Brain Swelling


Healthgrades Editorial Staff

What is brain swelling?

A variety of conditions are known to cause brain swelling, which is enlargement of the brain due to excessive fluid collection in the chambers, or ventricles, of the brain or the accumulation of fluid within the brain tissue itself.

Excess fluid in the ventricles of the brain leads to a condition known as hydrocephalus. The fluid exerts outward pressure on the brain tissue, pressing it into the skull. In the skull of an infant or small child, where there are soft areas known as fontanelles and sutures between the bony plates that have not yet hardened, the head can increase in size.

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Fluid collection within the brain tissue, called cerebral edema, can result from numerous causes, including infections, trauma, stroke, brain tumors, certain toxic substances, complications of diabetes, chemical imbalances, abuse of opioids, extreme high blood pressure (malignant hypertension), or high altitude sickness.

Symptoms of brain swelling include headache, dizziness, nausea, numbness or weakness, loss of coordination or balance, loss of the ability to see or speak, seizures, lethargy, memory loss, incontinence, or altered level of consciousness. In infants, the fontanelles ("soft spots") may bulge, the head may increase in size, cries may be high-pitched or shrill, and irritability or feeding difficulties may occur.

Brain swelling causes ongoing damage to the brain tissue, so it needs to be treated as quickly as possible to save as much brain tissue as possible. Seek immediate medical care (call 911) for head trauma, significant high altitude sickness, high fever accompanied by neck stiffness or rigidity, severe headache, known ingestion of toxins, bites from poisonous animals or insects, or symptoms suggestive of brain swelling.