1- Injury Mechanism & Recovery Flashcards
Open vs Closed TBI
- An open, or penetrating TBI , when head is hit by an object that breaks the skull and enters the brain.
- A closed TBI occurs when the brain is injured but the skull remains intact.
The single most common cause of death and injury in automobile accidents?π
Ejection of the occupant from the vehicle
Cuccurollo 4th Editio Chapter 2 TBI pg55
Types and causes of traumatic ABI (TBI)?
Intentional
- Violence (Adult)
- Child Abuse
- Blast Injuries (Military)
Non-Intentional
- Falls (Too young, too old)
- MVA (Teenagers)
- Sport Injuries (Adult)
Causes of Non-Traumatic ABI? ππ
- Tumours (benign/meningioma only)
- Anoxia
- Subarachnoid hemorrhage (non-focal)
- Meningitis
- Encephalitis/encephalopathy (viral, bacterial, drug, hepatic)
- Subdural Hematoma
ERABI Module 1 pg4
List 4 causes of TBI. ππ
Adult
- MVA: 53%
- Falls: 24%
- Violence: 13%
Pediatric
- Falls (72.8%)
- Transportation related (28%)
- Sports and recreational activities (17%)
- Assault (7%)
Cuccurollo 4th Editio Chapter 2 TBI pg56-57
Demographics/Risk Factors for TBI.
Who is at risk for TBI?
- Too young <5 years or too old >65 years
- Male > Female
- African American
- Violence/assault
- Ethyl alcohol (ETOH) use
- Substances abuse
- Psychosocial stress
- Prior psychiatric history (history of anxiety, depression)
- Lower socioeconomic status
increased exposure to high risk occupations, personal violence, older vehicles, and substandard housing
Braddom 6th Edition Chapter 43 TBI pg917-918
Two primary categories of injury mechanisms π
Primary Injury. Definition, Location & Mechanism of Injury. ππ
π‘ Direct disruption of the brain tissue from impact which occurs immediately (minutes to hours after the impact) and is not amenable to medical intervention.
1. CONTUSIONS
Coup Injury: Contusions under the impact site and result from a rapid change in skull distortion during impact.
Counter Coup Injury: Contusions in the opposite to the impact occur due to negative pressure generated
Location
- Inferior frontal lobe
- Anterior paretial lobe
- Inferior occipital lobes
2. DIFFUSE AXONAL INJURY(DAI)
Result from accelerationβdeceleration and rotational forces
Lead to loss of consciousness and coma
MRI: White matter punctate petechial hemorrhages
3. IMPACT DEPOLARIZATION
Increase in extracellular potassium and glutamate release (excitatory) β excitotoxicity (secondary injury).
Cuccurollo 4th Edition Chapter 2 TBI pg57
ERABI Module 1 pg14
List 4 Signs of basal skull fracture ππ
Anterior fossa fracture:
- CSF rhinorrhea
- Raccon eye (Bilateral periorbital heamatoma)
- Subconjuntival hemorrhage
Petrous bone fracture
- Ear bleeding
- Otorrhea
- Battleβs sign (bruising over the mastoid)
Primary vs Secondary Injury ππ 6 primary neuropathologic changes in TBI
PRIMARY INJURY
π‘ Direct injury causing ecchymosis, bleeding or shearing forces
- Extracerebral hemorrhage
- Subdural hemorrhage
- Subarachnoid hemorrhage
- Epidural hemorrhage
- Intracerebral hemorrhage
- Cerebral contusion
- Cerebral laceration
- Diffuse Axonal injury
SECONDARY INJURY
π‘ Chemical cascade with electrolytes imbalance leading to delayed injury
- Diffuse Axonal injury
- Diffuse Brain Swelling
- Hypoxic Injury
- Metabolic Dysfunction
- Diffuse Ischemic Injury
- Hydrocephalus
- Increase in ICP
List 4 complications of Subarachnoid Hemorrhage ππ
- Focal neurological deficit
- Seizures
- High ICP/hydrocephalus
- Neurogenic pulmonary edema
- Hyponatraemia (CSW/SIADH)
- Rebleeding
- Vasospasm and delayed cerebral ischemia
- Takotsubo cardiomyopathy or βBroken Heart Syndromeβ
Secondary Injury. Definition, Location & Mechanism of Injury.π
TBI what is the site of diffuse axonal injuries ππ
Adamβs classification for Grading of DAI ππ
SECONDARY INJURY
Cascade of biochemical, cellular, and molecular events, which include both endogenous cerebral damage as well as extracerebral damage that comes with trauma.
- Ischemia (pericontusional hypoperfusion), excitotoxicity, energy failure, and apoptosis
- Secondary cerebral swelling (brain swelling and brain edema)
- Axonal injury
- Inflammation and regeneration
ADAMβS CLASSIFICATION
Grade I
- Widespread white matter/axonal damage
- No focal abnormalities on imaging
Grade II
- Widespread white matter/axonal damage
- Focal findings (most common in the corpus callosum)
Grade III
- Damage involving the brainstem
Cuccurollo 4th Editio Chapter 2 pg57 & 59
Locations of diffuse axonal injury other than midbrain and corpus collusum.
- Parasagittal white matter
- Interventricular septum
- Walls of the third ventricle
- Brainstem (midbrain and pons).
Cuccurollo 4th Edition Chapter 2 TBI pg59 & ERABI Module 1 pg12
- Corpus callosum: cognitive dysfunction.
- Parasagittal/periventricular white matter.
- Grey-white matter junction: slowed mental processing, fatigue.
- Superior cerebral peduncles: hemiparesis/tetraparesis.
- Midbrain (dorsolateral quadrant): dysarthria, dysphagia.
- Pons.
DeLisa pg 577-578.
Diffuse Axonal Injury: 2 Mechanism of Injury / Causes ππ
PRIMARY INJURY β MECHANICAL INJURY
1. Traumatic shearing forces (rapid acceleration or deceleration injury)
- High-speed motor vehicle collisions above 15 mph or 24 km/h.
- High-speed collisions in sports (i.e. football, hockey, soccer, rugby)
- Shaken baby syndrome.
SECONDARY INJURY β PATHOPHYSIOLOGICAL
1. Excitotoxicity
Release of glutamate causes calcium influx causing axonal swelling and breakage
2. Hypoxia
3. Apoptosis
Cuccurollo 4th Edition Chapter 2 TBI pg59
ERABI Module 1 pg13
Most common cause of LOC after TBI?π
Axonal injury is the most common cause of unconsciousness during and following the first 24 hours of injury.
Cuccurollo Chapter 2 TBI pg59