Traumatic Brain Injury
A traumatic brain injury (TBI) is defined as a
blow to the head or a penetrating head injury that disrupts the normal
function of the brain. TBI can result when the head suddenly and
violently hits an object, or when an object pierces the skull and enters
brain tissue. Symptoms of a TBI can be mild, moderate, or severe,
depending on the extent of damage to the brain. Mild cases may result in
a brief change in mental state or consciousness, while severe cases may
result in extended periods of unconsciousness, coma, or even death.
About 1.7 million cases of TBI occur
in the United States every year. Approximately 5.3 million people live
with a disability caused by TBI in the United States alone.
- Annual direct and indirect TBI costs
are estimated at $48 to $56 billion.
- There are about 235,000
hospitalizations for TBI every year, which is more than 20 times the
number of hospitalizations for spinal cord injury.
children ages 14 and younger, TBI accounts for an estimated 2,685
deaths, 37,000 hospitalizations, and 435,000 emergency room visits.
year, 80,000 to 90,000 people experience the onset of long-term or
lifelong disabilities associated with TBI.
- Males represent 78.8
percent of all reported TBI accidents, and females represent 21.2
- National statistics estimate between 50 and 70 percent
of TBI accidents are the result of a motor vehicle crash.
and recreational activities contribute to about 21 percent of all
traumatic brain injuries among American children and adolescents.
mortality rate for TBI is 30 per 100,000, or an estimated 50,000 deaths
in the United States annually. Of those who die, 50 percent do so
within the first two hours of their injury.
- Deaths from head
injuries account for 34 percent of all traumatic deaths. Beginning at
age 30, the mortality risk after head injury begins to increase. Persons
age 60 and older have the highest death rate after TBI, primarily
because of falls, which have a rising incidence in this age group.
for Disease Control and Prevention, Traumatic Brain Injury (TBI):
Incidence and Distribution, 2004.
Traumatic Brain Injury
Model System, University of Alabama at Birmingham, Introduction to Brain
Injury – Facts and Stats, February, 2000
vary greatly depending on the severity of the head injury, but may
include any of the following:
- Loss of
- Dilated pupils
- Vision changes (blurred
vision or seeing double, not able to tolerate bright light, loss of eye
- Cerebrospinal fluid (CSF) (which may be
clear or blood-tinged) coming out of the ears or nose
and balance problems
- Breathing problems
- Slow pulse
breathing rate, with an increase in blood pressure
- Ringing in
the ears, or changes in hearing
- Cognitive difficulties
- Speech difficulties (slurred speech, inability to understand and/or articulate words)
- Body numbness or tingling
- Droopy eyelid or facial weakness
- Loss of bowel
control or bladder control
If a TBI is suspected, call 911
immediately or take the person to an emergency room.
When discussing TBI, the term "mass lesion" is often
used. This refers to an area of localized injury that may cause pressure
within the brain. The most common mass lesions related to TBI are
hematomas and contusions.
A hematoma is a blood clot within the
brain or on its surface. Hematomas may occur anywhere within the brain.
An epidural hematoma is a collection of blood between the dura mater
(the protective covering of the brain) and the inside of the skull. A
subdural hematoma is a collection of blood between the dura mater and
the arachnoid layer, which sits directly on the surface of the brain.
cerebral contusion is bruising of brain tissue. When examined under a
microscope, cerebral contusions are comparable to bruises in other parts
of the body. They consist of areas of injured or swollen brain mixed
with blood that has leaked out of arteries, veins, or capillaries.
Contusions are seen most commonly at the base of the front parts of the
brain, but they may occur anywhere.
An intracerebral hemorrhage
(ICH) describes bleeding within the brain tissue, which may be related
to other brain injuries, especially contusions. The size and location of
the hemorrhage helps determine whether it can be removed surgically.
hemorrhage (SAH) is caused by bleeding into the subarachnoid space. It
appears as diffuse blood spread thinly over the surface of the brain,
and is seen commonly after TBI.
