Module 11 - Traumatic Brain Injury Flashcards
Head Injury
term used to describe all structural damage to the head
Head Injury is synonymous with…
brain injury or traumatic brain injury (TBI)
The leading cause of death in ages 24+
Head Injury
Main causes of head Injury
road accidents
falls (biggest contributor)
assaults including violence and fire arms
Skull Fracture Types
Simple
Comminuted
Depressed
Basilar
Head Injury Types
Closed
Open
Main Diagnostic Tool for Skull Fractures
Skull X Ray
Simple Skull Fracture
linear break in the continuity of the bone
Comminuted Skull Fracture
refers to a splintered or multiple fracture line
Depressed Skull Fracture
when bone fragments are embedded into brain tissue
basilar skull fracture
fracture of the bones that form the base of the skull
this is an area of the skull that is more fragile
Basilar Area of the skull includes what areas
Include temporarily bone, occipital one, ethmoid bone, sphenoid bone
Ethmoid Cribriform Plate
Most fragile portion of the cranium
Is shattered in basal skull fractures
What 3 things occur with a Basilar Skull Fracture breaking the Ethmoid Cribriform Plate
- CSF leakage from nose or ear leading to potential source for infection of the meninges or brain
- Lacerations to the vessels of the dura leading to intracranial bleeding
- Damage to cranial nerves 1, 2, 3, 7, and 8 if the fracture is near the foramen magnum where the cranial nerves exit the skull
Rhinorrhea
CSF leakage out the nose
can test for high glucose since thats high in CSF and see if it tries in a yellow halo as CSF does
Ottorrhea
CSF leakage from the ear
Types of Brain Injuries
Primary
Secondary
Primary brain injury types
Concussion
post-concussion syndrome
contusion
laceration
Primary Brain Injury (Direct Brain Injury)
damage is caused by impact
Concussion
primary brain injury
Momentary interruption of brain function with or without loss of consciousness
Recovery usually within 24 hours
Cannot be visualized except microscopically (does not appear on CT)
Post Concussion Syndrome
primary brain injury
despite concussions being 24 hours, this can last months
HA, irritability, insomnia, poor concentration and memory issues persisting for months
Contusion
primary brain injury
bruising of the brain
CAN be seen on CT
often distributed along the rough irregular inner surface of the brain
Where are contusions more likely to occur
frontal or temporal lobes –> leads to cognitive and motor deficits
Secondary brain injury types
ischemia
increased ICP
cerebral edema
brain herniation
Secondary Brain Injuries
damage resulting from subsequent brain swelling
The most common cause of secondary brain injuries is…
ischemia
Classifications of brain injuries can be ___ or ___
focal or diffuse
Focal Brain injuries
pinpoint in one area like a knife wound
trauma and bleeding occurs from only one space
neurological deficits a function of the area injured
ex: contusion, laceration, hemorrhaging
Diffuse Brain Injury
widespread brain injury from something like whiplash, shaken baby syndrome, O2 deprivation
ex: Concussion, contusion, diffuse axonal injury (shearing lesion), hypoxic brain injury
Mild Brain Injury
Momentary LOC w/out demonstrating neuro symptoms or residual damage except for possible residual amnesia
Microscopic changes can be detected in neurons and glia within hours of injury
Moderate Brain Injury
longer period of unconsciousness
May be assoc. with focal manifestations such as hemiparesis, aphasia, cranial nerve palsy
many small hemorrhages occur along with some swelling of brain tissue
could be seen on CT
Severe Brain injury
more extensive damage to brain structures and a deeper level of coma
Primary damage to brain is often instantaneous and irreversible
Due to shearing and pressure forces causing diffuse axonal injury, disruption of blood vessels, and tissue damage
Often accompanied by neuro deficits like hemiplegia
often occurs with injury to other parts of the body
Whiplash or shaken baby can cause this
What is the mechanism of brain injury?
- Brain suffer injury and swells or bleeds thus increasing ICP
- Rigid cranium doesn’t allow expansion of contents so ICP increases more
- More pressure on blood vessels within the brain causes blood flow to brain to slow and cerebral hypoxia and ischemia to occur
- ICP continues to rise and the brain may herniate
- Cerebral blood flow ceases
Locations for Hemorrhage
Subdural Hematoma
Intracerebral Hematoma
Epidural Hematoma
Subdural Hematoma area
Bleeding below the dura
Epidural Hematoma area
Bleeding above the dura
Intracerebral Hematoma area
Bleeding below the pia - brain tissue is bleeding
Dura
what connects to the skull’s wall (inside the skull)
Coup-Contrecoup Injury
When the brain hits a rough surface of the cranial vault leading to blood vessels, nerve tracts, and other structures to bruise and tear
Why can Coup-Contrecoup injury occur
because the brain floats freely in the CSF BUT the brain stem is stable (like florets on a broccoli)
Coup
The initial throwing of the brain against one side of the skull in a continuous motion –> causes damage immediately below site of impact
Contrecoup
brain rebounds and strikes the opposite side of the skull –> injures regions in the brain opposite the side of impact
Hematoma
Ruptured vessel resulting from vascular injury and bleeding but not necessarily a clot
Can occur in any compartment lie epidural, subdural, subarachnoid space, brain
Epidural (Extradural) Hematoma
usually from head injury where skull is fractured
develops between the inner table of the bones of the skull and the dura
Immediate compression occurs
There is a strong association between epidural hematoma and…
skull fractures
Usually, epidural hematomas occur from what?
a tear in an artery leading to rapid compression of the brain
Arteries bleeding faster as they are under pressure but venous bleeding is slowed and insidious
Most common area of the head for an epidural hematoma?
middle meningeal membrane located under the thin temporal bone
What age group is more common for epidural hematoma?
in young b/c the dura is not as firmly attached to the skull surface and is easily stripped away allowing hematoma to form
this can mean shaken baby syndrome can lead to this
When looking at a hematoma it is important to distinguish what
whether the bleeding is arterial or venous
What is the presentation for an epidural hematoma?
