Day 1 - Pathophysiology Flashcards
List 8 Risk factors for ABI
- Too young <5 years or too old >65 years
- Male > Female
- Violence/assault
- Ethyl alcohol (ETOH) use
- Substances abuse
- Prior psychiatric history
- less likely to participate in preventative measures such as wearing seatbelts
- poor stander housing
- increased exposure to high risk occupations
Etiology of TBI in Adults
- MVA: 53%
- Falls: 24%
- Violence: 13%
- Alcohol-related injuries: 46%
Etiology of TBI in Pediatrics
- Falls (72.8%)
- Transportation related (28%)
- Sports and recreational activities (17%)
- Assault (7%)
Shaken baby syndrome (SBS) Triad
- Subdural haemorrhage
- Retinal bleeding
- Hypoxaemic encephalopathy or brain swelling
Age is considered risk factor in ABI with prognosis for couple reasons, mention 2.
- Decreased balance and syncopal episodes → Falls
- Fragile bridging veins → SDH
- On anticoagulant → Bleeding
- less neuronal plasticity
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.
Non-traumatic causes of ABI include 🔑🔑
- Focal brain lesions
- Anoxia
- Vumours
- Vascular malformations (aneurysm)
- Infections of the brain (Encephalitis, Meningitis)
- Stroke
- Toxic brain injury
Definition of Primary Injury
Direct disruption of the brain tissue from impact which occurs immediately (minutes to hours after the impact) and is not amenable to medical intervention.
Definition of Primary Injury
Direct disruption of the brain tissue from impact which occurs immediately (minutes to hours after the impact) and is not amenable to medical intervention.
Mechanisms and location of primary injury
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
2- Diffuse axonal injury (DAI)
Result from acceleration–deceleration 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) → excitotoxicity (secondary injury).
Definition of Secondary Injury
Cascade of biochemical, cellular, and molecular events, which include both endogenous cerebral damage as well as extracerebral damage that comes with trauma.
Mechanisms of secondary injury include 🔑🔑
- Secondary cerebral swelling (brain swelling and brain edema)
- Ischemia and apoptosis
- Axonal injury
- Inflammation and regeneration
Swelling results in elevated intracranial pressure (ICP) and decreased cerebral perfusion pressure (CPP). If severe enough, brain swelling can lead to herniation, which has potentially fatal consequences.
Definition of Focal Injury
Localized injury in the brain occurring immediately after the injury and easily visualized by CT or MRI
Mechanisms or types of focal injury include
- Cerebral contusions
- Focal hemorrhages
- Epidural hematoma (EDH) 90%
- Subdural hematoma (SDH)
- Subarachnoid hemorrhage (SAH)
Primary Injury vs Secondary Injury. Definition & Types.
PRIMARY INJURY
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
2- Diffuse axonal injury (DAI)
Result from acceleration–deceleration 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) → excitotoxicity (secondary injury).
SECONDARY INJURY
Cascade of biochemical, cellular, and molecular events, which include both endogenous cerebral damage as well as extracerebral damage that comes with trauma.
Mechanisms of secondary injury include 🔑🔑
- Ischemia, excitotoxicity, energy failure, and resultant apoptosis
- Secondary cerebral swelling (brain swelling and brain edema)
- Axonal injury
- Inflammation and regeneration