Understanding the Mechanics TRAUMATIC BRAIN INJURIES
Traumatic brain injury (TBI) occurs when a blow to the head causes brain damage. TBI includes anything from mild concussions up to severe brain damage. Treatment can range from rest only to intensive care and emergency surgery. Survivors can face a lifetime of disruptions, physical and mental impairment severe cognitive changes. Most patients will undergo long-term rehabilitation, and some might even need to relearn basic skills.
MAIN CAUSES OF TRAUMATIC BRAIN INJURIES
In the United States, the most common causes of TBI include falls (35.2%), motorcycle and car accidents, automobile accidents involving pedestrians (17.3%) and assaults (10%) with or without a weapon. Combat injuries combine blunt (closed head injuries), penetrating (with retained fragments, perforating, grooving the skull, tangential and cranial facial degloving) and blast-over pressure CNS injuries. Approximately one and a half million people suffer TBI annually in the United States. Fifty-two thousand people die, and 1.365 million people are treated and released, while another 275,000 people are hospitalized with moderate to severe symptoms. More than 30,000 children have disabled annually. The estimated cost of TBI annually exceeds $48 billion.
PRIMARY AND SECONDARY TRAUMATIC BRAIN INJURIES
The primary injury, caused at the moment of impact, can involve a specific part of the brain, or it can affect the entire brain. The impact of the blow to the head might cause the brain to literally crash against the inside of the skull repeatedly as it moves back and forth. The impact can cause bruising, bleeding and tearing of nerve fibers.
Directly after the impact, symptoms might be absent. Often though, the condition of the patient can deteriorate very rapidly. At first, the patient might be confused. Memory and vision might be impaired, and dizziness and even unconsciousness might follow.
The brain often experiences delayed trauma. Swelling, when it occurs, can push the brain against the skull, and this might reduce the flow of blood and access to oxygen. Injuries resulting from trauma are classified as secondary injuries. The secondary injuries are very often more detrimental than the primary injuries were.
TBI ARE CLASSIFIED INTO THREE MAIN CATEGORIES, DEPENDING ON SEVERITY
Mild TBI (Concussions included) will, if at all, result in only brief loss of consciousness, and the patient will normally be awake – with eyes open. Symptoms might include a headache, disorientation, confusion, and loss of memory.
Moderate TBI will lead to loss of consciousness between twenty minutes and six hours. The patient will be sluggish and inert, but the eyes will open to stimulation. The eyes will respond to any stimulation and will not open.
The central nervous system dictates our thoughts and feelings and our movement and activities with the information received from our nerve cells, mind and environment. The main parts of our central nervous system are the brain, the spinal cord and the nerves throughout the body.
The brain is divided into two halves. The two halves (hemispheres) work together to command our thoughts and behaviors. It also controls reasoning, speaking, writing and numerical skills. The right side controls the left side of the body’s movements and is the center of insight and imagination, awareness of the multi-dimensional nature of reality (three dimensions), creativity and musical ability as well as our interpretation skills.
Each hemisphere of the brain is further divided into smaller parts or lobes. The frontal lobe is responsible for the most important movements of the eyes, the trunk, and the extremities. This is where memory is located, judgment as well as the control mechanisms to moderate behavior.
Behind the frontal lobe, the parietal lobe controls the remaining movements and the senses, as well as our perception and sense of space. Alongside the frontal and parietal lobes, we find the temporal lobe. The temporal lobes are co-responsible for memory, controls language and are crucial in the experience and control of emotions.
At the back of the brain, we find the occipital lobe, which interprets what we see with our eyes. These lobes are all part of the cerebrum of the brain. Under the cerebrum, just above the brainstem, the cerebellum controls our coordination and timing. The brainstem – also popularly known as the reptile brain – is responsible for the automatic functions in the body. This includes breathing, blood pressure and arousal. The slightest injury to the brainstem can lead to coma or a very low level of consciousness.
PREVENTION OF TRAUMATIC BRAIN INJURIES
Prevention is better than cure. This still holds true, especially for traumatic brain injuries which are to a very large degree preventable.
