A traumatic brain injury (TBI) can be caused by a forceful bump, blow, or jolt to the head or body, or from an object that pierces the skull and enters the brain. Not all blows or jolts to the head result in a TBI.

Some types of TBI can cause temporary or short-term problems with normal brain function, including problems with how the person thinks, understands, moves, communicates, and acts. More serious TBI can lead to severe and permanent disability, and even death.

Some injuries are considered primary, meaning the damage is immediate. Other outcomes of TBI can be secondary, meaning they can occur gradually over the course of hours, days, or appear weeks later. These secondary brain injuries are the result of reactive processes that occur after the initial head trauma.

Most TBIs that occur each year are mild TBIs or concussions. A mild TBI or concussion is caused by:

• A bump, blow, or jolt to the head, or
• By a hit to the body that causes the head and brain to move quickly back and forth

This sudden movement can cause:

• The brain to bounce around or twist in the skull
• Chemical changes in the brain
• Stretching and damaging brain cells

These changes in the brain lead to symptoms that may affect how a person thinks, learns, feels, acts, and sleeps.

Mild TBIs and concussions are serious

Healthcare providers may describe these injuries as mild because they are usually not life-threatening. Even so, the effects of a mild TBI or concussion can be serious.

Get medical care for a mild TBI or concussion

People with a mild TBI or concussion need to be seen by a healthcare provider. Contact your healthcare provider as soon as you can if you think you have a mild TBI or concussion.

You may consider using telemedicine or telehealth services if you are unable to visit a healthcare provider in person. Telemedicine and telehealth services:

• Connect patients and their healthcare providers through a phone or video chat
• Allow patients to get checked for mild TBI or concussion symptoms and get recovery tips without needing to travel to a medical office or hospital

Your healthcare provider can identify whether these services are available to you.

Patients experiencing mild TBI or concussion danger signs should seek care right away at an emergency department.

Healthcare providers check for symptoms and help with recovery

Your healthcare provider may ask about symptoms and test you to see if you have any problems with:

• Learning
• Memory
• Concentration, and
• Problem solving

These tests are called “neuropsychological” or “neurocognitive” tests and can help your healthcare provider identify the effects of a mild TBI or concussion. Even if the injury doesn’t show up on these tests, you may still have a mild TBI or concussion.

A scan of your brain (such as a CT scan) is not needed to spot a mild TBI or concussion, but may sometimes be used for patients at risk for bleeding on the brain after a head or brain injury.

Ask your healthcare provider for instructions on how to safely return to activities following a mild TBI or concussion. Be sure to follow all of your healthcare provider’s instructions carefully.

Repeated mild TBIs or concussions may lead to a longer recovery

A person with a history of multiple or repeated mild TBIs or concussions may experience a longer recovery or more severe symptoms. They may also have long-term problems, including:

• Ongoing problems with concentration, memory, headache
• Physical problems, such as keeping one’s balance

A moderate or severe TBI is caused by a bump, blow, or jolt to the head or by a penetrating injury (such as from a gunshot) to the head. In the United States, severe TBIs are linked to thousands of deaths each year.

For those who survive, a moderate or severe TBI may lead to long-term or life-long health problems that may affect all aspects of a person’s life. These health problems have been described as being similar to the effects of a chronic disease.

Falls and firearm-related injuries lead to most moderate and severe TBIs

Research shows:

• Falls are one of the leading causes of TBI-related hospitalizations among Americans, especially among older adults (age 75 years and older)
• Firearm-related suicide is linked to many TBI-related deaths in the United States
• Motor vehicle crashes and assaults are other common ways a person may get a moderate or severe TBI

Moderate and severe TBIs are serious and costly

A person with a moderate or severe TBI may need ongoing care to help with their recovery. A moderate or severe TBI not only impacts the life of an individual and their family, but it also has a large societal and economic toll. The lifetime economic cost of TBI, including direct and indirect medical costs, was estimated to be approximately $76.5 billion (in 2010 dollars).⁶ Additionally, the cost of fatal TBIs and TBIs requiring hospitalization account for approximately 90% of total TBI medical costs.⁶

A TBI affects how the brain works

A traumatic brain injury, or TBI, is an injury that affects how the brain works. It may be caused by a:

• Bump, blow, or jolt to the head, or
• Penetrating injury (such as from a gunshot) to the head

There are three main types of TBI:

• Mild TBI or concussion
• Moderate TBI
• Severe TBI

TBI is a major cause of death and disability

There were over 69,000 TBI-related deaths in the United States in 2021. That’s about 190 TBI-related deaths every day.

TBIs affect the lives of people of all ages. Anyone can experience a TBI, but data suggest that some groups are at greater risk of dying from a TBI or experiencing long-term health problems after the injury. Examples of groups who are more likely to be affected by TBI, include:

• Racial and ethnic minorities
• Service members and Veterans
• People who experience homelessness
• People who are in correctional and detention facilities
• Survivors of intimate partner violence
• People living in rural areas

People most commonly get TBIs from a fall, firearm-related injury, motor vehicle crash, or an assault

Research shows that:

• Falls lead to nearly half of the TBI-related hospitalizations
• Firearm-related suicide is the most common cause of TBI-related deaths in the United States
• Motor vehicle crashes and assaults are other common ways a person may get a TBI

For more detailed information on the leading ways people get TBIs and the groups of people most likely to get a TBI, check out CDC’s TBI data reports.

A TBI may lead to short- or long-term health problems

Depending on the severity of the injury, those who get a TBI may face health problems that last a few days or the rest of their lives. For example, a person with a mild TBI or concussion may experience short-term symptoms and feel better within a couple of weeks or months. And a person with a moderate or severe TBI may have long-term or life-long effects from the injury.

A person with a possible TBI should be seen by a healthcare provider. Your healthcare provider may have treatment to help speed your recovery.

