MMSE Assignment
Secondary injuries follow the primary injury and promote the spread of injury. Although there is considerable debate about the pathogenesis of secondary injuries, the tissue destruction that occurs ends in _______________________________________ neurologic damage. Secondary injury to the spinal cord may be due to damaged blood vessels, vasospasm or proteolytic enzymes released from damaged tissues.
Brain Injury Anatomically and functionally, the brain is the most complex structure in the body. Therefore, the brain is much more vulnerable to lesions, trauma and infections that in other organs might produce no significant effects. Injury to brain tissue can result from a number of conditions, including ischemia, trauma, tumors, degenerative processes, and metabolic derangements. Brain damage resulting from these disorders involves several common pathways, including the effects of hypoxia and ischemia; cerebral edema; and increased intracranial pressure, herniation, and hydrocephalus. Brain hypoxia refers to a condition where there is a deprivation of _______________________ and blood flow is maintained. This situation may be seen with conditions such as carbon monoxide poisoning, severe anemia and failure of the lungs to oxygenate the blood. Brain ischemia refers to a condition where there is an interruption of __________________ ______________ which causes a reduction of both oxygen and glucose to the brain tissue. Brain ischemia can be focal, as in a stroke due to cerebral artery occlusion, or can be global, as with a cardiac arrest. Unconsciousness occurs within seconds of severe global ischemia. The cranial cavity contains blood, brain tissue, and CSF within the rigid confines of a non-expandable skull. Each of these three volumes contributes to the increased intracranial pressure (ICP). The volumes of each of these components can vary slightly without causing marked changes in ICP. This is because small increases in the volume of one component can be compensated for by a decrease in the volume of one or both of the other two components. Abnormal variation in intracranial volume with subsequent change in ICP can occur because of a significant volume change in any of the three intracranial compartments. For example, an increase in tissue volume can result from a brain tumor, brain edema, or bleeding into brain tissue. An increase in blood volume develops when there is vasodilatation of cerebral vessels or obstruction of venous outflow. Excess production, decreased absorption, or obstructed circulation of CSF affords the potential for an increase in the CSF component. What happens when intracranial pressure exceeds arterial pressure?
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