Traumatic Brain Injury (TBI)

What is a traumatic brain injury?

A traumatic brain injury, or a TBI, is an injury to the brain caused by a blow or jolt to the head from blunt or penetrating trauma. The injury that occurs at the moment of impact is known as the primary injury. Primary injuries can involve a specific lobe of the brain or can involve the entire brain. Sometimes the skull may be fractured, but not always. During the impact of an accident, the brain crashes back and forth inside the skull causing bruising, bleeding, and tearing of the nerve fibers. Immediately after the accident the person may be confused, not remember what happened, have blurry vision and dizziness, or lose consciousness. At first the person may appear fine, but their condition can decline rapidly. After the initial impact occurs, the brain undergoes a delayed trauma – it swells – pushing itself against the skull and reducing the flow of oxygen-rich blood. This is called secondary injury, which is often more damaging than the primary injury.

Traumatic brain injuries are classified according to the severity and mechanism of injury:

Mild: person is awake; eyes open. Symptoms can include confusion, disorientation, memory loss, headache, and brief loss of consciousness.
Moderate: person is lethargic; eyes open to stimulation. Loss of consciousness lasting 20 minutes to 6 hours. Some brain swelling or bleeding causing sleepiness, but still arousable.
Severe: person is unconscious; eyes do not open, even with stimulation. Loss of consciousness lasting more than 6 hours.

What are the types of TBI?

A concussion is a mild head injury that can cause a brief loss of consciousness and usually does not cause permanent brain injury.
A contusion is a bruise to a specific area of the brain caused by an impact to the head; also called coup or contrecoup injuries. In coup injuries, the brain is injured directly under the area of impact, while in contrecoup injuries it is injured on the side opposite the impact.
A diffuse axonal injury (DAI) is a shearing and stretching of the nerve cells at the cellular level. It occurs when the brain quickly moves back and forth inside the skull, tearing and damaging the nerve axons. Axons connect one nerve cell to another throughout the brain, like telephone wires. Widespread axonal injury disrupts the brain’s normal transmission of information and can result in substantial changes in a person’s wakefulness.
A traumatic subarachnoid hemorrhage (tSAH) is bleeding into the space that surrounds the brain. This space is normally filled with cerebrospinal fluid (CSF), which acts as a floating cushion to protect the brain. Traumatic SAH occurs when small arteries tear during the initial injury. The blood spreads over the surface of the brain causing widespread effects.
A hematoma is a blood clot that forms when a blood vessel ruptures. Blood that escapes the normal bloodstream starts to thicken and clot. Clotting is the body’s natural way to stop the bleeding. A hematoma may be small or it may grow large and compress the brain. Symptoms vary depending on the location of the clot. A clot that forms between the skull and the dura lining of the brain is called an epidural hematoma. A clot that forms between the brain and the dura is called a subdural hematoma. A clot that forms deep within the brain tissue itself is called an intracerebral hematoma. Over time the body reabsorbs the clot. Sometimes surgery is performed to remove large clots

Secondary brain injury occurs as a result of the body’s inflammatory response to the primary injury. Extra fluid and nutrients accumulate in an attempt ot heal the injury. In other areas of the body, this is a good and expected result that helps the body heal. However, brain inflammation can be dangerous because the rigid skull limits the space available for the extra fluid and nutrients. Brain swelling increases pressure within the head, which causes injury to parts of the brain that were not initially injured. The swelling happens gradually and can occur up to 5 days after the injury.

What are the symptoms?

Although described as individual injuries, a person who has suffered a TBI is more likely to have a combination of injuries, each of which may have a different level of severity. This makes answering questions like “what part of the brain is hurt?” difficult, as more than area is usually involved. Depending on the type and location of the injury, the person’s symptoms may include:

Loss of consciousness
Confusion and disorientation
Memory loss/amnesia
Fatigue
Headaches
Visual problems
Poor attention/concentration
Sleep disturbances
Dizziness/loss of balance
Irritability/emotional disturbances
Feelings of depression
Seizures
Vomiting

Diffuse injuries (such as a concussion or diffuse axonal injury) will typically cause an overall decreased level of onsciousness. Whereas, focal injuries (such as an ICH or a contusion) will have symptoms based on the brain area affected.

Every patient is unique and some injuries can involve more than one area or a partial section, making it difficult to predict which specific symptoms the patient will experience.

	Healthy Brain	Injured Brain
Frontal Lobe	Personality, emotions Planning, problem solving Speech (speak & write) Intelligence, concentration Body Movement	Behavior and emotional changes Impaired judgement, motivation, inhibition Difficulty with language (Broca’s aphasia) Reduced mental abilities, memory loss Paralysis on one side of the body
Parietal Lobe	Interprets language, words Sense of touch, pain Interprets vision, hearing, motor Spatial/visual perception	Problems with reading, writing, naming Difficulty distinguishing left from right Lack of awareness/neglect of body parts Difficulties with eye-hand coordination Difficulty with mathematics
Occipital Lobe	Interprets vision Color, light, movement	Defects in vision or blind spots Blurred vision, illusions, hallucinations Difficulty reading and writing
Temporal Lobe	Understanding language Memory Hearing Sequencing Organization	Problems in short- and long-term memory Changes in sexual behavior Increased aggressive behavior Difficulty recognizing faces, naming objects Difficulty understanding language (Wernicke’s aphasia) Common location for seizures
Cerebellum	Balance Coordination Posture	Difficulty coordinating fine movements Difficulty walking, tremors, dizziness Slurred speech
Brainstem	Breathing, heart rate, body temperature, wake and sleep cycles, digestion, coughing, swallowing	Changes in breathing Difficulty swallowing food and water Problems with balance and movement Dizziness and nausea (vertigo)

What causes a TBI?

