Lecture 70, 66: Neural Damage, Repair, TBI

Question 1

Injury in the soma is based on…

Answer 1

Spreading excitotoxicity

Question 2

Describe mechanism of excitatory toxicity

Answer 2

F

Question 3

Can a focally demyelinated axon remyelinate?

Answer 3

Yes, good prognosis

Question 4

It’s easier to regenerate after axonal damage if…

Answer 4

The connective tissue wrappings are still present (epi, peri, endoneurium)

Question 5

The worst prognosis is associated with loss of?

Answer 5

Epineurium

Question 6

Axonal loss is picked up in neural conduction studies with what finding?

Answer 6

Decreased AP amplitude

Question 7

Wallerian Degeneration (PNS)

Answer 7

Intra-axonal organelle/microtube breakdown –> macrophages enter –> path cleared for axons to regrow proximal to distal

Question 8

Does degeration work better in the CNS or PNS?

Answer 8

PNS

Question 9

How long does it take to begin to regrow peripheral nervous tissue?

Answer 9

Weeks to months

Question 10

What’s different in CNS degeneration? (2)

Answer 10

1. Junk not cleared for regrowth; 2. CNS cells are inhibitory for regeneration

Question 11

What are two potential targets for recovery after CNS injury?

Answer 11

CNS extrinsic inhibitors and intrinsic RAGs (regeneration associated genes)

Question 12

Growth cone contains…

Answer 12

Actin bundles and microtubules

Question 13

What can we control in an acute nerve injury situation?

Answer 13

Fever, hyperglycemia, infection

Question 14

What is more realistic that regeneration?

Answer 14

Re-routing!

Question 15

In rehab, what is more effective that general exercise alone? Describe the presentation of these tasks.

Answer 15

Learning skilled, task specific, repetitive tasks with random practice order (better than ordered blocks)

Question 16

Three stem cell types

Answer 16

Totipotent (can form any body cell and extra fetal tissues); pluripotent (can form any cell in body); multipotent (can form a speciic lineage)

Question 17

What stem cell is important in regeneration research? Source?

Answer 17

Pluripotent; excess IVF-derived embryos (non-implanted)

Question 18

Fetal stem cells contain few, if any…where in the fetus?

Answer 18

Pluripotent stem cells; extra-fetal/aborted fetal tissue

Question 19

Adult stem cells are of what type?

Answer 19

Multipotent

Question 20

All stem cells are?

Answer 20

Renewable!

Question 21

Describe somatic cell nuclear transfer; what type of cell? Completely autologous?

Answer 21

Adult somatic cell nuclei + donor egg cell; pluripotent; NO – donor cytoplasm/mitochondria

Question 22

Describe induced pluripotent stem cells; what type of cell? Completely autologous?

Answer 22

Adult somatic cells + activated stem cell genes; pluripotent; 100% autologous

Question 23

Stem cell uses (4)

Answer 23

Developmental studies; disease-specific cells for in vitro drug screening; cell transplants (replace degenerated cells); organ transplants

Question 24

Which would be a better stem cell target, HD or Alzhemier’s? What about ALS, PD?

Answer 24

HD: one type of neuron in one site; ALS and PD = one type of neuron but many sites

Question 25

How might stem cells be used for axonal injury?

Answer 25

Might help circuits remyelinate via plasticity

Question 26

Scale to assess coma. What does it assess?

Answer 26

Glasgow Coma Scale: eye opening, motor response, verbal response

Question 27

What do you learn about while examining the patient with a head injury (5)

Answer 27

Level of consciousness, motor response, pupil reaction, ability to talk/orientate, ability to breath

Question 28

What are signs of skull fracture? (4)

Answer 28

Raccoon eyes, Battle's sign (blood behind ear), CSF rhinorrhea/otorrhea (beta-2-transferrin), hemotypanum (blood behind ear drum)

Question 29

% of head injuries associated with neck injuries

Answer 29

10%

Question 30

Gold standard for evaluating head injuries

Answer 30

CAT scan (better than MRI for acute blood and bone)

Question 31

Epidural hematoma is associated with what classical sign? Prognosis?

Answer 31

"Lucid interval"; good if treated surgically because the brain is OK

Question 32

What is the typical source of bleeding in epidural hematoma?

Answer 32

Arterial

Question 33

Subdural hematomas generally involves; associated with?

Answer 33

Bridging veins; shaken babies, alcoholism

Question 34

Mortality with subdural hematoma compares to EDH how?

Answer 34

Much higher: often associated with underlying brain injury/edema

Question 35

Brain contusion (def); where, mass effect, operable?

Answer 35

Cell death accompanied by hemorrhage often at a site distant from impact, little mass effect, not operable

Question 36

How to treat intracranial hypertension (4 first tier therapies)

Answer 36

Positioning, ventricular drainage, osmototic diuresis, hyperventiliation

Question 37

Subarachnoid hemorrhage

Answer 37

F

Question 38

Diffuse axonal injury caused by what forces? Scan findings

Answer 38

Shearing; person often looks worse than the scans, but sometimes "punctate" scarring

Question 39

Concussion definition and scan findings

Answer 39

Transient alteration of consciousness due to an impact to the head; NORMAL catscan

Question 40

Most common memory deficit following concussion?

Answer 40

Anterograde amnesia

Question 41

Post-concussion syndrome can last how long? Common symptoms.

Answer 41

Few days to months; headache, N/V, fatigue, difficulty concentrating

Question 42

Second impact syndrome (def)

Answer 42

Reinjury occurs before resolution of previous concussion leading to cerebral edema --> death

Question 43

Chronic traumatic encephalopathy: definition/symptoms and a proposed mechanism

Answer 43

Repetitive brain injury w/ mental decline, depression, erratic behavior; related to repetitive axonal stretching and deformation

Question 44

Early symptoms of CTE

Answer 44

STM impairment, cognitive dysfunction, depression and emotional instability

Question 45

Late symptoms of CTE

Answer 45

Dementia, PD

Question 46

How to get a certain diagnosis CTE? Describe findings.

Answer 46

Only through autopsy; brain atrophy, pallor of monoamine nuclei, tau-opathy (more severe than AD)

Question 47

Tip-off for CTE

Answer 47

VERY severe tau-opathy