what causes brain swelling

Brain swelling, also called cerebral edema, happens when fluid builds up in or around brain tissue and raises pressure inside the skull. Common causes include head injury, stroke, infection, brain tumors, low oxygen, liver failure, certain toxins or medications, and high-altitude illness.

Common causes

• Traumatic brain injury.
• Ischemic or hemorrhagic stroke.
• Infections such as meningitis or encephalitis.
• Brain tumors or bleeding near a tumor.
• Low blood flow or low oxygen to the brain.
• Liver failure, severe metabolic problems, or toxin exposure.
• High-altitude cerebral edema.

Why it is dangerous

The skull is a closed space, so swelling can quickly increase pressure and reduce blood flow to the brain. That pressure can worsen injury and, in severe cases, become life-threatening.

When to get urgent help

Seek emergency care right away for severe headache, confusion, vomiting, seizures, weakness, vision changes, or trouble staying awake, especially after a head injury or during a stroke-like episode.

TL;DR: Brain swelling is usually caused by injury, stroke, infection, tumors, low oxygen, or metabolic/toxin problems, and it needs urgent medical attention when symptoms are sudden or severe.