Pain

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Pain
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defining pain

• Pain is an unpleasant sensory and emotional event
  with actual or potential tissue damage
• It is subjective and modified by past experiences

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Types of pain

• 1. Acute
• 2. Chronic
• 3. Referred
• 4. Radiating

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Causes of Pain

• Most common Arthritis.
• Elderly have different perceptions of pain

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Transmission of Pain

• Stimulus? Nocioceptors
• Nocioceptors are 80 C fibers and 20 A delta
  fibers.
• About 50 of sensory fibers have nocioceptive
  functions.
• C fibers are blocked in the presence of opiates.
• A delta fibers are unaffected by opiates

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Second order neurons

• Also called T cells (transmission). Are located
  in the spinal cord.
• Connect the spinal cord and the cortex.
• T cells are inhibited by the inhibitory
  interneurons in the Substancia Gelatinosa.
• T cells receive excitatory input from the A
  delta and C fibers and inhibitory input from A
  Beta and descending fibers from the higher brain
  centers.
• Sooooooooooo..

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T cells

• The balance of inhibitory and excitatory
  influences determines whether the patient
  perceives and or not and the the severity of the
  pain experience

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The Gate Theory

• Increased firing of the nonnocioceptor sensory
  afferents A Beta causes presynaptic inhibition of
  the T cells and closes the gate to the cerebral
  cortex and decreases the sensation of pain.
• Recent findings also include influences from
  descending neurons from the limbics raphe nucleus
  and reticular systems.

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Endorphins

• Control pain by binding to specific opiate
  binding sites.

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Sympathetic involvement

• Occurs secondary to a hyperactive response of the
  SNS to injury or failure of its response to
  subside.
• RSD
• Causalgia
• Regional pain syndrome

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Pain?Spasm? Pain Cycle

• Increased m spasm can be caused by T cell
  activation via a spinal cord reflex.
• Continual m contraction mechanically compresses
  the nocioceptors.
• Also m spasm can cause an accumulation of fluid
  and tissue irritants, causing further
  contribution to this cycle.

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Tracks

• Ascending
• Lat spinthalamic
• Anterospinothalamic

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Assessing Pain

• Remember that this is a subjective response that
  is influenced by previous experiences, beliefs
  and culture

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Pain profiles

• Important to identify
• 1. Type of pain
• 2. Quantity of pain
• 3. Effect of pain on function

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Visual Analog Scales

• None----------Severe
• No pain relief----------Complete pain relief

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Pain charts

• Spatial information about pain
• Graphic portrayal

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Numeric Pain Scale

• By far most commonly used today.
• Based on response to 0-----------10
• 0 indicates absence of pain
• 10 the worst pain you could imagine

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Most sensitive bodily tissues

• 1. Perosteum-jt. Capsule
• 2. Subchrondral bone, tendons, and ligs.
• 3. Muscle and Cortical Bone
• 4. Synovium and articular cartilage

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Goals for pain management

• 1. Encourage healing
• 2. Increase function
• 3. Return to previous levels of function

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Pain control

• Interventions used in PT
• 1. Block ascending pathways (SG)? Stimulate aBeta
  fibers
• 2. Block decending pathways? encephalins
• 3. Release Beta Endorphins? acupuncture
  stimulates aDelta and C fibers. TENS with long
  phase durations and low pulse rates