Closed head injury is what it sounds like -- injury to your head that doesn't result in your skull splitting open to allow your brains and precious fluids to leak away. Closed head injuries can occur when you hit your head into the windshield of your car, get punched in the face, fall down stairs, are shaken roughly, headbang, etc.
Closed head injuries cause brain damage. This is how:
- If the injury was the result of a blow to the head, the inward movement of the skull (even if the skull is not fractured) compacts the brain, causing bruises. This is sometimes referred to as the coup. In injuries with no blow to the head (i.e. shaking or headbanging), the same kind of damage can result from violent head movement that causes the brain to hit the inside of the skull.
- At the opposite side of the head from the blow, the brain is pushed into the skull, causing additional brain bruising. This is referred to as the countercoup.
- Movement of the brain inside the skull causes twisting and shearing of nerve fibers, resulting in microscopic lesions throughout the affected area. This damage is especially common in the frontal and temporal lobes, the corpus callosum and the anterior commissure.
- Bleeding caused by the damage can result in the formation of a hematoma. This swelling puts pressure on surrounding brain matter, causing additional damage.
- As with many injuries, a generalized collection of fluid (an edema) occurs around the damaged area, putting additional pressure on the brain.
Even in patients with minor head injuries, MRI scans often reveal brain abnormalities. So, wear a seatbelt, keep the boxing and headbanging to a minimum, flee your abusive parents, and stop the cycle of violence. You can do it!