Traumatic brain injury (TBI), also known as intracranial injury, is a substantial head injury that results in damage to the brain. This damage can cause a wide spectrum of possible health outcomes.
TBI may also be caused by objects, such as bullets or a smashed piece of skull penetrating brain tissue. Causes of TBI also include falls, vehicle accidents and violence.
In this article, we will look at the causes, diagnosis, treatment, possible complications and prevention of TBI.
Contents of this article:
Here are some key points about traumatic brain injury. More detail and supporting information is in the main article.
- The effect of a TBI can vary depending on the severity of the injury and where it occurs
- Around 1 in 3 injury-related deaths involve a TBI
- Roughly 2% of Americans live with a TBI-related disability
- The majority of TBIs are caused by falls
- TBI symptoms may include confusion, persistent headaches and sleeping problems
- If someone receives a head injury and experiences convulsions or slurred speech, they should seek urgent medical attention
- A concussion is classed as a mild TBI
- In America, TBI is the third most common injury to result from child abuse
- Blood pressure can severely drop after a head injury.
What is a TBI?
TBIs can be generated in a wide range of ways, from falls to collisions in sport.
TBI is generally the result of a sudden, violent blow or jolt to the head. The brain is launched into a collision course with the inside of the skull, resulting in possible bruising of the brain, tearing of nerve fibers and bleeding.
TBI severity varies enormously depending on which part of the brain is affected, whether it occurred in a specific location or over a widespread area, as well as the extent of the damage.
A head injury usually refers to a traumatic head injury, but is a broader category. Head injury may also involve damage to other structures (apart from the brain), such as the scalp or skull.
According to the Centers for Disease Control and Prevention (CDC):
- About one third of injury-related American deaths are linked to TBI
- About 230,000 hospitalizations occur annually in the US as a result of TBI
- 1.1 million Americans are treated for TBI and released from an emergency department
- Almost 2% of the US population lives with TBI-related disabilities
- About 2 million American adults and children suffer from TBI injury annually
- 50,000 patients die annually in the US as a result of TBI
- Every 15 seconds, one American man, woman or child sustains a significant TBI
- The total number of individuals with TBI who are not seen in an emergency department or receive any care is unknown
- Direct medical costs and indirect costs - such as lost productivity - of TBI totaled an estimated $60 billion in the US in 2000.
Among American children aged up to 14 years, TBI results in an estimated:
- 2,685 deaths
- 37,000 hospitalizations
- 435,000 emergency department visits annually.
Scientists have not managed, thus far, to identify effective medications to improve outcomes for such patients, despite the extent of the problem.
The CDC also reports that the main causes of TBI are falls (28%), motor vehicle traffic crashes (20%), struck by/against events (19%) and assaults (11%).
Symptoms of traumatic brain injury
TBI signs and symptoms may sometimes be subtle and might not appear for days or weeks after the injury. Some patients may look well, even though they may feel or behave differently.
Our brain controls our movements, thoughts, sensations and behaviors. A TBI can have several different physical and psychological effects. Initial physical effects are bruising and swelling. When injured brain tissue swells up pressure is increased; the injured brain tissue presses against the skull causing additional damage.
The most common signs and symptoms of TBI include:
- Fatigue (tiredness) and lethargy
- Getting lost easily
- Persistent headaches
- Persistent pain in the neck
- Slowness in thinking, speaking, reading or acting
- Moodiness - suddenly feeling sad or angry for no apparent reason
- Sleep pattern changes - this may include either sleeping much more or much or less than usual, or having trouble sleeping
- Light headedness, dizziness
- Becoming more easily distracted
- Increased photosensitivity (sensitivity to light)
- Increased sensitivity to sounds
- Loss of sense of smell or taste
- Tinnitus (ringing in the ears).
A child with a TBI may become irritable and listless.
Children - the same signs and symptoms as those listed above are possible. However, children typically are less likely to let others know how they feel. If a child has received a blow or jolt to the head and you notice any of the following signs or symptoms, call a doctor:
- Changes in sleeping patterns
- Irritability - the child does not stop crying and is hard to console, for example
- Loss of balance
- Loss of newly acquired skills (such as toilet training)
- Playing behavior changes
- Refusal to eat
- Loss of interest in their favorite activities or toys
- Unsteady walking
When to see a doctor - according to the Mayo Clinic, you should see a doctor if you suffered a blow to the head, and should seek emergency medical care if any of the following signs are present:
- Repeated vomiting
- Slurred speech
- Weakness or numbness in the arms or legs (hands and feet).
The Mayo Clinic also lists two types of signs or symptoms, depending on the severity of the TBI.
