Traumatic Brain Injury
Traumatic brain injury (TBI) is damage to the brain caused by a blow to the head. The severity of the injury may range from minor, with few or no lasting consequences, to major, resulting in profound disability or death.
Although any injury to the brain is serious, and severe damage can be fatal, medical and surgical advances have improved the odds for surviving a TBI. Nevertheless, coping with the life-changing consequences of traumatic brain injury presents a great challenge for patients, families, physicians, therapists, and society.
Traumatic Brain Injury Types
Early Brain Injury
Early brain injury, or early complications of a head injury, can be diffuse or focal.
Diffuse injuries are characterized by microscopic damage throughout many areas of the brain. Forces exerted on the brain tissues cause damage to the axons—the “wires” that enable nerve cells to communicate with each other.
A focal brain injury is confined to a specific area of the brain and causes localized damage that can often be detected with a CT scan or x-ray.
Diffuse Axonal Injury
A diffuse axonal injury (DAI) causes shearing of large nerve fibers and stretching of blood vessels in many areas of the brain. In addition to bleeding (hemorrhage), this type of injury can trigger a biochemical cascade of toxic substances in the brain during the days following the initial injury.
DAI occurs throughout the brain, and the frontal and temporal lobes are particularly susceptible. The most prominent manifestation of DAI is impaired cognitive function, resulting in
- impaired memory, and
- varying degrees of inattentiveness.
DAI also can occur in relatively small, but important, nerve centers (or white matter tracts) causing visual field loss or weakness on one side of the body.
Hypoxic-ischemic injury (HII) causes swelling in the brain that restricts the flow of blood-borne oxygen, glucose, and other nutrients. These injuries can be exacerbated by other injuries to the body that further reduce the amount of oxygen entering the bloodstream through the lungs.
Patients with HII and DAI face a poor prognosis and typically experience memory impairment and reduced cognitive function.
Focal contusions are bruises that cause swelling, bleeding, and destruction of brain tissue. They typically occur in the frontal and temporal lobes, where memory and behavior centers are located. Less often, they occur in the parietal and occipital lobes. Tiny contusions in the brainstem can interfere with the muscles that control eye movement, resulting in double vision (diplopia).
Symptoms of brain contusion include the following:
- Abnormal sensations
- Behavior impairment
- Loss of some or all vision
- Loss of coordination, weakness (less common)
- Memory impairment
Contusions shrink as swelling diminishes but can leave scars in brain tissue that cause permanent neurological impairment.
Signs and Symptoms of TBI
Signs and symptoms of neurological impairment caused by TBI depend on which structures in the brain are damaged.
Common symptoms of brain injury include:
- Anxiety, nervousness
- Behavioral changes:
- difficulty controlling urges (disinhibition)
- inappropriate laughter
- Blurry or double vision (diplopia)
- Difficulty concentrating or thinking
- Difficulty finding words or understanding the speech of others (aphasia)
- Difficulty swallowing (dysphagia)
- Incoordination of movements
- Loss of balance; difficulty walking or sitting
- Loss of memory
- Muscle stiffness and/or spasms
- Sleep difficulties (more or less sleep than pre-injury)
- Slurred and/or slowed speech
- Tingling, numbness, pain, or other sensations
- Sense of spinning (vertigo)
- Weakness in one or more limbs, facial muscles, or on an entire side of the body
Diagnosis of TBI
Patients suffering TBI are typically brought to a hospital emergency room for initial diagnosis and treatment. Once vital signs are assessed and stabilized, and other life-threatening injuries are identified and treated, the process of diagnosing the extent of brain injury begins.
A complete neurological evaluation is performed to rule out conditions requiring neurosurgical attention, such as hematomas, depressed skull fractures, and elevated intracrantial pressure (ICP). X-rays, CT scans, and/or MRI scans may be performed to determine if the bones of the skull are fractured and if bone fragments have penetrated the brain tissues.
The patient may be presented with a series of questions (What is your name? Where are you? What day is it?) and given simple commands (Wiggle your toes. Hold up two fingers.) to determine if he or she can open their eyes, move, speak, and understand what is happening around them. If possible, a detailed medical history is performed to identify any previous injuries, existing seizure disorders, learning disabilities, prior psychiatric or psychological treatment, and/or substance abuse.
The patient’s degree of consciousness is assessed to determine the severity of brain injury and predict his or her chances for recovery. To do this, physicians typically use the Glasgow Coma Scale (GCS), which measures the patient’s ability to open their eyes, move, and speak. The more severe the injury, the lower the total score suggesting little chance for complete recovery.
Glasgow Coma Scale
4 = Responds spontaneously
3 = Responds to voice
2 = Responds to pain
1 = No response
Best Motor Response
6 = Follows commands
5 = Localizes to pain
4 = Withdraws to pain
3 = Decorticate (produces an exaggerated posture of upper extremity flexion and lower extremity extension in response to pain)
2 = Decerebrate (produces an exaggerated posture of extension in response to pain)
1 = No Response
Best Verbal Response
5 = Oriented and converses
4 = Disoriented and converses
3 = Inappropriate words
2 = Incomprehensible sounds
1 = No response
Total scores of 8 or below indicate a true coma and severe brain injury. Scores of 9 to 12 suggest moderate brain injury; scores of 13 and above indicate mild brain injury. However, the severity of the brain injury is not determined by GCS alone, as treatable conditions such as infection and dehydration may lower the GCS score.
