How is severe hyponatremia managed?

From the Guidelines

Severe hyponatremia should be managed with immediate treatment using hypertonic saline (3% NaCl) for symptomatic patients, aiming to raise serum sodium by 4-6 mEq/L in the first 6 hours, while avoiding correction exceeding 8-10 mEq/L in 24 hours to prevent osmotic demyelination syndrome, as recommended by recent guidelines 1.

Management Approach

The management of severe hyponatremia depends on the patient's symptoms and the rate of sodium decline. Key considerations include:

• Symptomatic severe hyponatremia (serum sodium <120 mEq/L with neurological symptoms) requires immediate treatment with hypertonic saline (3% NaCl), given as a 100-150 mL bolus over 10-20 minutes, which can be repeated if symptoms persist.
• The goal is to raise serum sodium by 4-6 mEq/L in the first 6 hours to reduce brain edema and prevent herniation.
• Correction must not exceed 8-10 mEq/L in 24 hours or 18 mEq/L in 48 hours to avoid osmotic demyelination syndrome.

Asymptomatic Patients

For asymptomatic patients, a slower correction using fluid restriction (typically <1-1.5 L/day) is appropriate. Underlying causes must be addressed simultaneously, which may include:

• Discontinuing offending medications
• Treating SIADH with fluid restriction or vasopressin receptor antagonists like tolvaptan (starting at 15 mg daily)
• Correcting volume status in hypovolemic patients with isotonic saline

Monitoring and Adjustments

Frequent monitoring of serum sodium (every 2-4 hours initially) is essential to ensure appropriate correction rates. If correction occurs too rapidly, desmopressin (2-4 μg IV/SC every 8 hours) and hypotonic fluids can be administered to slow the rate of correction and prevent neurological complications, as suggested by studies 1.

From the FDA Drug Label

Removal of excess free body water increases serum osmolality and serum sodium concentrations. All patients treated with tolvaptan, especially those whose serum sodium levels become normal, should continue to be monitored to ensure serum sodium remains within normal limits If hypernatremia is observed, management may include dose decreases or interruption of tolvaptan treatment, combined with modification of free-water intake or infusion.

The management of severe hyponatremia with tolvaptan involves monitoring serum sodium levels and adjusting treatment as needed to prevent hypernatremia. Key considerations include:

• Dose decreases or interruption of tolvaptan treatment if hypernatremia occurs
• Modification of free-water intake or infusion to manage serum sodium levels 2

From the Research

Management of Severe Hyponatremia

Severe hyponatremia is a life-threatening condition that requires prompt and definitive intervention. The management of severe hyponatremia involves the use of hypertonic saline to increase serum sodium levels.

• Hypertonic Saline Administration: Hypertonic saline is administered as a bolus injection or continuous infusion to increase serum sodium levels 3, 4, 5.
• Dosing and Administration: The dose and administration of hypertonic saline vary depending on the severity of symptoms and the patient's condition. A 4- to 6-mmol/L increase in serum sodium concentration is adequate in the most seriously ill patients, and this is best achieved with bolus infusions of 3% saline 3.
• Therapeutic Goals: The therapeutic goals for correcting hyponatremia are to increase serum sodium levels by 6 to 8 mmol/L in 24 hours, 12 to 14 mmol/L in 48 hours, and 14 to 16 mmol/L in 72 hours 3.
• Monitoring and Prevention of Overcorrection: Frequent monitoring of serum sodium concentration and urine output are mandatory to prevent overcorrection, which can lead to iatrogenic brain damage 3, 4.
• Use of Desmopressin: Desmopressin can be used to terminate an unwanted water diuresis and prevent overcorrection 3.
• Alternative Treatments: Other treatments, such as tolvaptan, may be used in specific cases, such as syndrome of inappropriate antidiuretic hormone hypersecretion (SIADH) 6.

Considerations for Hypertonic Saline Use

The use of hypertonic saline for hyponatremia requires careful consideration of several factors, including:

• Indications: Hypertonic saline should be used in patients with hyponatremia associated with moderate or severe symptoms to prevent neurological complications 7.
• Dosing and Administration Modality: The dose and administration modality of hypertonic saline should be individualized based on the patient's condition and response to treatment 7.
• Combined Use with Desmopressin: Desmopressin may be used concomitantly with hypertonic saline to prevent rapid correction of serum sodium 7.
• Fluid Restriction: Fluid restriction may be necessary in some cases to prevent overcorrection and ensure safe correction of serum sodium levels 7.