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Flashcards in TBIs Deck (43):
1

TBI def

alteration/malfunction of brain function from external force
TBI is a process, not an event!
Secondary injury can be more damaging than primary injury
i.e. hit head and occlude airway-->airway occlusion has most sev. effects

2

main mechs of brain injury

Brain Contusion

Increased intracranial pressure ( ICP)

Diffuse Axonal Injury

3

primary injury

Irreversible cellular injury as a direct result of the injury
*Prevent the event* (wear helmet)

4

secondary injury

Damage to cells that are not initially injured-"watershed"
Occurs hours to weeks after injury
*Prevent hypoxia and ischemia (hypotension)*

5

brain contusion

cell death accompanied by hemorrhage (leakage of blood)

The soft brain tissue is vulnerable to contusion in head trauma

The contusion often occurs at a site distant from the point of impact
(coup and counter-coup)

6

volume of intracranial vault

80% brain tissue
10% blood
10% cerebrospinal fluid
*An increase in the volume of any of these causes increased ICP*
ha, AMS, coma

7

inc. IC pressure

The brain can swell (edema), but little room esp. in young adults (more room in infants, old ppl)

Excess blood can accumulate due to hemorrhage

Cerebrospinal fluid can accumulate due to blockage of outflow

8

key ICP concepts

The intracranial vault is a fixed volume --> Bone does not expand!

There is only one way out of the intracranial vault --> the opening at the base of the skull known as the foramen magnum

When the brain is squeezed through the foramen magnum (herniation), the brainstem is compressed, the patient stops breathing, and the patient dies

9

Diffuse Axonal Injury

Occurs in up to 1/2 of traumatic brain injuries1

Is a diffuse form of injury, meaning that damage occurs over a more widespread area than in focal brain injury

Involves the shearing of axons in the white matter tracts

10

DAI manifests

Is one of the major causes of unconsciousness and persistent vegetative state after head trauma.

Over 90% of patients with severe DAI never regain consciousness (those that do wake up often remain significantly impaired)

11

Head Injury-Normal Physiology

Brain consumes 20% of total O2
Receives 15% of Cardiac Output
Brain tissue perfusion
CPP versus CBF
CPP=MAP-ICP
MAP=(SBP-DBP/3) + DBP

Autoregulation
(CPP) 50-150 mm Hg

12

ICP measurements

Normal

13

ICP physical findings of inc. ICP

Neurologic deterioration (know dermatomes)
Unilaterally dilated pupil
Hemiparesis
Posturing

14

TBI pks in who

Peak male 15-24 years *MVA, assault*
Peak male > 65 years *falls*
falls>unknown>MVA>struck>assault

15

TBI key hx

Mechanism of Injury
Patient’s condition prior to incident
Co-morbid factors
Patient’s immediate post trauma condition
Patient’s current condition

16

other injuries w. TBI

consider mech. of injury
Always consider a spinal cord or vertebral column injury in a patient with a traumatic brain injury
(Esp in those pts that are unconscious!!) -C-scan spines, don't want to miss
Remember: SCIWORA! (SCI w.out radiological abnormality)

17

TBI primary survey

Airway (while maintaining cervical spine stabilization)
Breathing
Circulation (checks all)
Disability (Neurologic assessment) AVPU—alert ;responds to verbal stimuli; responds to painful stimuli; unresponsive
Exposure

ATLS? prim. survey

18

prevent secondary brain injury from

Hypoxemia
Hypotension
Anemia
hyperglycemia
evacuation of mass

19

Airway control with cervical spine immobilization, If a definitive airway is needed..
goal??

