Pain Flashcards
name the two descending pain pathways
serotonergic
noradrenergic
How does the descending pain pathway work
fibres project down the spine, and release serotonin and noradrenaline which impinge on the pain gate to close it
True or False: pain is the most common reason people seek clinical advice
True
Describe Aσ fibres (mechanical)
- sharp pricking, fast pain
- larger diameter due to myelination
- Faster conduction velocity
Give 2 ways pain can be managed/treated
- drugs
- local anaesthetics
- physical therapy to retrain nerves/NS
- psychotherapy and associated psychological support
- holistic approaches i.e. CBT/accupuncture/meditation
- Guided physical activity
- Surgery
Define nociception
The neural process of encoding noxious stimuli.
Describe SOMATIC Superficial pain
- Tissue Damage
- Skin
- Sharp/fast pain
- Localised
In inhibitory interneurons, what are the two neurotransmitters likely to be
GABA
Enkephalin
What is the role of the Putamen and Primary motor cortex in the pain response
the motor response i.e. move away from pain source
Many neuropathic conditions result from changes in the electrical activity of peripheral neurons.
What do these cellular level changes do?
- Facilitate sub-threshold depolarisation
- Increase action potential duration
- Increase the excitation threshold
- Lower the excitation threshold
- Reduce neurotransmitter release
Facilitate sub-threshold depolarisation
Define neuropathic pain
Pathological damage to somatosensory system
What is outlined here?
The descending pain pathway
Describe the endogenous opioids theory.
- The brain releases endogenous opioids in response to pain perception
- Internally produced molecules with opioid-like action to regulate transmission of nociceptive signals
- Similar brain regions that modulate the signal from nociceptive afferents
How does nociception information ascend the spine?
Pain fibres (A or C) ascend the spinal cord via the direct spinothalemic pathway
Define pain catastrophising
the concept of an irrationally negative forecast of future events
negative cognitive affective response to anticipated or actual pain
Sensitisation molecules (prostaglandin, bradykinin and nerve growth factor) are all produced by damage to the skin and activate what
nociceptors
What is the purpose of us experiencing pain?
- Warning of ‘actual or potential harm’
- Actual or potential tissue damage
- Elicits changes in behavior
Give 2 ‘objective’ measurements of pain
- cold pressor test
- VAS
- Numerical scale i.e. 1-10
- Smiley face (abbey pain) scale
What functions does Substance P have
- activation of vasodilation
- activation of degranulation of mast cells (contains histamine)
contributes to neurogenic inflammation
Define Allodynia
Extreme increased sensitivity following tissue injury
- Central mechanism
- Microglia – activated during inflammation
- Switch inhibitory input to excitatory
What is the difference between nociception and pain perception
Pain perception is key to defining the series of AP propagating to the spinal cord
Nociception is the process of encoding the noxious stimuli
Outline the fear avoidance model
A psychiatric model that describes how individuals develop and maintain chronic musculoskeletal pain as a result of attentional processes and avoidant behavior based on pain-related fear.
Describe the indirect spinothalemic pathway
- Slower C fibres
- Limbic system
- Hypothalamus
- Reticular formation
- Reticular activating system
- Poorer spatial discrimination
How does physical activity ease pain physiologically
- causes a decrease in hormones associated with inflammation
- chronic pain is linked to tight, week muscles so PA can help to relieve this
- increases blood and oxygen flow to muscles
- stress reduction
- distraction technique
What is the scientific reasoning behind TENS machines?
Based on pain gate theory- by vibrating at the frequency of the Aσ fibres, this closes the pain gate and activates the inhibitory interneuron in the dorsal horn zone
In clinical practice, how could you help someone come to terms with their chronic pain and its psychological impacts
- teach them avoidance isn’t always the answer as pain doesn’t always = damage
- Involve patients in their care
- Help them make sense of the pain (what’s causing it)
- Be consistent
- Show them techniques for coping with anger and other reactions