Traumatic Brain Injury (TBI): What Is It, Causes, Types

A traumatic brain injury, or TBI, can happen when there is a blow to the head. The injury can be penetrating, such as a gunshot wound, or a non-penetrating injury, such as being struck in the head in a car accident.

Traumatic brain injuries vary in severity. Many people recovery from TBIs within days and more severe forms can cause permanent brain injury or even death.

Traumatic Brain Injury (TBI)

Who might get a traumatic brain injury (TBI)?

Anyone can experience a TBI, although nearly 80% of them happen to males. TBIs are also more common among people older than 65. People in this age group are more prone to losing their balance, falling and hitting their heads. But even infants can experience TBIs from incidents like falling from a bed or changing table, or more rarely, from abuse.

People involved in certain professions or activities have a higher risk of TBIs, including:

Athletes (both recreational and professional).
Construction workers.
Military members.
Police and law enforcement.

How common are traumatic brain injuries (TBIs)?

TBIs are a leading cause of disability and death in the United States. The most current numbers available from the Centers for Disease Control and Prevention (CDC) are from 2014. That year, TBIs contributed to close to 3 million emergency department visits, hospitalizations and deaths. More than 54,000 adults and 2,500 children died from TBIs that year.

What are the types of traumatic brain injuries (TBIs)?

The severity of the head injury is determined by several different factors, such as loss of consciousness, certain neurological symptoms that happened at the time of the injury, loss of memory for the injury and time surrounding it, and abnormalities on head CT or brain MRI.

There are several different types and grades of TBI:

Mild concussion (mTBI): Concussions are the most common type of TBI. Three out of 4 TBIs every year are concussions. These mTBIs can include brief alterations of consciousness such as feeling “dazed” or loss of consciousness for less than 30 minutes. People who have an mTBI can experience confusion for about one day, which is different from difficulties with attention or memory.
Moderate TBI: this type of head injury is associated with loss of consciousness for over 30 minutes but less than one day. Confusion can last for up to one week.
Severe TBI: individuals with this type of head injury lose consciousness for over one full day. These injuries are typically associated with changes on head CT or brain MRI.
Uncomplicated TBI: Head CT/brain MRI are normal, regardless of mild, moderate or severe grade.
Complicated TBI: Head CT or brain MRI show changes, such as bleeding.
Closed: Most TBIs are closed. A closed TBI means an outside force causes a blow or jolt to the head that did not penetrate the skull. This impact injures the brain, causing it to swell.
Open: Healthcare providers may call open TBI a penetrating TBI. This injury occurs when a bullet, knife or something else goes through the skull. If the object goes into the brain, it directly damages brain tissue.
Nontraumatic: Also known as a hypoxic/anoxic brain injury. Some TBIs aren’t from trauma. They can result from strokes, seizures and events like choking and near-fatal drownings. These incidents can deprive the brain of oxygen (cerebral hypoxia).

SYMPTOMS AND CAUSES

What causes a traumatic brain injury (TBI)?

When you take a violent, hard hit to your head, your brain may experience changes in chemical and energy use as a way to compensate for the injury. These changes can result in headaches, light/sound sensitivity, and confusion. In mild TBIs, these changes are short and do not permanently damage the brain. However, with more severe injuries, these changes can last longer and result in damage to the brain cells. These effects can cause the brain to swell and expand inside the skull. The swelling can lead to even more brain damage.

What are the top causes of traumatic brain injuries (TBIs)?

Falls account for almost half of emergency department visits for TBIs. People older than 65 and children under age 17 experience the most fall-related TBIs.

Other causes include:

Domestic violence, assaults, child abuse and shaken baby syndrome.
Gunshot wounds, including attempted suicides.
Motor vehicle accidents.
Sports, recreational, work or military injuries.

What are the symptoms of a traumatic brain injury (TBI)?

TBI symptoms vary depending on how severe the injury is. A key sign is loss of consciousness (passing out) after a blow. Some people feel dazed for a couple of minutes and others are unresponsive for long periods (coma or persistent vegetative state).

People with mild TBIs can have several different symptoms, most of which occur right after the head injury or the days following. Sometimes people do not feel the severity of a symptom until they return to school or work.

Signs of a TBI include:

Behavior or mood changes.
Confusion or memory problems.
Convulsions or seizures.
Dilated pupils or blurred vision.
Dizziness, fainting or fatigue.
Headaches.
Nausea and vomiting.
Restlessness or agitation.
Sensitivity to light and smell.
Sleeping too much or too little.
Slurred speech.

Infants and children with TBIs may also:

Be inconsolable, crying nonstop.
Refuse to eat, drink or breastfeed.

DIAGNOSIS AND TESTS

How is a traumatic brain injury (TBI) diagnosed?

Your healthcare provider will examine you and ask about your symptoms. They will also want to learn more about what caused the injury. Depending on the severity of the injury and symptoms, you may have:

Neurological evaluation: A neurologist (specialist in the brain) checks your memory, thinking, motor function (balance, reflexes and coordination) and sensory functions (hearing and vision).
Imaging tests: A CT scan or MRI checks for brain bleeding and swelling.
Blood test: The Banyan Brain Trauma Indicator™ (BTI) looks for proteins in your blood that indicate concussion or mild TBI.

