Lecture 8: Long Term Consequences of TBI Flashcards
What is the epidemiology of severe TBI?
230,000 annual hospitalizations 50,000 deaths 80,000 long term disability/year M:F 2:1 Caused by: falls, firearms, transportation Prevalence = 5.3 million citizens 4.5 billion in expenditure
What is the leading cause of death in TBI?
Firearms
Transportation is leading worldwide cause, rather than cause of death
Why are older men more likely to have TBI?
They are more likely to drink and fall down stairs lmao
What is the Glasgow Coma Scale?
Motor score Eye score Verbal score Developed so that observers can describe extent of brain injury Subtotal is 3-15
What is the most important aspect of Glasgow coma scale?
Motor score because you can always get this score even if patient is passed the fuck out
Why do you want to apply a pain stimulus at supraorbital notch or trapezius and NOT at sternum or below neck?
Because 15% of people with TBI have concomitant spinal cord injury so you want to give stimulus where they can feel it
What are the scores for eye response?
Eyes open spontaneously = 4
Eyes open ONLY to verbal command = 3
Eyes open to pain = 2
No response = 1
What are the scores for motor response?
To verbal command =6 Localizes painful stimulus (grabs hand) = 5 Flexion-withdrawal = 4 Flexion-abnormal (decorticate) = 3 Extension – abnormal (decerebrate) = 2
What are the scores for verbal response?
Oriented and can converse = 5 Disoriented and can converse = 4 Inappropriate words = 3 Incomprehensible words = 2 No response = 1
What is characteristic of somebody with a decorticate response? Significance?
Flexion-abnormal response (3) on Glasgow Cortex is isolated from brainstem Shows that the cortex is NOT responding Hand comes up to chest Damage at or above red nucleus
What is a decerebrate posture?
Extension of arms
Damage below red nucleus
More severe than decortical posture
2 on Glasgow scale
What is the indication of SEVERE head injury?
GCS score less than or equal to an 8
What is the indication of MODERATE head injury?
GCS score 9-12
What is the indication of MILD head injury
GCS score 13-15
What is the Glasgow Outcome Scale?
1 = good recovery = individual is independent
2 = moderate disability = individual needs physical/cognitive assistance
3 = severe disability = individual is significantly challenged in most daily activitys
4 = vegetative = unresponsive
5 = death
e.g. Gabby Giffords has a score of 1
How else do you grade severe TBI?
CT diagnosis of diffuse injury I = no swelling II = minimal swelling III = cisterns absent IV = swelling + shift Evacuated mass lesion vs. non-evacuated mass lesion
What is the significance comparing CT diagnosis with Glasgow Outcome?
You get a very good idea of expected mortality of patient (the better the Glasgow outcome score combined with CT diagnosis, the better the expected survival)
Then you add age + oxygen status + hypotension
What are the treatment guidelines for TBI?
Split into 1. In the field 2. In the ER 3. In the Hospital Standardized throughout country
What are the most common systemic complications in severe TBI?
- Hypoxia 45%
- Hypotension 30%
- Anemia: 30%
- All complications: 50%
What are the goals of TBI management?
- Continue/initiate RESUSCITATION (ABC’s) is KEY
- Prevent secondary injury by maintaining adequate perfusion
Resist the following:
-decreased perfusion
-increased cerebral vascular resistance
-decreased oxygenation or glucose
-increased metabolism - Obtain diagnosis of type of TBI (CT scan)
How well do animal models mimic human TBI?
No single animal model of TBI can mimic whole spectrum of clinical TBI
Thus, a number of distinct yet complementary animal models are necessary to reproduce a whole range of injury severity/characteristics
e.g. rats and pigs
How do you diagnose DAI?
Diagnosis of exclusion
What are the key molecular events in severe TBI?
- necrosis
- inflammation
- apoptosis
All three result in brain atrophy, particularly in the hippocampus
What is the significance of hippocampus and its association with severe TBI?
Hippocampus often times shrinks with severe TBI
Is shown in both humans and animals
Long term degeneration (memory related problems)
Hippocampus = where epilepsy originates
What are ways the brain recovers after severe mTBI?
- Plasticity within the hippocampus
-sprouting from septal nuclei to replace lost projections from entorhinal cortex to hippocampus - Neural regeneration in dentate gyrus
(neurons are born throughout life? Enables you to learn new shit)
-bromo-deoxyUridine (BDU) injected in humans with glioblastoma as proof - Physiologic consequences of synaptic reorganization
-hippocampus becomes HYPEREXCITABLE (risk factor epilepsy)
-CA1 also becomes HYPOexcitable (risk factor for worse memory) - Behavioral recovery
-rats subjected to TBI can relearn Morris Water task, suggesting behavioral recovery
What are the key cells in hippocampus with regards to severe TBI to test hippocampal regeneration?
Afferents to dorsal molecular layer of dentate gyrus
Projections from ENTORHINAL CORTEX
We can look to see if there is a connection between granular layer and outer molecular layer
-if no connection but still presence of neurons, then we are left with the conclusion that sprouting took place
If you lose projections from entorhinal cortex, where may you get neuronal sprouting?
From the septal projections coming from the one of the septal nuclei
Can be detected by cholinesterase stains
In humans, what happens as a result of hippocampal atrophy?
Epilepsy…learning and memory loss
Animal models do not show the same so no clear correlation
What is the medial septal nucleus?
One of the septal nuclei (around area of anterior commissure)
-projects from medial septal nucleus and terminates in hippocampal formation
If you take the left brain out of a child, what happens? Significance?
Child will develop normal language function!
Demonstrates that younger people have more plastic brain than older people
When can plasticity be aberrant or bad?
Phantom limb pain
The Glasgow Coma Scale is used to grade severity of TBI. Using this system, what is the GCS for the following patient?
Motor: localizes a painful stimulus by grabbing the examiner’s head
Verbal: disoriented, but can converse
Eyes: opens eyes to command
Answer: 12 … M = 5, V = 4, E = 3
True or false: this patient should be graded as having moderate injury (GCS = 12)
True (because moderate injury = 9-12)
True or False: TBI is not associated with epilepsy
FALSE because TBI is a risk factor for epilepsy
The hippocampus plays a crucial role in:
A. Learning and memory
