Tissue Healing

Question 1

Can central nerves regenerate?

Answer 1

no

Question 2

Can peripheral nerves regenerate?

Answer 2

yes, often incompletely

Question 3

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• severe contusion to nerve
• decreased conduction
• recovery takes several weeks

Answer 3

Neuropraxia

Question 4

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• injury to axon with wallerian degen
• recover in months-years
• crush injuries

Answer 4

Axonotmesis

Question 5

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• complete severence of a nerve
• irreversible damage
• nerve will never recover
• can treat neuroma
• cutting wounds

Answer 5

neurotmesis

Question 6

• NOTES-

- axonal degeneration does not begin immediately after injury; ie can still produce ap and xmit signals

Answer 6

-blood brain barrier is compromised

Question 7

what happens to the axon distal to the injury site?

Answer 7

-swells

Question 8

Calpain is activated and there is Ca2+ influx during nerve injury.
What is calpain?

Answer 8

Protease essential for the cytoskeleton degeneration and axonal degeneration

Question 9

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• granular degeneration of cytoskeleton
• fine debris produced
• occurs within an hr

Answer 9

axonal degeneration

Question 10

What is required for myelin sheath breakdown?

Answer 10

phospholipase a2

Question 11

what aids in axonal regeneration, secrete trophic factors, secretes cytokines, and phagocytose myelin debris?

Answer 11

schwann cells

Question 12

what removes myelin debris?

Answer 12

macrophages

Question 13

What is the order of involvement of inflammatory cells during nerve inurjy?

Answer 13

1. hours/days-neutorphils
2. 3 days- t lymphocytes
3. 1 week-macrophages

Question 14

Why do we do manual muscle testing?

Answer 14

have to determine if any abnormalities are coming from the nerve, nm junction, or the muscle

Question 15

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• tap along course of the nerve
• what is it when you have pain distally and pain proximally?

Answer 15

Tinel’s=distal->less concerning

Valleaux=proximal -> more concerning

Question 16

What do NCV studies test?

Answer 16

sensory component
motor component
f wave
h reflex

Question 17

what is the time it takes the electricity to travel from stimulation site to the recording site?

Answer 17

sensory and motor latency

-change in latency or amplitude indicates nerve injury

Question 18

What does the F-wave study?

Answer 18

• measures the resulting action potential
• not an reflex
• electrical activity travels from site of stimulation through ventral horn to muscle
• conduction velocity between the spinal cord and the limb

Question 19

What does H reflex study?

Answer 19

• electrical discharge of muscle

- connection between the limb and the spinal cord

Question 20

What occurs in rapid myonecrosis? (degeneration)

Answer 20

-Sarcolema disruption-> inc permeability; inc serum creatine kinase, prevelent skeletal troponin I

-increased infiltration of inflammatory cells
neutrophils then macrophages

Question 21

what occurs during myogenic proliferation?

Answer 21

myogenic cells differentiate and fuse to existing damaged fibers

• new fibers formed->cells enlarge->nuclei move to periphery
• new fibers are identical

Question 22

why can muscle cells regenerate?

Answer 22

undifferentiated mononuclear monogenic cells at periphery of mature skeletal fibers

Question 23

What is the steriotypical blood vessel response to injury?

Answer 23

stimulation of smooth muscle cell growth and associated matrix synthesis that thickents the intima forming a neointima

Question 24

How is neointima formed?

Answer 24

1. defect in endothelium
2. epithelial cells migrate into the area to fill the deficit
3. smooth muscle cells proliferate and synthesize ecm
4. neointima is formed

Question 25

what happens when there is decrease in blood flow?

Answer 25

- local tissues become hypoxic and ischemic - increase VEGF production - binds to cognate recepetor tyrosine kinases - angiogenesis

Question 26

6 P's | -signs of vascular injury

Answer 26

Pale, Pallor, Polar, Pulselessness, Pokilothermia, pain

Question 27

what type of vascular injury is this? - embolic shower - crush/laceration injury

Answer 27

acute vascular injury

Question 28

- What test is this?- - dependent rubor - palor with elevation - raise legs 60 degrees x1min

Answer 28

Brueger's test

Question 29

- What test is this?- - evaluates competency of valves in the veins - elevate legs 90 degrees - cuff around the high thigh occlude the grater saphenous vein - have pt stand - evaluate filling of the veins

Answer 29

Brodie-trendelenberg test

Question 30

What different in pressure indicates pathology when using abi/pvr with segmental pressures

Answer 30

greater than 30mmHg

Question 31

What indicates a healthy waveform?

Answer 31

- brisk sharp rise | - dichrotic notch

Question 32

waveform pathology with absence of a dichrotic notch and gradual prolonged downstroke?

Answer 32

-early pathology

Question 33

waveform pathology with rounded systolic peak

Answer 33

moderate pathology

Question 34

flattened wave with slow upstroke and downstroke

Answer 34

severe occlusion

Question 35

what is photoplethysomography?

Answer 35

infrared frequency is emitted and reflected by hemoglobin molecules in microcirculation to show waveforms

Question 36

what are the aims for arterial duplex and when do you use it?

Answer 36

- assess velocity of blood flow in the LE arteries - localize and characterize stenosis, collaterals, and occlusions - detailed assessment of the arterial tree -evaluation of atherosclerotic, aneurysm, bypass grafts, evaluation of arterial trauma

Question 37

What is the gold standard test for DVT?

Answer 37

venogram

Question 38

What is the difference between arterial and venous hemorrhage?

Answer 38

artery-pulsatile flow, bright red blood | vein-oozing, red to dark red blood