Pathophysiology of Nervous System Trauma Flashcards
What is the definition of traumatic brain injury?
Any form of external injury that affects the normal function of the brain, either transiently or permanently
Who are the most vulnerable populations for TBI and what is the most common cause of non-fatal TBI?
Children and adolescents whose cranial cavities are not fully formed, also adults >75
Leading cause of TBIs is falls
What is the most important outcome of TBI and what patient factors influence recovery?
Disability
Patient pre-injury functioning, socioeconomic status, and access to rehabilitation services have a large effect on recovery
What are the two classifications of TBI related to timing of trauma?
Primary injury - damage caused by mechanical force, occurring at the moment of injury
Secondary injury - damage not caused directly by primary event, but superimposed on brain already affected by primary injury (i.e. bruising, swelling, herniation, all sequellae)
What are some examples of focal vs diffuse injury in TBI?
Focal - scalp injury, skull fracture, or surface contusions
Diffuse injury - diffuse axonal injury, hypoxic-ischemic injury, meningitis, or vascular injury
What is the rating scale of the Glasgow Coma Scale (GCS) and what corresponds to mild, moderate, and severe TBI?
3-15
Mild: 13-15
Moderate: 9-12
Severe: 3-8 (<=8 is comatose)
What are the three categories of evaluation for GCS?
- Eye opening
- Verbal response
- Motor response
What is the scoring scheme for eye opening on GCS?
1 - no opening
2 - opens to pain only (i.e. on forehead)
3 - opens to verbal request
4 - Spontaneously open
What is the scoring scheme for verbal response in GCS?
1 - no response 2 - random sounds 3 - random nonsensical word strings 4 - confused response (not oriented) 5 - oriented to time, place, and person
What is the scoring scheme for motor response in the GCS?
1 - no response
2 - decerebrate - abnormal extension in response to pain
3 - decorticate - abnormal flexion in response to pain
4 - flexion withdrawal of limb from painful stimulus
5 - touch area of painful stimulus (localizes)
6 - obeys commands
-> most objective scale
What is a closed / blunt head injury? What typically causes them?
TBI where skull remains intact. Commonly accidents, falls, acts of violence, sports injuries.
Also, blast-related closed head injuries -> changes in atmospheric pressure, objects dislodged from blasts, or people being thrown into motion by blast
What is a concussion? What are the possible sequellae?
A type of closed head injury where there is instant onset transient neurological dysfunction, with or without loss of consciousness
Possible sequellae include post-concussive syndrome. Repetitive concussions may cause chronic traumatic encephalopathy
What is post-concussive syndrome?
Prolonged symptoms of concussion lasting longer than usual 7-10 days.
Clinical features: headache, dizziness, nausea, memory disturbance, depression, sleep problems, difficulty concentration, mental fog
What is chronic traumatic encephalopathy (CTE)?
Progressive degenerative disease of the brain found in people with severe or repeated blows to the head. Commonly occurs in boxers and football players.
What are common pathological findings of CTE?
Neurofibrillary tangles of tau, and amyloid plaques, accompanied by cerebral atrophy, enlarged ventricles (ex vacuo hydrocephalus), and reduced pigmentation of substantia nigra + locus coeruleus.
Where do contusions occur in terms of dural space and which areas of the brain are most susceptible?
These are bruises / bleeds in the brain parenchyma, caused by rapid brain displacement and disruption of vascular channels -> hemorrhage. Hemorrhage can extend into subarachnoid space as well.
Crests of gyri are most susceptible, where direct force is the greatest. These are most commonly damaged over rough surfaces (i.e. frontal lobes over orbital ridges)
What are blossoming contusions?
Hemorrhagic progression of a contusion ->
Contusions with hemorrhage which expand overtime
or
NEW, non-contiguous contusions