Mild TBI signs and symptoms (concussion) may include:
- A short period of unconsciousness
- Blurred vision, tinnitus (ringing in the ears), or a bad taste in the mouth
- Cannot remember events immediately before and after the injury took place
- Dizziness or loss of balance
- Memory problems
- Problems focusing mentally.
Moderate to severe TBI signs and symptoms may include:
- Agitation, confrontational
- Continuous headache
- Convulsion or seizures
- Coordination problems
- One or both pupils of the eyes are dilated
- Patient does not wake up from sleep
- Persistent nausea and/or vomiting
- Profound confusion
- Slurred speech
- Weakness and numbness in hands, feet, arms or legs.
Causes of traumatic brain injury
TBI is caused by a severe jolt or blow to the head, or a head injury that penetrates and disrupts normal brain function.
Our brains are like a mass of gelatin which is protected from jolts and bumps by the cerebrospinal fluid around it - the brain literally floats in this fluid inside the skull. A violent blow or jolt to the head can push the brain against the inner wall of the skull, which can lead to the tearing of fibers and bleeding in and around the brain.
Not only can a blow cause injury to the brain, sudden and rapid acceleration or significant deceleration may cause TBI well.
Falls are the most common source of TBIs in America.
According to the CDC, the leading causes of TBI in the US are:
- Falls 28% - most commonly affecting children aged up to 4 years and adults over 75 years
- Motor vehicle accidents 20% - highest among people aged 15-19 years
- Struck by/against events 19% - including colliding with a moving or stationary object. About 1.6-3.8 million sports and recreation-related TBI occur in the USA annually. Most are mild and receive no hospital or emergency treatment
- Assaults 11%- TBIs caused by firearm use are the leading cause of deaths related to TBI. 90% of patients with a firearm-related TBI die. Nearly two thirds of TBIs caused by firearms are classified as suicidal with intent. For military personnel in war zones, the leading cause of TBI are blasts. In the majority of cases, the skull remains intact and the damage is thought to be caused by a pressure wave from the explosion which passes through the brain causing injury
- Non motorized pedal cycles (bicycles, tricycles, etc.) 3%
- Transport 2%
- Suicide 1%.
Child abuse: TBI is the third most common injury to result from child abuse in the US.
Other causes of TBI include domestic violence, and work-related and industrial accidents.
Diagnosing traumatic brain injury
TBIs require rapid diagnosis and treatment because they are frequently medical emergencies which can easily and quickly lead to complications.
The Glasgow Coma ScaleDoctors often use the Glasgow Coma Scale (GCS) before deciding whether to use a CT scan. The GCS is a way for doctors and nurses to assess the severity of brain damage following a head injury. It scores patients according to verbal responses, motor responses (physical reflexes), and how easily they can open their eyes.
Eyes - Glasgow Coma Scale
Score of 1 - does not open eyes.
Score of 2 - opens eyes in response to painful stimuli (when given pain).
Score of 3 - opens eyes in response to voice.
Score of 4 - opens eyes spontaneously.
Verbal - Glasgow Coma Scale
Score of 1 - makes no sound.
Score of 2 - incomprehensible sounds (mumbles).
Score of 3 - utters inappropriate words.
Score of 4 - confused, disorientated.
Score of 5 - oriented, chats normally.
Motor (physical reflexes) - Glasgow Coma Scale
Score of 1 - makes no movements.
Score of 2 - extension to painful stimuli (straightens limb when given pain).
Score of 3 - abnormal flexion to painful stimuli (moves in a strange way when given pain).
Score of 4 - flexion/withdrawal to painful stimuli (moves away when given pain).
Score of 5 - localizes painful stimuli (can pinpoint where pain is).
Score of 6 - obeys commands.
Brain injury will be classified in the Glasgow Coma Scale as:
Coma = a score of 8 or less.
Moderate = a score of 9 to 12.
Minor = a score of 13 or more.
Imaging scans of the brain
Imaging scans of the brain will help determine whether there is any brain injury/damage, and where. Examples include the following:
Brain imaging is essential for assessing the internal damage.
CT (computed tomography) scan - also known as a CAT (Computer Axial Tomography) scan. It is a medical imaging method that employs tomography. Tomography is the process of generating a two-dimensional image of a slice or section through a 3-dimensional object (a tomogram).
The medical device is called a CTG scanner; it is a large machine and uses X-rays. It used to be called an EMI scan, because it was developed by the company EMI.
X-ray - X-rays are still used for head trauma. But experts say they are not so useful. If a head injury is mild no imaging is usually needed, while a severe injury would merit the more accurate CT scan.
MRI (magnetic resonance imaging) scan - an MRI machine uses a magnetic field and radio waves to create detailed images of the body, which in this case would be the brain.