• Most people with a mild TBI or concussion can recover safely at home following a medical check-up
• People with a moderate or severe TBI may need ongoing care to help with their recovery

A TBI during childhood may affect brain development

TBI affects children differently than adults. An injury of any severity to the developing brain may:

• Disrupt a child’s development
• Limit their ability to participate in school and other activities, like sports

As a result of a TBI, children may experience changes in their health, thinking, and behavior that affect learning, self-regulation, and social participation, all of which are important to becoming a productive adult.

CDC’s Report to Congress on the management of traumatic brain injury in children details the potential effects of a TBI on children and their families.

TBIs may be missed in older adults

Older adults are more likely to be hospitalized and die from a TBI compared to all other age groups. Still, TBIs may be missed or misdiagnosed in older adults because symptoms of TBI overlap with other medical conditions that are common among older adults, such as dementia.

Healthcare providers should check for signs and symptoms of TBI if an older adult has:

• Fallen or has a fall-related injury, such as a hip fracture
• Been in a car crash

This is especially important among older adults who are taking blood thinners, such as:

• Anticoagulants like warfarin (Coumadin), rivaroxaban (Xarelto), and apixaban (Eliquis)
• Antiplatelet medications like clopidogrel (Plavix), ticagrelor (Brilinta), and acetylsalicylic acid (Aspirin)

These medicines may increase the risk for bleeding in the brain following a TBI. Bleeding in the brain after a TBI may put a person at risk for more severe injury or death.

A car accident. A football tackle. An unfortunate fall. These things—and more—can cause head injuries. Head injuries can happen to anyone, at any age, and they can damage the brain.

Here’s how damage can happen: A sudden movement of the head and brain can cause the brain to bounce or twist in the skull, injuring brain cells, breaking blood vessels, and creating chemical changes. This damage is called a traumatic brain injury (TBI).

The U.S. Food and Drug Administration continues to study TBI and encourages the development of medical devices to help diagnose and treat it.

Causes and Symptoms of TBI

TBI is often caused by a bump, blow, jolt, or explosive blast to the head, or a penetrating head injury that disrupts the brain’s normal function. Not all hits to the head result in TBI. But when it happens, TBI can range from mild (like a brief change in mental status or consciousness) to severe (like a longer period of unconsciousness or major problems with thinking and behavior after injury).

About 75 percent of TBIs (or 3 out of every 4) that occur each year are mild. If a person has the symptoms of TBI after a blow to the head, then the brain has been injured. Mild TBIs always involve some degree of brain injury.

Symptoms of mild TBI include:

• headache
• confusion
• dizziness
• ringing in the ears
• memory impairment
• blurred vision
• behavioral changes

Moderate and severe TBI can produce more symptoms including:

• repeated vomiting or nausea
• slurred speech
• weakness in the arms or legs
• problems with thinking and learning
• death

If you have questions about TBI, talk to your health care provider. Anyone with signs of TBI should receive medical attention as soon as possible. Call 911 in emergency situations.

Diagnosis of TBI

While some symptoms of mild TBI can be hard to detect, the Centers for Disease Control and Prevention (CDC), the American College of Rehabilitation Medicine, and some others have published guidelines for diagnosing TBI.

A medical exam is the first step to diagnose a potential brain injury. Assessment usually includes a neurological exam. This exam evaluates thinking, motor function (movement), sensory function, coordination, eye movement, and reflexes.

Imaging tests, including CT scans and MRI scans, cannot detect all TBIs. But tests from these FDA-regulated medical devices can help health care providers rule out some of the more serious brain injuries. In particular, these scans can detect bleeding that resulted from the traumatic injury which requires immediate medical or surgical attention.

None of the medical devices cleared or approved by FDA are intended to be used alone without the judgment of a health care provider trained to diagnose and treat TBI. The FDA has not cleared or approved any medical products that are intended to diagnose or treat TBI alone without other diagnostic tests or treatments managed by a health care provider.

Important safety note: The FDA issued a safety communication in 2019 that includes recommendations and warnings against the use of medical devices that have not been FDA-approved or FDA-cleared for the assessment, diagnosis, or management of a head injury or “concussion,” another name for mild traumatic brain injury.

Medical devices that are not FDA-approved or FDA-cleared may not correctly diagnose a TBI. FDA-approved and FDA-cleared devices may not correctly diagnose a TBI if used alone without other diagnostic tests managed by a healthcare provider. An incorrect diagnosis may lead to:

• A wrong decision to let a person return to play or other activities with a brain injury
• A missed diagnosis of brain injury, or
• The lack of proper treatment for a head injury

If you have a head injury, seek medical attention right away. The FDA has not approved any devices that can assess or diagnose a traumatic brain injury without an evaluation by a health care provider.

More FDA Actions and Research on TBI

The FDA continues to work with the research and clinical community to develop better-designed clinical studies so new medical products can be developed. And the FDA continues to review and evaluate medical devices for safety and effectiveness.

More sensitive and objective ways to diagnose and detect mild TBI are needed. Timely diagnosis is important to prevent repetitive injury and to help develop new therapies. That’s because repetitive injury carries the risk of “second impact syndrome.” If people who have not recovered from a head injury have a second head injury, this can result in more significant injury to the brain and more neurological deficits. And, in some cases, repetitive injury can be fatal or cause dementia later in life.

The FDA’s scientists continue to conduct research on diagnostic tests for mild TBI. The scientists are studying TBI blood tests, special brain imaging, eye movements, and brain wave patterns. They are also investigating using portable imaging devices to detect mild TBI.

What to Know About the Effects of TBI

Little can be done to reverse initial brain damage caused by trauma according to the National Institute of Neurological Disorders and Stroke. But health care professionals will work to stabilize patients and try to prevent further harm. The severity of long-term effects depends on the seriousness of the injury, location of the injury, the number of previous brain injuries, and the age and general health of a patient.

Helping Protect Athletes’ Brains from Repeated Minor Impacts to the Head

In early 2021, the FDA authorized marketing of a device to aid in the protection of the brain from effects associated with repeated minor impacts to the head seen on special MRI scans.

The device, called the Q-Collar, is intended for athletes aged 13 years and older. The device should be used with other protective sports equipment, which it does not replace. The Q-Collar does not require a prescription. Use has not been shown to allow for more rapid return to TBI risk activities or to allow for undertaking activities with increased risk of TBI or use of increased force during sports activities.

