What can cause cerebral edema?

• A. Dehydration
• B. Hyperglycemia
• C. Ischemia from a blockage of an artery in the brain (hypoxia)
• D. Low temperature

Answer: (C)

Cerebral edema happens when brain tissue swells from fluid buildup. A common trigger is ischemia from a blocked artery in the brain, which cuts off oxygen and glucose to brain cells. Without enough energy, the Na+/K+ ATPase pumps fail, causing sodium and water to flood into cells. The result is cytotoxic edema, where individual brain cells swell. If injury progresses, the blood–brain barrier can become leaky, letting fluid spill into the surrounding tissue and causing vasogenic edema. Together, these processes raise intracranial pressure and threat neural function.

Dehydration tends to reduce brain water overall and can cause brain cells to shrink rather than swell, so it isn’t a typical cause of edema. Hyperglycemia by itself doesn’t directly produce edema, though severe osmotic or metabolic disturbances can contribute in certain contexts. Very low temperatures can lower metabolic demand and may have protective effects in some situations, not a primary cause of cerebral edema.