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71 Cards in this Set
- Front
- Back
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What is the preferred term for TBI?
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acquired brain injury
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List some etiologies for TBIs.
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-blows to head
-gunshot wounds -brain tumors -birth traumas -shaken baby syndrome -hypoxia (cardiac arrest; severing of carotid artery) -anoxia (near-drowning; suffocation) -CVAs -brain hemorrhages -exposure to explosions |
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What is the IDEA definition of a TBI?
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an acquired injury to the brain caused by an external physical force (blow or change in acceleration/deceleration forces), resulting in total or partial functional disability or psychological impairment that adversely affects a child's educational performance
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TBIs are the _______ most common death in the US; and ________ __________ cause of death in people under the age of 38.
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-third
-most common |
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True or false: Most people who sustain mild TBIs are not hospitalized.
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True
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What are the most common causes of mild TBIs? Severe TBIs?
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-Mild: falls and fights
-Severe: traffic accidents |
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Are TBIs more common in males or females?
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males (2 times)
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What are the highest risk groups for TBIs?
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0-4, 15-24, >75
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What is the lowest risk group for TBIs?
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5-9
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What percent of students with TBI are referred for services?
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9-38%
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What type of rest activity is recommended for mild TBI patients?
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rest and inactive during recovery (a few days off)
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What type of rest activity is recommended for severe TBI patients?
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rest briefly (initially) but then work thru intense therapy
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When do primary mechanisms of TBIs occur?
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at the time of the trauma (instant effects of acceleration/deceleration and rotational forces on the skull and brain)
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What are secondary mechanisms of TBIs?
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injuries resulting from the primary mechanisms but not occurring at the time of the injury (chain reaction of events that follow the primary injuries)
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What are examples of secondary mechanisms of injury?
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-cerebral edema
-cerebral swelling -increased intracranial pressure -hematomas |
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What is translational acceleration?
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occurs whenever the head is not immobilized (pushes it straight ahead)
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Does a fixed head prevent damage?
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yes (20 times greater blow causes very little damage)
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Describe translational acceleration.
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-no intermolecular stress because all particles travel at the same rate of acceleration and in the same direction
-positive pressure at point of impact -negative pressure at point directly opposite impact -no pressure change in middle of object |
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True or false: Brain tissue can withstand long periods of positive pressure without damage.
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True
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True or false: Brain tissue can withstand long periods of negative pressure without damage.
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False; brain tissue is very sensitive to negative pressure
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What is contre coup?
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damage on opposite side of impact
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Contre coup negative pressure causes:________________.
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problems because of cavitation effects
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What are cavitation effects?
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popping of the bubbles
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Describe cavitation effects that occur during a TBI.
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-with sufficient acceleration with respect to diameter of head, negative pressure will drop below vapor pressure level of intracellular fluid
-causes change from liquid to gaseous state (gas bubbles form within cells) -within milliseconds, pressure returns to above vapor pressure level and gas bubbles burst with return to liquid state -causes multiple small explosions that destroy brain cells |
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When does rotational acceleration occur?
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occurs when vector force does not pass through an object's center of gravity (causes a rotation of the object around its center gravity)
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What damage to the brain does rotation acceleration result in?
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diffuse shearing strain
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What is DAI?
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Diffuse Axonal Injury (from rotational acceleration: damage to axons due to shearing)
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Where is the greatest damage in the brain when rotational acceleration occurs?
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ripping of the cortex with the greatest damage in the frontal and temporal regions; also the corpus callosum
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What are the different types of hematomas caused from a TBI?
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-epidural or extradural
-subdural -intracranial |
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Where are epidural or extradurl hematomas located?
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between dura mater and skull
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What is the least dangerous type of hematoma?
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epidural or extradural hematoma
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What are the 2 explanations for the formation of epidural/extradural hematomas?
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-pressure of pooling blood causes dura mater to pull away from inner surface of skull
-elastic rebound of skull pulls dura mater away from skull and then blood spills into the space created |
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Where are subdural hematomas located?
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between the layers of the meninges (either in subdural or subarachnoid space)
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How common are subdural hematomas?
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twice as common as epidural hematomas
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True or false epidural hematomas are less serious than epidural hematomas.
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False; more serious because of proximity to brain tissue
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Where are intracranial hematomas located?
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within the brain itself
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Which type of hematoma is the most serious and most difficult to treat?
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intracranial hematoma
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True or false: Intracranial hematomas cause a person to lose consciousness.
