An Overview of Traumatic Brain Injury

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A traumatic brain injury (TBI) occurs when a traumatic event causes harm to the brain. Falling, car accidents, sports injuries, and being physically attacked can all cause TBIs.

Some TBIs are mild, producing headaches or dizziness that improve on their own within a few days. TBI can also cause serious long term effects (like physical paralysis or personality changes), especially if there are multiple areas of damage in the brain.

If you have had a head injury, you may need several tests to diagnose a TBI, including a physical examination, brain imaging, and neuropsychiatric evaluation. Sometimes a TBI can heal without long term consequences. Serious TBIs may require emergency surgical treatment, medical management, and long term rehabilitation.


A variety of symptoms can occur as a result of a TBI. You might notice the symptoms immediately after experiencing the trauma, or you can have a delay of several weeks before the effects of the brain injury are noticeable.

Effects of a minor TBI can resolve in a few hours. Severe TBIs are more likely to cause prolonged effects that can last for weeks, months, or even for a lifetime.

With TBI, you may experience obvious bleeding of your scalp, face, nose, or ears. But TBI can occur even without any external signs of trauma.

Symptoms of a TBI can include:

You can experience any combination of these symptoms from a TBI.

Delayed Effects

In some situations, a TBI may not cause substantial discomfort or neurological effects right away. A type of bleeding in the brain called a subdural hematoma might not cause any noticeable symptoms in the immediate aftermath of a TBI, and the effects can worsen slowly over the course of several days.

Keep in mind that even though a subdural hematoma can cause delayed effects, it may cause symptoms and serious neurological changes immediately right after the injury.

The effects of a TBI can worsen rapidly over the course of a few hours. So it is important not to be falsely assured that a TBI is minor just because the immediate symptoms are not overwhelming.


Traumatic brain injury (TBI) can occur due to any type of trauma that affects the brain. Repeated trauma can cause multiple brain injuries and make the effects of TBI worse, but the effects of TBI can occur after one traumatic event.

Incidents that can result in TBI include:

  • Sudden head jerking, such as in motor vehicle accidents
  • Falling and hitting your head on a hard surface
  • Head impact from sports such as soccer, football, and lacrosse
  • Direct blows to the head from sports such as boxing
  • Physical attacks or abuse that include being deliberately hit in the head
  • Repetitive head jerking, as in shaken baby syndrome
  • A severe head injury, such as a gunshot to the head or getting hit in the head with a hard object

TBI does not necessarily involve a skull fracture or a skin wound on the scalp. Closed traumatic brain injuries (also called closed head injuries or CHI) occur when the powerful force of a blow to the head causes a brain injury without causing harm to the scalp or skull.

How TBI Happens

The neurons and blood vessels inside the brain are usually well protected by the skull, three layers of meninges, and the scalp. A powerful impact or rapid or sudden movement can damage the neurons and blood vessels in the brain. Bleeding and microscopic injuries can occur in and around the brain as well.

The brain can be injured by several mechanisms due to trauma, including:

  • Impact: When the head is hit directly, shockwaves go through the brain tissue. The shockwaves travel in all directions simultaneously, causing damage to individual neurons in the brain.
  • Deceleration: When your head moves rapidly, it eventually stops—usually abruptly. This causes the brain to bang against the inside of the skull. In severe trauma, the brain can bang against one side of the skull and bounce back to hit the other side too. A brain injury can occur wherever the brain hits the skull. This type of trauma can also cause blood vessels to stretch, tear, and bleed.
  • Rotation: A violent twisting of the head or neck can cause rotation of the brain inside the skull. An injury to the nerves and blood vessels can occur.
  • Edema (swelling): Along with bleeding and nerve damage, the brain may undergo severe swelling after TBI. This can cause additional brain damage due to compression of the brain within the skull.


TBI is diagnosed using several methods. If you have had a TBI, your medical team will assess the extent and severity of your brain injury. Your healthcare provider will assess your symptoms by taking a medical history and performing a physical examination. Your physical examination will include an assessment of your vision and hearing.

You may need to have an urgent brain imaging test such as a brain and/or spine computerized tomography (CT) or magnetic resonance imaging (MRI).

Neuropsychological testing or concussion testing may be done as well.

In some youth sports, a baseline evaluation of cognitive function is required. The results of this test provide a baseline for assessing a loss of function after head trauma.

Brain Imaging

Brain imaging tests can usually detect edema. A brain or spine CT can identify acute (recent) blood better than an MRI, but an MRI is more sensitive in detecting small areas of brain damage.

These tests can identify the location of bleeding caused by TBI. An intracerebral bleed is located in the brain. A subdural hematoma is located between the meninges and the brain, and an epidural hematoma is located between the meninges and the skull.

Associated Conditions

There are several conditions that are associated with TBI. A concussion, which is usually associated with loss of consciousness, can occur after a TBI. The effects of a concussion may resolve fairly quickly, but prolonged effects are described as post-concussive syndrome.

You can have TBI with or without a concussion, but you can't have a concussion without TBI. Typically, more severe TBI causes a concussion, but mild TBI can cause a concussion as well.

Treating a Concussion

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Chronic traumatic encephalopathy (CTE) is a condition characterized by behavioral and cognitive changes that occur after recurrent head trauma. These changes are caused by trauma-induced structural damage to the brain.


The treatment of TBI depends on the severity and type of brain injury. You may need a combination of medical therapy, surgical procedures, and rehabilitation. Immediate treatment for TBI is focused on preventing further brain damage.

It is important to call for emergency help if you experience or witness TBI. Emergency responders have protocols in place to minimize the long term impact of the injury. For example, they will not immediately remove objects (such as a knife) from the brain to avoid causing further harm.

Symptomatic treatment for the effects of TBI includes medication for pain and/or seizures. Recovery may take months or longer.


If you have a large bleed in your brain, you may need to have it evacuated (removed). This often requires emergency brain surgery. Sometimes a portion of the skull has to be temporarily removed, particularly is there is substantial swelling of the brain.

In some situations, surgical removal of blood after a TBI can be done through a burr hole, which is a small hole drilled into the skull.

Medical Treatment

Medical management may be needed to help reduce edema and to control the symptomatic consequences of TBI such as head pain and seizures. You may need steroids and/or intravenous (IV) fluids to control edema in the first few days after experiencing head trauma.

Medications for pain are used with great caution to avoid side effects that interfere with alertness or level of consciousness. If you have had a seizure, your healthcare provider may start an anti-epilepsy drug (AED), especially if blood is seen on your brain imaging test.


A brain injury may result in the loss of some physical and cognitive (thinking) abilities. Rehabilitation strategies can involve a number of approaches, including physical therapy, occupational therapy, speech therapy, cognitive therapy,, and counseling.

Therapy requires effort and can be exhausting. It is important to be patient and consistent as you recover from the effects of a TBI.

A Word From Verywell

Trauma to the brain is not uncommon. You may experience a quick recovery after TBI, but sometimes these injuries can cause lasting damage.

If you need to have rehabilitation, it is important that you work on your goals with your therapist and monitor your own progress. Don't be discouraged if your improvement seems to slow down or stagnate at times—sometimes improvement after TBI can seem choppy, but most people experience substantial improvement over time.

8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Rod Brouhard, EMT-P
Rod Brouhard is an emergency medical technician paramedic (EMT-P), journalist, educator, and advocate for emergency medical service providers and patients.