What is the primary goal of treating TBI? How is this done?
preventing secondary brain injury. This is done by maintaining blood pressure and providing
... [Show More] adequate profusion.
After managing ABCDEs of TBI what MUST be identified if present? How is this done?
mass lesion that requires surgical evacuation is critical! this is done with CT. NOTE: obtaining a CT should not delay patient transfer to trauma center.
Which brain lobes do the following hold:
1. anterior fossa:
2. middle fossa:
3. posterior fossa:
1. anterior fossa: frontal lobes
2. middle fossa: temporal lobes
3. posterior fossa: lower brainstem and cerebellum
What are the 3 layers of the meninges?
dura mater, arachnoid mater, pia mater
What does the dura mater adhere firmly to?
the skull. it is tough and fibrous
What layer of the meninges splits into two leaves as specific sites to enclose large venous sinuses? What do these sinuses do?
dura mater.
these sinuses provide major venous drainage from the brain.
What is the midline sinus of of the brain that splits into two sinuses: bilateral transverse and sigmoid sinus? What side are these bigger on?
The main sinus enclosed by the dura major is the midline superior sagital sinus. This splits into the sigmoid and bilateral transverse sinuses which are larger on the right side.
What are the arteries that lie between the skull and the dura mater (epidural space)?
meningeal arteries.
What is the most commonly injured meningeal artery and where is it located?
middle meningeal artery.
Located over the temporal fossa
T/F: the arachnoid mater is fused to the dura mater?
FALSE: not attached. This produces a potential space for a subdural hematoma
In a subdural hematoma, what is the cause?
injury to bridging veins that extend from brain surface to the sinuses within the dura.
_______ fills the space between the arachnoid and pia mater?
CSF. this cushions the brain and spinal cord.
What location of brain hemorrhage is frequently seen in brain contusion or injury to major blood vessels at base of brain?
subarachnoid.
The ____ and _____ contain the reticular activating system which is responsible for ____.
midbrain and upper pons
state of alertness
What important function resides in the medulla?
cardiorespiratory centers.
What important functions are in the following brain segments:
1. left hemisphere:
2. frontal lobe:
3. parietal lobe:
4. temporal:
1. left hemisphere: language center
2. frontal lobe: executive function, emotions, motor
3. parietal lobe: sensory function/spatial orientation
4. temporal: memory functions
What divides the brain into supratentorial and infratentorial compartments?
tentorium cerebelli. (tent over cerebellum)
What is the physiology behind a blown pupil?
blown pupil: dilation of pupil
-CN III runs along the tentorium cerebelli. parasympathetic fibers that constrict the pupil run along CN III (oculomotor). When temporal lobe is herniated, it can compress these fibers. Unapposed sympathetic activity causes pupillary dilation.
What is the tentorial notch/hiatus
this is where the midbrain passes through into the infratentorial compartment.
what part of the brain most commonly herniates through the tentorial notch?
Uncus (medial part of temporal lobe)
does weakness occur on the same or opposite side of the uncal herniation?
OPPOSITE. the corticospinal tract of the midbrain is compressed and then crosses at the foramen magnum.
state: Ipsilateral/contralateral
____ pupillary dilation associated with _____ hemiparesis is the classic sign of uncial herniation.
ipsi
contra
average ICP is _____ mmHg.
10
The monro-kellie doctrine states that the total volume of intracranial contents must remain constant, because the cranium is ___
a rigid, non expandable container.
The monro-kellie doctrine states that _____ and _____ may be compressed out of the skull providing a degree of buffering.
CSF and venous blood.
Once the CSF and venous blood reach a certain level of displacement the ICP rapidly increases.
What is the equation for CPP (cerebral perfusion pressure)?
CPP=MAP-ICP
in TBI, Every effort should be made to reduce ______, while normalizing ____, ___, and _____.
ICP
MAP, oxygenation, intravascular volume
What GCS ranges for the following classes:
1. Minor
2. Moderate
3. Severe
1. 13-15
2. 9-12
3. 3-8
What nerve palsy may occur with basilar skull fracture?
seventh nerve.
A GCS of ___ is accepted definition of coma?
8 or less
How do you assess a GCS of someone with asymmetric responses?
Use the best possible because this will be the best predictor of outcome
Basilar fractures of the skull usually require what type of imaging?
this requires CT with bone-window setting.
What are the typical clinical signs of basilar skull fractures?
1.periorbital ecchymosis (raccoon eyes)
2. retroauriculor ecchymosis (battle sign)
3. CSF leak from nose or ears
4. 7th or 8th CN dysfunction (facial paralysis and hearing loss)
What should be a primary consideration for any patient with a skull fracture, especially a linear skull fracture?
hematoma. linear skull fracture increases likelihood of intracranial hematoma by about 400x
What mechanism is common with diffuse axonal injury and what is the likely outcome?
these injury often occur with high velocity or deceleration injures. They appear as diffuse cerebral hemorrhage often between grey and white matter. These are associated with variable but often poor outcomes.
Epidural hematomas often occur in the _____ area of the skull and result from a tear of the _______ arteries.
temporal
middle meningeal artery
What is the classic presentation of a epidural hematoma?
a lucid interval between time of injury and neurologic a deterioration.
What are more common brain injury: epidural or subdural?
subdural 30%
epidural 0.5%
Subdural hematoma occur from tear of _________.
bridging vessels of the cerebral cortex
Contusion occur in ___% of TBI. They often occur in _____ or ______ lobes of brain. They may coalesce to form ______ in as many as 20$%.
20-30%
frontal or temporal
intracerebral hematoma. [Show Less]