Traumatic Brain Injury: Causes, Symptoms, and Treatments (2023)

Traumatic brain injury (TBI) is a disruption in normal brain function that can be caused by a blow, blow or shake to the head, the head striking an object suddenly and violently, or when an object pierces the skull and enters brain tissue. The observation of one of the following clinical signs constitutes a disturbance of normal brain function:

• Loss or decrease of consciousness
• Loss of memory of events before or after the event (amnesia)
• Focal neurological deficits such as muscle weakness, vision loss, speech changes
• Altered mental status, such as disorientation, slow thinking, or difficulty concentrating

Symptoms of a traumatic brain injury can be mild, moderate or severe, depending on the extent of the brain damage. Mild cases may result in a brief change in mental status or consciousness. Severe cases can lead to prolonged periods of unconsciousness, coma, or even death.

Predominance

According to the CDC, approximately 2.87 million cases of TBI occurred in the US in 2014, with more than 837,000 cases in children. An estimated 13.5 million people are living with a disability due to traumatic brain injury in the United States alone.

• TCE's estimated annual direct and indirect costs are $76.5 billion.
• There are approximately 288,000 TBI hospitalizations each year, more than 20 times the number of spinal cord injury hospitalizations.
• Since 2006, there has been a 53% increase in the total number of emergency room visits, hospitalizations and TBI-related deaths.
• Among children age 14 and younger, TBI is responsible for approximately 2,529 deaths, 23,000 hospitalizations, and 837,000 emergency room visits.
• Each year, between 80,000 and 90,000 people experience the onset of long-term or lifelong disabilities associated with TBI.
• Men account for 78.8% of all reported TBI crashes and women account for 21.2%, with higher rates of TBI among men (959 per 100,000) than among women (811 per 100,000).
• Sports and recreational activities contribute to about 21 percent of all traumatic brain injuries among American children and adolescents.
• The highest rates of TBI are seen in older adults (≥75 years; 2232 per 100,000), very young (0 to 4 years; 1591 per 100,000), and young adults (15 to 24 years; 1081 per 100,000).
• The TBI death rate is 30 per 100,000, or an estimated 50,000 deaths in the US annually.
• Head trauma deaths account for 34% of all traumatic deaths. From the age of 30, the risk of mortality after a head injury begins to increase.
• The main causes of TBI-related deaths are due to car accidents, suicides and falls.
• The leading causes of non-fatal TBI in the US are falls (35%), motor vehicle-related injuries (17%) and bumps or blows to the head by or against an object (17%), such as sports injuries. .

Sources:

Centers for Disease Control and Prevention (CDC), Traumatic Brain Injury (TBI): Incidence and Distribution, 2014.
Introduction to brain injuries: facts and statistics, February 2000.

Symptoms

Symptoms vary greatly depending on the severity of the head injury. They can include any of the following:

• vomit
• Lethargy
• Headache
• Confusion
• Paralysis
• Coma
• Loss of consciousness
• Dilated pupils
• Vision changes (blurred or double vision, inability to tolerate bright light, loss of eye movement, blindness)
• Cerebrospinal fluid (CSF) (clear or tinged with blood) appears in the ears or nose
• Dizziness and balance problems
• Breathing problems
• slow pulse
• Slow respiratory rate with increased blood pressure
• Ringing in the ears or hearing changes
• cognitive difficulties
• inappropriate emotional responses
• Speech difficulties (slurred speech, inability to understand and/or articulate words)
• Difficulty swallowing
• Numbness or tingling in the body
• Droopy eyelid or facial weakness
• Loss of bowel control or bladder control

If TBI is suspected, call 911 immediately or take the person to an emergency room.

types of injuries

TBIs can cause "massive injuries" such as a localized area of ​​injury such as bruises and contusions that increase pressure within the brain. The following summarizes the different types of sequelae that develop from TBI:

Hematoma:A hematoma is a blood clot within the brain or on its surface. Hematomas can occur in any part of 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 lies directly on the surface of the brain.

Contusion:A concussion is a bruise to brain tissue. When examined under a microscope, brain concussions are comparable to concussions on other parts of the body. They consist of injured or inflamed areas of the brain mixed with blood that has leaked from arteries, veins or capillaries. Contusions are usually found at the base of the front parts of the brain, but they can occur anywhere.

Hemorragia intracerebral:An intracerebral hemorrhage (ICH) describes bleeding within brain tissue, it can be related to other brain injuries, especially concussions. The size and location of the bleed help determine whether it can be surgically removed.