When the patient is unconscious, the duration or length of coma (LOC) may be used to assess the severity of TBI and predict outcome. The longer the length of coma, the more severe the injury is. An LOC of less than about 20 minutes reflects a mild brain injury; longer than about 6 hours after admission reflects severe injury; between 20 minutes and 6 hours suggests moderate injury.
The neurological examination may show signs indicating the severity of injury such as increased reflexes and muscle tone (spasticity), abnormal movements (tremors), difficulty swallowing, or slurring of speech, all of which may indicate a moderate to severe head injury.
Treatment for TBI
There are three stages of treatment for brain injury:
- Acute—to stabilize the patient immediately after the injury;
Subacute—to rehabilitate and return the patient to the community; and
Chronic—to continue rehabilitation and treat the long-term impairments.
Acute Treatment for TBI
Initial acute treatment focuses on saving the victim’s life. Rescue or emergency personnel unblock airways, assist breathing, and keep blood circulating. Cardiopulmonary resuscitation may be as necessary. Treatment then focuses on stabilizing the patient. Hospital personnel then take over, working to maintain the body fluid levels and prevent or treat infections and other complications. Several types of TBI require surgery.
Seizures may occur seconds, weeks, or years after TBI. A seizure can be a minor twitching of one finger or limb, or a complete loss of consciousness accompanied by involuntary movements of the entire body. Seizures can be particularly dangerous during this time, so most patients with moderate to severe TBI receive antiseizure medication for at least the first few weeks.
Another important aspect of acute care is the prevention of other medical problems. One concern is the development of abnormally high or low levels of sodium, calcium, sugar, or other substances in the blood that can worsen confusion and precipitate seizures. TBI patients also are at high risk for infections, including pneumonia, urinary tract infections, and sinusitis, which must be treated promptly and aggressively.
Subacute Treatment for TBI
Subacute treatment for TBI is provided after stabilization, which ranges from medical stability to a patient’s return to the community or admission to a chronic care facility. The patient is usually admitted to an acute rehabilitation hospital equipped to manage TBI and its complications. At admission, most patients still are in post-traumatic amnesia (PTA).
The main goals of subacute treatment are
- early detection of complications,
- facilitation of neurological and functional recovery, and
- prevention of additional injury.
Early Detection of TBI Complications
In subacute treatment, facility staff watches for and treat bedsores, muscle contractions, infections, and other complications, such as fluid accumulation in the brain (e.g., hydrocephalus, subdural hygromas), that may require surgical treatment. A neurologist investigates for complications if the patient fails to progress as expected.
Treatment for Chronic TBI
Disabilities from TBI may last a lifetime, and different interventions may be appropriate even many years later. This is particularly true for survivors of moderate to severe TBI. It is essential for survivors, their families, and caregivers to be involved in designing and implementing the rehabilitation plan.
There are two categories of chronic treatment:
- Community-based rehabilitation and return to work or school, and
- Treatment of long-term consequences of the injury.
Community-based Rehabilitation for TBI
Ultimately, rehabilitation must take place in the community rather than the controlled environment of a rehabilitation facility. Some patients do best with individual therapy (speech, occupational, physical) at an outpatient facility or at home.
For others, a multidisciplinary, case-managed program works best. Most urban regions in the United States have these programs. This approach utilizes a team of professionals that is usually composed of one or more therapists and social workers, a case manager, and vocational specialist. Case-managed programs are very effective, especially for patients with complex medical and social problems.
Treatment of TBI Consequences
Patients may have residual symptoms that require skilled management by qualified neurologists, physiatrists, and neuropsychologists.
Common symptoms and their related treatments include:
- Abnormal muscle tone (e.g., spasticity, dystonia) may be treated with physical therapy, oral medication, and minor surgery.
- Chronic pain sometimes requires medication, physical therapy, and psychological techniques.
- Depression, anxiety, and behavioral problems usually are treated with medication and psychotherapy.
- Seizures and headaches may require medication.
The Glasgow Coma Scale is useful for predicting early outcome from a head injury but it is less useful for estimating how a patient eventually will function in daily, independent living.
Many rehabilitation centers use the Ranchos Los Amigos Scale of Cognitive Functioning to follow the recovery of the head injury survivor and to determine when he/she is ready to begin a structured rehabilitation program. The scale is divided into eight stages, from coma to appropriate behavior and cognitive functioning.
Rancho Los Amigos Levels of Cognitive Functioning
I. No response to stimulation
II. Generalized response to stimulation
III. Localized response to stimulation
IV. Confused, agitated behavior
V. Confused, inappropriate, nonagitated behavior
VI. Confused, appropriate behavior
VII. Automatic, appropriate behavior
VIII. Purposeful, appropriate behavior
This scale does not take into account many changes in the patient’s cognitive, memory, and motor functions that suggest whether he or she will be able to return to work or school. Assessments by neuropsychologists, speech pathologists, and therapists are needed.
The amount of social support a person receives gradually becomes the most important factor in ensuring the fullest possible recovery. Once the patient plateaus, family, friends, and an experienced treatment team of physicians, therapists, social workers and psychologists must work together to provide critical emotional, physical, medical, and psychological support.