Remember, if you have any have questions about a possible brain injury, please talk with your health care provider.

There are two broad types of head injuries: Penetrating and non-penetrating.

1. Penetrating TBI (also known as open TBI) happens when an object pierces the skull (e.g., a bullet, shrapnel, bone fragment, or by a weapon such as hammer or knife) and enters the brain tissue. Penetrating TBI typically damages only part of the brain.
    
2. Non-penetrating TBI (also known as closed head injury or blunt TBI) is caused by an external force strong enough to move the brain within the skull. Causes include falls, motor vehicle crashes, sports injuries, blast injury, or being struck by an object.

Some accidents such as explosions, natural disasters, or other extreme events can cause both penetrating and non- penetrating TBI in the same person.

Introduction

Contrecoup brain injury involves a contusion remote from, and classically opposite to, the actual site of impact to the head. Contrecoup, a French term, means counterblow. The first use of the contrecoup was made by Hippocrates to describe a fracture opposite to the point of impact. From the 16th to the 19th centuries, it has been occasionally referenced in the literature. Sometimes the term countercoup has been used. The etiology and significance of this type of injury have been discussed and debated for centuries. Contrecoup injury is a focal phenomenon and is unlike diffuse axonal injury or brain edema, which are extensive and may also result from trauma. Contrecoup injury has also been considered to play a role in visual abnormalities following minor head injuries.

Etiology

Contrecoup injuries classically occur when the moving head (brain) strikes a stationary object; whereas, a coup injury is associated with a moving object impacting a stationary head. Classic evidence of both coup and contrecoup injury is an intracerebral hemorrhage or contusion in a focal area noted on computed tomographic (CT) scan or magnetic resonance imaging (MRI). Contrecoup lesions arise from forces within the intracranial cavity, which are not directly related to the site of the focal blow but instead is related to stress on the brain and its structure caused by the force of the blow on an already moving head. After the head receives an impact, the floating brain rebounds in the opposite direction.

There are four theories for the development of contrecoup injury. In the positive pressure theory, these stresses are caused by the brain lagging the initial movement of the skull followed by brain compression against the opposite stationary irregular skull. The moving brain hits the opposite side of the skull, usually at bony prominences, creating a contusion. The negative pressure or cavitation theory is that the movement of the brain in one direction generates stress to the opposite area of the brain and causes damage to the cerebral tissue at that point. The rotational shear stress theory incorporates a rotation of the brain in addition to the displacement along the axis of the trauma. The angular acceleration theory postulates that the brain is tethered in some areas such, for example, the brainstem, causing specific areas potential for greater acceleration and deceleration within the brain.

The difference in the density of the brain and cerebrospinal fluid (CSF) has been implicated as another mechanism for contrecoup injury. In this theory, the brain moves away from the impact site to be injured on the opposite area of the skull from the impact. During an impact, the denser CSF moves toward the site of skull impact displacing the less dense brain in the opposite direction. The fact that no one explanation accounts for all aspects of contrecoup injury may show that a combination of mechanisms contributes to the final result of contrecoup injury. The actual injury to the brain often occurs in the irregular surface of the temporal fossa and the area of the frontal poles. Often, the severity of the injury at the contrecoup site is greater than that occurring at the coup site. Indeed, there are several reports of patients with contrecoup injuries in the absence of coup injuries.

Epidemiology

Contrecoup brain injury is one type of traumatic brain injury of which several others may coexist in a particular patient. Falls and vehicular accidents are the most common etiologies. These injuries predominate in males at younger ages with a more even gender distribution in older adults. Intracerebral hemorrhage occurs in 13 to 48% of adults with traumatic brain injury. Of these patients, 13 to 77% have contrecoup hemorrhages which most often occur with an occipital and temporal impact. Pediatric contrecoup injuries before the age of four are rare, but thereafter the frequency increases rapidly.[1] This is due to the elasticity of the bone at a young age and the open sutures in infants.

Pathophysiology

Location of contrecoup brain injuries has been the subject of several studies, sometimes with conflicting results. Temporal bone injuries in one study had the best correlation with contrecoup injuries also in the temporal lobe area on the opposite side. Another study found that posterior impact injuries in the occipital area were most likely to cause contrecoup injuries in the frontal or temporal lobe areas. Many of these patients simply fell backward; also, some of them were older. Some authors define a contrecoup brain injury by using a location greater than 90 degrees from the site of the coup impact. This implies that many contrecoup lesions are not exactly opposite the side of the coup impact. There is an association between posterior impact sites and temporal intracerebral hemorrhage from contrecoup lesions. A frontal impact usually generates hemorrhages in the area of the initial impact. Lateral contrecoup intracerebral hemorrhage is more likely to show hemorrhagic progression compared with the frontal and posterior locations of the contrecoup.

The contrecoup brain injury has also been implicated in contralateral extra-axial skull pathology secondary to the trauma. One case report indicates a case of mild head injury in which a skull fracture was noted on the opposite side of the head from the impact of the fall. The contralateral fracture had no impact on that side. The authors proposed that the force of the impact caused local bending of the skull with no fracture at the site of the impact; this force was then transmitted through the skull to the opposite side to cause the fracture.

There are also reports of epidural hematomas being located in a contralateral location from the side of the trauma. These contrecoup epidural hematomas were sometimes accompanied by an epidural hematoma at the site of impact but not invariably. The contrecoup epidural sometimes was larger than the epidural associated with the coup impact. It is hypothesized that the dura may have detached from the inner table of the skull, and the small arteries may have caused the accumulation of blood.

History and Physical

The main aspect of patient history includes obtaining a careful evaluation of the circumstances involved in the trauma and any other significant aspects of the history. There is usually an impact opposite to the area in the brain which is injured. This impact can be subtle and sometimes not easily identified. The neurological findings depend on the exact location of the contrecoup injury. Altered mental status is frequently seen. Most frontal lobe lesions will not present with specific findings. Patients may be disoriented and confused. Temporal lobe injury can produce speech alterations or hemiparesis. Some patients present with seizures.

