5/27- Traumatic Brain Injury Flashcards
TBI is the leading cause of death for what demographic?
- People under 40
(also now a signature injury of contemporary warfare)
What are (broad) results of TBI?
- Hospitalization
- Epilepsy
- Chronic disability
- Death
What is the mechanism of primary injury of TBI?
Energy transfer to tissue
(cellular processes may continue for a long time; trauma is a process, not an event!)
What causes secondary injury with TBI?
- Hypoxia
- Ischemia
- Elevated ICP
- Acidosis (from lactic acid metabolism)
- Free radical injury
- Excitotoxicity
Epidural hematoma?
- damage to:
- blood located:
- clinical Sx:
Epidural hematoma:
- damage to: skull (fracture), laceration of middle meningeal a.
- blood located: between bone and dura
- clinical Sx: may have lucid period prior to deterioration
Features of scalp injuries?
Tons of bleeding! (although not likely to bleed to death)
(dangerous distraction if weighed above an internal hematoma)
Subdural hematoma?
- damage to:
- blood located:
- clinical Sx:
Subdural hematoma
- damage to:
+ reactive granulations tissue (fresh blood)
+ initial hemorrhage/remote bleeding into granulation tissue (old blood)
- blood located: in dura in weak inner border cell layer
(terminology slightly inaccurate since within dura rather than truly beneath it)
- clinical Sx: fluctuating consciousness (?)
Purpose of skull?
Dissipate injury (its job is to fracture)
Subdural hematoma membranes involve what cells/tissue?
- Fibroblasts
- Granulation tissue
What are the difference in boundary constraints between epidural and subdural hematomas?
- Epidural: stop at suture lines
- Subdural: crosses suture lines
What is a contusion?
Hemorrhagic damage to brain tissue itself (from brain coming into contact with bony features of skull)
Contusions are found in what locations?
Crests of gyri
Most commonly in inferior aspects of frontal/temporal lobes (“gliding” contusions)
How to differentiate between contusions and ischemic lesions?
Contusions affect crests of gyri while ischemic lesions are most severe in the depths of sulci (which are relatively less profused than crests)
How to differentiate between acute and chronic cerebral contusions?
Chronic: contusions cleared out by macrophages; hemosiderin left in the area
… results in impaired judgment
(often seen in people with seizures, alcoholics, fighters…)
Definition of coup? contracoup?
Coup: contusion largest at site of impact Contracoup: contusion largest opposite to site of impact
Big differences between epidural and subdural hematomas?
- Subdural hematomas can enlarge over months (with re-bleeding and damage to granulation tissue, as opposed to fast-growing epidural hematomas)
- Subdural is not just liquid blood; tougher and harder b/c has granulation tissue too
- Subdural does not typically have skull fracture
What types of situations are associated with coup injuries?
STATIONARY head:
- Assaults
- Head struck by object in motion
What types of situations are associated with contracoup injuries?
MOVING head:
- Falls
- Vehicular accidents
What is the primary determinant of kinetic energy of a projectile?
Velocity (parabolic) E = 1/2 mv^2
What is a common symptom of contusions related to cranial nerves?
Loss of smell (anosnia) due to damage to CN I
What indicates bullet trajectory?
Skull beveling
(thinner at entry; wider at exit)
What is seen in this picture?
Contusion (CT image)
- White masses are blood (frontal and temporal lobes)
- Some subarachnoid blood posteriorly as well
What is necessary to truly evaluate projectiles in the head?
Two views in imaging (x-ray)
Where is the injury located in DAI (Diffuse Axonal Injury)?
White matter
How can diffuse axonal injury be diagnosed?
- APP immunohistochemistry (more sensitive)
- Axonal spheroids identified with H&E
What is the time frame of changes/injury with diffuse axonal injury?
- Changes identified in as few as 3 hours after injury (axons disconnecting from one another)
- Changes progressively accumulate over days to weeks …It’s a process, not an event!
What precipitating events cause fat emboli?
Secondary to bone fractures
(especially long bones, pelvis in MVA’s)
What is seen following fat emboli in the brain?
Diffuse petechial hemorrhages in white matter (“flea bitten brain”)
What causes “swiss-cheese brain”
Post-mortem artifact due to gas forming bacteria in the corpse
What symptoms will occur with fracture dislocation and transection of the spinal cord?
Complete paralysis and sensory loss below the level of transection
Where does fracture dislocation and transection of the spinal cord most commonly occur?
Cervical and lumbar regions
(Common gun calibers)
.22
.25
.32 .
380 (pistol (‘semi/auto’)),
.38 (police, typ revolver),
.357 (really .380)
9 mm
.40
.45
What is this?
Histological appearance of fat emobli
