Lecture 8: Long Term Consequences of TBI

Question 1

What is the epidemiology of severe TBI?

Answer 1

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

Question 2

What is the leading cause of death in TBI?

Answer 2

Firearms

Transportation is leading worldwide cause, rather than cause of death

Question 3

Why are older men more likely to have TBI?

Answer 3

They are more likely to drink and fall down stairs lmao

Question 4

What is the Glasgow Coma Scale?

Answer 4

Motor score
Eye score
Verbal score
Developed so that observers can describe extent of brain injury
Subtotal is 3-15

Question 5

What is the most important aspect of Glasgow coma scale?

Answer 5

Motor score because you can always get this score even if patient is passed the fuck out

Question 6

Why do you want to apply a pain stimulus at supraorbital notch or trapezius and NOT at sternum or below neck?

Answer 6

Because 15% of people with TBI have concomitant spinal cord injury so you want to give stimulus where they can feel it

Question 7

What are the scores for eye response?

Answer 7

Eyes open spontaneously = 4
Eyes open ONLY to verbal command = 3
Eyes open to pain = 2
No response = 1

Question 8

What are the scores for motor response?

Answer 8

To verbal command =6
Localizes painful stimulus (grabs hand) = 5
Flexion-withdrawal = 4
Flexion-abnormal (decorticate) = 3
Extension – abnormal (decerebrate) = 2

Question 9

What are the scores for verbal response?

Answer 9

Oriented and can converse = 5
Disoriented and can converse = 4
Inappropriate words = 3
Incomprehensible words = 2
No response = 1

Question 10

What is characteristic of somebody with a decorticate response? Significance?

Answer 10

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

Question 11

What is a decerebrate posture?

Answer 11

Extension of arms
Damage below red nucleus
More severe than decortical posture
2 on Glasgow scale

Question 12

What is the indication of SEVERE head injury?

Answer 12

GCS score less than or equal to an 8

Question 13

What is the indication of MODERATE head injury?

Answer 13

GCS score 9-12

Question 14

What is the indication of MILD head injury

Answer 14

GCS score 13-15

Question 15

What is the Glasgow Outcome Scale?

Answer 15

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

Question 16

How else do you grade severe TBI?

Answer 16

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

Question 17

What is the significance comparing CT diagnosis with Glasgow Outcome?

Answer 17

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

Question 18

What are the treatment guidelines for TBI?

Answer 18

Split into
1. In the field
2. In the ER
3. In the Hospital
Standardized throughout country

Question 19

What are the most common systemic complications in severe TBI?

Answer 19

1. Hypoxia 45%
2. Hypotension 30%
3. Anemia: 30%
4. All complications: 50%

Question 20

What are the goals of TBI management?

Answer 20

1. Continue/initiate RESUSCITATION (ABC’s) is KEY
2. Prevent secondary injury by maintaining adequate perfusion
   Resist the following:
   -decreased perfusion
   -increased cerebral vascular resistance
   -decreased oxygenation or glucose
   -increased metabolism
3. Obtain diagnosis of type of TBI (CT scan)

Question 21

How well do animal models mimic human TBI?

Answer 21

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

Question 22

How do you diagnose DAI?

Answer 22

Diagnosis of exclusion

Question 23

What are the key molecular events in severe TBI?

Answer 23

1. necrosis
2. inflammation
3. apoptosis
   All three result in brain atrophy, particularly in the hippocampus

Question 24

What is the significance of hippocampus and its association with severe TBI?

Answer 24

Hippocampus often times shrinks with severe TBI
Is shown in both humans and animals
Long term degeneration (memory related problems)
Hippocampus = where epilepsy originates

Question 25

What are ways the brain recovers after severe mTBI?

Answer 25

1. Plasticity within the hippocampus
   -sprouting from septal nuclei to replace lost projections from entorhinal cortex to hippocampus
2. 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
3. Physiologic consequences of synaptic reorganization
   -hippocampus becomes HYPEREXCITABLE (risk factor epilepsy)
   -CA1 also becomes HYPOexcitable (risk factor for worse memory)
4. Behavioral recovery
   -rats subjected to TBI can relearn Morris Water task, suggesting behavioral recovery

Question 26

What are the key cells in hippocampus with regards to severe TBI to test hippocampal regeneration?

Answer 26

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

Question 27

If you lose projections from entorhinal cortex, where may you get neuronal sprouting?

Answer 27

From the septal projections coming from the one of the septal nuclei
Can be detected by cholinesterase stains

Question 28

In humans, what happens as a result of hippocampal atrophy?

Answer 28

Epilepsy…learning and memory loss

Animal models do not show the same so no clear correlation

Question 29

What is the medial septal nucleus?

Answer 29

One of the septal nuclei (around area of anterior commissure)
-projects from medial septal nucleus and terminates in hippocampal formation

Question 30

If you take the left brain out of a child, what happens? Significance?

Answer 30

Child will develop normal language function!

Demonstrates that younger people have more plastic brain than older people

Question 31

When can plasticity be aberrant or bad?

Answer 31

Phantom limb pain

Question 32

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 32

Answer: 12 … M = 5, V = 4, E = 3

Question 33

True or false: this patient should be graded as having moderate injury (GCS = 12)

Answer 33

True (because moderate injury = 9-12)

Question 34

True or False: TBI is not associated with epilepsy

Answer 34

FALSE because TBI is a risk factor for epilepsy

Question 35

The hippocampus plays a crucial role in:

Answer 35

A. Learning and memory