Lecture 70, 66: Neural Damage, Repair, TBI Flashcards
Injury in the soma is based on…
Spreading excitotoxicity
Describe mechanism of excitatory toxicity
F
Can a focally demyelinated axon remyelinate?
Yes, good prognosis
It’s easier to regenerate after axonal damage if…
The connective tissue wrappings are still present (epi, peri, endoneurium)
The worst prognosis is associated with loss of?
Epineurium
Axonal loss is picked up in neural conduction studies with what finding?
Decreased AP amplitude
Wallerian Degeneration (PNS)
Intra-axonal organelle/microtube breakdown –> macrophages enter –> path cleared for axons to regrow proximal to distal
Does degeration work better in the CNS or PNS?
PNS
How long does it take to begin to regrow peripheral nervous tissue?
Weeks to months
What’s different in CNS degeneration? (2)
- Junk not cleared for regrowth; 2. CNS cells are inhibitory for regeneration
What are two potential targets for recovery after CNS injury?
CNS extrinsic inhibitors and intrinsic RAGs (regeneration associated genes)
Growth cone contains…
Actin bundles and microtubules
What can we control in an acute nerve injury situation?
Fever, hyperglycemia, infection
What is more realistic that regeneration?
Re-routing!
In rehab, what is more effective that general exercise alone? Describe the presentation of these tasks.
Learning skilled, task specific, repetitive tasks with random practice order (better than ordered blocks)
Three stem cell types
Totipotent (can form any body cell and extra fetal tissues); pluripotent (can form any cell in body); multipotent (can form a speciic lineage)
What stem cell is important in regeneration research? Source?
Pluripotent; excess IVF-derived embryos (non-implanted)
Fetal stem cells contain few, if any…where in the fetus?
Pluripotent stem cells; extra-fetal/aborted fetal tissue
Adult stem cells are of what type?
Multipotent
All stem cells are?
Renewable!
Describe somatic cell nuclear transfer; what type of cell? Completely autologous?
Adult somatic cell nuclei + donor egg cell; pluripotent; NO – donor cytoplasm/mitochondria
Describe induced pluripotent stem cells; what type of cell? Completely autologous?
Adult somatic cells + activated stem cell genes; pluripotent; 100% autologous
Stem cell uses (4)
Developmental studies; disease-specific cells for in vitro drug screening; cell transplants (replace degenerated cells); organ transplants
Which would be a better stem cell target, HD or Alzhemier’s? What about ALS, PD?
HD: one type of neuron in one site; ALS and PD = one type of neuron but many sites
How might stem cells be used for axonal injury?
Might help circuits remyelinate via plasticity
Scale to assess coma. What does it assess?
Glasgow Coma Scale: eye opening, motor response, verbal response
What do you learn about while examining the patient with a head injury (5)
Level of consciousness, motor response, pupil reaction, ability to talk/orientate, ability to breath
What are signs of skull fracture? (4)
Raccoon eyes, Battle’s sign (blood behind ear), CSF rhinorrhea/otorrhea (beta-2-transferrin), hemotypanum (blood behind ear drum)
% of head injuries associated with neck injuries
10%
Gold standard for evaluating head injuries
CAT scan (better than MRI for acute blood and bone)
Epidural hematoma is associated with what classical sign? Prognosis?
“Lucid interval”; good if treated surgically because the brain is OK
What is the typical source of bleeding in epidural hematoma?
Arterial
Subdural hematomas generally involves; associated with?
Bridging veins; shaken babies, alcoholism
Mortality with subdural hematoma compares to EDH how?
Much higher: often associated with underlying brain injury/edema
Brain contusion (def); where, mass effect, operable?
Cell death accompanied by hemorrhage often at a site distant from impact, little mass effect, not operable
How to treat intracranial hypertension (4 first tier therapies)
Positioning, ventricular drainage, osmototic diuresis, hyperventiliation
Subarachnoid hemorrhage
F
Diffuse axonal injury caused by what forces? Scan findings
Shearing; person often looks worse than the scans, but sometimes “punctate” scarring
Concussion definition and scan findings
Transient alteration of consciousness due to an impact to the head; NORMAL catscan
Most common memory deficit following concussion?
Anterograde amnesia
Post-concussion syndrome can last how long? Common symptoms.
Few days to months; headache, N/V, fatigue, difficulty concentrating
Second impact syndrome (def)
Reinjury occurs before resolution of previous concussion leading to cerebral edema –> death
Chronic traumatic encephalopathy: definition/symptoms and a proposed mechanism
Repetitive brain injury w/ mental decline, depression, erratic behavior; related to repetitive axonal stretching and deformation
Early symptoms of CTE
STM impairment, cognitive dysfunction, depression and emotional instability
Late symptoms of CTE
Dementia, PD
How to get a certain diagnosis CTE? Describe findings.
Only through autopsy; brain atrophy, pallor of monoamine nuclei, tau-opathy (more severe than AD)
Tip-off for CTE
VERY severe tau-opathy
