Flashcards in TBIs Deck (43):
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
main mechs of brain injury
Increased intracranial pressure ( ICP)
Diffuse Axonal Injury
Irreversible cellular injury as a direct result of the injury
*Prevent the event* (wear helmet)
Damage to cells that are not initially injured-"watershed"
Occurs hours to weeks after injury
*Prevent hypoxia and ischemia (hypotension)*
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)
volume of intracranial vault
80% brain tissue
10% cerebrospinal fluid
*An increase in the volume of any of these causes increased ICP*
ha, AMS, coma
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
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
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
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)
Head Injury-Normal Physiology
Brain consumes 20% of total O2
Receives 15% of Cardiac Output
Brain tissue perfusion
CPP versus CBF
MAP=(SBP-DBP/3) + DBP
(CPP) 50-150 mm Hg
ICP physical findings of inc. ICP
Neurologic deterioration (know dermatomes)
Unilaterally dilated pupil
TBI pks in who
Peak male 15-24 years *MVA, assault*
Peak male > 65 years *falls*
TBI key hx
Mechanism of Injury
Patient’s condition prior to incident
Patient’s immediate post trauma condition
Patient’s current condition
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)
TBI primary survey
Airway (while maintaining cervical spine stabilization)
Circulation (checks all)
Disability (Neurologic assessment) AVPU—alert ;responds to verbal stimuli; responds to painful stimuli; unresponsive
ATLS? prim. survey
prevent secondary brain injury from
evacuation of mass
Airway control with cervical spine immobilization, If a definitive airway is needed..
Orotracheal Rapid Sequence Intubation
Goal of RSI is to blunt rise in ICP and maintain adequate MAP
Acute Neurological Examination in severe TBI
Motor gross function (posturing)
Glasgow Coma Scale
Best Eye Response. (4)
1 No eye opening.
2 Eye opening to pain.
3 Eye opening to verbal command.
Best Verbal Response. (5)
1 No verbal response
2 Incomprehensible sounds.
3 Inappropriate words.
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.
Any alteration of Cerebral Function Caused by a Force to the Head with any or one:
May lead to massive blood loss (even w. small cut)
Small galeal lacerations may be left alone
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?
assessment for concussion
Most common-petrous portion of temporal bone, the EAC and TM
get small slice imaging, typ. CT may miss
Basilar skull fx w. dural tear signs
hemotympanum (may be occluded)
7th nerve palsy (facial, Bell's)
CSF testing (basilar fx)
Ring sign, glucose or CSF transferrin
(basilar) skull fx injuries should be started on...
Ceftriaxone 1-2 gm
specific head injuries
*ddx based on presentation, cause, imaging*
Rupture of Middle Meningeal Artery
Associated with fracture of Temporal bone (or just blunt injury)
epidural hematoma asso. w. fx of temporal bone
*Rapid* expansion under systemic arterial pressure
“Lucid” interval (fine for a bit)
CN III Palsy-down and out
CT shows *Biconvex* disk-bulges out like lens
Rupture of Bridging Veins
*Slow* dev. due to low pressure venous system (days-wks)
Seen in elderly, alcoholics, blunt head trauma, shaken baby
Subdural Hematoma CT
Crescent-shaped hemorrhage-goes along lines of cranium
Crosses suture lines; Midline shift-->herniation
Rupture of an aneurysm
Usually a Berry aneurysm or AVM
ocular nerve palsy-down and out (like epidural?)
subarachnoid hemorrhage can be traumatic or atraumatic
Atraumatic -> Hypertension, aneurysm
Traumatic -> Usually blunt head trauma
*Rapid time course
“Worst headache of life”
Subarachnoid Hemorrhage CT
Many times bilateral or Circle of Willis
If CT negative then recommend lumbar puncture (atraumatic)
Basal ganglia and internal capsule
In trauma, can be lobar
Also due to vasculitis, neoplasm and trauma
IP hemorrhage doesn't usually ???
rapidly expand or cause significant edema or midline shift
Unless patient is on an anticoagulant
IP hem dx
CT scan of brain
Depending upon cause (good in trauma)
Supportive care while it resolves