Can hypernatremia cause seizures?

Hypernatremia and Seizures

Yes, hypernatremia can cause seizures due to brain cell dehydration that occurs when water shifts from the intracellular to extracellular space. 1

Pathophysiology and Neurological Effects

• Hypernatremia (serum sodium >145 mmol/L) causes brain cells to dehydrate as water shifts from the intracellular to extracellular space, leading to neurological symptoms 1
• The severity of symptoms depends on both the magnitude of hypernatremia and the rate of onset 2
• Brain cell dehydration can progress to severe neurological manifestations including seizures and coma if not properly managed 3

Clinical Manifestations

• Mild symptoms: nausea, vomiting, weakness, headache, and mild neurocognitive deficits 3
• Severe symptoms: delirium, confusion, impaired consciousness, ataxia, seizures, and rarely brain herniation and death 3
• Seizures are more likely to occur with:
  • Rapid onset of hypernatremia 2
  • Severe hypernatremia (typically with sodium levels significantly above 145 mmol/L) 1, 3
  • Pre-existing neurological conditions 2

Management Considerations

• For chronic hypernatremia, correction should generally not exceed 8-10 mmol/L per 24 hours to avoid neurological complications 1
• A reduction rate of 10-15 mmol/L/24h is recommended for hypernatremia correction to prevent cerebral edema, seizures, and neurological injury 2
• Rapid correction of hypernatremia may induce cerebral edema, seizures and neurological injury 2
• Treatment should be based on the underlying cause of hypernatremia 3, 4

Special Considerations

• In traumatic brain injury patients, prolonged induced hypernatremia is not recommended for controlling intracranial pressure 2
• Hypernatremia is often "iatrogenic" in very low birth weight infants, resulting from incorrect replacement of transepidermal water loss, inadequate water intake, or excessive sodium intake 2
• Hypernatremia most commonly occurs due to water loss or inadequate water intake, particularly in patients with impaired thirst mechanisms or limited access to water 4

Treatment Approach

• Address the underlying cause of hypernatremia 3
• Correct fluid deficits with hypotonic fluids when sodium is severely elevated 3
• Monitor serum sodium levels regularly during correction 1
• Be vigilant for signs of neurological deterioration during correction 1

While recent research suggests that rapid correction of hypernatremia may not increase mortality risk in critically ill adults 5, the established clinical guidelines still recommend cautious correction to prevent neurological complications including seizures 2, 1.