Headgear & Protection
Millions of people can be protected from traumatic brain injuries by simply wearing protective gear when participating in certain activities. By selecting the best headgear available, safety can be maximized. Whether riding a bicycle, skateboard, motorcycling or driving an all-terrain vehicle, wearing the required safety and head gear will improve your chances considerably. This is especially true when participating in sports. Football, hockey, and numerous other sports require headgear. Choosing and fitting the right headgear that fits well, is essential. When driving, always wear a seatbelt. Make sure that all children are secured and that age-appropriate child safety seats are properly secured to the car and to the child.
Alcohol & Drugs
One of the leading causes of vehicular accidents and accidents involving pedestrians is intoxication. Driving – or even walking – while under the influence of drugs and alcohol is dangerous. No one should ever get behind the wheel of a car or walk where there is any traffic, while even slightly intoxicated. The same goes for diabetics who use insulin and patients on medication. Do not drive when you are vulnerable to either the side effects of medication or the condition the medication is used for. People with poor eyesight must have their eyes checked regularly, and those with night-blindness must stay off the roads after dusk. Sensitive eyes can be protected and enhanced by wearing suitable sunglasses.
Exercise and Fitness
Falls account for a very large proportion of all traumatic brain injuries. One of the primary preventative strategies to prevent falls are exercises that can enhance dexterity, coordination, and balance, and improve strength and stamina. This is especially true for the elderly. Falls more often than not, occurs in the home. Decluttering the home by removing items from the floor and installing safety equipment (non-slip mats in the bathtub; handrails on stairways) can improve safety by a large margin. Adequate lighting on stairways can make a difference. By placing bars on the windows, children can be prevented from falling.
Firearms, Weapons and High Crime Areas
It is advisable to store firearms in a safe or locked cabinet and to store the ammunition separately. When entering a high crime zone, vigilance improves safety. Crowded spaces known for low levels of control, like bars and some restaurants and clubs, can be dangerous too. Again, avoiding these zones altogether or remaining very vigilant, can help prevent possible injury.
DIAGNOSIS OF TRAUMATIC BRAIN INJURIES
When a patient arrives at the emergency room with head injuries, time is of the essence. Doctors need to assess the patient’s condition very quickly to determine the damage. This is done by finding out as much as possible about how the injury happened and what the patient’s symptoms are.
GLASGOW COMA SCORE (GCS)
The Glasgow Coma Score (GCS) is the industry standard. The GCS is a fast 15-point test to grade the patient’s level of consciousness in order to determine whether the injury is mild, moderate or severe. The patient is asked to open his/her eyes, to respond to orientation questions like name, or date, and to follow commands like hold up two fingers or show a thumbs-up. If the patient is unconscious or unable to follow commands, his/her response to painful stimuli is checked. Each response is graded according to the GCS scorecard and added together. Scores range from three to fifteen, a score of 13 – 15 indicates mild TBI; a score of 9-12 indicates a moderate TBI and a score of eight and below, indicates severe traumatic brain injury.
DIAGNOSTIC IMAGING TESTS
Computed Tomography (CT)
A CT scan takes X-ray images from different angles around the head and by using advanced computer algorithms then create cross-sectional images stacked over each other of the bones, blood vessels and soft tissue inside the head and the brain. In this way, detailed images of the anatomical structures of the brain become visible. A scan of the head taken as soon after the injury as possible can help to identify the extent of the damage and the presence of hematomas, bleeding, and fractures. CT scans remain useful throughout the treatment and recovery phase to monitor the evolution of the injury and to aid in making decisions about treatment.
Magnetic Resonance Imaging (MRI)
MRI scans are especially useful for examining the soft tissues of the brain and spinal cord. An MRI uses a large magnet combined with radio waves to give a detailed view of organs and structures inside the body. This is very helpful for the diagnoses of various conditions. Sometimes a contrast agent (dye) might be injected into the patient’s bloodstream. An MRI scan complements the CT scan – it can detect subtle changes in the brain that is invisible to the CT scan.
Magnetic Resonance Spectroscopy(MRS)
The MRS scan uses a large magnet combined with radiofrequency waves to feed signals to a computer that creates detailed images. These tests are added to the MRI scan of the brain after the MRS analyzes molecules like hydrogen ions and protons to measure the chemical metabolism of the brain. The numerical analysis generated this way provides prognoses for the patient’s ability to recover from injury.
