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What are the 3 mechanisms of brain injury? - ANSWER ischemia
hypoxia
increased ICP
Primary brain injury - ANSWER Occurs immediately at onset of brain injury
Typically results in irreversible damage
Secondary brain injury - ANSWER Development of further neurological
damage after the primary injury; may progress over days to weeks
Progressive with delayed cell death (apoptosis)
what are the 3 compartments of the cranium? - ANSWER brain tissue
CSF (cerebrospinal fluid)
blood
What is the normal range for ICP? - ANSWER 0-15 mmHg
, Monro-Kellie hypothesis - ANSWER because of limited space in the skull,
an increase in any one of the cranium components (brain tissue, blood, CSF)
must be compensated by a decrease in the volume of the others
What can cause increased ICP? - ANSWER brain tumor
hemorrhage
edema
obstruction/excessive production of CSF
What are complications of increased ICP? - ANSWER brain compression,
inadequate perfusion, or *herniation* (protrusion of brain tissue through an
opening in the dura)
If a patient has increased ICP, should you do a lumbar puncture? -
ANSWER HELL no
What is ischemia? - ANSWER supply of oxygenated *blood* is too low to
meet metabolic demands of brain tissue
Can be primary and secondary
What is hypoxia? - ANSWER an inadequate amount of *oxygen* reaching
the tissues
a result of ischemia + hypoxemia (↓ O2 in blood)
, Decorticate posturing - ANSWER elbows are flexed, extremities have
contractures towards the core of the body
Decerebrate posturing - ANSWER posturing in which the neck is extended
with jaw clenched; arms are pronated, extended, and close to the sides; legs are
extended straight out; more ominous sign of brain stem damage. *Most
Severe.*
Nystagmus - ANSWER Involuntary rapid eye movements
Dysconjugate gaze - ANSWER eyes do not move together
Ocular palsies - ANSWER One or more cranial nerves dysfunctional such
that motor paralysis of the eye impairs movements in one or more directions
*Eye movement controlled by CN III, IV, and VI*
Doll's eye reflex - ANSWER when you move the head, the eyes should
move, then return to a central position; in some brain injuries, the eyes will be
fixed centrally
*testing oculovestibular reflex*
Cold Caloric Test - ANSWER when cold water is inserted into the ear canal,
eyes rotate to that side
*testing oculovestibular reflex*
, Corneal reflex test - ANSWER contact with a wisp of cotton stimulates a
blink in both eyes
How are TBIs classified? - ANSWER Using the GCS
Mild: 13-15
Moderate: 9-12
Severe: < 8
GCS is assessed how long after TBI? - ANSWER within 48hrs of TBI
TBI focal (coup) injury - ANSWER localized to area of brain at the site of
impact on skull
TBI polar (contracoup) injury - ANSWER contracoup; whiplash injury;
brain injured by bouncing off skull
occurs on opposite side of impact
what are the 3 types of hematoma that can occur from a TBI? -
ANSWER epidural
subdural
subarachnoid
How is a hematoma diagnosed? - ANSWER CT scan
MRI
Angiogram