Traumatic Brain Injury

Traumatic Brain Injury (TBI) is a disruption in the normal function of the brain that can be caused by a blow, bump or jolt to the head, the head suddenly and violently hitting an object or when an object pierces the skull and enters brain tissue. Observing one of the following clinical signs constitutes alteration in the normal brain function

• Loss of memory for events before or after the event (amnesia)
• Loss of or decreased consciousness
• Focal neurological deficits such as muscle weakness, loss of vision, change in speech
• Alteration in mental state such as disorientation, slow thinking or difficulty concentrating

Symptoms of a TBI can be mild, moderate, or severe, depending on the extent of damage to the brain. Mild cases can result in a brief change in mental state/ consciousness. Severe cases can result in extended periods of unconsciousness, coma, or even death.

PREVALENCE

According to the CDC, about 2.87 million cases of TBI occurred in the U.S. in 2014 with over 837,000 cases occurring amongst children. An estimated 13.5 million live with a disability due to traumatic brain injury in the U.S. alone.

• Estimated annual direct and indirect TBI costs=$76.5 billion.
• About 288,000 hospitalizations for TBI every year, more than 20x the number of hospitalizations for spinal cord injury.
• From 2006, there has been a 53% increase in the total number of TBI related ED visits, hospitalizations and deaths.
• Among children ages 14 and younger, TBI accounts for an estimated 2,529 deaths, 23,000 hospitalizations, and 837,000 emergency room visits.
• Each year, 80,000-90,000 people experience the onset of long-term or lifelong disabilities associated with TBI.
• Males are 78.8% of all reported TBI accidents, while females represent 21.2%, with higher rates of TBI amongst males (959 per 100,000) than females (811 per 100,000).
• Sports and recreational activities contribute to about 21% of all TBIs among American children and adolescents.
• The highest rates of TBI are observed in older adults (≥75 years; 2,232 per 100,000 population), very young (0 to 4 years; 1591 per 100,000), and young adults (15 to 24 years; 1081 per 100,000).
• The mortality rate for TBI is 30/100,000, or an estimated 50,000 deaths in the U.S. annually.
• Deaths from head injuries account for 34% of all traumatic deaths. Beginning at age 30, the mortality risk after head injury begins to increase.
• The leading causes of TBI-related deaths are due to motor vehicle crashes, suicides, and falls.
• The leading causes of non-fatal TBI in the US occur from falls (35%), motor vehicle-related injuries (17%), and strikes or blows to the head from or against an object (17%), such as sports injuries.

SYMPTOMS

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

• Vomiting
• Paralysis
• Coma
• Loss of consciousness
• Slow breathing rate with an increase in blood pressure
• Ringing in the ears or changes in hearing
• Cognitive difficulties
• Inappropriate emotional responses
• Speech difficulties (slurred speech, inability to understand and/or articulate words)
• Lethargy
• Headache
• Confusion
• Dilated pupils
• Vision changes (blurred vision or seeing double, unable to tolerate bright light, loss of eye movement, blindness)
• Cerebrospinal fluid (CSF) (clear or blood-tinged) appear from the ears or nose
• Dizziness and balance concerns
• Breathing problems
• Slow pulse
• Difficulty swallowing
• 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.

TYPES OF INJURIES

TBIs can cause “mass lesions,” with an area of localized injury such as hematomas and contusions that increase pressure within the brain. Summarized below are different types of sequelae developed from TBIs:

• Hematoma
• Contusion:
• Intracerebral Hemorrhage: Describes bleeding within the brain tissue, can be related to other brain injuries, especially contusions. The size and location of the hemorrhage helps determine whether it can be removed surgically.
• Subarachnoid Hemorrhage: Caused by bleeding into the subarachnoid space. It appears as diffuse blood spread thinly over the surface of the brain and commonly after TBI. Most cases of SAH associated with head trauma are mild. Hydrocephalus can result from severe traumatic SAH.
• Diffuse Injuries: Microscopic changes that do not appear on CT scans and are scattered throughout the brain. This category of injuries, called diffuse brain injury, can occur with or without an associated mass lesion.
• Diffuse Axonal Injury: Refers to impaired function and gradual loss of axons.These long extensions of nerve cells enable them to communicate with each other. If enough axons are harmed in this way, the ability of nerve cells to communicate with each other and to integrate their function can be lost or greatly impaired, possibly leaving a 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 occur commonly in a significant number of TBI patients. This is crucial since a brain that has just undergone a traumatic injury is especially sensitive to slight reductions in blood flow. Changes in blood pressure during the first few days after head injury can also have an adverse effect.
• Skull Fractures: Linear skull fractures or simple breaks or “cracks” in the skull can accompany TBIs.

