Ch 2 - TBI: Pathophysiology Flashcards
What is the MCC of head injury in adolescents and adults?
Motor vehicle accidents (~50% of cases0
What is the single MCC of death and injury in automobile accidents?
Ejection of occupant from the vehicle
What is the married status of patients with TBI?
Single (47%) > married (32%) > divorced (16%) > widowed/separated (5%)
What % of TBI etiology involve alcohol?
> 50%
What is Primary Injury in TBI?
Direct disruption of brain parenchyma from shear forces of the impact occurring immediately and not amenable to medical intervention
What are types of Primary Injury in TBI?
Contusion
Diffuse axonal injury (DAI)
Impact depolarization
What is brain contusion?
Bruising of the cortical tissue
What is Diffuse axonal injury (DAI)?
Immediate disruption of the axons due to acceleration–deceleration and rotational forces that cause shearing upon impact
What is secondary axotomy in DAI due to?
Increased axolemmal permeability, calcium influx, and cytoskeletal ABN that propagate after the injury
What is the characteristic of DAI on imaging?
White matter petechial hemorrhages
What is impact depolarization?
Massive surge in extracellular K+ and glutamate release (excitatory) occurs after severe head injury and leads to excitotoxicity (secondary injury)
What are types of secondary injury in TBI?
Ischemia, excitotoxicity, energy failure, and resultant apoptosis
Brain swelling/edema
Axonal injury
Inflammation and regeneration
What is excitoxicity?
NT (glutamate) causes calcium influx, oxygen-free radical release, lipid peroxidation, mitochondrial failure, and DNA damage > nerve cell death
When does brain swelling occur after TBI?
w/in 24 hours due to an increase in cerebral blood volume (intravascular blood).
How is brain swelling identified on CT?
Collapse of ventricular system and loss of CSF cisterns around the midbrain
When does brain edema occur after TBI?
Later than brain swelling due to an inc in brain volume 2/2 inc brain water content > extravascular fluid
What is vasogenic brain edema due to?
Outpouring of protein rich fluid through damaged vessels
What is vasogenic brain edema related to?
Extracellular edema
Cerebral contusion
What is cryptogenic brain edema due to?
Failing of the cells’ energy supply system > inc cell-wall pumping system> intracellular edema in the dying cells
What is cryptogenic brain edema related to?
Hypoxic and ischemic brain damage