Damage to the brain may occur immediately, as a result of the injury, or it may develop as a result of swelling or bleeding that follows the injury. The skull is usually filled like this:
Normal Brain:
Changes can occur as a result of brain injury. The brain tissue may swell causing it to take up more room in the skull. This is called edema. When this occurs, the swollen brain tissue will push the other contents of the skull to the side.
There may be bruising called contusions or a collection of blood called a hematoma or clot. This may also push the other contents to one side.
The flow of CSF may also become blocked. This will cause the open spaces (ventricles) to become enlarged. This is called hydrocephalus.
Brain with Hydrocephalus:
Any of these changes can cause increased intracranial pressure.