Most cases of SAH associated with head trauma are mild. Hydrocephalus may result from severe traumatic SAH.
can produce microscopic changes that cannot be seen on CT scans and
that are scattered throughout the brain. This category of injuries is
called diffuse brain injury, which may occur with or without an
associated mass lesion.
Diffuse axonal injury refers to impaired
function and gradual loss of some axons, which are the long extensions
of a nerve cell that enable such cells to communicate with each other
even if they are located in parts of the brain that are far apart. If
enough axons are injured in this way, then the ability of nerve cells to
communicate with each other and to integrate their function may be lost
or greatly impaired, possibly leaving a patient with severe
Another type of diffuse injury is ischemia, or
insufficient blood supply to certain parts of the brain. It has been
shown that a decrease in blood supply to very low levels may occur
commonly in a significant number of TBI patients. This is crucial
because a brain that has just undergone a traumatic injury is especially
sensitive to even slight reductions in blood flow. Changes in blood
pressure during the first few days after head injury can also have an
No treatment is
required for most linear skull fractures, which are simple breaks or
"cracks" in the skull. Of greater concern is the possibility that forces
strong enough to cause a skull fracture may also have caused some
damage to the underlying brain. Fractures of the base of the skull are
problematic if they cause injury to nerves, arteries, or other
structures. If a fracture extends into the sinuses, there may be leakage
of cerebrospinal fluid (CSF) from the nose or ears. Most leaks will
stop spontaneously. Sometimes, however, it may be necessary to insert a
lumbar drain, which is a long, thin, flexible tube that is inserted into
the CSF space in the spine of the lower back. This provides an
alternate route for CSF drainage so that the dural tear that is
responsible for the CSF leak in the base of the skull has time to seal.
skull fractures are those in which part of the bone presses on or into
the brain. These may require surgical treatment. The damage caused by
depressed skull fractures depends upon the region of the brain in which
they are located and also upon the possible coexistence of any
associated diffuse brain injury.
trauma patients, persons with TBI need to undergo a systematic yet rapid
evaluation in the emergency room. Cardiac and pulmonary function is
assessed first. Next, a quick examination of the entire body is
performed, followed by a complete neurological examination. The
neurological examination includes an assessment utilizing the Glasgow
Coma Scale (GCS). In addition to the GCS, the ability of the pupils to
become smaller in bright light is also tested. In patients with large
mass lesions or with high intracranial pressure (ICP), one or both
pupils may be very wide or "blown". The presence of a wide or dilated
pupil on only one side suggests that a large mass lesion may be present
on the same side as the dilated pupil. Brainstem reflexes including gag and corneal (blink) may also be tested.
computed tomography scan (CT or CAT scan) is the gold standard for the
radiological assessment of a TBI patient. A CT scan is easy to perform
and is an excellent test for detecting the presence of blood and
fractures, which are the most crucial lesions to identify in medical
trauma cases. Plain x-rays of the skull are recommended by some as a way
to evaluate patients with only mild neurological dysfunction. However,
most centers in the United States have readily available CT scanning,
which is a more accurate test. For this reason, the routine use of skull
x-rays for TBI patients has declined.
Magnetic resonance imaging
(MRI) is not commonly used for acute head injury because it takes longer
to perform MRI than CT scanning. MRI is not as practical for acute
trauma because it is difficult to transport an acutely-injured patient
from the emergency room to the MRI scanner. However, after a patient has
been stabilized, MRI may demonstrate the existence of lesions that were
not detected on the CT scan. This information is generally more useful
for determining prognosis than for influencing treatment.
