) and low chloride (hypochloremia) are often caused by conditions such as excessive fluid intake, prolonged vomiting or diarrhea, certain medications like diuretics, kidney diseases, adrenal insufficiency, syndrome of inappropriate antidiuretic hormone secretion (SIADH), heart failure, liver cirrhosis, and severe burns. The most recent and highest quality study, published in 2021 in the journal Hepatology 1, provides guidance on the management of ascites, spontaneous bacterial peritonitis, and hepatorenal syndrome in cirrhosis, which includes the treatment of hyponatremia.
Causes of Hyponatremia and Hypochloremia
Some of the common causes of hyponatremia and hypochloremia include:
- Excessive fluid intake which dilutes electrolytes
- Prolonged vomiting or diarrhea which leads to electrolyte loss
- Certain medications like diuretics (especially thiazides such as hydrochlorothiazide and loop diuretics like furosemide)
- Kidney diseases that impair electrolyte reabsorption
- Adrenal insufficiency
- Syndrome of inappropriate antidiuretic hormone secretion (SIADH)
- Heart failure
- Liver cirrhosis
- Severe burns
- Excessive sweating during intense physical activity without proper electrolyte replacement Some medical conditions like cystic fibrosis or certain types of kidney tubular acidosis specifically affect chloride levels.
Treatment of Hyponatremia and Hypochloremia
Treatment depends on the underlying cause and severity but may include:
- Fluid restriction
- Salt supplementation
- Medication adjustments
- Intravenous saline solutions Severe cases require careful correction to avoid complications like osmotic demyelination syndrome.
Important Considerations
Anyone experiencing symptoms like confusion, weakness, seizures, or irregular heartbeat should seek immediate medical attention as severe electrolyte imbalances can be life-threatening. According to the study published in 2021 in the journal Gut 1, hypovolaemic hyponatraemia results from overzealous diuretic therapy, and its management requires expansion of plasma volume with normal saline and cessation of diuretics. Another study published in 2021 in the journal Gut 1 recommends fluid restriction to 1–1.5 L/day for those who are clinically hypervolaemic with severe hyponatraemia (serum sodium <125 mmol/day). It is essential to note that the treatment of hyponatremia and hypochloremia should be individualized based on the underlying cause and severity of the condition, and patients should be closely monitored for adverse events and complications.
From the FDA Drug Label
In two double-blind, placebo-controlled, multi-center studies (SALT-1 and SALT-2), a total of 424 patients with euvolemic or hypervolemic hyponatremia (serum sodium <135 mEq/L) resulting from a variety of underlying causes (heart failure, liver cirrhosis, syndrome of inappropriate antidiuretic hormone [SIADH] and others) were treated for 30 days with tolvaptan or placebo, then followed for an additional 7 days after withdrawal.
The causes of hyponatremia (low sodium levels) mentioned in the drug label are:
- Heart failure
- Liver cirrhosis
- Syndrome of inappropriate antidiuretic hormone (SIADH)
- Other underlying causes
There is no information in the drug label about the causes of hypochloremia (low chloride levels) 2.
From the Research
Causes of Hyponatremia
- Pseudohyponatremia, which occurs due to hyperproteinemia, hyperlipidemia, or hyperglycemia 3
- Hypovolemic hyponatremia, commonly caused by fluid loss 3
- Hypervolemic hyponatremia, often resulting from fluid retention due to heart failure, cirrhosis, or renal failure 3, 4, 5
- Euvolemic hyponatremia, most often caused by the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) 3, 4, 6, 5
- Other causes, such as diabetes mellitus, chronic kidney disease, and certain medications like thiazides and mannitol 5
Causes of Hypochloremia
- Although the provided studies do not directly address the causes of hypochloremia, it can be inferred that hypochloremia may occur in conjunction with hyponatremia, particularly in cases of fluid loss or retention 3
- However, there is limited information available in the provided studies to fully explain the causes of hypochloremia
Management of Hyponatremia
- Rehydration with isotonic saline for hypovolemic hyponatremia 3
- Addressing the underlying cause for hypervolemic hyponatremia 3
- Restricting free water intake, addressing the underlying cause, and occasionally using drugs like vasopressin receptor antagonists for euvolemic hyponatremia 3, 4, 6, 7
- Administration of hypertonic saline for severe or acutely symptomatic hyponatremia 3, 5, 7