Pain Control Theories

1
Pain Control Theories
2
Pain Anatomy Review

• Primary Afferent Fibers
• 1st Order Neurons

3
Pain Anatomy Review

• Primary Afferent Fibers
• 1st Order Neurons
• Dorsal Horn

4
Pain Anatomy Review

• Primary Afferent Fibers
• 1st Order Neurons
• Dorsal Horn
• Spinothalamic Tract

5
Gait Control Theory

• Pain can be altered by blocking impulses within
  pathways
• Stimulate A-beta stimulates substantia gelatinosa
• A-betas are faster than A-delta and C fibers
• How does this work?
• Gate Open
• Gate Closed

6
Endogenous Pain Control

• Ascending Influence on Pain Control
• Similar to Gate Control
• A-beta triggers release of Enkephalin
• Inhibits Substance P at junction between 1st and
  2nd order neurons

7
Endogenous Pain Control

• Descending Influence on Pain Control (Central
  Biasing)
• Stipulates that higher brain centers can modulate
  pain
• PAG and RN
• Dorsal Lateral Tracts
• Enkephalin Interneurons
• Release of serotonin
• Past experience, emotional influences and sensory
  perception

8
Endogenous Pain Control

• Beta-Endorphin Mediated Model
• What is Endorphin?
• Found in hypothalamus and periaqueductal gey
  matter
• Activation of small diameter fibers
• Release of BEP

9
Acute vs Chronic Pain

• Acute Pain
• Definition
• Pain of recent or sudden onset
• Function
• Primary Hyperalgesia
• Secondary Hyperalgesia
• Pain-Spasm-Pain Cycle

10
Acute vs Chronic Pain

• Chronic Pain
• Definition
• Pain of long duration, often associated with
  anguish, apprehension, depression, hopelessness
• Consider neurophysiologic and psychologic factors
• Four Levels of Chronic Pain
• Nociception
• Pain
• Suffering
• Pain Behaviors

11
Other Types of Pain

• MFPS
• Chronic Pain
• No single cause
• S/S

12
Pain Management

• Must consider physiological, behavioral and
  cognitive
• Physical
• Modalities
• Behavioral
• Reducing anxiety
• Explain treatments
• Cognitive
• Central Biasing
• Relaxation techniques, motivation etc