Pain Flashcards
Describe the PT’s goal for pain
Change the pt. perception of pain and restore function
3 Dimensions of Pain
- Sensory-discrimination (SENSORY)
- Motivational-affective (EMOTIONAL)
- Cognitive-evaluative (COGNITIVE)
Dimension of Pain: Location, magnitude, duration, quality
Sensory-discrimination
Dimension of Pain: Emotions, anxiety, depression
Motivational-affective
Dimension of Pain: post experience, possibility of outcomes, influenced by one’s culture and beliefs
Congitive-evaluative
Term: Increased sensitivity to noxious stimulus
Hyperalgesia
Term: Feeling of pain from a non-noxious stimulus
Allodynia
Describe the difference between primary and secondary pain
Primary - pain at the site of injury
Secondary - pain away from the site of injury, same as referred pain
Term: Increased responsiveness or decreased threshold of neurons
Sensitization
Describe the difference between peripheral and central sensitization
Peripheral = dysfunction in PNS, PRIMARY hyperalgesia/allodynia
Central = dysfunction in CNS, SECONDARY hyperalgesia/allodynia
Describe the basic concept of the Ascending Pain Pathways
3 order neuron system
1st order = primary afferent fibers (have two axons)
2nd order = spinothalamic tract
3rd order = thalamocortical neurons
Describe the difference between Alpha Delta/C fibers and Group 3/4 fibers
Alpha Delta and C fibers innverate the skin while Group 3/4 fibers innervate deep tissues (mm, joint, synovium, ligament, etc.)
Describe the difference between Alpha delta/G 3 pain and C/G 4 pain
Alpha beta/G 3 = fast, sharp pain from thermal or mechanical noxious stimulus; low-threshold
C/G 4 = slow, dull pain from thermal, mechanical or chemical noxious stimulus; high-threshold
Describe the difference between slow and fast pain
Fast: immediate sharp sensation and id of location; processed by lateral pain system (spinothalamic)
Slow: dull/burning/throbbing followed by sharp pain that is not easily localized; processed by medial pain system
Term: Sensory receptor that can transduce pain stimulus
Nociceptor
3 Types of pain processed by the PNS
Chemical, thermal, mechanical
Describe the noxious mechanical stimulus in the following tissue types
- Skin
- Visceral
- Joint
- Muscle
- cut, burn, stretch, pressure
- distension
- friction, pressure/compression, tension
- tear, stretch, ischemia
3 Peripheral Pain Mechanisms
- Uni/Polymodal neurons (indicates types of stimulus responded to)
- Receptors (ion channels and receptors)
- Chemical
2 Main functions of the Primary Afferent Neuron
- Transduction
- Transmission
Term: Detection of noxious or damaging stimuli
Transduction
Term: Passage of the resulting sensory input from peripheral terminals to spinal cord
Transmission
Describe why we can only have primary hyperalgesia/allodynia in the PNS
Because of the two main functions of the primary afferent
Can pain at location due to transduction but won’t transmit information to CNS due to damage
Term: Tissue damage resulting in release of chemicals
Inflammation
3 Sx of Inflammation
- Constant pain from normal stimuli
- Heat
- Edema
Describe the process that results in peripheral sensitization
After persistent inflammation there is up-regulation of ion and glutamate receptors
The threshold for pain is lowered and there is increased synaptic activity
Leading to increased responsiveness of peripheral nociceptors
Finally phenotypic plasticity of nociceptors can occur (meaning nerves not meant to respond to pain begin to)
Describe neurogenic inflammation and its cause
Neurogenic inflammation occurs as a result of persistent inflammation. In this condition the neurons themselves are adding to the inflammation process by releasing glutamate
Describe the subjective and objective clinical findings for peripheral pain
SE: sx in nerve distribution, along n. trunk, hot spots along nerve, burning, sharp, night pain
OE: neurodynamic testing, skin/temp changes
Describe the treatment for chemical and mechanical peripheral neurogenic pain
chemical: use of appropriate modalities, neurodynamic sliders, meds - NSAIDs
mechanical: unload joint, change posture, look at ergonomics
3 Central pain mechanisms
- Spinal mechanisms
- Midbrain mechanisms (descending pathways)
- Corticla mechanisms
Spinal pain mechanisms
- Location
- NT
- Receptors
- Dorsal Horn
- Glutamate and Substance P (both excitatory)
- NMDA receptors, NK receptors, Ca ion channels
3 Classifications of DH neurons and their location and effect
- Projection n. – part of spinothalamic tract in Rexed LI – excitatory
- Interneurons – span Rexed LII-IV – inbhititory
- Wide dynamic range n. – body in Rexed LV, span to Rexed LI – excitatory or inhibitory
Describe the type of information sent to Rexed Lamina I-V
I, II, IV, V = pain information
