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Kin 2236 Athletic Injuries > Lecture 6: Hot and Cold > Flashcards

Lecture 6: Hot and Cold Flashcards

1
Q

Pain

A

Unpleasant sensory and emotional experience associated with actual or potential tissue damage

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2
Q

Pain receptors

A

Nociceptors

sensitive to mechanical (tearing), thermal, chemical

afferent nerve fibres carry info from nociceptors to spinal cord

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3
Q

Types of Pain Signals

A

A delta (myelinated) = fast pain
C fibres (UNmyelinated) = slow pain

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4
Q

A delta fibres

A
  • myelinated + large diameter = fast pain
  • touch, pressure and temp
  • located in skin
  • ex. hand in alligator’s mouth or hand on stove (tells to move hand right away)
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5
Q

C fibres

A
  • unmyelinated + small diameter = slow pain
  • pain and temp
  • located skin and deep tissue (muscle/lig)
  • reminder that you’re sore
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6
Q

Gate Control Theory of Pain (no stimulation)

A

Without stimulation, A beta (large) + C (small) fibres are quiet
- SG and inhibitory interneuron block signal in T cell
- gate is closed = NO pain

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7
Q

Substantia Gelatinosa

A

Transfer station or volume control
- located in dorsal horn of lateral spinothalamic tract

Blocks pain by increasing signals from inhibitory interneuron to block C fibre signals from getting to T cell and feeling pain

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8
Q

Gate Control Theory of Pain (pain stimulation)

A

With pain stimulation, C fibres are active and BLOCK inhibitory SG and activate T cells
- inhibitory interneuron is blocked = CANNOT block output of T cell
- gate is open = PAIN

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9
Q

Gate Control Theory of Pain (non-painful stimulation)

A

With non-painful stimulation, A beta (large) fibres are activated
- activates SG = activation of inhibitory interneuron = BLOCKS signal in T cell
- gate is closed = NO pain

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10
Q

What fibres do we want to block? What do we not want to block?

A

Want to decrease C-fibre pain b/c it’s leftover pain

NEVER want to block A-delta pain b/c it protects us

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11
Q

A-beta fibres

A

Blocks C fibre input
- responds to pressure, vibration, position sense

Pressure: rubbing head when you bump it, massage
- stimulates A-beta input = increase in SG = block C fibre

Vibration: 4 Hz taps on ankle x 10 min = released opiates and closed gate

Position sense: shaking finger, AROM/PROM

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12
Q

Fibre accommodation

A

Accommodation = rise in threshold

  • if a nerve shows constant strength of current, site of nerve has lower excitability

Constant input = no sensation to body
- A fibres will accommodate (A-beta fibres will be ignored and pain starts again)
- C fibres will NOT accommodate

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13
Q

Cold and Superficial Heat

A
  • therapeutic modalities
  • conduct heat to or away from the body
  • applied to speed up healing… evidence?
  • may cause injury if used improperly
  • cold = cryotherapy, heat = thermotherapy
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14
Q

Cold and blood flow

A
  1. Spinal cord: decrease in blood flow in 1st 5-15 mins
  2. Local/superficial: oscillations
    - reflex vasodilation/constriction to try to reheat cold area
  3. Hypothalamus (linear level of cold)

go from 1 to 3 as time increases

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15
Q

Body’s response to cold depends on…

A
  1. cold media being applied (ice, cold water immersion)
  2. conductivity of area being cooled
    - high water content in tissue = less cooling
    - muscle > fat
    - joints > muscle (b/c of synovial fluid)
  3. Length of time of exposure
    - longer is not always better
    - Bleakley et al.: 10 on- 10 off - 10 on
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16
Q

Bleakley et al

A

Explained that ice should be used in this way: 10 on/10 off/10 on (superior to 20 mins on)

avoids vasodilation/vasoconstriction reflex that causes blood flow to be pushed to area to rewarm cool skin (stays cold)

17
Q

What happens w/ acute injuries?

A
  • tissue injury at primary + secondary sites = cell death due to hypoxia
  • increased bleeding into area
  • pain
  • swelling/edema
18
Q

Body’s physiological responses to cryotherapy

A
  • decrease in muscle guarding = breaks pain/spasm cycle
  • decrease blood flow
  • decrease capillary permeability
  • decreased O2 required= less secondary injury
  • decreased collagen elasticity
  • increased joint stiffness
  • decreased pain perception (C fibre conduction rate drops)
  • edema is controversial (does not reduce current swelling but might reduce future swelling)
19
Q

Metabolic rate and cryotherapy

A

When injured, blood flow is reduced and can lead to cell death from hypoxia

Ice decreases metabolism of cells = less O2 is needed
- O2 provided after injury is now enough to survive