Evaluation

Traumatic brain injury patients require a thorough general trauma evaluation. All patients should be managed with advanced trauma life support measures. A detailed neurological examination is mandatory. A head CT scan is performed for the initial assessment of brain injury. Cervical X-rays or cervical CT scans must be performed to exclude associated cervical fractures as most injuries are secondary to falls.

Treatment / Management

Treatment of contrecoup brain injury depends on the severity of the injury. For those lesions that do not require immediate surgical decompression, close clinical monitoring with repeat head CT at 12 or 24 hours is indicated. Some patients with decreased neurological status with a Glasgow coma scale of 8 or lower should have intracranial pressure monitoring and are treated as per the trauma guidelines. Depending on the neurological exam and the type and size of the injury, some patients will require surgery. The intervention may be only for drainage of the hematoma but can be more extensive to involve a lobectomy and/or decompressive hemicraniectomy. Patients will require antiepileptic medications for 7 days, according to the guidelines. Contrecoup brain injury is one manifestation of traumatic brain injury and must be integrated with other types of brain injury and multiple body trauma.

Differential Diagnosis

The main differential for contrecoup injury is the condition of diffuse axonal injury (DAI). In DAI, petechial hemorrhages forms at the gray-white matter junction, corpus callosum, and brainstem. It is the result of traumatic acceleration/deceleration or rotational injuries, not attributed to a direct impact to the skull. It is a frequent cause of persistent vegetative state in patients.

Prognosis

The prognosis of contrecoup injury is variable based on the extent of the affected areas and the presence of other types of head injury such as subarachnoid hemorrhage, DAI, and the other multiple types of traumatic brain injury. In one study, the outcome at 6 months was favorable in 48% of cases.

Complications

Traumatic brain injury may cause multiple neurological deficits, some of which might be permanent. The exact type of deficit is dependent on the area of the brain affected by the contrecoup injury. If the contrecoup injury is not managed promptly and properly, the patient can have devastating complications, eventually leading to coma or death.

Deterrence and Patient Education

Patient education as to the multiple aspects of traumatic brain injury and its manifestations, such as contrecoup injury, is necessary to make them and their families aware of the possible life-changing nature of these injuries and to deter dangerous behavior. Some patients have long neuropsychological problems that have to be addressed after the acute phase is over.

Pearls and Other Issues

Contrecoup brain injury has multiple manifestations in addition to the primary one of contralateral intracerebral hemorrhage, which is used to define contrecoup injury in most cases.

The essential factors in contrecoup injury are an impact on the head and some form of acceleration, deceleration, rotational stress, or angular stress. Several of these factors are necessary to cause contrecoup injury.

Acceleration, deceleration, and rotation injury such as might occur in shaken baby syndrome in the absence of impact directly to the head is not noted to cause contrecoup injury.

Prognosis is favorable in about half of the cases.

Enhancing Healthcare Team Outcomes

While the neurosurgeon is almost always involved in patient care with a contrecoup injury, it is important to consult with an interprofessional team of specialists that include a trauma surgeon and a critical care specialist. The nurses are also vital members of the interprofessional group as they will monitor the patient's vital signs, neurological status, intracranial pressure and assist with the education of the patient and family. The pharmacist will ensure that the patient is on the right analgesics, sedatives, and appropriate antibiotics. The radiologist also plays a vital role in determining the cause and mechanism of the injury.

Since contrecoup injury is only one type of traumatic brain injury, it is difficult to make specific recommendations for its treatment. The patient must have a treatment plan to include multiple types of associated traumatic brain injuries such as subdural hematoma, epidural hematoma, subarachnoid hemorrhage, cerebral edema, DAI, and coup and contrecoup brain injury. Any other body traumatic injuries have to be treated simultaneously.

Adults age 65 and older are at greatest risk for being hospitalized and dying from a TBI, most likely from a fall. In every age group, serious TBI rates are higher for men than for women. Men are more likely to be hospitalized and are nearly three times more likely to die from a TBI than women.

The leading causes of TBI include:

• Falls—According to data from the Centers for Disease Control and Prevention (CDC), falls are the most common cause of TBIs and occur most frequently among the youngest and oldest age groups.
   
• Blunt trauma accidents—Accidents that involve being struck by or against an object, particularly sports-related injuries, are a major cause of TBI.
   
• Vehicle-related injuries—Pedestrian-involved accidents, as well as accidents involving motor vehicles and bicycles, are the third most common cause of TBI.
   
• Assaults/violence Assaults—Abuse-related TBIs are head injuries that result from domestic violence or shaken baby syndrome, and gunshot wounds to the head. TBI-related deaths in children age 4 and younger are most likely the result of assault.
   
• Explosions/blasts—TBIs caused by blast trauma from roadside bombs became a common injury to service members in military conflicts. The majority of these TBIs are classified as mild head injuries.

TBI has contributed to the deaths of more than one million Americans over the last two decades. For survivors, a TBI can lead to short- or long-term problems that may affect all aspects of a person’s life, including the ability to work or build relationships with others, and it can change how a person thinks, acts, feels, and learns.

Health disparities are differences in health outcomes and their causes among groups of people. Groups can be defined by factors such as race, ethnicity, sex, education, income, disability, geographic location (e.g., rural or urban), sexual orientation, and gender identity. When examining disparities in TBI, CDC analyzes differences in incidence rates, prevalence rates, and outcomes by group.

Which groups are most affected by TBI?

While anyone is at risk for getting a TBI, some groups have a greater likelihood of dying from a TBI or living with long-term problems that resulted from the injury.

Certain groups have a higher chance of sustaining a TBI.

Older adults

People aged 75 years and older had the highest numbers and rates of TBI-related hospitalizations and deaths. This age group accounts for about 32% of TBI-related hospitalizations and 28% of TBI-related deaths.

Racial and ethnic minorities

American Indian/Alaska Native children and adults have higher rates of TBI-related hospitalizations and deaths than other racial or ethnic groups. Factors that contribute to this disparity include higher rates of motor vehicle crashes, substance use, and suicide as well as difficulties in accessing appropriate healthcare.

