How to manage severe hyponatremia in a 50-year-old male?

From the Guidelines

Managing severe hyponatremia in a 50-year-old male with a sodium level of 117 requires careful correction to avoid neurological complications, with the goal of increasing sodium by 4-6 mEq/L in the first 24 hours and no more than 8 mEq/L/day thereafter, as recommended by the most recent guidelines 1. The initial treatment should focus on determining if the patient has symptoms of cerebral edema (seizures, altered mental status) which would necessitate urgent intervention with 3% hypertonic saline at 100-150 mL boluses over 10-20 minutes, repeated up to 2-3 times if symptoms persist. For asymptomatic severe hyponatremia, a more gradual correction is appropriate. Key considerations include:

• Fluid restriction to 800-1000 mL/day for euvolemic or hypervolemic hyponatremia
• Administration of isotonic saline (0.9% NaCl) if the patient is hypovolemic
• Use of oral salt tablets (1-2 g TID) or urea (15-60 g/day) for SIADH
• Consideration of vasopressin receptor antagonists like tolvaptan (starting at 15 mg daily) for resistant cases, with close monitoring
• Addition of loop diuretics such as furosemide (20-40 mg IV) for hypervolemic patients Throughout treatment, serum sodium should be monitored every 2-4 hours initially, then every 4-6 hours, adjusting therapy to prevent overly rapid correction which could lead to osmotic demyelination syndrome, as cautioned by recent studies 1. The underlying cause of hyponatremia (medications, endocrine disorders, heart failure, cirrhosis) must be identified and addressed simultaneously for effective long-term management, emphasizing the importance of a comprehensive approach as highlighted in 1.

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.

Patients were randomized to receive either placebo (N = 220) or tolvaptan (N = 223) at an initial oral dose of 15 mg once daily. The mean serum sodium concentration at study entry was 129 mEq/L

The dose of tolvaptan could be increased at 24-hour intervals to 30 mg once daily, then to 60 mg once daily, until either the maximum dose of 60 mg or normonatremia (serum sodium >135 mEq/L) was reached

For a 50-year-old male with severe hyponatremia (sodium 117), tolvaptan can be considered as a treatment option. The initial dose is 15 mg once daily, and it can be increased to 30 mg once daily, then to 60 mg once daily at 24-hour intervals until the maximum dose or normonatremia is reached.

• Monitoring of serum sodium levels is crucial to avoid hypernatremia.
• Fluid restriction should be avoided during the first 24 hours of therapy to prevent overly rapid correction of serum sodium.
• Patients should be monitored for signs of hypernatremia, and management may include dose decreases or interruption of tolvaptan treatment, combined with modification of free-water intake or infusion 2.

From the Research

Severe Hyponatremia Management

• Severe hyponatremia is defined as a sodium concentration of less than 125 mEq per L 3
• Symptoms of severe hyponatremia include delirium, confusion, impaired consciousness, ataxia, seizures, and, rarely, brain herniation and death 3
• Patients with severe hyponatremia and severe symptoms require emergency infusions with 3% hypertonic saline 3, 4

Treatment Approaches

• Treatment of severe hyponatremia involves identifying the underlying cause and managing it accordingly 3, 5
• Hypovolemic hyponatremia is treated with normal saline infusions 3
• Euvolemic hyponatremia is treated by restricting free water consumption or using salt tablets or intravenous vaptans 3
• Hypervolemic hyponatremia is treated primarily by managing the underlying cause (e.g., heart failure, cirrhosis) and free water restriction 3

Hypertonic Saline Use

• Hypertonic saline has been used for the treatment of hyponatremia for nearly a century 6
• The use of hypertonic saline should be guided by the severity of symptoms and the rate of sodium correction 6, 4
• Bolus-wise administration of 150 mL of 3% hypertonic saline is recommended for symptomatic hyponatremia 4
• However, the risk of overcorrection and sodium fluctuations should be monitored closely 4

Considerations

• The treatment of hyponatremia should not be delayed while a diagnosis is pursued 3
• Common causes of hyponatremia include certain medications, excessive alcohol consumption, very low-salt diets, and excessive free water intake during exercise 3
• The use of hypertonic saline requires careful consideration of the patient's volume status and the risk of overcorrection 6, 7