head injury word.docx

Head Injuries Head injury is a broad classification that encompasses any damage to the head as a result of trauma. A head injury does not necessarily mean a brain injury is present. Traumatic brain injury (TBI) or craniocerebral trauma describes an injury that is the result of an external force and...

Head Injuries Head injury is a broad classification that encompasses any damage to the head as a result of trauma. A head injury does not necessarily mean a brain injury is present. Traumatic brain injury (TBI) or craniocerebral trauma describes an injury that is the result of an external force and is of sufficient magnitude to interfere with daily life and prompts the seeking of treatment. The most common causes of TBIs are falls (48%), motor vehicle crashes (14%), being struck by objects (15%), and assaults (10%). Approximately 81% of all TBIs among adults aged 65 years and older result from falls. Several factors place older adults at increased risk for hematomas. Brain weight decreases, the dura becomes more adherent to the skull, and reaction times slow with increasing age. Also many older adults take aspirin and anticoagulant agents as part of routine management of chronic conditions. Fractures of the base of the skull tend to traverse the paranasal sinus of the frontal bone or the middle ear located in the temporal bone. Therefore, they frequently produce hemorrhage from the nose, pharynx, or ears, and blood may appear under the conjunctiva. An area of ecchymosis (bruising) may be seen over the mastoid (Battle sign). Basal skull fractures are suspected when CSF escapes from the ears (CSF otorrhea) and the nose (CSF rhinorrhea). Drainage of CSF is a serious problem, because meningeal infection can occur if organisms gain access to the cranial contents via the nose, ear, or sinus through a tear in the dura. Brain injury The most important consideration in any head injury is whether the brain is injured. Even seemingly minor injury can cause significant brain damage secondary to obstructed blood flow and decreased tissue perfusion. The brain cannot store oxygen or glucose to any significant degree. Because the cerebral cells need an uninterrupted blood supply to obtain these nutrients, irreversible brain damage and cell death occur if the blood supply is interrupted for even a few minutes. A traumatic brain injury, closed (blunt) occurs when the head accelerates and then rapidly decelerates or collides with another object (e.g., a wall, the dashboard of a car) and brain tissue is damaged but there is no opening through the skull and dura. A traumatic brain injury, open (penetrating) occurs when an object penetrates the skull, enters the brain, and damages the soft brain tissue in its path or when blunt trauma to the head is so severe that it opens the scalp, skull, and dura to expose the brain. Types of Brain Injury Injuries to the brain can be focal or diffuse. Focal injuries include contusions and several types of hematomas. Concussions and DAI are the major diffuse injuries. Contusions can be characterized by loss of consciousness associated with stupor and confusion. The effects of injury, particularly hemorrhage and edema, peak after about 18 to 36 hours. A concussion is a temporary loss of neurologic function with no apparent structural damage to the brain. The mechanism of injury is usually blunt trauma from an acceleration–deceleration force, a direct blow, or a blast injury. If brain tissue in the frontal lobe is affected, the patient may exhibit bizarre irrational behavior, whereas involvement of the temporal lobe can produce temporary amnesia or disorientation.The duration of mental status abnormalities is an indicator of the grade of the concussion. DAI results from widespread shearing and rotational forces that produce damage throughout the brain—to axons in the cerebral hemispheres, corpus callosum, and brain stem. The injured area may be diffuse with no identifiable focal lesion. DAI is associated with prolonged traumatic coma; it is more serious and is associated with a poorer prognosis than a focal lesion. The patient with DAI in severe head trauma experiences no lucid interval, immediate coma, decorticate and decerebrate posturing, and global cerebral edema. Brain Death When a patient has sustained a severe head injury incompatible with life, the patient is a potential organ donor. The nurse may assist in the clinical examination for determination of brain death and in the process of organ procurement. The three cardinal signs of brain death on clinical examination are coma, the absence of brain stem reflexes, and apnea.