Most MRI machines look like a long tube, with a large magnet present in the circular area. When beginning the process of taking an MRI, the patient is laid down on a table. Then depending on where the MRI needs to be taken, the technician slides a coil to the specific area being imaged.
The coil is the part of the machine that receives the MR signal. MRI scans are good for examining the brainstem and deep brain structures. The doctor may inject a special dye which shows up on the scans and distinguishes healthy tissue from damaged tissue.
Angiography - a medical imaging technique used to visualize the inside, or lumen, of blood vessels and organs of the body. This may be used to detect blood vessel pathology when risk factors, such as penetrating head trauma are involved.
EEG (electroencephalography) - the device measures the electrical activity within the brain. Electrodes are placed on the patient's scalp; they pick up electrical impulses that occur in the brain. These impulses are recorded on the EEG device. An EEG can tell whether the patient is having non-convulsive seizures.
Intracranial pressure monitor - a device is placed inside the head. It senses the pressure inside the skull and sends its measurements to a recording device. Brain injuries tend to result in swelling of brain tissue which may cause additional damage to the brain.
Treatment options for traumatic brain injury
Most concussion or mild traumatic brain injury (MTBI) symptoms will go away without treatment. In the US, approximately 1% of patients with MTBI require surgery. Click here to read more about MTBI. In more severe cases the patient will be hospitalized and will require intensive care.
When treating TBI, the focus of emergency care is to prevent any worsening of brain damage. The greatest risk of further brain damage is when the brain swells. The human skull is made of bone and is not very flexible; any swelling soon results in an increase of pressure. If blood vessels were damaged when the injury occurred, there is a further risk of pooled blood or clots accumulating in this small space (inside the skull where pressure is rising).
Swelling of the brain within the skull can put undue pressure on the surrounding tissues.
The increased pressure in the brain can cause:
- Damage to brain tissue, just because of the pressure itself
- The blood vessels to get squeezed, undermining their ability to supply the brain cells with oxygen and essential nutrients.
Blood pressure - brain injuries can result in a serious drop in blood pressure, further reducing blood supply to the brain.
- Diuretics - a diuretic is anything that encourages the formation of urine by the kidneys; in other words, they increase urine output and reduce the amount of fluid in tissue. These are administered intravenously. Mannitol is the most commonly used diuretic for TBI patients. Some studies suggest that children may benefit from certain concentrations of saline solution.
- Anti-seizure medication - the risk of seizures during the first week following the traumatic injury is higher for patients with moderate to severe TBI. This medication may be administered to prevent further brain damage caused by seizures.
- Coma-inducing medications - comatose patients require less oxygen. Doctors may sometimes deliberately induce coma if the blood vessels are unable to supply adequate amounts of food and oxygen to the brain.
Rehabilitation - a number of TBI patients with significant injury need rehabilitation. This may involve relearning how to walk, talk and carry out tasks which used to be done automatically. The aim is to help the patient gain as much physical independence as possible.
Typically, therapy starts in the hospital, and later continues in a residential treatment facility, or in outpatient services. Depending on the patients' needs, they will be treated by either a physical therapist (UK: physiotherapist) or occupational therapist, or both.
- Removing hematomas - a hematoma is an abnormal collection of blood (localized) which is either partially clotted or completely clotted. Often, when TBI patients arrive in hospital they are taken straight to the operating theater and have large deposits of clotted blood removed from between the skull and the brain, resulting in a reduction of pressure inside the skull, preventing further brain damage.
- Skull fractures - if any part of the skull is pressing into the brain it will need to be surgically repaired. In most cases skull fractures which are not pressing into the brain heal on their own.
- Create an opening in the skull - this is done to relieve the pressure inside the skull. This procedure is only done if other interventions have not worked.
Tips that can aid recovery:
- Avoid activities which could cause another blow/jolt to the head
- Do exactly what doctors and other healthcare professionals recommend. Do not take drugs your physician has not approved
- Do not rush back to daily professional or school activities
- Get plenty of rest
- If you have memory problems, write things down
- Only drive a car, ride a bicycle/motorbike, or use heavy equipment when the doctor says it is OK to do so. People's reflexes after a TBI may be slower
- Seek help in re-learning skills that were lost.
Complications of traumatic brain injury
Seizures - these may occur during the first week after the injury occurred. Experts say that TBIs do not increase an individual's risk of developing epilepsy, unless there have been major structural brain injuries.
Infections - the meninges, the membranes around the brain, can be ruptured during a TBI, allowing bacteria to get in. If the infection spreads to the nervous system there is a risk of serious complications.