MANAGEMENT AND TREATMENT

How is a traumatic brain injury (TBI) managed or treated?

People with mild to moderate TBIs may only need minimal treatment. Your care may involve a short period of rest from sports, school or work. Symptoms should improve within a few weeks.

For severe TBI, people often need hospital care and more intense treatments.

For all TBI grades, treatments may include:

Counseling for emotional support. Many individuals experience stress and worries about their recovery. They may find that it is more difficult to get back to their work and hobbies than anticipated. Therefore, counseling is often very helpful in conjunction with other medical treatments.
Surgery to treat bleeding in the brain (intracranial hemorrhage) or reduce pressure from brain swelling.
Rehabilitation, including physical, occupational and speech therapy.
Rest. Talk to your doctor about how long to rest after a TBI. Depending on the type of TBI, some may need to rest for 1 to 2 days before going back to their typical activities. More severe head injuries may require longer periods of rest.
Return to typical activities. For milder head injuries, sometimes if people rest for too long after their head injury, they may have more difficulty returning to work, school, and other activities like socializing and hobbies. For more severe injuries, returning to activities too soon can make symptoms worse. Talk to your doctor for specific recommendations.

Treatments focus on easing your symptoms and improving your quality of life. Some effects may gradually get better with lots of time — sometimes years for more severe head injuries.

What are the complications of a traumatic brain injury (TBI)?

A moderate or severe TBI can cause permanent brain damage and disabilities. People with TBIs also have a higher risk of:

Anxiety, depression and post-traumatic stress disorder (PTSD).
Brain bleed.
Seizures (epilepsy).

In rare cases, severe head injuries or having had several moderate to severe TBI’s can increase someone’s risk to developing Alzheimer’s disease, dementia, or movement disorders later in life. Reassuringly, this is unlikely to happen with a mild TBI.

Finally, chronic traumatic encephalopathy or CTE can occur. This is a condition that happens when someone has had several blows to the head over an extended period, such as professional athletes. This condition is in the early stages of research and is still in the process of being understood. Currently, this condition cannot be diagnosed until the brain tissue at autopsy.

PREVENTION

How can I prevent a traumatic brain injury (TBI)?

Many TBIs aren’t preventable. They happen without warning due to an accident or fall. But you can take these steps to avoid some incidents that commonly cause TBIs:

Monitor medicines: Ask your doctor or pharmacist to review your prescription and over-the-counter medications, including supplements. Be sure you know which ones might make you dizzy, sleepy and more prone to falls. You may be able to change medications.
Have clear vision: Get regular eye exams so you can see well enough to prevent falls and injuries. Arrange good lighting at home to light the way.
Fall-proof your home: Remove rugs that are tripping hazards. Install stair handrails and bathtub grab bars. And if you have young children, install window guards on high windows and safety gates on stairs. Be aware of toys and pets underfoot.
Be smart behind the wheel: Buckle everyone up with seat belts, and use car seats or booster seats for children. Don’t drive if you’re drowsy or under the influence.
Put on a helmet: Protect your head when you play sports like hockey or football or when you bike, skate, ski or snowboard. And wear a helmet when you ride a motorcycle, scooter, ATV or horse.
Stay active: Activities like yoga, tai chi and strength training build muscle and improve balance.
Use a walking assist device: Walkers and canes can help you be steadier on your feet.

OUTLOOK / PROGNOSIS

What is the prognosis (outlook) for people with traumatic brain injuries (TBIs)?

Recovery from a TBI is highly individualized. It depends on the severity, cause and type of injury. People with mild TBIs are expected to improve and return to their pre-injury functioning within days to a few months. Some people with mild TBIs have few concerns and never seek treatment.

Moderate to severe TBIs can cause more significant difficulties with changes to their thinking and behavior. People with severe TBIs can have lifelong changes.

There are several different factors that can influence someone’s recovery.

Additional injuries: sometimes individuals experience other injuries at the same time as their TBI. For example, an individual who was in a car accident may have a TBI and a shoulder injury. In these types of situations, an individual may experience additional difficulties with pain or treatments needed for the other injury. This can cause additional stress in adjusting to changes related to both their head injury and physical injuries.
Age: Sometimes older adults have a slower recovery than younger adults.
Past TBIs: Individuals that had multiple head injuries in a short period of time may have more difficulty in their recovery. This is not always the case and individuals who sustained multiple mild TBIs and were able to fully recover can still experience a good recovery from additional head injuries.
Stress: Individuals who experience emotional changes and stress after their head injury often have more difficulty recovering. Sometimes emotional symptoms can even appear as physical symptoms. It’s important to work with your doctor to make sure that a physical symptoms that last longer than anticipated aren’t emotional symptoms. Reassuringly, counseling and medications are effective in treating these types of symptoms.
Support: People with strong support from family and friends can have easier recoveries from mild to moderate TBIs.