The First Few Days
DISORDERS OF CONSCIOUSNESS
After emergency treatment patients can be confronted by a variety of possible conditions and scenarios. To begin with, patients may suffer from altered levels of consciousness or disorders of consciousness (DOC). DOCs can be categorized as coma, vegetative state (VS), minimally conscious state (MCS) and Posttraumatic Confusional State (PTCS).
As a general rule, TBI will often result in the patient entering a comatose state for anything between a few days to several weeks. As the brainstem and the posterior part of the forebrain resume function, the patient will enter a VS state. Some patients may go directly into the VS without ever entering a comatose state.
Coma is a state of deep unconsciousness in which the eyes remain closed, and the patient cannot be aroused at all. Notable is the complete absence of any sign of a sleep-wake cycle. The JFK Coma Recovery Scale-Revised (CRS-R) is the most accurate clinical evaluation measure of disorders of consciousness. It assesses auditory, visual, verbal and motor functions together with communication and arousal levels.
There is no reliable way to predict how long a person will remain in a coma, nor what the long-term effects of the brain injury that caused the coma, will be. People have individual recovery trajectories, and no two injuries of the brain are the same. However, it seems self-evident that a rapid recovery from a coma will be considered a very good sign.
Some people though, after recovering from a coma quickly, might experience some serious problems at a later stage, while some patients might remain in a coma for months and months before making a full recovery.
Despite this, the length of a coma is one of the most reliable predictors of the severity of long-term symptoms after TBI. The longer the coma, the more likely there will be lasting problems.
VEGETATIVE STATE (VS)
A VS can be described as the absence of any behavioral evidence of self-awareness or awareness of the environment when there is evidence of the restoration of the reticular activating system (eyes are opening, or patient is awake). In these circumstances, there is a complete absence of purposeful responses to visual stimuli, touch or unpleasant prodding (pinprick), and an apparent lack of understanding of language or the expression of language.
The outdated use of Persistent VS and Permanent VS are discouraged now, simply because these terms not only describe a level of consciousness but also imply a prognosis, which might be quite misleading.
Even so, statistically the period of sustained VS is relevant for prognosis. Victims who remain in a VS for more than one year after suffering a TBI has a lowered probability of recovering awareness. However, miracles happen very often. According to studies more than 20% of patients in a VS for between 14 and 28 months after injury onset will progress to a minimally conscious state or will regain consciousness. Outcomes for younger patients are on average, more favorable.
Patients who remain in VS can live for five years, and even ten years and miracles revive some of these patients years later, too.
Functional neuroimaging can help to identify covert cognitive functioning in patients with VS by demonstrating physiological reactions (such as changes in regional blood flow) to environmental stimuli. Functional MRI can detect brain activity by detecting the blood oxygen level dependent signal, and studies showed that patients in which fMRI detected brain activity in this way, almost all of them eventually processed to at least a minimally conscious state during the observational period..
MINIMALLY CONSCIOUS STATE (MCS)
Despite MCS being a severely altered state of consciousness, in this state minimal but undeniable behavioral evidence of self-awareness or environmental awareness is demonstrated. In MCs reactions to stimuli occur, but inconsistently. It is, however, clear and present enough to be reproducible and sustained long enough to be differentiated from normal reflexive behavior.
When a patient is asked to follow simple commands or responds with gestural or verbal yes or no affirmations, purposeful behavior or even intelligible verbalization, a diagnosis of MCS can be inferred. MCS has to be carefully differentiated from coma or VS. This can be done by carefully recording the presence of behavioral features absent from the same.
MCS patients will display some signs of cognitive processing and pain perception, while patients in VS do not respond to any noxious stimuli. In MCS, interactive communication is possible. Verbalization, writing and yes/no responses occur and sometimes augmented communication devices can be used. Before the functional use of objects can be inferred the patient has to be able to use two different objects appropriately. Functional outcome for MCS patients is significantly better than for those in VS. It is important to take note that for patients who suffered TBI and are in either a VS or MCS, treatment with amantadine has been shown to improve functional recovery. The use of amantadine should as a matter of course be considered for this population.