Sometimes, a TBI can alter a person's sense of smell.
Nerve damage - if the base of the skull is affected, the nerves of the face can be affected, causing paralysis of facial muscles, double vision, problems with eye movement, and a loss of the sense of smell.
Cognitive problems - people with moderate to severe TBI, especially severe TBI, may experience some cognitive problems, including their ability to:
- Communicate properly - some patients may have problems with written and spoken language. Others may find their ability to process non-verbal signals is worse than before their injury occurred
- Judge situations
- Mentally process things rapidly
- Pay attention
- Process information
- Remember things - especially the short-term memory; remembering things before the injury occurred, but not after
- Solve problems
- Think, organizing thoughts and ideas properly
- There may also be personality changes - especially during recovery and rehabilitation. The patient's impulse control may be altered, resulting in more inappropriate behavior. Personality changes are often a source of enormous stress and anxiety for family members, friends and caregivers.
Problems with the senses:
- Tinnitus (ringing in the ears)
- Recognizing objects may become difficult
- Clumsiness, due to poor hand-eye coordination
- Double vision
- Blind spots
- Sensing bad smells
- Sensing a bitter taste.
Long-term depression and concussion (moderate TBI) - in a report authored by Dr. Robert C. Cantu, FACSM and published in Medicine & Science in Sports & Exercise, a study of 2,552 retired professional football players revealed that recurrent sport-related concussion appears to be related to an increased risk of clinical depression in retired professional football players. There is also a risk of Post-concussion syndrome, in which headaches and dizziness persist for weeks or months after the blow/jolt to the head.
Alzheimer's disease - TBIs increase the risk of developing Alzheimer's disease later in life. Risk is linked to severity of the TBI (as well as how many TBIs the patient had).
Parkinson's disease - TBIs increase the risk of eventually developing Parkinson's disease. Risk is linked to severity of the TBI (as well as how many TBIs the patient had).
Coma - a deep state of unconsciousness - longer-term comatose patients may be reclassified as being in a permanent vegetative state. The patient cannot be awakened and does not respond to pain, light or sound in a normal way - the person in coma cannot react with the surrounding environment.
A person in a coma does not take voluntary actions and does not have sleep-wake cycles. A percentage of patients with TBI become comatose, go into a vegetative state, and/or eventually die without ever waking up.
Some wake up and have long-term problems and disabilities, while others recover some abilities and functions. (Click here to see: What is coma?)
Crime in young people - in October 2012, researchers from the University of Exeter, England, found that there is an association between brain injury during childhood and crime in young people. They say there is evidence that brain trauma may make maturing brains "misfire" and disrupt the development of impulse control, social judgment and self-restraint.
Preventing traumatic brain injuries
Never drink and drive.
Car seat belts:
- Wear a seatbelt every time you drive your car or ride as a passenger
- Children should continue using the booster seat until the lap/shoulder belts fit properly; usually when they are about 4ft 9inches (1meter 45 centimeters) tall
- Make sure children are buckled up using either a safety seat, booster seat, or a seat belt that is suitable for the child's size and age. When children outgrow their safety seats - usually when they weight about 40 pounds (18 kilos) - they should start using a booster seat.
Drinking and driving
- Never drive when you are under the influence of alcohol.
Helmets or specific protective headgears should always be worn when:
- Batting in baseball/softball or cricket (and running bases in baseball)
- Engaged in contact sports, such as karate, boxing, or American football
- Riding a horse
- Riding on a motorbike, snowmobile, scooter, or all-terrain vehicle (both riders and passengers)
- Using a skateboard
- When roller-skating or in-line skating.
Living areas for seniors:
- Grab bars should be installed next to the bathtub, shower or toilet
- Seniors should keep physically active to make sure lower body strength and balance is adequate (thus lowering the risk of falls)
- Make sure lighting in the house is bright enough
- On bathtub and shower floors use nonslip mats
- Remove throw rugs and other objects which may be cause tripping
- Stairways should ideally have handrails on both sides.
Living areas for children:
- Install window guards
- Place safety gates at the bottom and top of stairs if the children are young.
- The ground surface of a child's playground should be made of hardwood mulch, sand or some specific shock-absorbing material.
- Firearms should be stored, unloaded, in a locked safe or cabinet. Bullets should not be stored in the same location.
In recent years, researchers have highlighted the potential long-term effects of TBI, which include increased risk of dementia and other neurological disorders. Now, a new study has uncovered a drug that shows promise for reducing the brain damage caused by such an injury.
A new study, published in Neurology, finds plaques in the brains of middle-aged people who have experienced head injuries. These amyloid plaques match those found in Alzheimer's, but their spatial distribution differs.