Central Nervous System Trauma PDF

Central Nervous System Trauma  trauma to the brain and spinal cord is a significant cause of death and disability. the severity and site of injury affect the outcome: injury of several cubic centimeters of brain parenchyma may be clinically silent (if in the frontal lobe), severely disabling (...

Central Nervous System Trauma  trauma to the brain and spinal cord is a significant cause of death and disability. the severity and site of injury affect the outcome: injury of several cubic centimeters of brain parenchyma may be clinically silent (if in the frontal lobe), severely disabling (affecting the spinal cord), or fatal (involving the brain stem). Cont….. a blow to the head may be penetrating or blunt; it may cause an open or a closed injury. severe brain damage can occur in the absence of external signs of head injury when the brain is damaged, the injuries may involve the parenchyma, the vasculature, or both. Traumatic Parenchymal Injuries when an object impacts the head, brain injury may occur at the site of impact—a coup injury—or opposite the site of impact on the other side of the brain—a contrecoup injury.  a contusion is caused by rapid tissue displacement, disruption of vascular channels, and subsequent hemorrhage, tissue injury, and edema, it common in regions of the brain overlying rough and irregular inner skull surfaces, such as the orbitofrontal regions and the temporal lobe tips. Morphology contusions are wedge-shaped, with the widest aspect closest to the point of impact, within a few hours of injury, blood extravasates throughout the involved tissue, across the width of the cerebral cortex, and into the white matter and subarachnoid spaces. Cont….. old traumatic lesions characteristically appear as depressed, retracted, yellowish brown patches involving the crests of gyri. A B (A) Acute contusions are present in both temporal lobes, with areas of hemorrhage and tissue disruption. (B) Remote contusions, seen as discolored yellow areas, are present on the inferior frontal surface of this brain. Traumatic Vascular Injury CNS trauma often directly disrupts vessel walls, leading to hemorrhage. depending on the affected vessel, the hemorrhage may be epidural, subdural, subarachnoid, or intraparenchymal, occurring alone or in combination. Cont….. subarachnoid and intraparenchymal hemorrhages most often occur at sites of contusions and lacerations. Epidural Hematoma dural vessels—especially the middle meningeal artery —are vulnerable to traumatic injury. in infants, traumatic displacement of the easily deformable skull may tear a vessel, even in the absence of a skull fracture. in children and adults, by contrast, tears involving dural vessels almost always stem from skull fractures. Cont….. once a vessel tears, blood accumulates under arterial pressure and dissects the tightly applied dura away from the inner skull surface, producing a hematoma that compresses the brain surface. clinically, patients can be lucid for several hours after the traumatic event before neurologic signs appear. Cont.….. an epidural hematoma may expand rapidly and constitutes a neurosurgical emergency necessitating prompt drainage and repair to prevent death  Epidural hematoma covering a portion of the dura Subdural Hematoma rapid movement of the brain during trauma can tear the bridging veins that extend from the cerebral hemispheres through the subarachnoid and subdural space to the dural sinuses. their disruption produces bleeding into the subdural space. subdural hematomas typically become manifest within the first 48 hours after injury. Cont….. they are most common over the lateral aspects of the cerebral hemispheres and may be bilateral. neurologic signs are attributable to the pressure exerted on the adjacent brain. symptoms are most often nonlocalizing, taking the form of headache, confusion, and slowly progressive neurologic deterioration.  Large organizing subdural hematoma attached to the dura Morphology acute subdural hematoma appears as a collection of freshly clotted blood apposed to the contour of the brain surface, without extension into the depths of sulci.