Cedars-Sinai Blog

Heads Up: When Minor Head Injuries Aren't Minor at All

A colorized scan of a head and brain injury.

One way or another, most of us will hit our head at some point in our lives. And most of us will walk away unharmed thanks to our rigid skull, which protects our brain.

While that's good news, it hides a more alarming truth: Even a minor head injury can lead to serious symptoms and, if left unattended, even death. Does that mean you should visit the emergency room (ER) any time your head takes a hit? 

"It's not uncommon for someone to hit their head and feel fine. They may figure everything is all right when it's actually not."

Cedars-Sinai Associate Professor, Neurosurgery, Ray M. Chu, MD.

If not, what symptoms should you look for? What if you hit your head hard, but you feel fine and don’t notice any problems? We've got answers to these questions and more from Dr. Ray Chu, associate professor of Neurosurgery and Unaffiliated Neurotrauma Consultant for the NFL.

People hit their heads all the time. Isn't it easy to tell the difference between a minor hit and a major one?

Dr. Ray Chu: Not always, and that's the problem. It's not uncommon for someone to hit their head and feel fine. They may figure everything is all right when it's actually not. If an injury to the brain is serious enough, it affects your perception and mental processes. You can't tell that you're suddenly behaving differently. 

What should someone do when they hit their head?

RC: If you hit your head but it wasn't a major blow and you feel fine, or if you are only noticing subtle symptoms, make sure to quickly interact with friends or family. If there's nobody around, you can chat on the phone instead. Tell them what happened and ask if you seem like yourself. 

For example, have them ask you questions to test your memory. If they tell you that something seems wrong, have someone take you to the ER or call 911. 

Can you give examples of common head injuries that can turn serious?

RC: Concussions and hematomas are two of the most common brain injuries we see. Most concussions are mild, and most people recover completely from a concussion without medical treatment.

Permanent damage is rare, and concussions generally are not fatal. By contrast, while hematomas may resolve on their own, they can cause very serious long-term damage and may be life-threatening. So, hematomas require medical attention.

How do hematomas happen, and why are they so dangerous?

RC: A hematoma is when there is bleeding in or near the brain and the blood has more or less clotted. Your brain is encased in several layers of tissue, all surrounded by your skull. 

If a blood vessel bursts in your brain, the blood has nowhere to go. It can't escape the region. So, it ends up gathering between the brain and the skull. As it expands, this mass of blood compresses brain tissue and increases the pressure within the skull, which can seriously damage the brain.

There are two main types of hematomas: epidural and subdural. In epidural hematomas, the blood is confined to the epidural space—the space between the coverings of the brain, the dura and the skull. Subdural hematomas can run from the front of the head to the back. They are also twice as common as epidural hematomas. Both epidural and subdural hematomas can be life-threatening.

An acute subdural hematoma is almost always a medical emergency. It's triggered by a major blow to the head. Common causes include falling from a scaffold or ladder, car crashes, violence (including shaken baby syndrome), and sporting accidents. Being older puts you at higher risk because the brain shrinks a bit with age, making blood vessels more vulnerable. 

What are the symptoms of a hematoma?

RC: In an acute hematoma, the symptoms appear right away, and can include loss of balance, headache, nausea, confusion, dizziness, drowsiness, seizures and speech or vision problems.

A chronic hematoma grows slowly, so you don't notice its signs for weeks. The changes in behavior are also more subtle, which can be deceptive. The good news is that they are treatable—as long as they are dealt with in a timely manner. 

The bad news is that people don't always know that they've had a serious enough injury to trigger a brain bleed. Tragically, if someone hits their head very badly and then goes to sleep because they only felt mild symptoms, they might not wake up.

How do you treat a hematoma?

RC: We can perform a craniotomy, which involves making a window in the skull to evacuate the blood, remove clots and ease the pressure on the skull. Another method is to drill one or more small holes (known as burr holes) in the skull to allow the blood to drain and ease the pressure on the skull. 

In some cases, if the hematoma is small, we monitor patients in the intensive care unit instead. We use a sensor to measure the pressure in your head, provide medication to control symptoms and perform repeated CT scans to watch the hematoma.

Any final words of advice?

RC: You don't need to visit the ER every time you mildly hit your head. But you shouldn't decide whether to go to the ER based entirely on how you feel, either.

Of course, you should always head to the ER if the blow resulted in acute symptoms. But if you experienced a major trauma to the skull—whether you banged your head on cement or were violently struck and feel like something is off neurologically—go to the ER even if you don't think you need to. 

Older persons or people who are taking blood-thinning medication are at higher risk of intracranial hemorrhage, so they should not hesitate to go to the ER even if they aren't noticing symptoms. 

Finally, put your energy into prevention. On a bike, skis, scooter or motorcycle, a helmet can mean the difference between life and death.