Many patients with moderate or severe head injuries
are taken directly from the emergency room to the operating room. In
many cases, surgery is performed to remove a large hematoma or contusion
that is significantly compressing the brain or raising the pressure
within the skull. After surgery, these patients are usually observed and
monitored in the intensive care unit (ICU).
patients may not go to the operating room immediately, but instead are
taken from the emergency room to the ICU. Contusions or hematomas may
enlarge over the first hours or days after head injury, so some patients
are not taken to surgery until several days after an injury. Delayed
hematomas may be discovered when a patient's neurological exam worsens
or when their ICP increases. On other occasions, a routine follow-up CT
scan that was ordered to determine if a small lesion has changed in size
indicates that the hematoma or contusion has enlarged significantly. In
many cases, removing the lesion before it enlarges and causes
neurological damage may be the safest approach for the patient.
surgery, the hair over the affected part of the head is usually shaved.
After the scalp incision is made, the bone that is removed is usually
taken out in a single piece or flap, which is then replaced after
surgery. Sometimes, however, the bone may be shattered or heavily
contaminated. In these cases, the contaminated or shattered fragments
may be removed and not replaced. The dura mater is carefully cut to
reveal the underlying brain. After any hematoma or contusion is removed,
the neurosurgeon ensures that the area is not bleeding. He or she then
closes the dura, replaces the bone, and closes the scalp. If the brain
is very swollen, some neurosurgeons may decide not to replace the bone
until the swelling decreases, which may take up to several weeks. The
neurosurgeon may elect to place an ICP monitor or other types of
monitors if these were not already in place. The patient is then
returned to the ICU for observation and additional care.
At the present time, there is no medication or
"miracle treatment" that can be given to prevent nerve damage or promote
nerve healing after TBI. The primary goal in the ICU is to prevent any
secondary injury to the brain. The "primary insult" refers to the
initial trauma to the brain, whereas the "secondary insult" is any
subsequent development that may contribute to neurological injury. For
example, an injured brain is especially sensitive and vulnerable to
decreases in blood pressure that might otherwise be well tolerated. One
way of avoiding secondary insults is to try to maintain normal or
slightly elevated blood pressure levels. Likewise, increases in ICP,
decreases in blood oxygenation, increases in body temperature, increases
in blood glucose, and many other disturbances can potentially worsen
neurological damage. The prevention of secondary insults is a major part
of the ICU management of head-injured patients.
monitoring devices may assist healthcare personnel in caring for the
patient. Placement of an ICP monitor into the brain itself can help
detect excessive swelling of the brain. One commonly used type of ICP
monitor is a ventriculostomy, which is a narrow, flexible, hollow
catheter that is passed into the ventricles, or fluid spaces in the
center of the brain, to monitor ICP and to drain CSF if ICP increases. Another commonly used type of intracranial pressure monitoring device involves placement of a small fiberoptic catheter directly into the brain tissue. Additional catheters may be added that measure brain temperature and brain tissue oxygenation.
Placement of an oxygen sensor into the jugular vein can detect how much
oxygen in the blood is arising from the brain and can indicate how much
oxygen the brain is using. This may be related to the degree of brain
damage. Many other monitoring techniques are currently under
investigation to see if they can help to improve outcome after head
injury or provide other critical information about caring for TBI
One of the most widely used systems
to classify outcome from head injury is the Glasgow Outcome Scale
(GOS). Patients with mild head injury (usually defined as GCS score on
admission of 13-15) tend to do well. They may experience headaches,
dizziness, irritability, or similar symptoms, but these gradually
improve in most cases.
Patients with moderate head injuries fare
less well. Approximately 60 percent will make a positive recovery, and
an estimated 25 percent will be left with a moderate degree of
disability. Death or a persistent vegetative state will be the outcome
in about 7 to 10 percent of cases. The remainder of patients will have a
severe degree of disability.
The group comprised of severely
head-injured patients has the worst outcomes. Only 25 to 33 percent of
these patients have positive outcomes. Moderate disability and severe
disability each occur in about a sixth of patients, with moderate
disability being slightly more common. About 33 percent of these
patients do not survive. The remaining few percent remain persistently
The above statistics apply to patients with so-called
closed head injuries. For penetrating head injuries, which today are
caused most commonly by handguns, outcomes follow a different pattern.