Orotracheal Rapid Sequence Intubation

Goal of RSI is to blunt rise in ICP and maintain adequate MAP

20

decerebrate

extended

21

decorticate

flexed

22

Acute Neurological Examination in severe TBI

Pupil assessment
Motor gross function (posturing)
Secondary Survey

23

Glasgow Coma Scale

Best Eye Response. (4)
1 No eye opening.
2 Eye opening to pain.
3 Eye opening to verbal command.
4 spontaneously

Best Verbal Response. (5)
1 No verbal response
2 Incomprehensible sounds.
3 Inappropriate words.
4 Confused
5 Orientated


Best Motor Response. (6)
1 No motor response.
2 Extension to pain.
3 Flexion to pain.
4 Withdrawal from pain.
5 Localising pain.
6 Obeys Commands.

24

concussion

Any alteration of Cerebral Function Caused by a Force to the Head with any or one:

Brief LOC
Headache
Visual changes
Personality change
Fatigue
Balance disturbances
Light headed
Concentration disruptions
Amnesia

25

scalp lacerations

May lead to massive blood loss (even w. small cut)
Small galeal lacerations may be left alone

26

skull fx

Linear and simple comminuted skull fractures
Exploration of wound
Ppx antibiotics are controversial
*Occipital fxs* have a high incidence of other injury
If depressed beyond outer table-requires NS repair?

27

assessment for concussion

SCAT3

28

basilar fracture

Most common-petrous portion of temporal bone, the EAC and TM
get small slice imaging, typ. CT may miss

29

Basilar skull fx w. dural tear signs

CSF otorrhea
CSF rhinorrhea
Battle Sign
Raccoon Sign
hemotympanum (may be occluded)
vertigo
hearing loss
7th nerve palsy (facial, Bell's)

30

CSF testing (basilar fx)

Ring sign, glucose or CSF transferrin

31

(basilar) skull fx injuries should be started on...

ppx abx
Ceftriaxone 1-2 gm

32

specific head injuries

Epidural Hematoma

Subdural Hematoma

Subarachnoid Hemorrhage

Intraparenchymal Hematoma

*ddx based on presentation, cause, imaging*

33

epidural hematoma

Rupture of Middle Meningeal Artery

Associated with fracture of Temporal bone (or just blunt injury)

34

epidural hematoma asso. w. fx of temporal bone

*Rapid* expansion under systemic arterial pressure
“Lucid” interval (fine for a bit)

Transtentorial herniation
CN III Palsy-down and out
CT shows *Biconvex* disk-bulges out like lens

35

Subdural Hematoma

Rupture of Bridging Veins
*Slow* dev. due to low pressure venous system (days-wks)

Seen in elderly, alcoholics, blunt head trauma, shaken baby

36

Subdural Hematoma CT

Crescent-shaped hemorrhage-goes along lines of cranium
Crosses suture lines; Midline shift-->herniation

37

Subarachnoid Hemorrhage

Rupture of an aneurysm
Usually a Berry aneurysm or AVM

ocular nerve palsy-down and out (like epidural?)

38

subarachnoid hemorrhage can be traumatic or atraumatic



time course?

Atraumatic -> Hypertension, aneurysm

Traumatic -> Usually blunt head trauma

*Rapid time course
“Worst headache of life”
"thunderclap"

39

Subarachnoid Hemorrhage CT

subarachnoid blood
Many times bilateral or Circle of Willis
If CT negative then recommend lumbar puncture (atraumatic)

40

Intraparenchymal Hematoma


occurs where?

cause?


Basal ganglia and internal capsule
In trauma, can be lobar


Systemic hypertension
Also due to vasculitis, neoplasm and trauma

41

IP hemorrhage doesn't usually ???

rapidly expand or cause significant edema or midline shift
Unless patient is on an anticoagulant

42

IP hem dx

px?

CT scan of brain

usually good
Depending upon cause (good in trauma)
Supportive care while it resolves

43

specific head injuries: diffuse axonal injury

Disruption of axons in white matter and brainstem

Injury occurs immediately and is irreversible

Seen after MVC or shaken baby syndrome

Usually have persistent vegetative state

CT usually normal
MRI with multiple, diffuse abnormalities