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True
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Which type of hematoma may have a delayed onset of up to 3 weeks post-injury? AND describe.
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intracranial hematoma
-swelling within brain initially controls bleeding; as swelling reduces, bleeding may reoccur and result in formation of hematoma -must perform repeat CT scans to detect |
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What is acute cerebral swelling?
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-increased blood flow to the brain because of elevated blood pressure and vasodilation
-causes increased volume within cranium -more commonly a problem in children than adults |
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What is cerebral edema?
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increased water content in brain
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What are the 2 types of cerebral edema?
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-vasogenic edema
-cytotoxic edema |
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What is vasogenic edema?
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breakdown in blood-brain barrier such that capillary walls become semi-permeable membranes and allow for passage of water into brain tissue
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What is cytotoxic edema?
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damage to cell membranes that results in an increased drawing of water into cells
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What serves as a safety valve to combat fluctuations in ICP?
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the ventricles
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What is normal ICP (intracranial pressure)?
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0-10 mmHg (millimeters of mercury)
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What type of ICP is abnormal?
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over 20 mmHg
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What does ICP above 40 mmHg cause?
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causes neurological dysfunction and impairment of brain electrical activity
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What does ICP above 60 mmHg cause?
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almost invariably fatal
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What are the 4 different types of blast injuries?
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-primary
-secondary -tertiary -quaternary |
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What type of cavities are most impacted by blast injuries? Second?
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-Most: air-filled cavities (lungs, middle ear, sinuses)
-Second: fluid-filled cavities (i.e., brain) |
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What is a primary blast injury?
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-brain's response to atmospheric pressure changes near the site of the explosion
-causes displacement, stretching, and shearing |
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What is a secondary blast injury?
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penetrating injuries to the brain caused by debris and projectiles propelled thru the surrounding area
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What is a tertiary blast injury?
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occur when person strikes head because of being thrown to the ground or against a stationary object
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What is a quaternary blast injury?
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an array of other explosion-related injuries (i.e., gas/toxin exposure, crush injuries, falling, or struck when building collapses)
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What are the 2 components of a blast wave?
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-shock wave (pressure sky rockets above original)
-blast wind (goes slightly below original pressure) |
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What structures are most prone to injury from a blast injury?
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air-fill structures (i.e., lungs, middle ear, sinuses)
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What areas of the brain are damaged from primary blast injuries?
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-gray matter of frontal/temporal lobes
-diffuse axonal injury (internal capsule, upper brainstem structures, corpus callosum) -air emboli (air pocket) in vessels supplying blood to brain (causes stroke-like effect) |
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Someone __ meters from the central point experiences a blast wave that is ___ times greater than that experienced by a person ___ meters away.
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-3 meters
-9 times greater -6 meters |
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Are blast waves more damaging in air or water? Why?
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-more damaging in water
-because water has higher density |
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True or false: Body armor is not effective in protecting individuals from primary blast injuries.
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True (but will help for secondary, tertiary, and quaternary)
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What are the most frequent tertiary injuries?
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-skull fractures
-brain contusions or concussion -open and closed brain injuries |
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What are the 2 primary sources of quaternary blast sources?
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-structural collapse of buildings (crush injuries, falling, struck by heavy objects)
-exposure to noxious materials (fire, gas, toxic dust, or radiation exposure) |
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What are the major advantages of the Glasgow Coma Scale?
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-high inter-rater reliability (don't need a lot of medical training to administer)
-avoids vague and subjective terminology such as "comatose", "semi-alert", or "stuporous" |
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What does Glasgow Coma Scale measure?
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-measures a person's level of consciousness
-state of arousal and awareness of external environment |
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What are the major disadvantages of the Glasgow Coma Scale?
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-length of time post-injury will not be consistent from patient to patient (limits severity comparisons- based on arrival to ER)
-drugs to control brain swelling or to relax muscles will adversely affect performance -high BAC will affect score -paralysis or hemipareis will affect score |
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What are the 3 components of the Glasgow Coma Scale?
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-eye opening response
-best motor response -best verbal response |
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What score range is there for the Glasgow Coma Scale?
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from 3 to 15 points
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When does the eye opening response component of the Glasgow Coma Scale point system stop counting?
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10-14 days post-injury
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What are the severity ratings for the Glasgow Coma Scale?
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based on initial administration of GCS upon arrival to ER
-3 to 7: severe -8 to 11: moderate -12 to 15: mild |
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What time period does the term "coma" apply to?
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only for the first 2 weeks
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