Causes

Your brain has the consistency of gelatin. It's cushioned from everyday jolts and bumps by cerebrospinal fluid inside your skull.

A violent blow to your head and neck or upper body can cause your brain to slide back and forth forcefully against the inner walls of your skull.

Sudden acceleration or deceleration of the head, caused by events such as a car crash or being violently shaken, also can cause brain injury.

These injuries affect brain function, usually for a brief period, resulting in signs and symptoms of concussion.

This type of brain injury may lead to bleeding in or around your brain, causing symptoms such as prolonged drowsiness and confusion. These symptoms may develop immediately or later.

Such bleeding in your brain can be fatal. That's why anyone who experiences a brain injury needs monitoring in the hours afterward and emergency care if symptoms worsen.