What are the indications for hospitalization in patients with severe hyponatremia (sodium levels below 125 mEq/L)?

From the Guidelines

Patients with severe hyponatremia (sodium levels below 125 mEq/L) should be hospitalized if they have severe symptoms, moderate symptoms, rapid onset hyponatremia, or underlying conditions that complicate management, as well as those with sodium levels below 120 mEq/L regardless of symptoms, unable to maintain adequate oral intake, or requiring close monitoring. The indications for hospitalization in patients with severe hyponatremia include severe symptoms such as seizures, coma, or respiratory arrest, moderate symptoms like confusion, disorientation, or gait disturbances, and rapid onset hyponatremia (developing in less than 48 hours) 1. Underlying conditions that complicate management, such as heart failure, liver cirrhosis, or kidney disease, also warrant hospitalization 1. Additionally, patients with sodium levels below 120 mEq/L, regardless of symptoms, should be hospitalized, as well as those unable to maintain adequate oral intake or requiring close monitoring 1. During hospitalization, careful correction of sodium levels is crucial, aiming for an increase of no more than 8-10 mEq/L in the first 24 hours and no more than 18 mEq/L in 48 hours to prevent osmotic demyelination syndrome 1. Treatment may include fluid restriction, hypertonic saline (3% NaCl) for severe symptomatic cases, discontinuation of contributing medications, and management of underlying causes 1. Close monitoring of serum sodium levels every 2-4 hours during initial correction is necessary to ensure appropriate correction rates and prevent complications 1. It is essential to distinguish the type of hyponatremia and treat accordingly, with fluid resuscitation for hypovolemic hyponatremia and fluid restriction for hypervolemic hyponatremia 1. The effect of restricting fluid intake on the serum sodium concentration is unclear, but it may prevent deterioration of serum sodium level below a certain level 1. Plasma expanders like albumin infusion have been tried but require further study to confirm their effectiveness 1. Hypertonic sodium chloride administration can provide temporary elevation in the serum sodium concentration and symptom relief but requires close attention due to potential worsening of edema and ascites 1. In summary, hospitalization is indicated for patients with severe hyponatremia who have severe symptoms, moderate symptoms, rapid onset, or underlying conditions that complicate management, as well as those with sodium levels below 120 mEq/L, unable to maintain adequate oral intake, or requiring close monitoring, and treatment should be tailored to the type of hyponatremia and individual patient needs 1.

From the Research

Indications for Hospitalization in Severe Hyponatremia

The following are indications for hospitalization in patients with severe hyponatremia (sodium levels below 125 mEq/L):

• Severe symptoms such as delirium, confusion, impaired consciousness, ataxia, seizures, and rare cases of brain herniation and death 2, 3
• Patients with a sodium concentration of less than 125 mEq per L and severe symptoms require emergency infusions with 3% hypertonic saline 2
• Severely symptomatic hyponatremia (with signs of somnolence, obtundation, coma, seizures, or cardiorespiratory distress) is a medical emergency 3
• Hyponatremia with acute or large decreases in serum sodium, which may cause serious neurologic complications 4
• Patients with hypovolemic, euvolemic, or hypervolemic hyponatremia who require close monitoring and management of their underlying condition 2, 3

Management of Severe Hyponatremia

Management of severe hyponatremia includes:

• Treating the underlying cause of hyponatremia 2, 3
• Using calculators to guide fluid replacement and avoid overly rapid correction of sodium concentration 2
• Restricting free water consumption or using salt tablets or intravenous vaptans for euvolemic hyponatremia 2
• Managing the underlying cause (e.g., heart failure, cirrhosis) and free water restriction for hypervolemic hyponatremia 2
• Using urea and vaptans for the syndrome of inappropriate antidiuresis and hyponatremia in patients with heart failure 3
• Tolvaptan as a treatment option for patients with euvolemic or hypervolemic hyponatremia who have serum sodium levels < 125 mEq/L or persistent symptoms resistant to fluid restriction 4

Correction of Sodium Levels

Correction of sodium levels should be done carefully to avoid overly rapid correction, which can cause osmotic demyelination syndrome 2, 3, 5, 6

• The recommended correction rate is 4-6 mEq/L within 1-2 hours, but no more than 10 mEq/L within the first 24 hours 3
• Limiting the sodium correction rate to less than 6 mEq/L/24 hours may be associated with higher mortality and longer length of stay 5