20
Q

Case AGAINST ice use

A
  • inflammatory/destruction phase of healing is necessary

Evidence that ONE early ice treatment may slow down healing over first 3-7 days (impaired tissue repair)
- more necrosis in ice group at day 3
- less neutrophils day 1 and more day 3 in ice group
- less macrophages at day 1 and 3 w/ more at day 7 in ice group = delayed inflammation

21
Q

Case FOR ice use

A

Good for pain
- C fibres are not myelinated
- every 1 degree drop in temp = decreasing conduction velocity of a nerve
- 4 degree cooling = C fibres knocked out

Combined w/ exercise = better ability to decrease swelling compared to heat
- significant improvement in function

Maintaining cell viability after injury
- drop in chemical reactions + drop in ATP demand = drop in cellular collapse (anti-oxidant)
- don’t need as much of these things since we won’t get them either way

22
Q

Body’s response to heat depends on…

A
  1. Type of heat applied
    - moist heat (better for deep tissues)
    - dry heat (better tolerated)
    - ultrasound (mechanical)
  2. Intensity of heat energy (some ppl are more sensitive)
  3. Duration of application
    - blood flow until heat source is removed
    - will peak 6-8 mins (body protects from getting too hot)
    - when heat source is removed, tissue temp drops
23
Q

Blood flow with cryotherapy and thermotherapy

A

Cryotherapy: variable blood flow (increases and decreases w/ oscillations)

Thermotherapy: increases then plateaus and stays constant to prevent tissue from getting too hot

24
Q

Physiological responses to thermotherapy

A
  • increased blood flow
  • increased capillary permeability
  • increased metabolic rate (good b/c we want to increase blood flow to area)
  • increased collagen elasticity
  • decreased jt. stiffness
  • decreased spasm (ischemic)
  • decreased pain
  • edema depends on timing of heat
25
Q

Inflammation/destruction phase

What is happening at tissue level?

A
  • red, hot, painful and swollen
  • primary and secondary destruction/inflammation
26
Q

Inflammation/destruction phase

Immediate goals

A

Timeline: 2-4 days

  • optimize healing environment
  • palliate/reduce pain
  • decrease swelling
27
Q

PEACE & LOVE

A

Protection
Elevation
Avoid
Compression
Education
&
Load
Optimism
Vascularization
Exercise

28
Q

POLICE

A

Protect
Optimal
Loading
Ice
Compression
Elevation

29
Q

Protection

A
  • interventions should shield, unload and or/prevent jt. movement
  • recent animal models show short periods of unloading are needed after acute soft tissue injury (aggressive loading should be avoided)

Goal: control inflammation and prevent further injury

30
Q

Loading

A

Optimal loading = replacing rest w/ balanced incremental rehab where early activity is encouraged
- includes safe cardio = increase blood flow = vascularization

Ex. functional rehab of ankle sprain includes early weight-bearing w/ external support is BETTER than cast immobilization

31
Q

Compression

A

Decreases local edema

Applying a pad/ice bag under = increased pressure over injured area
- helps disperse edema and makes it more available for absorption by limiting physical space able to occupy it

32
Q

Elevation

A

NO reduction of blood flow until injured area is at least 30cm ABOVE the heart

At 50cm, flow is 80% of normal

At 70cm, flow is 65%

33
Q

Optimism and Education

A

Educate your athlete, let them know:
- why they are doing things
- how you will measure progress (set goals w/ patient and share results)
- setting and achieving small goals = brain is positive and confident (buy-in will continue to pay dividends and they will work harder and stay motivated)
- teach them that rehab is an active process

34
Q

Icing

A
  • best cooling = ice mixed w/ water in plastic bag directly on skin
  • compression over top is best (use of towel, wet or dry compression bandage decreases conductivity)
  • NEVER apply gel packs directly to skin (temp remains very cold)
35
Q

Repair/Fibroblastic phase

What is happening at tissue level?

A

Laying down new tissue (scars form)

Type 3 collagen is used (NOT great tissue)

36
Q

Repair/Fibroblastic phase

Immediate goals

A

Protect tissue and idealize healing environment
- increase blood flow (HEAT)

Before end of this stage:
- idealize ROM
- begin gentle strengthening

37
Q

Why heat in repair/fibroblastic and remodeling stages?

A
  • increases blood flow to promote healing
  • decreases spasm
  • increases collagen elasticity
  • decreases stiffness
38
Q

Remodeling/Maturation Stage

What is happening at tissue level?

A

Must progressively increase force acting through tissues

Wolf’s law
- change from Type 3 to Type 1 collagen
- realign fibres

39
Q

Remodeling/Maturation Stage

Rehab goals

A

Before end of this stage:
- idealize strength
- functional movements (speed, power, agility)
- prepare for return to play
- a little pain during treatment is ok but now following (tearing cross-bridges and realignment)

Kin 2236 Athletic Injuries (20 decks)

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