III, IV = tactile information
Describe what information type and to which Rexed Lamina the neurons send the informatin
- Alpha Delta/G 3
- C/G 4
- Alpha Beta
- Sharp pain with it’s intensity and location to Rexed L I, IV, and V
- Dull pain to Rexed L II
- Pressure information to Rexed L III and IV
Describe the function and importance of Wide Dynamic Range Neurons
Function: Integrate painful/non-painful information received from both sides of the body and from multiple tissues/sites
Importance: Are the reason for referred pain!! There is a convergence of input from various tissues and misinterpretation from the cortex resulting in referred pain
List the pathways of the lateral and medial pain system
Lateral = Lateral spinothalamic tract
Medial = Anterior spinothalamic tract and spinolimbic tract
Main Descending Pain Pathway and its function
Periaqueductal gray-rostroventromedial medulla (PAG-RVM) of the midbrain
Synapses directly and indirectly with the SC to modulate pain (typically inhibitory but can also be excitatory)
2 Locations Descending Pathways Modulate Pain
- By blocking the signal at the central terminal of the 1st order neuron
- By blocking the singal at the DH neurons (thus stopping the activation of the DH neurons)
5 Descending Pathway NT
- Opiods (-)
- Serotonin (-)
- GABA (-)
- NE (+/-)
- Glutamate (+)
3 Inhibitory output and 2 excitatory output of the Descending PAthway
Inhibitory: electrical simulation, exercise, opioid meds
Excitatory: increased glutmate release and tissue injury
Describe the Gate Control Theory
Describes the physiological mechanisms whil accounting for phsychological factors
Overriding pain signals with non pain signals
The balance between the periperhal nocicpetors and the other periperhal fibers stimulation as well as descending pain pathways leave the gate “open” or “closes” and modify your perception of pain
Describe the location of the gate and what opens and closes the gate
The “gate” is located in the DH
Opened by: increased nociceptor activity, decreased activity of descending pathways
- extent of injury, overstimulation to injured tissue, anxiety, depression, focusing on pain, linking to prior painful experience
Closed by: increased activity of large afferents (i.e. Alpha Beta) and inhibitory descending pathways
- medications, modalities conservative intervention, positive emotions, relaxation, meditation, distraction, involvement in other activities
Describe how DH neurons are sensitized (central sensitization)
The DH neurons up regulate and sprout axons/dendrites to Rexed L I, II, V
Additonally there is production of genes, death of interneruons, and decreased descending pathway inhibition
All of this leads to increased responsiveness of DH neurons to noxious and innocuous stimuli
Term: Brain regions that process and regulate pain information
Pain Matrix
Cortical areas that correspond to the following dimensions of pain
- Sensory-discrimative
- Motivational-affective
- Cognitive-evaluative
(4. Descending Control)
- Thalamus and S1/2
- Cerebrum (insula, cingulate, prefrontal cortex), Amygdala, Hypothalamus, Thalamus (ILN)
- Prefrontal cortex
- Brainstem and midbrain
Describe the type of system the pain matrix uses
Top-down
Responds to acending pain signals after integrating sensory and affective pain regions to determine whether the information is normal or needs suppressed/amplified/reorganized
Describe the effects of central sensitization in the brain
- Changes in the somatotopic arrangement (increased proportion given to area of sensitization)
- Decreased brian chemicals essential to brain health (more glutamate and sub P, less inhibitory)
- Loss of gray matter volume
Describe how the ANS can complicate pain
Contributes to emergency analgesia and provides E
However, also adds to inflammation, causes DH sprouting and trophic skin changes
Describe the physiology behind persistent pain
- Upregulation of specific ion channels
- Phenotypic switching of large myelinated axons
- Sprouting within DH
- Loss of inhibitory neurons
- Misinterpretation by the brain
Type of Pain: Superficial or Deep pain
Somatic
Type of Pain: Associated with high anxiety or depression
Psychological
Results from distrubances in neural and non-neural cells that leads to maladaptive changes in the neurons and sensory system
Neuropathic
Type of Pain: Spontaneous nerve pain that is sharp/shooting/tingling, increased heat/cold sensitivity, increased pain perception
Neuropathic
List 5 Objective Pain Measures
- McGill sensory and affective pain
- Beck depression
3 Tampa kinesiophobia
- Fear Avoidance
- Oswestry disability (functional)
Describe the importance of CV fitness for (chronic) pain
It helps to stimulate the opiod system to control pain
- mod intensity, 10-20 minutes, walking etc.
