Brain Injury Support Group

Traumatic brain injury (TBI), traumatic injuries to the brain, also called intracranial injury, or simply head injury, occurs when a sudden trauma causes brain damage. TBI can result from a closed head injury or a penetrating head injury and is one of two subsets of acquired brain injury (ABI). The other subset is non-traumatic brain injury (i.e. stroke, meningitis, anoxia). Parts of the brain that can be damaged include the cerebral hemispheres, cerebellum, and brain stem (see brain damage). Symptoms of a TBI can be mild, moderate, or severe, depending on the extent of the damage to the brain. Outcome can be anything from complete recovery to permanent disability or death. A coma can also affect a child's brain.

The damage from TBI can be focal, confined to one area of the brain, or diffuse, involving more than one area of the brain. Diffuse trauma to the brain is frequently associated with concussion (a shaking of the brain in response to sudden motion of the head), diffuse axonal injury, or coma. Localized injuries may be associated with neurobehavioral manifestations, hemiparesis or other focal neurologic deficits.

Types of focal brain injury include bruising of brain tissue called a contusion and intracranial hemorrhage or hematoma, heavy bleeding in the skull. Hemorrhage, due to rupture of a blood vessel in the head, can be extra-axial, meaning it occurs within the skull but outside of the brain, or intra-axial, occurring within the brain. Extra-axial hemorrhages can be further divided into subdural hematoma, epidural hematoma, and subarachnoid hemorrhage. An epidural hematoma involves bleeding into the area between the skull and the dura. With a subdural hematoma, bleeding is confined to the area between the dura and the arachnoid membrane. A subarachnoid hemorrhage involves bleeding into the space between the surface of the brain and the arachnoid membrane that lies just above the surface of the brain, usually resulting from a tear in a blood vessel on the surface of the brain. Bleeding within the brain itself is called an intracerebral hematoma. Intra-axial bleeds are further divided into intraparenchymal hemorrhage which occurs within the brain tissue itself and intraventricular hemorrhage which occurs into the ventricular system.

TBI can result from a closed head injury or a penetrating head injury. A closed injury occurs when the head suddenly and violently hits an object but the object does not break through the skull. A penetrating injury occurs when an object pierces the skull and enters brain tissue.

As the first line of defense, the skull is particularly vulnerable to injury. Skull fractures occur when the bone of the skull cracks or breaks. A depressed skull fracture occurs when pieces of the broken skull press into the tissue of the brain. A penetrating skull fracture occurs when something pierces the skull, such as a bullet, leaving a distinct and localized traumatic injury to brain tissue. Skull fractures can cause cerebral contusion.

Another insult to the brain that can cause injury is anoxia. Anoxia is a condition in which there is an absence of oxygen supply to an organ's tissues, even if there is adequate blood flow to the tissue. Hypoxia refers to a decrease in oxygen supply rather than a complete absence of oxygen, and ischemia is inadequate blood supply, as is seen in cases in which the brain swells. In any of these cases, without adequate oxygen, a biochemical cascade called the ischemic cascade is unleashed, and the cells of the brain can die within several minutes. This type of injury is often seen in near-drowning victims, in heart attack patients (particularly those who have suffered a cardiac arrest, or in people who suffer significant blood loss from other injuries that then causes a decrease in blood flow to the brain due to circulatory (hypovolemic) shock.

Medical care usually begins when paramedics or emergency medical technicians arrive on the scene of an accident or when a TBI patient arrives at the emergency department of a hospital. Because little can be done to reverse the initial brain damage caused by trauma, medical personnel try to stabilize the patient and focus on preventing further injury. Primary concerns include insuring proper oxygen supply, maintaining adequate blood flow, and controlling blood pressure. Since many head-injured patients may also have spinal cord injuries, the patient is placed on a back-board and in a neck restraint to prevent further injury to the head and spinal cord.

Medical personnel assess the patient's condition by measuring vital signs and reflexes and by performing a neurological examination. They check the patient's temperature, blood pressure, pulse, breathing rate, and pupil size and response to light. They assess the patient's level of consciousness and neurological functioning using the Glasgow Coma Scale.

Imaging tests help in determining the diagnosis and prognosis of a TBI patient. Patients with mild to moderate injuries may receive skull and neck X-rays to check for bone fractures. For moderate to severe cases, the gold standard imaging test is a computed tomography (CT) scan, which creates a series of crosssectional X-ray images of the head and brain and can show bone fractures as well as the presence of hemorrhage, hematomas, contusions, brain tissue swelling, and tumors. Magnetic resonance imaging (MRI) may be used after the initial assessment and treatment of the TBI patient. MRI uses magnetic fields to detect subtle changes in brain tissue content and can show more detail than X-rays or CT. The use of CT and MRI is standard in TBI treatment, but other imaging and diagnostic techniques that may be used to confirm a particular diagnosis include cerebral angiography, electroencephalography (EEG), transcranial Doppler ultrasound, and single photon emission computed tomography (SPECT).

Approximately half of severely head-injured patients will need surgery to remove or repair hematomas or contusions. Patients may also need surgery to treat injuries in other parts of the body. These patients usually go to the intensive care unit after surgery.

Sometimes when the brain is injured swelling occurs and fluids accumulate within the brain space. It is normal for bodily injuries to cause swelling and disruptions in fluid balance. But when an injury occurs inside the skull-encased brain, there is no place for swollen tissues to expand and no adjoining tissues to absorb excess fluid. This increased pressure is called intracranial pressure (ICP).

Medical personnel measure a patient's ICP using a probe or catheter. The instrument is inserted through the skull to the subarachnoid level and is connected to a monitor that registers the patient's ICP. If a patient has high ICP, he or she may undergo a ventriculostomy, a procedure that drains cerebrospinal fluid (CSF) from the ventricles to bring the pressure down. Drugs that can be used to decrease ICP include mannitol or barbiturates.

Rehabilitation is an important part of the recovery process for a TBI patient. During the acute stage, moderately to severely injured patients may receive treatment and care in an intensive care unit of a hospital. Once stable, the patient may be transferred to a subacute unit of the medical center, to a rehabilitation inpatient unit within the acute trauma center, or to an independent off-site or 'free-standing' rehabilitation hospital. Moderately to severely injured patients may receive specialized rehabilitation treatment that draws on the skills and knowledge of many specialists, involving treatment programs in the areas of physical therapy, occupational therapy, speech/language therapy, physiatry (medical specialist in physical medicine and rehabilitation), psychology/psychiatry, and social work, among others. The services and efforts of this team of healthcare professionals is generally applied to the practical concerns of and the problems encountered by the brain injury survivor in their daily life. This treatment program is generally provided through a coordinated and self-organized process in the context of a transdisciplinary model of team healthcare delivery. This model keeps the primary focus on the overarching goal of optimizing patient function and independence through the coordinated application of discipline-specific expertise brought to bear on this issue by individual experts from various disciplinary backgrounds.