Subarachnoid hemorrhage:Subarachnoid hemorrhage (SAH) is caused by bleeding into the subarachnoid space. Appears as diffuse blood that spreads thinly over the surface of the brain and usually after TBI. Most cases of SAH associated with head trauma are mild. Hydrocephalus may be due to severe traumatic subarachnoid hemorrhage.

diffuse lesions:TBIs can cause microscopic changes that don't show up on CT scans and are scattered throughout the brain. This category of injury, called diffuse brain injury, can occur with or without associated massive damage.

Diffuse axonal injury:Axonal injury refers to impaired function and gradual loss of axons. These long stretches of nerve cells allow them to communicate with each other. If enough axons are damaged in this way, the nerve cells' ability to communicate with each other and integrate their functions can be lost or greatly impaired, possibly leaving the patient with severe disabilities.

Ischemia:Another type of diffuse injury is ischemia, or insufficient blood supply to certain parts of the brain. A decrease in blood supply to very low levels can commonly occur in a significant number of TBI patients. This is crucial, as a brain that has just suffered a traumatic injury is especially sensitive to small reductions in blood flow. Changes in blood pressure during the first few days after a head injury can also have an adverse effect.

Skull fractures:Linear skull fractures or simple fractures or "cracks" in the skull can accompany TBIs.

Possible forces strong enough to cause a skull fracture could damage the underlying brain. Skull fractures can be alarming if found on patient assessment. Fractures at the base of the skull are problematic as they can injure nerves, arteries or other structures. If the fracture extends into the sinuses, cerebrospinal fluid (CSF) leakage from the nose or ears may occur. Depressed skull fractures, in which part of the bone presses against the brain, can also occur.

Tests and Diagnosis

Anyone with signs of moderate or severe TBI should receive medical attention as soon as possible. Because there's not much we can do to reverse the initial brain damage caused by trauma, doctors try to stabilize a person with TBI and focus on preventing further damage.

First, heart and lung function is assessed. A quick full-body examination is then performed, followed by a complete neurological examination. The neurological examination includes an assessment using 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 massive lesions or high intracranial pressure (ICP), one or both pupils may be very dilated or "bloated". The presence of a wide or dilated pupil on only one side suggests that a large mass lesion may be present. Brainstem reflexes, including gagging and corneal (blinking), can also be assessed.

radiological exams

A computed tomography (CT or CAT) scan is the gold standard for radiological evaluation of a patient with TBI. CT is easy to perform and an excellent test for detecting the presence of blood and fractures, the most crucial injuries to identify in cases of medical trauma. Some people recommend plain skull x-rays as a way to evaluate patients with mild neurologic dysfunction. However, most centers in the US have CT scans readily available, a more accurate test, decreasing the routine use of skull radiographs for patients with TBI.

Magnetic resonance imaging (MRI) is not commonly used for acute head injuries because it takes longer to perform an MRI than a CT scan. Since it is difficult to transport a seriously injured patient from the emergency room to an MRI scanner, the use of MRI is impractical. However, once the patient is stabilized, the MRI may show lesions that were not detected on the CT scan. This information is generally more useful in determining prognosis than in influencing treatment.

Treatment

Surgery

Many patients with moderate or severe head trauma go directly from the emergency room to the operating room. In many cases, surgery is done to remove a large bruise or bruise that is significantly compressing the brain or increasing pressure within the skull. After surgery, these patients are under observation in the intensive care unit (ICU).

Other head trauma patients may not go to the operating room right away, but are rushed from the emergency room to the ICU. Because bruising or contusions can increase during the first few hours or days after a head injury, immediate surgery is not recommended in these patients until several days after the injury. Delayed hematomas may be discovered when a patient's neurologic examination worsens or when ICP increases. Other times, a routine follow-up CT scan to determine whether a small lesion has changed in size indicates that the hematoma or bruise has significantly increased. In these cases, the safest approach is to remove the lesion before it grows large and causes neurological damage.

During surgery, the hair on the affected part of the head is usually shaved. After the scalp incision, the removed bone is removed in one piece or flap and replaced after surgery, unless it is contaminated. The dura mater is carefully cut away to reveal the underlying brain. After removing any bruises or bruises, the neurosurgeon checks that the area is not bleeding. He then closes the dura mater, replaces the bone and closes the scalp. If the brain is severely inflamed, some neurosurgeons may decide not to replace the bone until the swelling subsides, which can take several weeks. The neurosurgeon may choose to place a PCI monitor or other types of monitors if they are not already installed. The patient returns to the ICU for observation and further care.

non-surgical treatments

Currently, medication given to prevent nerve damage or promote nerve healing after TBI is not available. The main goal in the ICU is to prevent any secondary injury to the brain. "Primary assault" refers to the initial trauma to the brain, while "secondary assault" is any later development that may contribute to neurological damage. For example, an injured brain is especially sensitive and vulnerable to well-tolerated drops in blood pressure. One way to avoid secondary insults is to aim for 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 disorders can potentially worsen neurological damage. The main role of ICU management is the prevention of secondary injuries in patients with head trauma.

