What happens if hypernatremia is corrected too rapidly?

From the Guidelines

Rapid correction of hypernatremia can lead to severe neurological complications, including osmotic demyelination syndrome (ODS), and therefore, correction should not exceed 8 mEq/L per 24-hour period to ameliorate this risk. The goal rate of increase of serum sodium is 4-6 mEq/L per 24-hour period, as recommended by the American Association for the Study of Liver Diseases 1. This is crucial in preventing ODS, which can cause destruction of the myelin sheaths that cover nerve cells in the brain, particularly in the pons (central pontine myelinolysis), but can also affect other brain areas (extrapontine myelinolysis).

Some key points to consider when correcting hypernatremia include:

• The risk of ODS is highest in patients with chronic hyponatremia (>48 hours), alcoholism, malnutrition, liver disease, or potassium depletion.
• Symptoms of ODS typically appear 2-6 days after rapid correction and include dysarthria, dysphagia, behavioral changes, movement disorders, seizures, lethargy, confusion, and in severe cases, locked-in syndrome, coma, or death.
• If overcorrection occurs, prompt action should be taken by administering hypotonic fluids (D5W) with or without desmopressin (DDAVP) at 2-4 μg IV/SC every 8 hours to re-lower sodium levels.
• Frequent monitoring is necessary when correcting the serum sodium concentration to prevent excessive correction, which can cause many side effects or complications, as noted in the KASL clinical practice guidelines for liver cirrhosis 1.

In clinical practice, it is essential to prioritize caution when correcting hypernatremia to prevent severe neurological complications, and the recommended goal rate of increase of serum sodium should be strictly followed to minimize the risk of ODS.

From the Research

Correction of Hypernatremia

• Hypernatremia is not directly addressed in the provided studies, which primarily focus on hyponatremia.
• However, the principles of correcting electrolyte imbalances may be relevant.

Risks of Rapid Correction

• Rapid correction of hyponatremia, rather than hypernatremia, is discussed in the studies.
• Overly rapid correction of chronic hyponatremia may lead to osmotic demyelination syndrome 2.
• This condition can result in severe neurological damage, including parkinsonism, quadriparesis, or even death 3, 2.
• Risk factors for osmotic demyelination syndrome include alcohol use disorder, hyporkelmia, liver disease, and malnutrition 2, 4.

Guidelines for Correction

• European guidelines recommend correcting hyponatremia by ≤10 mEq/L in 24 hours to prevent osmotic demyelination syndrome 2.
• However, some studies suggest that even with correction rates ≤10 mEq/L in 24 hours, osmotic demyelination syndrome can still occur 2, 4.
• In patients with severe hyponatremia and high-risk features, limiting serum sodium correction to <8 mEq/L is recommended 2.

Mortality and Morbidity

• Limiting the sodium correction rate in patients with severe hyponatremia may be associated with higher mortality and longer length of stay 4.
• Rapid correction of hyponatremia may be associated with lower in-hospital mortality and shorter length of stay, but may also increase the risk of neurologic complications 4.