TBI: pathology, classification, exam, outcomes measures Flashcards
What is the #1 cause of TBIs
Unintentional falls
Caused by a bump, blow, or jolt to the head or a penetrating head injury that disrupts the normal function of the brain.
Traumatic brain injury
Mild– a brief change in mental status or consciousness
Severe– an extended period of unconsciousness or amnesia after the injury
Type of TBIs caused by direct contact
Concussion
contusion (coup/contrecoup)
hematoma (epidural, intracerebral, subarachnoid)
Type of TBIs caused by penetrating injury
invasive injury to neuronal and vasculature tissue
Type of TBIs caused by acceleration/deceleration
concussion
hematoma (subdural)
diffuse axonal injury
Type of TBIs caused by blast injury
Diffuse axonal injury
Type of TBIs caused by heart attack, near drowning (acquired brain injuries)
anoxia (the absence of oxygen)
hypoxia (inadequate oxygen to tissues)
contusion
Swollen brain tissue where there is vascular and tissue damage
- can be a response to the brain moving around in the skull (same side = coup; opposite side from contact = contrecoup)
- identified on CT; appears as hemorrhagic lesion
- differentiated from hematoma in that blood is intermixed with brain tissue
Hematoma
Damage to major blood vessels in the head or heavy bleeding into or around the brain
- epidural: bleeding between skull and dura
- Subdural: bleeding between dura and arachnoid
- subarachnoid/intracerebellar: bleeding within the brain
Diffuse axonal injuries
Torsion or shearing of long axons
- greater likelihood of disruption of white matter tracts: corpus callosum, internal capsule, brainstem, cerebellar peduncles
- axonal injury not always diffuse
- interruptions of axonal transport and axonal swellings
- not identified on CT and sometimes on MRI
Blast injuries
Primary: occur following high order over-pressurization shock wave moving through the body, affects gas-filled organs such as lungs, GI tract, middle ear, etc.
Secondary: caused by bomb fragments and other objects propelled by an explosion resulting in penetrating injuries
Tertiary: result from the blast wind throwing the victim and include bone fractures and amputation
Quaternary: include injuries not included in the first three (burns, crush injuries, and respiratory injuries)
What are the typical intracranial pressure values?
10-15 mm Hg in supine
-10 mm Hg in standing
Cerebral Perfusion Pressure (CPP) = Mean Arterial Pressure (MAP) - Intracranial Pressure (IP)
What can result from excess intracranial pressure?
papilledema, herniation, brain tissue damage, stroke, etc.
Signs: decreased pulse rate, change in consciousness, agitation, coma
What is Cushing’s Triad?
Three primary signs that often indicate increased intracranial pressure: increased Systolic BP decreased pulse decreased respiration *opposite of shock symptoms*
Glasgow Coma Scale: eye opening response scoring
Spontaneous: open before stimulus- 4 pts
To verbal stimuli (spoken or shouted request)- 3 pts
to pressure (finger tip stimulus)- 2 pts
No opening at any time, no interfering factor- 1 pt
Non-testable: closed by local factor- NT
Glasgow Coma Scale: verbal response scoring
Oriented: correctly gives names/place/date- 5 pts
Confused conversation, but coherent- 4 pts
Words: intelligible but inappropriate- 3 pts
Sounds: incomprehensible, moans/groans- 2 pts
No response, no interfering factor- 1 pt
non-testable: closed by local factor- NT
Glasgow Coma Scale: motor response
Obeys commands for movement- 6 pts
Purposeful movements to stimulus- 5 pts
Withdraws in response to pain- 4 pts
Flexion response to pain (decorticate)- 3 pts
Extension response to pain (decerebrate)- 2 pts
No response, no interfering factor- 1 pt
Non-testable: closed by local factor- NT
Abnormal flexion response to stimulus
slow stereotyped arm across chest forearm rotates thumb clenched leg extends
Normal flexion response to stimulus
rapid
variable
arm away from body
Head injury classification via GCS
3-8–severe
9-12– moderate
13-15– mild
classification of TBI severity: loss of consciousness (LOC)
0-30 min– mild
> 30 min and < 24 hrs– moderate
> 24 hrs– severe
classification of TBI severity: alteration of consciousness/ mental state (AOC)
up to 24 hrs– mild
> 24 hrs; severity based on other criteria– moderate or severe
classification of TBI severity: post-traumatic amnesia (PTA)
0-1 day– mild
>1 day and < 7 days– moderate
> 7 days– severe
classification of TBI severity: Glasgow Coma Scale (best available scores in first 24 hrs)
13-15– mild
9-12– moderate
< 9– severe
Coma
unconscious and no sleep wake cycles; may have reflexive movement
Persistent Vegetative state
unconscious, but have sleep wake cycles;
withdraws to noxious stimuli;
occasional non-purposeful movement;
brief orientation to sound or an object
Minimally conscious state
partially conscious
localize noxious stimulus and sound
inconsistent following commands
Stupor
general unresponsiveness
require repeated stimuli
obtunded
reduced alertness
slow to respond to stimuli
Delirium
disoriented
fearful and misinterpret stimuli
