Hypernatremia Management

Clinical Manifestations and Dangers

Hypernatremia causes brain cell dehydration as water shifts from the intracellular to extracellular space, leading to neurological symptoms in patients with serum sodium >145 mmol/L 1
Hypernatremia is associated with hyperchloremia which may impair renal function in affected individuals 2, 3

For chronic hypernatremia, correction should generally not exceed 8-10 mmol/L per 24 hours, as recommended by the Neurosurgery society 4
In traumatic brain injury patients, prolonged induced hypernatremia is not recommended for controlling intracranial pressure due to the risk of "rebound" intracranial pressure during correction, according to the Anaesthesia society 2, 3, 5
The American Neurosurgery society recommends cautious correction to avoid neurological complications, with a correction rate of ≤0.5 mmol/L/h 1, 4

Regular monitoring of serum sodium, other electrolytes, and clinical status is essential, and treatment should be adjusted based on the patient's response and correction rate, with vigilance for signs of neurological deterioration during correction, as advised by the Neurosurgery society 4

The severity of symptoms in hypernatremia depends on both the magnitude of hypernatremia and the rate of onset, with rapid onset and high sodium levels contributing to increased severity 6

Seizures are more likely to occur with rapid onset of hypernatremia, severe hypernatremia, and pre-existing neurological conditions 6

A reduction rate of 10-15 mmol/L/24h is recommended for hypernatremia correction to prevent cerebral edema, seizures, and neurological injury 7
Rapid correction of hypernatremia may induce cerebral edema, seizures, and neurological injury 7

In traumatic brain injury patients, prolonged induced hypernatremia is not recommended for controlling intracranial pressure 8, 9
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 7

In patients with hemorrhagic stroke, deliberately inducing hypernatremia (serum Na 150‑155 mmol/L) to control ICP is not recommended because the correlation between serum sodium elevation and ICP reduction is weak and rapid correction can cause a rebound increase in ICP, potentially worsening neurological injury. 10

Hypernatremia in hemorrhagic stroke is linked to concurrent hyperchloremia, which may compromise renal function and increase the risk of acute kidney injury. 10

The hypothesized neuroprotective benefit of hypernatremia relies on an intact BBB; however, in hemorrhagic stroke the BBB is frequently disrupted, limiting any potential advantage of elevated serum sodium. 10