In addition to differences in rates of TBI, racial and ethnic minority groups, particularly non-Hispanic Black and Hispanic patients, are less likely to receive follow-up care and rehabilitation following a TBI compared to non-Hispanic white patients. Racial and ethnic minorities are also more likely to have poor psychosocial, functional, and employment-related outcomes after sustaining a TBI than non-Hispanic white individuals.

Military service members and Veterans

More than 450,000 U.S. service members were diagnosed with a TBI between 2000 and 2021. Military conflicts involve risks for TBI among service members, still TBIs among this group most commonly occur when the person is not deployed, such as from a motor vehicle crash. Studies suggest that service members and Veterans who have sustained a TBI may:

• have ongoing symptoms,
• experience co-occurring health conditions, such as post-traumatic stress disorder (PTSD) and depression,
• have difficulty accessing healthcare (particularly mental health services), and
• report thinking about or planning a suicide attempt.

People in correctional or detention facilities

Research in the United States and from other countries suggests almost half (46%) of people in correctional or detention facilities such as prisons and jails have a history of TBI, but the exact number is not known. Research shows an association between people in correctional or detention facilities with a history of TBI and:

• mental health problems, such as severe depression and anxiety,
• substance use disorders,
• difficulty controlling anger, and
• suicidal thoughts and/or attempts.

People in correctional or detention facilities with TBI-related problems may not be screened for a TBI or may face challenges with getting TBI-related care. These challenges may continue after a person is released from the facility.

People who experience homelessness

Compared to the general population, people who experience homelessness are:

• 2 to 4 times more likely to have a history of any type of TBI and
• up to 10 times more likely to have a history of a moderate or severe TBI.

People who experience homelessness and have a history of TBI have worse overall physical and mental health and are more likely to report experiencing violence and/or trauma during childhood, substance use, and thinking about or attempting suicide.

Survivors of intimate partner violence

Survivors of intimate partner violence who have a TBI due to an assault are more likely to:

• be diagnosed with PTSD, insomnia, and depression, and
• report worse overall health.

People with lower incomes and those without health insurance have less access to TBI care.

Survivors of a moderate or severe TBI may face a difficult road to recovery that requires services such as physical therapy and mental health treatment for months or years in order to return to pre-injury function. TBI survivors with lower incomes or who are uninsured face significant barriers in accessing appropriate TBI care. Compared with patients who have private health insurance, those who are uninsured are:

• Less likely to receive a TBI procedure (e.g., craniectomy/craniotomy, ventriculostomy, intracranial pressure monitor placement, arterial line placement, or central line placement).
• Less likely to receive inpatient services, such as rehabilitation.
• More likely to die in the hospital.

People in rural areas are more likely to die from a TBI.

People living in rural areas have a greater risk of dying from a TBI compared to people living in urban areas. Some reasons for this disparity include:

• More time needed to travel to emergency medical care.
• Less access to a Level I trauma center (the highest level of medical care).
• Difficulty getting services, such as specialized TBI care.

Children living in rural areas are more likely to get a TBI and to die as a result of this injury compared to children living in urban areas. Children in rural areas may also be more likely to:

• Experience delays in getting TBI-related care.
• Be unnecessarily transferred to another hospital for TBI-related care.

Seek immediate medical attention if you experience any of the following physical, cognitive/behavioral, or sensory symptoms, especially within the first 24 hours after a TBI:

Physical

• Headache
• Convulsions or seizures
• Blurred or double vision
• Unequal eye pupil size or dilation

• Clear fluids draining from the nose or ears
• Nausea and vomiting
• New neurologic deficit, such as slurred speech; weakness of arms, legs, or face; loss of balance

Cognitive/behavioral

• Loss of or change in consciousness anywhere from a few seconds to a few hours
• Decreased level of consciousness (e.g., hard to awaken)
• Mild to profound confusion or disorientation

• Problems remembering, concentrating, or making decisions
• Changes in sleep patterns (e.g., sleeping more, difficulty falling or staying asleep); inability to waken from sleep
• Frustration, irritability

Perception/sensation

• Light-headedness, dizziness, vertigo, or loss of balance or coordination
• Blurred vision
• Hearing problems, such as ringing in the ears
• Bad taste in the mouth

• Sensitivity to light or sound
• Mood changes or swings, agitation, combativeness, or other unusual behavior
• Feeling anxious or depressed
• Fatigue or drowsiness; a lack of energy or motivation

Headache, dizziness, confusion, and fatigue tend to start immediately after an injury but resolve over time. Emotional symptoms such as frustration and irritability tend to develop during recovery.

TBI in children

Children might be unable to let others know that they feel different following a blow to the head. A child with a TBI may display the following signs or symptoms:

• Changes in eating or nursing habits
• Persistent crying, irritability, or crankiness; inability to be consoled
• Changes in ability to pay attention
• Lack of interest in a favorite toy or activity
• Changes in sleep patterns

• Seizures
• Sadness or depression
• Loss of a skill, such as toilet training
• Loss of balance or unsteady walking
• Vomiting

Effects on consciousness

A TBI can cause problems with consciousness, awareness, alertness, and responsiveness. Generally, there are four abnormal states that can result from a severe TBI:

1. Minimally conscious state—People with severely altered consciousness who still display some evidence of self-awareness or awareness of one's environment (such as following simple commands, yes/no responses).
    
2. Vegetative state—A result of widespread damage to the brain, people in a vegetative state are unconscious and unaware of their surroundings. However, they can have periods of unresponsive alertness and may groan, move, or show reflex responses. If this state lasts longer than a few weeks, it is referred to as a persistent vegetative state.
    
3. Coma—A person in a coma is unconscious, unaware, and unable to respond to external stimuli such as pain or light. Coma generally lasts a few days or weeks after which the person may regain consciousness, die, or move into a vegetative state. 
    
4. Brain death—The lack of measurable brain function and activity after an extended period of time is called brain death and may be confirmed by studies that show no blood flow to the brain.

