Is a serum sodium level of 127 mmol/L considered true hyponatremia?

From the Guidelines

Yes, a serum sodium level of 127 mmol/L is considered true hyponatremia. Hyponatremia is defined as a serum sodium concentration below 135 mmol/L, with normal range typically being 135-145 mmol/L. At 127 mmol/L, this represents mild to moderate hyponatremia. According to the most recent guidelines, mild hyponatremia (Na 126-135 mEq/L) in cirrhosis without symptoms does not require specific management apart from monitoring and water restriction 1.

Key Considerations

• The underlying causes of true hyponatremia should be investigated, which may include excessive fluid intake, heart failure, cirrhosis, kidney disease, adrenal insufficiency, hypothyroidism, medications (particularly thiazide diuretics, SSRIs, or certain antiepileptics), or syndrome of inappropriate antidiuretic hormone secretion (SIADH).
• Treatment depends on the severity, chronicity, and underlying cause, but may include fluid restriction, salt supplementation, or in some cases, careful administration of hypertonic saline.
• It is essential to note that 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 (ODS) 1.

Management Approach

• For patients with cirrhosis and hyponatremia, the management approach should be tailored to the individual's needs, taking into account the severity of hyponatremia, the presence of symptoms, and the underlying cause of the condition.
• Water restriction to 1,000 mL/day and cessation of diuretics is recommended in the management of moderate hyponatremia (120-125 mEq/L), and a more severe restriction of water intake with albumin infusion is recommended for severe hyponatremia (<120 mEq/L) 1.
• The use of vasopressin receptor antagonists, such as vaptans, can be considered for the treatment of hyponatremia in patients with cirrhosis, but should be used with caution and under close monitoring 1.

From the Research

Definition of Hyponatremia

• Hyponatremia is defined as a serum sodium concentration less than 135 mmol/L 2, 3, 4.
• It can be categorized into different types, including dilutional and depletional hyponatremia, and can be further classified as mild, moderate, or severe based on the sodium concentration 2, 3.

Classification of Hyponatremia

• Mild hyponatremia: sodium concentration between 130-134 mmol/L 2.
• Moderate hyponatremia: sodium concentration between 125-129 mmol/L 2.
• Severe hyponatremia: sodium concentration less than 125 mmol/L 2, 3.

Serum Sodium Level of 127 mmol/L

• A serum sodium level of 127 mmol/L falls into the category of moderate hyponatremia 2.
• This condition can be associated with symptoms such as lack of concentration, nausea, forgetfulness, apathy, and loss of balance 3.

Diagnosis and Management

• The diagnosis and management of hyponatremia depend on the underlying cause and the severity of the condition 2, 3, 4.
• Treatment options include fluid restriction, isotonic fluid infusion, and pharmacological agents such as vaptans 2, 3.

Osmotic Demyelination Syndrome

• Overly rapid correction of hyponatremia can lead to osmotic demyelination syndrome 5, 6.
• The risk of this complication is higher in patients with severe hyponatremia and certain risk factors, such as alcohol use disorder, hypokalemia, and liver disease 5, 6.