What is a traumatic brain injury?
A traumatic brain injury is an injury to the skull and brain. It can be closed, which means that the brain is not exposed or in danger of being exposed to the external environment, or open, when the brain is exposed to the external environment. In closed injury a skull fracture may also be present, while in open one there is always a fracture. Hematoma may also be present in traumatic brain injury. A hematoma is called epidural hematoma when it is outside the dura mater of the brain. A hematoma between the dura mater and the brain is called subdural, while when the hematoma is inside the brain it is called intracerebral.
The human brain is very sensitive and well protected from injury. It is closely surrounded by membranes (the meninges), inside the hard skull which is also covered by a muscular casing
The cells that make up the brain are fragile and can be easily injured if they are stretched or torn. This happens when a blow to the head causes the brain to collide with the hard and uneven inner surface of the bones, inside the skull.
The swelling that occurs after each injury exerts even more pressure on the cells and reduces blood flow. Adequate flow and oxygenation are vital for the brain cells. Any deprivation of blood or oxygen can cause an even greater harm.
What symptoms may be caused?
Usually, closed head injuries occur when the head comes into violent contact with another object in a way that causes the brain to move abruptly inside the skull. When the fragile brain tissue receives this violent push, it is subject to focal (i.e. localised at some point) and diffuse brain injury
There are various degrees of head injuries, from mild to severe. A mild head injury usually results in reversible brain damage and thus temporarily affects the patient’s neurological functions, whereas a severe injury almost always causes neurological damage. The location and severity of the injury determines the nature and degree of permanence of the neurological problems.
How is traumatic brain injury diagnosed?
The presence of a head injury is established by the history of a blow to the head and/or the presence of physical signs of head trauma, such as fractures, abrasions, or bruises of the skull or face. Blood or cerebrospinal fluid (CSF) flowing from the nose or ear may indicate a trauma to the skull. Both the Battle sign (bruise behind the ear) and the bruises of the eyelids are indicative of fractures of the base of the skull and definitely signs of a brain injury.
In addition, there may be neurological problems, these may be general, such as coma, lethargy or drowsiness, or seizures, and/or focal, (localised), such as paralysis of an arm and/or leg, or speech disorders. Diagnostic tests such as CT scans are used in an attempt to identify possible organic damage caused by the trauma. This can be blood clots (haematoma), skull fracture etc.
If detected, these abnormalities may mean that special surgical treatment is required. However, surgery can only reduce the pressure on the brain, but it cannot improve cerebral edema or brain cell damage.
How can a traumatic brain injury be treated?
The treatment of a head injury depends on its severity. In more severe cases, surgery may be required to reduce the increased intracranial pressure by removing the hematomas.
Medical measures to reduce intracranial pressure include: hyperventilation (increasing breathing), various medications, reducing body temperature and inducing a comatose state using sedative drugs (sedation). The doctor may also place an intracranial recording device in or on the brain to measure intracranial pressure and/or cerebral blood flow so that the effects of various treatments can be recorded and the desired corrections can be made.
Intracranial pressure can be successfully controlled with medication alone, and may not ultimately be so severe as to require surgery. In combination with the other means of controlling the increased intracranial pressure, the patient should be properly oxygenated and have his/her blood pressure controlled. They may need to be put on a ventilator to get oxygen, to control the rate of breathing and the pressure inside the lungs.
Seizures can occur in any case of brain injury. If they occur, then appropriate medication is applied.
What is Primary Injury?
When the head receives a strong blow, the meninges and skull act as a protective barrier to the swelling that follows. Cerebral oedema can cause an increase in pressure in the skull, resulting in an increase in intracranial pressure, so nerve cells are damaged even more. Another cause of increased intracranial pressure and cell damage associated with brain damage is hematomas.
There is space inside the skull, just enough for the brain, cerebrospinal fluid and blood. Any increase in mass or volume damages the neurons and reduces the blood supply to the brain.
What is Secondary Injury?
If the edema is severe, it may not be possible to reduce the pressure inside the skull. This puts even more strain on the already injured brain cells, and can put pressure on the brain stem, controlling all vital functions. This is called “herniation” and is a life-threatening complication.
Not only does the increased intracranial pressure associated with edema and hematoma cause herniation, but they can also cause a reduction in the blood flow to the brain and, consequently, ischemia. This means that traumatic brain injury could also be complicated by reduced blood flow (ischemia). In this case, the neurons do not receive sufficient amounts of nutrients, such as oxygen and glucose. Ischemia then may cause an even greater damage to the neurons and leads to even greater cerebral edema and further reduction of the cerebral blood flow.
What are Level of Consciousness Changes?
Brain injuries, whether mild, moderate or severe, also cause an alteration in the person’s ability to react and respond to the external environment. This is called a “change in the patient’s level of consciousness”. The level of consciousness varies from full alertness, through the ability to respond appropriately when the patient is awakened from sleepiness and lethargy, then to diminished reactions and up to coma. Coma represents the complete loss of consciousness and the inability to respond to stimuli in the environment in any way other than reflexively. Both the degree and duration of the coma reflect the severity of the brain injury. The longer the patient stays in a coma, the less chance of a good outcome.
Only after sufficient alertness has been achieved can the characters and qualities of the patient’s reactions be seen and appreciated. The content of the patient’s reactions is the most important element to assess when determining any change in personality, behaviour and quality of life. Changes due to brain injury can range from mild or barely noticeable to very significant. Given the complexity of the brain, it is very difficult to predict the extent of these changes. There are no tests or X-rays that show these changes. This uncertainty of outcome is the most difficult part that patient families face.