TBI-related damage can be confined to one area of the brain, known as a focal injury, or it can occur over a more widespread area, known as a diffuse injury. The type of injury also affects how the brain is damaged.

Primary effects on the brain include various types of bleeding and tearing forces that injure nerve fibers and cause inflammation, metabolic changes, and brain swelling.

• Diffuse axonal injury (DAI), one of the most common types of brain injuries, refers to widespread damage to the brain's white matter. White matter is composed of bundles of axons (the projections of nerve cells that carry electrical impulses and connect various areas of the brain to one another). DAI usually results from rotational forces (twisting) or sudden forceful stopping that stretches or tears these axon bundles. This damage commonly occurs in auto accidents, falls, or sports injuries. DAI can disrupt and break down communication among nerve cells (neurons) in the brain. It also leads to the release of brain chemicals that can cause further damage. Brain damage may be temporary or permanent and recovery can be prolonged.
   
• Concussion is a type of mild TBI that may be considered a temporary injury to the brain but could take minutes to several months to heal. Concussion can be caused by a number of things including a bump, blow, or jolt to the head, sports injury or fall, motor vehicle accident, weapons blast, or a rapid acceleration or deceleration of the brain within the skull, such as the person having been violently shaken. The individual either suddenly loses consciousness or has sudden altered state of consciousness or awareness. A second concussion closely following the first one causes further damage to the brain—the so-called “second hit” phenomenon—and can lead to permanent damage or even death in some instances. Post-concussion syndrome involves symptoms that last for weeks or longer.
   
• Hematomas are bleeding in and around the brain caused by a rupture to a blood vessel. Different types of hematomas form depending on where the blood collects relative to the meninges, the protective membranes surrounding the brain, which consist of three layers: dura mater (outermost), arachnoid mater (middle), and pia mater (innermost).
  • Epidural hematomas involve bleeding into the area between the skull and the dura mater. These can occur within minutes to hours after damage to a brain vessel under the skull and are particularly dangerous.
     
  • Subdural hematomas involve bleeding between the dura and the arachnoid mater, and, like epidural hematomas, exert pressure on the outside of the brain. They are very common in the elderly after a fall.
     
  • Subarachnoid hemorrhage is bleeding between the arachnoid mater and the pia mater.
     
  • Bleeding into the brain itself is called an intracerebral hematoma and damages the surrounding tissue.
     
• Contusions are a bruising or swelling of the brain that occurs when very small blood vessels bleed into brain tissue. Contusions can occur directly under the impact site (a coup injury) or, more often, on the complete opposite side of the brain from the impact (a contrecoup injury). They can appear after a delay of hours to a day. Coup and contrecoup lesions generally occur when the head abruptly decelerates, which causes the brain to bounce back and forth within the skull (such as in a high-speed car crash or in shaken baby syndrome).
   
• Skull fractures are breaks or cracks in one or more of the bones that form the skull. They are a result of blunt force trauma and can cause damage to the membranes, blood vessels, and brain under the fracture. One main benefit of helmets is to prevent skull fractures.
   
• Chronic traumatic encephalopathy (CTE) is a progressive neurological disorder associated with symptoms that may include problems with thinking, understanding, and communicating; motor disorders (affecting movement); problems with impulse control and depression; confusion; and irritability. CTE occurs in those with extraordinary exposure to multiple blows to the head and as a delayed consequence after many years. Studies of retired boxers have shown that repeated blows to the head can cause issues including memory problems, tremors, and lack of coordination and dementia. Recent studies have demonstrated rare cases of CTE in other sports with repetitive mild head impacts (e.g., soccer, wrestling, football, and rugby).
   
• A single, severe TBI also may lead to a disorder called post-traumatic dementia (PTD), which may be progressive and share some features with CTE. Studies assessing patterns among large populations of people with TBI indicate that moderate or severe TBI in early or mid-life may be associated with increased risk of dementia later in life.

Examples of secondary damage:

• Hemorrhagic progression of a contusion (HPC) are injuries that occur when an initial contusion from the primary injury continues to bleed in and around the brain and expand over time. This creates a new or larger lesion—an area of tissue that has been damaged through injury or disease. This increased exposure to blood, which is toxic to brain cells, leads to swelling and further brain cell loss.
   
• A breakdown in the blood-brain barrier refers to the disruption of the network of cells that controls the movement of cells and molecules between the blood and fluid that surrounds the brain's nerve cells. Once the blood-brain barrier is disrupted, blood, plasma proteins, and other foreign substances leak into the space between neurons in the brain and trigger a chain reaction that causes brain swelling. It also causes multiple biological systems to go into overdrive, including inflammatory responses which can be harmful to the body if they continue for an extended period of time. It also permits the release of neurotransmitters, or chemicals used by brain cells to communicate, which can damage or kill nerve cells when depleted or over-expressed.
   
• Increased intracranial pressure is usually caused by brain swelling inside the confined area of the skull as a result of the injury. This pressure can damage brain tissue and can prevent blood flow to the brain and deprive it of the oxygen it needs to function.
   
• Other secondary damage can be caused by infections to the brain, low blood pressure or oxygen flow as a result of the injury, hydrocephalus (a buildup of fluid in the brain that can increase pressure on brain tissue), and seizures.

A traumatic brain injury (TBI) happens when someone gets a bump, blow, or jolt to the head, or a penetrating injury to the head (such as a gunshot). TBIs can range from mild (such as concussions) to severe, life-threatening injuries. They can cause changes in:

• Thinking and remembering.
• Vision and balance.
• Emotions, such as anxiety, irritability, or sadness.
• Sleep.

TBIs can happen to anyone, but some groups are at greater risk of dying or having long-term health problems after the injury. These groups include racial and ethnic minorities, service members and veterans, people experiencing homelessness, people in correctional and detention facilities, survivors of intimate partner violence, and people living in rural areas.

TBIs can also cause epilepsy and seizures

Epilepsy is a broad term used for a brain disorder that causes repeated seizures. There are many types of epilepsy and there are also many different kinds of seizures. TBIs can cause a seizure right after the injury happens or even months or years later. Researchers agree that the more severe the TBI, the greater the chance the person may develop epilepsy. Age and other medical conditions may also play a role in whether or not a person may develop epilepsy after a TBI.