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

TESTING AND DIAGNOSIS

Anyone who has signs of moderate or severe TBI should be receiving medical attention ASAP. Because doctors cannot do much to reverse initial brain damage initiated through trauma, medical providers try to stabilize an individual with TBI and focus on preventing further injury.

First, the cardiac and pulmonary function is assessed. Next, a quick examination of the entire body is carried out, 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 one’s pupils to become smaller in bright light is also measured. In patients with large mass lesions or ICP, one or both pupils can be very wide ("blown."), suggesting that a large mass lesion can be present. Brainstem reflexes including gag and corneal (blink) can also be tested.

Radiological Tests

A computed tomography scan (CT/CAT scan) is the gold standard for the radiological assessment of a TBI patient. A CT scan is easy to perform and excellent for detecting the presence of blood and fractures, 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 U.S. have readily available CT scanning, a more accurate test, rendering the routine use of skull x-rays for TBI patients to decline.

Magnetic resonance imaging (MRI) is not commonly used for acute head injury, as it takes longer to perform a MRI than a CT. Because it is difficult to transport an acutely-injured patient from the emergency room to a MRI scanner, the use of MRI is impractical. However, once a patient’s condition stabilizes, MRI can demonstrate the existence of lesions that were not detected on the CT scan. This information is often more useful for determining prognosis than for influencing treatment.

TREATMENT

Surgery

Many patients with moderate to severe head injuries travel from the emergency to operating room. Often, surgery is performed to remove a large hematoma or contusion significantly compressing the brain or raising the pressure within the skull. Post-surgery, these patients are kept under observation in the intensive care unit.

Other head-injured patients who cannot head to the operating room immediately are instead taken from the emergency room to the ICU. Since contusions or hematomas can enlarge over the hours or days post head injury, immediate surgery is not recommended on these patients until several days afterward. Delayed hematomas can be discovered when a patient's neurological exam worsens or when their ICP increases. In other cases, a routine follow-up CT scan to determine whether a small lesion has changed in size shows that the hematoma or contusion has enlarged significantly. Here,, the safest approach is to remove the lesion before it enlarges and causes neurological damage.

During surgery, the hair over the affected part of the head is usually shaved. After the scalp incision, the removed bone is extracted in a single piece/flap then replaced after surgery unless contaminated. The dura mater is carefully cut to reveal the underlying brain. After hematoma or contusion is removed, the neurosurgeon ensures the area is not bleeding. They then close the dura, replace the bone, and close the scalp. If the brain is very swollen, some neurosurgeons can decide not to replace the bone until the swelling decreases, which can take up to several weeks. The neurosurgeon can elect to place an ICP monitor or another monitor if these were not already in place. The patient is returned to the ICU for observation and additional care.

Non-Surgical Treatments

Currently, medication administered to prevent nerve damage or promote nerve healing after TBI is not available. The primary goal in the ICU is to prevent secondary injury to the brain. The "primary insult" is the initial trauma to the brain, but the "secondary insult" is the subsequent development that can contribute to neurological injury. For example, an injured brain is very sensitive and vulnerable to decreases in blood pressure otherwise well tolerated. One way to avoid secondary insults is 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 major role of ICU management is the prevention of secondary insults in head-injured patients.

Various monitoring devices can assist health care personnel in patient care. Placement of an ICP monitor into the brain can help detect excessive swelling. One commonly used variety of ICP monitor is a ventriculostomy (a narrow, flexible, hollow catheter passed into the ventricles [fluid spaces in the center of the brain]) to monitor ICP and drain CSF if ICP increases. Another commonly used intracranial pressure monitoring device involves the placement of a small fiberoptic catheter directly into the brain tissue. Additional catheters can be added to measure brain temperature and tissue oxygenation levels. Placement of an oxygen sensor into the jugular vein can detect how much oxygen the brain is using, a measurement that can be related to the degree of brain damage. Many other monitoring techniques are under investigation to determine whether they can help improve outcome after head injury or provide additional information about caring for TBI patients.

OUTCOME

One of the most widely used systems to classify outcome from head injury is the Glasgow Outcome Scale (GOS). Patients with mild head injury (often defined as GCS score on admission of 13-15) tend to do well. They can experience headaches, dizziness, irritability or similar symptoms, but these gradually improve in most cases.

Patients with moderate head injuries fare less favorably. Approximately 60% make a positive recovery and about 25% are left with a moderate degree of disability. Death or a persistent vegetative state will be the outcome in about 7-10% of cases. The remainder of patients will have a severe degree of disability.