Various monitoring devices can help healthcare professionals to care for the patient. Placing a PCI monitor in the brain can help detect excessive inflammation. A commonly used type of PCI monitor is a ventriculostomy, a narrow, flexible, hollow catheter inserted into the ventricles or fluid spaces in the center of the brain to monitor PCI and drain CSF if PCI increases. Another commonly used type of intracranial pressure monitoring device involves placing a small fiberoptic catheter directly into brain tissue. Additional catheters can be added to measure brain temperature and brain tissue oxygenation. Placing an oxygen sensor in the jugular vein can detect 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 determine whether they can help improve outcome after head injury or provide additional information about the care of TBI patients.

Result

One of the most widely used systems for classifying head injury outcomes is the Glasgow Outcomes Scale (GOS). Patients with mild head trauma (generally defined as an admission GCS score of 13 to 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 worse. Approximately 60% will recover positively and approximately 25% will be left with a moderate degree of disability. Death or a persistent vegetative state will result in about 7 to 10 percent of cases. The rest of the patients will have a severe degree of disability.

The group consisting of patients with severe head injury had the worst results. Only 25 to 33% of these patients have positive results. Moderate disability and severe disability each occur in about one-sixth of patients, with moderate disability slightly more common. About 33% of these patients do not survive. The remaining small percentage remain persistently vegetative.

The above statistics apply to patients with so-called closed head injuries. For penetrating head injuries, now commonly caused by firearms, the results follow a different pattern. More than 50 percent of all patients with gunshot wounds to the head who are alive on arrival at the hospital do not survive due to severe initial injuries. Patients with relatively mild injuries (GCS score 13-15) tend to do very well. Comparatively few patients suffer injuries of intermediate severity (GCS score 9-12) from gunshot wounds; it is this group that has the greatest variability in results.

Despite its usefulness, the GOS is not a good tool for measuring subtle emotional or cognitive problems. Several months after a severe head injury, patients with a good GOS score may have significant neuropsychological impairments. Enormous effort is directed toward finding better ways to assess these problems, improving the quality of prehospital, acute, and rehabilitation care, and research to learn more about the effects of head injuries and possible treatment options.

Table 1: Glasgow Coma Scale

Table 2: Glasgow Outcome Scale

Sources:
Teasdale G, Jennett B. Assessment of coma and altered consciousness. Lancet 1974; 81-84.
Teasdale G, Jennett B. Evaluation and prognosis of coma after head injury. Neurochir Act 1976; 34:45-55.

Rehabilitation

Once head trauma patients leave the acute hospital, some benefit from a rehabilitation program. The main candidates for rehabilitation are patients with less severe initial injuries or those who have started to show significant improvement.

In some cases, transferring to a rehabilitation hospital or the rehabilitation service of a large hospital can speed up recovery. For patients with more severe injuries or slow recovery, constant vigilance is needed to avoid the gradual onset of problems with joint mobility, skin integrity, respiratory status, infection, and many other physiological functions. Patients with moderate or mild injuries, or patients with severe injuries who have sufficiently improved, are likely candidates for outpatient therapy.

Most TBI centers emphasize compensatory strategies to help patients learn to achieve the highest level of functioning that their impairments allow. The concept of cognitive retraining, a controversial concept which assumes that at least part of the brain's cognitive capacity can be restored by constant repetition of certain simple tasks, is also emphasized in many centres. Head injury rehabilitation centers work with patients' families to educate them about realistic expectations and better help their injured family members.

General tips for head injury prevention

• Wear a seat belt whenever driving or riding in a motor vehicle.
• Never drive under the influence of drugs or alcohol or ride as a passenger with someone who is under the influence.
• Keep firearms unloaded in a locked cabinet or safe, and store ammunition in a safe, separate place.
• Eliminate home hazards that can contribute to falls. Secure loose rugs and electrical cords, put away toys, use security gates, and install window guards. Install grab bars and handrails if you are frail or elderly.