The terms post-traumatic epilepsy (PTE) and post-traumatic seizures (PTS) are both used to describe seizures that happen because of a TBI. In 2018, there were about 223,050 hospitalizations for TBI in the United States. A CDC-funded study found that among people aged 15 years and older hospitalized for TBI, about 1 out of 10 developed epilepsy in the following 3 years.

Everyone can:

• Learn the signs and symptoms of TBI and when to seek medical care.
• Take the CDC’s HEADS UP training to learn how to recognize, respond to, and minimize the risk of concussion or TBI – especially if you’re a parent, coach, child care provider, or school professional.

If you or someone you care for has a head injury, here’s what you need to know:

• Seek medical attention and share information about TBI signs and symptoms.
• Talk to the doctor about the risk for having seizures or developing epilepsy after a TBI.
• Learn to recognize the signs of a seizure. Sometimes it can be hard to tell. Some seizures cause a person to fall, cry out, shake or jerk, and become unaware of what’s going on around them. Other seizures can make a person appear confused, make it hard for them to answer questions, twitch, or cause the person to feel like they taste, see, or smell something unusual.
• Learn first aid so you are prepared if someone has a seizure.

To prevent TBIs that may cause epilepsy, protect your brain from injury. For example:

• Use seat belts and properly installed car safety seats every time you drive or ride in a motor vehicle.
• Never drive while under the influence of alcohol or drugs.
• Wear a helmet when playing certain sports and riding bikes, horses, motorcycles, or all-terrain vehicles.
• Prevent falls, especially in older adults and young children.

All TBIs require immediate assessment by a professional who has experience evaluating head injuries. A neurological exam will judge motor and sensory skills and test hearing and speech, coordination and balance, mental status, and changes in mood or behavior, among other abilities. Screening tools for coaches and athletic trainers can identify the most concerning concussions for medical evaluation.

Initial assessments may rely on standardized instruments such as the Acute Concussion Evaluation (ACE) form from the Centers for Disease Control and Prevention (CDC) or the Sport Concussion Assessment Tool 2, which provide a systematic way to assess a person who has suffered a mild TBI. Reviewers collect information about the characteristics of the injury, the presence of amnesia (loss of memory) and/or seizures, as well as the presence of physical, cognitive, emotional, and sleep-related symptoms. The ACE is also used to track symptom recovery over time. It also takes into account risk factors (including concussion, headache, and psychiatric history) that can impact how long it takes to recover from a TBI.

Diagnostic imaging. When necessary, medical providers will use brain scans to evaluate the extent of the primary brain injuries and determine if surgery will be needed to help repair any damage to the brain. The need for imaging is based on a physical examination by a doctor and a person's symptoms.

• Computed tomography (CT) is the most commonly used imaging technology to assess people with suspected moderate to severe TBI. CT creates a two-dimensional image of organs, bones, and tissues and can show a skull fracture or any brain bruising, bleeding, or swelling.
   
• Magnetic resonance imaging (MRI) produces detailed images of body tissue. It may be used after the initial assessment and treatment as it is a more sensitive test and picks up subtle changes in the brain that the CT scan might have missed. Significant advances have been made in the last decade to image milder TBI damage. For example, diffusion tensor imaging can image white matter tracts, more sensitive tests like fluid-attenuated inversion recovery can detect small areas of damage, and susceptibility-weighted imaging very sensitively identifies bleeding. Despite these improvements, currently available imaging technologies, blood tests, and other measures remain inadequate for detecting these changes in a way that can help diagnose mild concussive injuries.

Neuropsychological tests to gauge brain functioning are often used along with imaging in people who have suffered mild TBI. Such tests involve performing specific cognitive tasks that help assess memory, concentration, information processing, executive functioning, reaction time, and problem solving.

The Glasgow Coma Scale is the most widely used tool for assessing the level of consciousness after TBI. The standardized 15-point test measures a person's ability to open his or her eyes and respond to spoken questions or physical prompts for movement. 

Many athletic organizations recommend establishing a baseline picture of an athlete's brain function at the beginning of each season, ideally before any head injuries occur. Baseline testing should begin as soon as a child begins a competitive sport. Brain function tests yield information about an individual's memory, attention, and ability to concentrate and solve problems. Brain function tests can be repeated at regular intervals (every one to two years) and also after a suspected concussion. The results may help healthcare providers identify any effects from an injury and allow them to make more informed decisions about whether a person is ready to return to their normal activities.

Many factors—including the size, severity, and location of the brain injury—influence how a TBI is treated and how quickly a person might recover. One of the critical elements to a person's prognosis is the severity of the injury. Although brain injury often occurs at the moment of head impact, much of the damage related to severe TBI develops from secondary injuries which happen days or weeks after the initial trauma. For this reason, people who receive immediate medical attention at a certified trauma center tend to have the best health outcomes. 

Mild TBI

Some people with mild TBI such as concussion may not require treatment other than rest and over-the-counter pain relievers. Treatment should focus on symptom relief and “brain rest.” Monitoring by a healthcare practitioner is important to note any worsening of symptoms or new ones.

Children and teens who have a sports-related concussion should stop playing immediately and return to play only after being approved by a concussion injury specialist.

Preventing future concussions is critical. While most people recover fully from a first concussion within a few weeks, the rate of recovery from a second or third concussion is generally slower.

Even after symptoms resolve entirely, people should return to their daily activities gradually once they are given permission by a doctor. There is no clear timeline for a safe return to normal activities although there are guidelines such as those from the American Academy of Neurology and the American Medical Society for Sports Medicine to help determine when athletes can return to practice or competition. Further research is needed to better understand the effects of mild TBI on the brain and to determine when it is safe to resume normal activities.

People with a mild TBI should:

• Make an appointment for a follow-up visit with their healthcare provider to confirm the progress of their recovery
• Inquire about new or persistent symptoms and how to treat them
• Pay attention to any new signs or symptoms even if they seem unrelated to the injury (for example, mood swings, unusual feelings of irritability)

These symptoms may be related even if they occurred several weeks after the injury.

