1 N5315 Advanced Pathophysiology Central Nervous System Trauma Traumatic Brain Injury Traumatic Brain Injury [TBI] results from a traumatic insult to the brain. The insult may result in permanent deficits which impair the person’s physical, intellectual, emotional, and social functioning. Those populations at the highest risk are: children under 4, adolescents 15-19y/o, and adults 65 and older. They are most common in men in any age group. The Glasgow coma scale is used to evaluate the severity of the TBI. The lower the score the more severe the injury and the worse the prognosis. Etiologies include falls, motor vehicle injuries, work and sports injuries, and assaults. There are three broad categories of TBI. They are primary, secondary and tertiary injuries. Primary injuries are those injuries which directly injure the brain. They can cause neural damage, glial injury, shearing and rotation forces. Primary brain injuries are further subdivided into focal brain injuries and diffuse brain injuries. A focal brain injury is a primary brain injury which is limited to one area of the brain. A closed (blunt) head trauma is the most common focal injury. The injury occurs when the head hits a hard, immobile surface or when a rapidly moving object strikes the head, like a baseball bat. The dura remains intact and the cranial contents do not come in contact with the environment. This will likely cause a concussion. A coup and contrecoup injury occurs when the head strikes an immobile object, bounces off the object causing the brain to rebound to the opposite side of the original injury and strike the inside of the skull. This causes the brain to be injured at the site of impact and at the site opposite of the direct impact. This motion causes a shearing of the dural veins. The term coup refers to the injury which lays directly under the area of impact. An injury to the frontal lobe usually results in only a coup injury. The term contrecoup is used to describe the occurrence of an injury on the opposite side of the impact. This type of injury is characteristic of lateral and occipital direct impacts. A contusion is literally a bruising of the brain tissue. The most common areas affected by a contusion are the frontal and temporal lobes and the frontotemporal junction. This results in brain edema, damaged neural tissues, IICP, and necrosis of the contused area. The person may experience an immediate loss of consciousness (no more than five minutes), a loss of reflexes, a transient loss of respirations, bradycardia and a low BP. Vitals stable quickly. An open (penetrating) trauma occurs when the dura is damaged and the contents of the cranial vault are open to the environment. A good example is a basilar skull fracture. This is a fracture at the base of the skull and usually involves the temporal bone. This allows CSF to leak from the ear canal and Battle’s sign (hematoma and swelling post auricular).
- Fall '15
- Traumatic brain injury