Hx of head injury, a brief period of LOC followed by a lucid period with regained consciousness
This is then followed by a rapid progression to LOC again
If an epidural hematoma is not removed…
increased ICP occurs –> tentorial herniation –> death
What makes an epidural hematoma prognosis excellent
removal before loss of consciousness
Epidural Hematoma Lucid Interval
does not always occur, but when it does its of diagnostic value
its a period of improvement followed by rapid decline again
LOC, Lucid Period, Rapid LOC is pathonomic for…
epidural hematoma
What causes the initial LOC and then the rapid LOC in epidural hematoma?
Initial LOC is from the injury
The second rapid LOC is from arterial blood loss
Focal symptoms of epidural hematoma are related to …
area of the brain involved in injury
ex: Ipsilateral pupil dilation if pressure on optic nerve same side as injury
ex: Contralateral hemiparesis - opposite side effect since motor nerves cross at medulla oblongata
Subdural Hematoma
Develops in the area between the dura and arachnoid space - the subdural space
Usually comes from a tear in the small bridging veins that connect veins on the surface of the cortex to the Dural sinuses - VENOUS TEAR = slower bleeding
Where can bleeding for a subdural hematoma occur?
Between the dura and arachnoid
OR
into the CSF filled subarachnoid space
Where does the tear usually occur for a subdural hematoma
usually in the small bridging veins that connect veins on the surface of the cortex to the Dural sinuses
These are readily snapped in head injuries when the brain moves suddenly in relation to the cranium
Subdural Hematoma are classified based on …
time interval before appearance of symptoms
Acute, Sub acute, Chronic
Acute, Sub Acute, and Chronic Subdural Hematoma occur within what time frames?
Acute - within 24 hours of injury
Sub acute - 2-10 days post injury - more dangerous than acute due to how slow it is
Chronic - several weeks after injury - can become recurrent problem
Acute Subdural Hematoma
Progresses rapidly (within 24 hours) due to a larger venous bleed
High mortality rate from severe secondary injuries from increased ICP
Similar to an epidural hematoma clinically, but lacks lucid period
The quicker the development of hematoma symptoms…
the quicker the treatment and the better the prognosis - subacute and chronic can be more dangerous than acute !
What may occur due to increased ICP in an acute subdural hematoma
uncontrolled increase in ICP
loss of consciousness
decerebrate posturing
delay in surgical removal of the hematoma
How does Acute Subdural hematoma differ from epidural hematoma?
They are clinically similar but there is no lucid period
So once they go unconscious they stay unconscious and do not wake up
Subacute Subdural hematoma
There is a reasonable level of consciousness and are often sent home
However, after 2-10 days there is deterioration and by the time the bleed is found there is already extensive damage if it was not caught early
Chronic Subdural Hematoma
Develops weeks after a head injury and the individual may not even remember the injury (especially elders)
Blood into the subdural space occurs very slowly
The blood is not absorbed and becomes encapsulated
Higher morbidity and mortality than with epidural and intracerebral hematoma
What occurs to cause the symptoms and mortality/morbidity of a chronic subdural hematoma?
bleed cells slowly lysed as they bleed slowly –> fluid with high osmotic pressure forms –> this pulls in fluid from surrounding subarachnoid spaces –> increases in mass size –> Increased ICP occurs –> Decreased LOC, drowsiness, confusion, apathy, and HA ensue
Acts similarly to a tumor
The earliest sign of increased ICP is…
loss of consciousness
Intracerebral Hematoma
bleeding occurring in the brain tissue itself, and this often leaks into the CSF
bleeding is rapid and arterial in origin
can occur in any lobe but more common in frontal and temporal
can be one hematoma or more at once
What groups more commonly have intracerebral hematoma? Why?
Elders and Alcoholics
Their brain vessels are more easily friable
What lobes most commonly have intracerebral hematoma?
It can occur in any lobe, but most commonly its the frontal and temporal lobe
S/S of Intracerebral Hematoma depend on …
size and location of the bleed
signs of increased ICP if large and encroaching on vital structures
What location of an intracerebral hematoma leaves the potential for lateral herniation?
temporal lobe location
What is the treatment for a rapidly developing versus a neurologically stable intracerebral hematoma?
Rapidly developing –> surgical evacuation of clot
Neurologically stable –> observation, gradual resolution
When the location of an intracerebral hematoma is in the frontal lobe, where will the brain herniate
downward away - so opposite the direction of the frontal lobe
Monitor blood pressure in hematomas because…
it can affect cerebral perfusion (lower it)
Epidural hematomas are __ in origin
arterial
Subdural hematomas are __ in origin
venous
Intracerebral hematomas are __ in origin
arterial
Burr Holes
4 holes made into the skull to remove a plate of bone and refrigerate it or put in another body part like the abdomen
Allows ICP pressure release and is important to keep ICP down
Once healed the bone is replaced
Intraventricular Cerebral Bleeds occur into ventricles, and if this bleeds into the 3rd ventricle…
this is where the choroid plexus is and that is responsible for making CSF
A cerebellar hemorrhage may impact…
gait and balance
Basal Ganglia hemorrhage may impact…
a lot of movement control so it impacts voluntary motor control, cognition, emotions, eye movement, decision making, and dopamine creation
