What Happens to the Brain During a Traumatic Brain Injury?

What Happens to the Brain During a Traumatic Brain Injury?

Today we’re presenting you with a crash course on what happens to the brain during a traumatic brain injury.

By the end of this article, you’ll understand exactly what is going on after TBI.

You’ll also find out what the difference is between primary and secondary brain injuries, and what steps you can take to reduce the damage those injuries have done to your brain.

Sound interesting? Then let’s dive in.

What Happens During a Traumatic Brain Injury?

A traumatic brain injury can be broken down into a series of damaging events which cause a disruption of healthy brain function.

First, there is the initial injury, when a strong, external force collides with a skull. This alone can leave serious damage in the brain.

For example, after a sudden impact, the delicate balance of ions and chemicals in the brain are altered, which impairs cell function. Nerve fibers are also often torn.

But the initial blow to the head is nearly always followed by a slew of other complications, called secondary injuries, which happen in the hours and days after the primary injury.

One example of a secondary injury is the production of free radicals in the brain after an injury. Free radicals are unstable molecules that damage your cells and cause the brain tissue to swell in response.

These secondary injuries are what usually cause all those TBI side effects that brain injury patients are familiar with.

Now that we have a general outline of what happens during a traumatic brain injury, let’s take a closer look at primary and secondary brain injuries.

Primary Traumatic Brain Injuries

person in coma after traumatic brain injury

There are two main types of primary brain injuries that a person can experience: closed head injuries and open head injuries.

Closed Head Injuries

By far the most common type of primary injuries are closed head injuries. These occur when there is no serious break in the skull or visibly open wound.

In a closed head injury, the head is rocked quickly back and forth or is slammed into something solid. The brain follows the movement of the skull, and ends up colliding into it.

Because the brain is so soft, it can also be twisted and stretched, which causes axons to tear.

Depending on how fast and how hard the brain was hit, a closed head injury can lead to anything from a mild concussion to a serious brain bleed. If too many axons are torn in the process, these injuries can also result in a coma.

Open Head Wounds

Also known as penetrating head injuries, these happen when a person’s head collides with a sharp object. After collision, the skull is opened and the brain tissue is exposed and damaged.

Even though these accidents are usually seen as horrific, the outcome is often much better than a closed head injury. This is because penetrating injuries typically only damage one specific area of the brain, whereas in a closed injury multiple regions can be affected.

Secondary Injuries

explanation of what happens to the brain after a traumatic brain injury

The most common secondary injury is oxygen deprivation. This can happen for a variety of reasons, but it is usually caused when the brain swells and squeezes up against the skull, or when too much blood in the brain is lost.

The lack of oxygen kills brain cells and worsens the damage from the primary injury.

But is there anything that can be done to prevent secondary injuries?

Preventing Secondary Brain Injuries

Some secondary injuries are unavoidable, like the damage done to the brain by free radicals released after an injury, which we mentioned above. Others can be avoided if the right medical care is given immediately.

In fact, that is the main goal of emergency traumatic brain injury treatment: to prevent secondary injuries from developing.

Some examples of secondary injuries that can be prevented by early medical interventions are:

  • Blood clots (hematomas)
  • Brain swelling
  • Airway obstruction
  • Blood loss from other injuries

This is why it is critical to call an ambulance or go to the ER immediately after a head injury. Some of these issues will not present for several hours, so it is important to be closely monitored until the risk of blood clots and swelling are over.

Changes in the Brain After Injury

Besides primary and secondary injuries, there are other changes in the brain that take place after a TBI.

Neurochemical Changes

neurons change in the brain after tbi

As we explained at the beginning of this article, the brain operates on a delicate chemistry, and a brain injury disturbs this natural balance.

More specifically, after an injury, the brain loses the ability to produce several crucial neurotransmitters, chemical substances that help neurons communicate with each other. This can lead to problems with thinking and behavior.

Sometimes the brain can resolve this chemical imbalance on its own, but sometimes it might require some medication to help it along.


The brain possesses a dynamic ability to adapt in response to changes in environment. It does this by establishing new neural pathways and connections.

This ability is known as neuroplasticity. After an injury, the brain enters a heightened state of plasticity, which means it can more easily rewire itself.

Neuroplasticity is activated by stimulating the brain through repetitive action. This is why it is so important to begin therapy as soon as possible after injury.

What Happens During a TBI?

So there you have it. That was a general overview of what happens to the brain during a traumatic brain injury.

But how can you use this information to aid your recovery?

Well, now that you know what happens during – and immediately after – a TBI, you can take more effective steps to boost your recovery!

For example, when you understand that free radicals are produced in response to a brain injury, you can start supplementing your diet with antioxidants to counter those molecules and reduce inflammation.

You can also work to promote your brain’s natural plasticity through exercise and intensive therapy.

As you can see, the more knowledge you have about TBI, the better you’ll be able to address problems related to it.