What are the risks of overcorrecting hypernatremia?

From the Guidelines

Overcorrecting hypernatremia poses significant risks, including osmotic demyelination syndrome (ODS), which can lead to severe neurological complications, such as seizures, encephalopathy, and quadriparesis.

Risks of Overcorrection

• ODS is a rare but potentially life-threatening condition that can occur when serum sodium levels are corrected too rapidly, typically within 2-7 days after correction 1.
• The risk of ODS is higher in patients with advanced liver disease, alcoholism, severe hyponatremia, malnutrition, and metabolic derangements, such as hypophosphatemia, hypokalemia, or hypoglycemia 1.
• To mitigate the risk of ODS, a goal rate of change of serum sodium of 4-8 mEq/L per day is recommended, not to exceed 10-12 mEq in a 24-hour period, with a lower goal of 4-6 mEq/L per day in patients at high risk of ODS 1.

Management of Hyponatremia

• Treatment of hyponatremia depends on the underlying cause, severity, and chronicity, with acute hyponatremia requiring rapid correction and chronic hyponatremia requiring more gradual correction 1.
• Hypertonic sodium chloride administration can improve natremia but may worsen volume overload and ascites, and should be limited to severely symptomatic hyponatremia or in patients expected to undergo liver transplantation within a few days 1.
• Vaptans, such as tolvaptan, can improve serum sodium concentration in patients with hypervolemic hyponatremia, but require close monitoring to avoid rapid increases in serum sodium levels and potential complications, such as dehydration and hypernatremia 1.

From the Research

Risks of Overcorrecting Hypernatremia

The risks of overcorrecting hypernatremia include:

• Cerebral edema, which can occur when the hypernatremia is corrected too rapidly, causing the brain to swell as it accumulates water 2
• Cerebral hemorrhage, which can result from acute brain shrinkage induced by rapid correction of hypernatremia 3, 2
• Demyelination, a condition where the protective covering of nerve fibers is damaged, which can occur as a result of rapid correction of hypernatremia 3
• Seizures and alteration of consciousness, which can occur due to the rapid shift of water into the brain cells during correction of hypernatremia 4, 3

Factors Influencing the Risk of Overcorrection

The risk of overcorrection is influenced by:

• The rate of correction, with faster rates increasing the risk of cerebral edema and other complications 4, 5, 2
• The severity and duration of hypernatremia, with chronic hypernatremia requiring slower correction to avoid cerebral edema 4, 2
• The patient's underlying medical condition, with critically ill patients being at higher risk of hypernatremia and its complications 3, 6

Recommended Correction Rates

The recommended correction rates for hypernatremia vary, but generally include:

• A maximum correction rate of 0.5 mmol/L per hour 4
• A maximum correction rate of 8-12 mmol/L per 24 hours 4, 2
• Individualized correction rates based on the patient's specific condition and response to treatment 6