More than 50 percent of all patients with gunshot wounds to the head who
are alive upon arrival at a hospital do not survive because their
initial injuries are so severe. However, most of the remaining patients
tend to do fairly well, largely because their injuries are relatively
mild (GCS score of 13-15). Relatively few patients suffer injuries of
intermediate severity (GCS score of 9-12) from gunshot wounds, but it is
this group that has the most variability in outcomes.
usefulness, the GOS is not a good tool with which to measure subtle
emotional or cognitive problems. Several months after a severe head
injury, patients who have a good score on the GOS may in fact have
significant neuropsychological disabilities. Tremendous effort is being
directed into finding better ways to evaluate these problems, into
improving the quality of prehospital, acute, and rehabilitative care,
and into research to learn more about the effects of head injury and
potential treatment options.
|Table 1: Glasgow Coma Scale|
||BEST MOTOR RESPONSE
||BEST VERBAL RESPONSE
||BEST EYE OPENING RESPONSE|
||Withdraws from stimulus
||Conversant, but confused
||Eyes open spontaneously|
||States recognizable words or phrases
||Eyes open to voice|
||Makes unintelligible sounds
||Eyes open to painful stimulus|
|Table 2: Glasgow Outcome Scale|
|Good Recovery (GR)
||Minor disabilities, but able to resume normal life.|
|Moderate Disability (MD)
||More significant disabilities, but still able to live independently.
Can use public transportation, work in an assisted situation, etc.|
|Severe Disability (SD)
||Conscious, but dependent upon others for daily care. Often
|Persistent Vegetative State (PVS)
||Not conscious, though eyes may be open and may "track" movement.|
Jennett B. Assessment of coma and impaired consciousness. Lancet 1974;
Teasdale G, Jennett B. Assessment and prognosis of
coma after head injury. Acta Neurochir 1976; 34:45-55.
head-injured patients leave the acute-care hospital, some may benefit
from a rehabilitation program. Prime candidates for rehabilitation are
patients that had less severe initial injuries, or those that have
started to show significant improvement. In some cases, further recovery
may be expedited by transfer to a rehabilitation hospital or to the
rehabilitation service of a large hospital. For more severely injured
patients or for those whose recovery is slow, constant vigilance is
required to prevent the gradual onset of problems with joint mobility,
skin integrity, respiratory status, infection, and many other physiological
functions. Patients with moderate or mild injuries, as well as severely
injured patients who have improved sufficiently, may be candidates for
Regardless of the setting, most head-injury
rehabilitation centers emphasize compensatory strategies, which
essentially help patients learn to reach the maximum level of function
allowed by their impairments. The concept of cognitive retraining, which
presumes that at least some of the brain's cognitive capacity can be
restored by constant repetition of certain simple tasks, is more
controversial but is also emphasized at many centers. Another major goal
of head injury rehabilitation is working with patients' families to
educate them about what they can realistically expect and how they can
best help their injured family member.
General Head Injury
- Wear a seatbelt every time you drive or
ride in a motor vehicle.
- Never drive while under the influence
of drugs or alcohol or ride as a passenger with anybody else who is
under the influence.
- Keep firearms unloaded in a locked cabinet
or safe, and store ammunition in a separate, secure location.
hazards in the home that may contribute to falls. Secure rugs and loose
electrical cords, put away toys, use safety gates, and install window
guards. Install grab bars and handrails if you are frail or elderly.
and Recreation Head Injury Prevention Tips
- Buy and use
helmets or protective head gear approved by the ASTM for specific sports
100 percent of the time.
- Supervise younger children at all
times, and do not let them use sporting equipment or play sports
unsuitable for their age. Do not let them use playgrounds with hard
- Follow all rules and warning signs at water
parks, swimming pools, and public beaches.
- Do not dive in water
less than 12 feet deep or in above-ground pools. Check the depth – and
check for debris in the water before diving.