Head injury prevention tips for sports and recreation

• For specific sports, 100% of the time, purchase and use American Society for Testing and Materials (ASTM) approved helmets or helmets.
• Supervise younger children at all times.
• Do not allow young children to use sports equipment or play sports that are inappropriate for their age.
• Avoid using playgrounds with hard surfaces.
• 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 the water for debris before diving.
• Wear appropriate clothing for sports.
• Do not wear clothing that could interfere with your vision.
• Do not play sports when you are sick or very tired.
• Obey all road signs and pay attention to drivers when riding a bicycle or skateboard.
• Avoid uneven or unpaved surfaces when bicycling, skateboarding or rollerblading.
• Conduct regular safety checks of sports fields, playgrounds and equipment.
• Discard and replace damaged sports equipment or protective gear.
• Never slide upside down when stealing a base.

glossary of terms

• agnosia– inability to recognize familiar objects despite intact sensory mechanism
• Agraphia– the inability to express thoughts in writing
• Alexia- the inability to read
• Amnesia– lack of memory about events that occur during a certain period of time
• Anosmia- loss of smell
• Anoxemia– a condition in which there is an absence of oxygen supply to the tissues of an organ, although there is adequate blood flow to the tissue
• Aphasia– loss of ability to express oneself and/or understand language
• Arachnoid– middle layer of membranes covering the brain and spinal cord
• Ataxia– shaky, unsteady movements resulting from the brain’s inability to regulate body posture and the strength and direction of movements
• axon– the nerve fiber that carries an impulse from the nerve cell to a target and also transports materials from the nerve endings back to the nerve cell
• brainstem- the stem-like part of the brain that connects to the spinal cord
• head trauma– impact to the head by an external force, without fracture or displacement of the skull
• Concussion– an interruption, usually temporary, of neurological function as a result of a head injury or violent agitation
• LCR– a clear fluid that surrounds the brain and spinal cord
• bruise- a bruise; an area where blood that has leaked from blood vessels mixes with brain tissue
• kickback injury– bruises that are at the site of impact and on the completely opposite side of the brain
• sunken skull fracture– a break in the bones of the head where some bone is pushed in, possibly pushing or pressing on the brain
• diplopia– a condition in which a single object appears as two objects; also called double vision
• tough mother– the outermost, toughest, and most fibrous of the three membranes (meninges) that cover the brain and spinal cord
• dysarthria– speech characteristically slurred, slow and difficult to understand
• Edema– accumulation of fluid in the tissue that causes swelling
• epidural– located inside or outside the dura mater, the outermost, toughest, and most fibrous of the three membranes (meninges) that cover the brain
• hemiplejía– paralysis on one side of the body as a result of damage to the neurons that transmit signals to muscles in the motor areas of the brain or spinal cord
• hemiparesis– weakness, paralysis or loss of movement on one side of the body
• hemianopsia– loss of part of the visual field of one or both eyes
• hydrocephalus– a condition in which excess CSF builds up inside the ventricles (fluid-containing chambers) of the brain and can cause increased pressure inside the head
• hypoxia– a condition in which there is decreased oxygen to the tissue despite adequate blood flow to the tissue
• intraparenquimatous- within the parenchyma of the brain
• Ischemia– a reduction in blood flow believed to be one of the main causes of secondary injury to the brain or spinal cord after trauma
• lock-in syndrome– a rare neurological condition where a person is unable to physically move any part of the body except the eyes
• open head injury– trauma to the brain resulting in loss of consciousness due to penetration of the brain by a foreign object such as a bullet
• subarachnoid hemorrhage– Blood or bleeding into the space below the arachnoid membrane, most commonly due to trauma or a ruptured aneurysm
• subcortical– the region below the cerebral cortex
• Subdural– the area under the dura mater that covers the brain and spinal cord
• vasospasm– spasm of the blood vessels which reduces their diameter
• Ventricles (brain)– four natural cavities in the brain that are filled with cerebrospinal fluid

Traumatic brain injury resources

• American Brain Injury Association
• Brain Injury Resource Foundation
• BrainLine
• International Brain Injury Association
• Bob Woodruff Foundation/reMIND
• The Brain Injury Recovery Network
• Centers for Disease Control and Prevention
• Model Systems Knowledge Translation Center

Information about the author

Published on 02/03/2020 by Nitin Agarwal, MD, Ruth Thakkar, Khoi Than, MD, FAANS

AANS does not endorse any treatment, procedure, product or physician mentioned in these patient information sheets. This information is provided as an educational service and is not intended to serve as medical advice. Anyone seeking specific neurosurgical advice or assistance should consult their neurosurgeon or search for one in their area through the AANS Find a Board-certified Neurosurgeon online tool.