Table 3 Mechanisms of cerebral edema

Cytotoxic edema

• Failure of the Na⁺–K⁺ ATPase pump ➔ influx of ions and water ➔ expansion of intracellular fluid and volume overload

• BBB integrity: intact

• Example: ischemia, trauma, and liver failure

Interstitial edema

• Imbalance of production and clearance of CSF ➔ increased intraventricular pressure ➔ overflow of CSF into periventricular extracellular space

• BBB integrity: intact

• Example: hydrocephalus, meningitis, and pseudotumor cerebri

Osmotic edema

• Lower plasma osmolarity compared to intracerebral osmolarity due to intravascular solute derangements ➔ water diffuses across the BBB

• BBB integrity: intact

• Example: metabolic derangements such as hyponatremia and SIADH

Vasogenic edema

• BBB is disrupted ➔ increased capillary permeability ➔ interstitial fluid seeps through

• BBB integrity: breakdown

• Example: tumors, ischemia (late stage), intracerebral hemorrhage, trauma, cerebral edema at high altitudes, and infections