Medications to treat some of the symptoms of TBI may include:

• Over-the-counter or prescribed pain medicines
• Anticonvulsant drugs to treat seizures
• Anticoagulants to prevent blood clots
• Diuretics to help reduce fluid buildup and reduce pressure in the brain
• Stimulants to increase alertness
• Antidepressants and anti-anxiety medications to treat depression and feelings of fear and nervousness

Severe TBI

Immediate treatment for someone who has suffered a severe TBI focuses on preventing death; stabilizing the person's spinal cord, heart, lung, and other vital organ functions; ensuring proper oxygen delivery and breathing; controlling blood pressure; and preventing further brain damage. Emergency care staff will monitor the flow of blood to the brain, brain temperature, pressure inside the skull, and the brain's oxygen supply.

Surgery may be needed to for emergency medical care and to treat secondary damage, including:

• Relieving pressure inside the skull (inserting a special catheter through a hole drilled into the skull to drain fluids)
• Removing debris or dead brain tissue (especially for penetrating TBI)
• Removing hematomas
• Repairing skull fractures

In-hospital strategies for managing people with severe TBI aim to prevent conditions including:

• Infection, particularly pneumonia
• Deep vein thrombosis (blood clots that occur deep within a vein; risk increases during long periods of inactivity)

People with TBIs may need nutritional supplements to minimize the effects that vitamin, mineral, and other dietary deficiencies may cause over time. Some individuals may even require tube feeding to maintain the proper balance of nutrients.

Rehabilitation

After the acute care period of in-hospital treatment, people with severe TBI are often transferred to a rehabilitation center where a multidisciplinary team of health care providers help with recovery.

The rehabilitation team includes neurologists, nurses, psychologists, nutritionists, as well as physical, occupational, vocational, speech, and respiratory therapists.

Therapy is aimed at improving the person's ability to handle activities of daily living and to address cognitive, physical, occupational, and emotional difficulties. Treatment may be needed on a short-term basis or throughout a person's life. Some therapy is provided through outpatient services.

Cognitive rehabilitation therapy (CRT) is a strategy aimed at helping individuals regain their normal brain function through an individualized training program. Using this strategy, people may also learn compensatory strategies for coping with persistent deficiencies involving memory, problem solving, and the thinking skills to get things done. CRT programs tend to be highly individualized and their success varies. A 2011 Institute of Medicine report concluded that cognitive rehabilitation interventions need to be developed and assessed more thoroughly.

Other factors that influence recovery include genes and age.

Genes—Genetics may play a role in how quickly and completely a person recovers from a TBI. For example, researchers have found that apolipoprotein E ε4 (ApoE4) — a genetic variant associated with higher risks for Alzheimer's disease — is associated with worse health outcomes following a TBI. Much work remains to be done to understand how genetic factors, as well as how specific types of head injuries, affect recovery. This research may lead to new treatment strategies and improved outcomes for people with TBI.

Age—Studies suggest that age and the number of head injuries a person has suffered over his or her lifetime are two critical factors that impact recovery. For example, TBI-related brain swelling in children can be very different from the same condition in adults, even when the primary injuries are similar. Brain swelling in newborns, young infants, and teenagers often occurs much more quickly than it does in older individuals. Evidence from very limited CTE studies suggest that younger people (ages 20 to 40) tend to have behavioral and mood changes associated with CTE, while those who are older (ages 50+) have more cognitive difficulties.

Compared with younger adults with the same TBI severity, older adults are likely to have less complete recovery. Older people also have more medical issues and are often taking multiple medications that may complicate treatment (e.g., blood-thinning agents when there is a risk of bleeding into the head). Further research is needed to determine if and how treatment strategies may need to be adjusted based on a person's age.

A person with a moderate or severe TBI may need specialized medical care, such as rehabilitation, after their injury. This may include getting help with re-learning skills (such as driving and remembering things) and getting back to work.

A healthcare provider can help find and connect people to services in their community. A healthcare provider may also:

• Screen for and treat problems, such as depression.
• Encourage lifestyles that promote brain health.
• Educate patients and their families to prevent or reduce problems that may show up after the injury, like chronic pain and headaches, loss of smell or taste, and problems with sleep and vision.

Rehabilitation seeks to improve the lives of people living with TBI

The goal of TBI rehabilitation is to improve the overall quality of life for persons living with a TBI and lower the chance for a TBI-related disability. Rehabilitation programs and services may help those living with TBI by improving their ability to:

• Do daily tasks independently,
• Engage with friends and family, and
• Participate in community activities

Getting help can improve recovery

Some of the health problems that result from a moderate or severe TBI may be prevented or lessened. Getting help is crucial for improving the lives of persons living with a TBI and lowering the chance for lifelong health problems.

How well a person recovers from a moderate or severe TBI depends on multiple factors, such as:

• The health of the person before the injury,
• Type and severity of the TBI,
• Access to healthcare and specialized TBI care, and
• Family and other social support.

Stay connected to others during recovery

There are many organizations who can help you and your family as you recover. You do not have to do it alone. Keep talking with your healthcare provider, family members, caregivers, and loved ones about how you are feeling. If you do not think you are getting better, tell your healthcare provider.

The best treatment for TBI is prevention. Unlike most neurological disorders, head injuries can be prevented. According to the CDC, the following actions can help prevent TBIs:

• Wear a seatbelt when you drive or ride in a motor vehicle  
• Wear the correct helmet and make sure it fits properly when riding a bicycle, skateboarding, and playing sports like hockey and football
• Install window guards and stair safety gates at home for young children
• Never drive under the influence of drugs or alcohol
• Improve lighting and remove rugs, clutter, and other trip hazards in the hallway
• Use nonslip mats and install grab bars next to the toilet and in the tub or shower for older adults
• Install handrails on stairways
• Improve balance and strength with a regular physical activity program
• Ensure children's playgrounds are made of shock-absorbing material, such as hardwood mulch or sand