Pain Physiology and Mechanisms Flashcards
Nociceptive pain
due to activation of nociceptors
- inflammation
- mechanical irritant
- injury
Nociplastic pain
due to disturbance in central pain processing
- increase in excitability
- decrease in inhibition
neuropathic pain
due to a lesion or disease of the somatosensory system such as a neuropathy
What other systems can affect pain
motor and psychosocial
Medical terms
1. a-/an-
2. -algia/-algesia/-dynia
3. par-/para-
4. -esthesia
5. kinesio-
6. allo-
7. dys-
- without
- pain
- beside/other/different
- feeling
- movement
- other/abnormal
- bad/abnormal
Nociceptors
- stimuli
- how it travels
- transmit stimuli that may be harmful/noxious (danger or damage)
- information travels from periphery to the spinal cord where the spinal cord to the brain is conscious pain
Nociceptive pain causes what type of movement
- mainly causes reflexive movement
- there are many ways that the information gets to the brain
What are the nociceptive mechanism of pain
- acute pain: usually less than 12 weeks (it will resolve)
- associated with a known injury
- nociceptors stimulated: pain is perceived
- should be associated with phases of healing
- often times increase in pain with inflammation and decrease in pain as inflammation decreases
What mediates inflammation
- cascade of chmeicals
- some examples:
1. prostaglandins, leukotrienes and thromboxanes
2. bradykinin
3. histamines
4. cytokines (interleukins, TNF)
5. substance P (neuropeptide associated with pain)
What are some treatments of Acute pain
- physical therapy
- medications
PT:
- modalities: cold, heat, TENS
- exercise: stretching/strength
- task oriented functional rehab
- massage
- education
Medications:
- NSAIDs
- Steroidal anti-inflammatory meds
- opioids
- topical analgesics
Gate Control theory of pain
- activation of fibers that are faster than C fibers (that carry pain information) can gate ascending painful stimuli at the spinal cord level
- natural use-scratching/rubbing and pressing
- TENS uses this idea as well as massage
Nociplastic Mechanism of pain
- Changes in the way that the brain perceives pain
- harmful changes in Nervous system’s response to pain
- chronic pain:
~may change movement patterns
~ may cause fear and avoidance of movement (kinesiophobia)
Hyperalgesia
- associated with peripheral release of bradykinin, cytokines, substance P, prostaglandins
- increased nocicpetor input (peripheral sensitization)
- increased input to the brain (central sensitization)
Peripheral sensitization
- abnormal increased sensation above and below where it may normally be affected
Central Sensitization
- brain responds to non-noxious stimuli as if they will produce pain
- over time the brain becomes more sensitive to even small amounts of potentially noxious stimuli
- increases release of pain reactions throughout the body
- end result: pain perception doesnt match peripheral stimulus
Treatment for chronic pain
- Physical therapy
- medications
PT
- modalities: TENS
- exercises: stretching/strength
- task oriented functional rehab
- massage
- patient education: pain neuroscience and reduced pain catastrophizing
medication:
- antidepressants: Serotonin noradrenaline reuptake inhibitors (SNRIs)
- tricyclic antidepressants
Exercise induced hypoalgesia
- endogenous opioids/endogenous cannabinoids
- can be released during exercise, massage and meditation
- interneurons in spinal cord
- periaqueductal gray release of serotonin
- overall increase in release of things such as endorphins that reduce pain
Treating pain using pain neuroscience education
- graded motor imagery: some are afraid to move so you can show them movement
- graded activity: take small movements that starts moving the area but puts less pressure on it
- graded exercises: more specific movements
Neuropathic mechanism of pain
- damage to peripheral nerves impairs sensation
- impairs sensory information
- happens with a neuropathy
Chronic pain and
1. paresthesia
2. allodynia
- burning, itchy, numbness, tingling, itchy
- pain from non-painful stimulus
- generally chronic pain is sharp pain
treatment of neuropathic pain
1. physical therapy
2. medications`
- PT
- exercises: stretching/strength ETC
- patient education
- task-oriented rehab - medications:
- gabapentinoid: decreased nerve pain
Psychosocial factors that can affect pain perception
- social support
- social status
- depression/anxiety
- relationships
- past experiences
- stress
- sleep disturbances
- pain self-efficacy: realize pain but also need to realize they can move
- substance use
Motor factors with pain physiology
- muscle activity: too much/too little and fear of movement/reinjury
- posture
- movement patterns
- interaction with other body systems
treatment of psychosocial factors
1. Physical therapy
2. medications
- PT
- exercise: stretching/strength, aerobic ETC
- task-oriented functional rehab
- massage
- pt education - medications
- antidepressants: SNRIs, tricyclic antidepressants
Treatment of motor factors
1. Physical therapy
2. medications
- PT
- exercises: stretching/strenght, aerobic, posture etc
- task oriented functional rehab
- manipulation
- pt education - medications:
- muscle relaxants
Pain assessment- how can it be assessed
- numeric pain rating scale
- visual analog scale
- McGill Pain questionnaire: groups of 20 that describe pain