The group of severely head-injured patients has the worst outcomes. 25-33% of these patients have positive outcomes. Moderate and severe disability each occur in about ⅙ of patients, with moderate disability being slightly more common. About 33% of these patients fail to survive. The remaining few percent remain persistently vegetative.

These statistics apply to patients with so-called closed head injuries. For penetrating head injuries (commonly by handguns) the outcomes follow a different pattern. More than 50% of all patients with gunshot wounds to the head, alive upon arrival at a hospital, do not survive. Patients with relatively mild injuries (GCS score of 13-15) tend to do fairly well. Comparatively few patients suffer injuries of intermediate severity (GCS score of 9-12) from gunshot wounds; it is this group that has the most variability in outcomes.

Despite its usefulness, the GOS is not a good tool to measure subtle emotional or cognitive problems. Several months after a severe head injury, patients with a good score on the GOS can have neuropsychological disabilities. Tremendous effort is directed to finding better ways to evaluate these problems, improving the quality of prehospital, acute and rehabilitative care, and research to learn more about the effects of head injury and potential treatment options.

REHABILITATION

After acute-care hospital, certain people benefit from a rehabilitation program, often those with less severe initial injuries or those that started to show significant improvement.

At times, transfer to a rehabilitation hospital or to the rehabilitation service of a large hospital can expedite further recovery. Constant vigilance is required for severely injured patients or slowly recovering patients to prevent the gradual problems that onset with joint mobility, skin integrity, respiratory status, infection, and many other physiological functions. Patients with moderate or mild injuries, or severely injured patients who have improved sufficiently, are likely candidates for outpatient therapy.

Most head-injury rehabilitation centers emphasize compensatory strategies, which help patients learn to reach the maximum function levels allowed by their impairments. The concept of cognitive retraining, a controversial concept, which presumes that at least some of the brain's cognitive capacity can be restored by constant repetition of certain simple tasks, is also emphasized at many centers. Head injury rehabilitation centers work with patients' families to educate them about realistic expectations and best help their injured family members.

General Head Injury Prevention Tips

• Keep firearms unloaded in a locked cabinet or safe, and store ammunition in a separate, secure location.
• Wear a seatbelt when you drive or ride in a motor vehicle.
• Never drive under the influence of drugs, alcohol, or ride as a passenger with anyone under the influence.
• Remove hazards in the home that can 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.

SPORTS AND RECREATION HEAD INJURY PREVENTION TIPS

• Buy and use helmets or protective headgear approved by the American Society for Testing and Materials (ASTM).
• Follow all rules and warning signs at water parks, swimming pools, and public beaches.
• Do not dive in water less than 12’ deep or in above-ground pools. Check the depth and for debris in the water before diving.
• Supervise younger children at all times.
• 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.
• Perform regular safety checks of sports fields, playgrounds and equipment.
• Discard and replace damaged sporting equipment or protective gear
• Never slide head-first when stealing a base.
• Do not allow younger children to use sporting equipment or play sports unsuitable for their age.
• Avoid playgrounds with hard surfaces.
• Wear appropriate clothing for the sport.
• Do not wear any clothing that can interfere with vision.
• Do not participate in sports when you feel ill or very tired.

GLOSSARY OF TERMS

• Anoxia – an absence of oxygen supply to an organ's tissues although there is adequate blood flow to the tissue
• Subcortical – the region beneath the cerebral cortex
• 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 CS
• Aphasia – loss of the ability to express oneself and/or to understand language
• Arachnoid – middle layer of membranes covering the brain and spinal cord
• Ataxia – shaky and unsteady movements that result from the brain's failure to regulate the body's 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 carries materials from the nerve terminals back to the nerve cell
• Brain Stem – the stem-like 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 displacement
• Concussion – a disruption, often temporary, of neurological function resulting from a head injury or violent shaking
• 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 double vision
• Dura mater – the outermost, toughest and most fibrous of the three membranes (meninges) covering the brain and the spinal cord
• 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 can 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
• Dysarthria – speech that is characteristically slurred, slow and difficult to understand
• Edema – 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
• Hemiplegia – 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 cord
• 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
• Agnosia – failure to recognize familiar objects with the sensory mechanism is intact
• Agraphia – inability to express thoughts in writing
• Alexia – inability to read
• Amnesia – lack of memory about events during a particular period of time
• Anosmia – loss of the smell
• Subarachnoid hemorrhage – Blood in, or bleeding into, the space under the arachnoid membrane, most commonly from trauma or from rupture of an aneurysm