Common causes include falls, car or motorcycle crashes, vehicular accidents involving pedestrians, athletics, and assaults with or without a weapon.

How is a TBI diagnosed?

When a person is brought to the emergency room with a head injury, doctors will learn as much as possible about his or her symptoms and how the injury occurred. The person’s condition is assessed quickly to determine the extent of injury.

The Glasgow Coma Score (GCS) is a 15-point test used to grade a patient’s level of consciousness. Doctors assess the patient’s ability to 1) open his or her eyes, 2) ability to respond appropriately to orientation questions, (“What is your name? What is the date today?”), and 3) ability to follow commands (“Hold up two fingers, or give a thumbs up”). If unconscious or unable to follow commands, his or her response to painful stimulation is checked. A number is taken from each category and added together to get the total GCS score. The score ranges from 3 to 15 and helps doctors classify an injury as mild, moderate, or severe. Other tests may include:

CT scan
MRI
MRS

How is a TBI treated?

Mild TBI usually requires rest and medication to relieve headache. Moderate to severe TBI require intensive care in a hospital. Bleeding and swelling in the brain can become an emergency that requires surgery. However, there are times when a patient does not require surgery and can be safely monitored by nurses and physicians in the neuroscience intensive care unit (NSICU).

Neurocritical care is the intensive care of patients who have suffered a life-threatening brain injury. Many patients with severe TBI are comatose or paralyzed.; they also may have suffered injuries in other parts of the body. Patients are monitored and awakened every hour for nursing assessments of their mental status or brain function.

Medication

After a head injury, it may be necessary to keep the patient sedated with medications. These medications can be turned off quickly in order to awaken the patient and check their mental status. Because patients often have other injuries, pain medication is given to keep them comfortable.

Hypertonic saline is a medication used to control pressure within the brain. It works by drawing the extra water out of the brain cells into the blood vessels and allowing the kidneys to filter it out of the blood.

Patients who’ve had a moderate to severe traumatic brain injury are at higher risk of having seizures during the first week after their injury. Patients are given an anti-seizure medication (levetiracetam or phenytoin) to prevent seizures from occurring.

Surgery

Surgery is something necessary to repair skull fractures, repair bleeding vessels, or remove large blood clots (hematomas). It is also performed to relieve extremely high intracranial pressure.

A craniotomy involves cutting a hole in the skull to remove a bone flap so that the surgeon can access the brain. The surgeon then repairs the damage (e.g., skull fracture, bleeding vessel, remove large blood clots). The bone flap is replaced in its normal position and secured to the skull with plates and screws.
A decompressive craniectomy involves removing a large section of bone so that the brain can swell and expand. This is typically performed when extremely high intracranial pressure becomes life threatening. At the time the patient is taken to the operating room where a large portion of the skull is removed to give the brain more room to swell. A special biologic tissue placed on top of the exposed brain and the skin is closed. The bone flap is stored in a freezer. One to 3 months after the swelling has resolved and the patient has stabilized from the injury, the bone flap is replaced in another surgery, called cranioplasty.

Clinical Trials

Clinical trials are research studies that test new treatments such as drugs, diagnostics, procedures and other therapies on people to see if they are safe and effective. Research is always being conducted to improve the standard of medical care. Studies can be sponsored by the National Institutes of Health (www.clinicaltrials.gov) as well as private industry and pharmaceutical companies (www.centerwatch.com).

What is recovery like from a TBI?

The recovery process varies depending on the severity of the injury, but typically progresses through stages: coma, confusion/amnesia, and recovery.

When a patient is in a coma, his or her eyes are closed and they show minimal reaction when spoken to or stimulated. Movement that may be seen at this time are basic reflexes or automatic responses to a stimulus. The brain wave activity in a comatose person is very different from that of a sleeping person.
When a patient begins to awaken, the first natural response is that of bodily protection. Patients at this stage will move away from any stimulus or tend to pull at items attached to them in an attempt to remove anything that is uncomfortable or irritating. Their eyes may be open more often, but they may not be aware of their behavior or be able to interact in a meaningful way. It is common for a patient to respond to each stimulus (hearing, seeing, or touching) in the same way. Responses may include increased rate of breathing, moaning, moving, sweating, or a rise in blood pressure.
As the patient continues to wake up, their interactions may become more purposeful. They may look at a person and follow them around the room with their eyes or follow simple commands such as “Hold up your thumb.” Patients tend to be confused and may have inappropriate or agitated behaviors.

Most patients are discharged from the hospital when their condition has stabilized and they no longer require intensive care.

Not all head injuries are the same. Patients recover at different rates and to varying degrees. It is difficult to determine at what point a patient will start understanding and interacting with their caregivers or family in a meaningful way. It is important to have patience; recovery from a brain injury can take weeks, months, or even years.

How can I reduce the risk of a TBI?

There are several ways you can reduce your risk of a traumatic brain injury, including:

Always wear your helmet when riding a bicycle, motorcycle, skateboard, or all-terrain vehicle.
Never drive under the influence of alcohol or drugs.
Always wear your seat belt and ensure that children are secured in the appropriate child safety seats.
Avoid falls in the home by keeping unsecured items off the floor, installing safety features such as non-slip mats in the bathtub, handrails on stairways, and keeping items off of stairs.
Avoid falls by exercising to increase strength, balance, and coordination.
Store firearms in a locked cabinet with bullets in a separate location.
Wear protective headgear while playing sports.