- Wear appropriate
clothing for the sport.
- Do not wear any clothing that can
interfere with your vision.
- Do not participate in sports when
you are ill or very tired.
- Obey all traffic signals and be
aware of drivers when cycling or skateboarding.
- Avoid uneven or
unpaved surfaces when cycling, skateboarding, or in-line skating.
regular safety checks of sports fields, playgrounds and equipment.
and replace sporting equipment or protective gear that is damaged.
slide head-first when stealing a base.
Agnosia – failure to recognize familiar objects
even though the sensory mechanism is intact.
Agraphia – the
inability to express thoughts in writing.
Alexia – the
inability to read.
Amnesia – lack of memory about events
occurring during a particular period of time.
loss of the sense of smell.
Anoxia – a condition in which
there is an absence of oxygen supply to an organ's tissues although
there is adequate blood flow to the tissue.
Aphasia – loss
of the ability to express oneself and/or to understand language.
– Middle layer of membranes covering the brain and spinal cord.
– shaky and unsteady movements that result from the brain's failure to
regulate the body's posture and the strength and direction of movements.
– the nerve fiber that carries an impulse from the nerve cell to a
target, and also carries materials from the nerve terminals back to the
Brain Stem – the stemlike part of the brain
that connects to the spinal cord.
Closed Head Injury –
impact to the head from an outside force, without any skull fracture or
Concussion – a disruption, usually temporary,
of neurological function resulting from a head injury or violent
Cerebrospinal fluid (CSF) – a clear fluid
surrounding the brain and spinal cord.
Contusion – a
bruise; an area in which blood that has leaked out of blood vessels is
mixed with brain tissue.
Coup-Contrecoup Injury –
contusions that are both at the site of the impact and on the complete
opposite side of the brain.
Depressed skull fracture – a
break in the bones of the head in which some bone is pushed inward,
possibly pushing on or pressing into the brain.
Diplopia – a
condition in which a single object appears as two objects; also called
Dura mater – the outermost, toughest, and
most fibrous of the three membranes (meninges) covering the brain and
the spinal cord.
Dysarthria – speech that is
characteristically slurred, slow, and difficult to understand.
– collection of fluid in the tissue causing swelling.
Epidural – located on or outside the dura mater, the outermost, toughest, and most fibrous of the three membranes (meninges) covering the brain.
– paralysis of one side of the body as a result of injury to neurons
carrying signals to muscles from the motor areas of the brain or spinal
Hemiparesis – weakness, paralysis or loss of movement
on one side of the body.
Hemianopsia – loss of part of
one's visual field in one or both eyes.
Hydrocephalus – a
condition in which excess CSF builds up within the ventricles
(fluid-containing cavities) of the brain and may cause increased
pressure within the head.
Hypoxia – a condition in which
there is a decrease of oxygen to the tissue despite adequate blood flow
to the tissue.
Intraparenchymal – inside the parenchyma of the brain.
Ischemia – a reduction of blood flow that is
thought to be a major cause of secondary injury to the brain or spinal
cord after trauma.
Locked-in Syndrome – a rare
neurological condition in which a person cannot physically move any part
of the body except the eyes.
Open head injury – trauma to
the brain resulting in loss of consciousness due to the penetration of
the brain by a foreign object such as a bullet.
hemorrhage – Blood in, or bleeding into, the space under the
arachnoid membrane, most commonly from trauma or from rupture of an
Subcortical – the region beneath the cerbral
Subdural – the area beneath the dura covering the
brain and spinal cord.
Vasospasm – spasm of blood vessels
which decreases their diameter.
Ventricles (brain) – four
natural cavities in the brain which are filled with CSF.
Brain Injury Resources
Brain Injury Association of America
Brain Injury Resource
Brain Injury Association
The Bob Woodruff Foundation/reMIND
The Brain Injury
Traumatic Brain Injury National Resource Center