Pain Flashcards
What is the biomedical model of pain?
- Pain as a sensation
- Pain is a response to external factors
- Source of pain via nerve impulses, is interpreted as pain in the brain
- The link is direct, causal and automatic
- Tissue damage causes the sensation of pain
- patients with little tissue damage but lots of pain = ‘making a fuss’
- patient with serious injury but no pain = ‘brave’
- when no physical cause can be found = psychogenic
- when clear physical ailment could not be seen = real pain
- psychological processes were not thought to play a role
- pain is an automatic response - person is passive
- there is no role for interpretatio or appraisal
What are some problems with the old view of pain?
- patients with the same degree of tissue damage reported different levels of pain - why? e.g. tooth extraction, epidurals
- phantom limb pain - amputees experienced pain in absent limb - how?
- most common form of pain is headache, yet there is no injury or tissue damage?
- how do athletes continue with severe pain?
- gross injury’s occur without much pain e.g severely wounded soldiers complained of little pain
- Is pain influenced by interpretations and perceptions?
What briefly is the gate control theory of pain?
- Melzack and Wall, 1982
- Pain is a pereception AND an exception
- pain is a multidimensional process that is mediated by other factors and is controlled by a ‘gate’ at the spinal cord level
What are inputs to the gate?
- peripheral nerve fibres - injury sends info about pain, pressure or heat to the gate
- descending central influences from the brain - brain sends info about psychological state of the individual to the gate (e.g. past experiences, fear, confidence etc.)
- large and small fibres - are part of the physiological input to pain perception (large = good, small = bad)
What are the outputs from the gate?
- gate integrates the information from sources
- send to an action system, resulting in perception of pain
What factors close the gate?
What factors open the gate?
Closed (no pain) - physical = medication, stimulation of large fibres - emotional = happiness, relaxation - behavioural = intense distraction Open (pain) - physical = activation of small fibres - emotional = anxiety, worry - behavioural = boredom, focusing on pain
How people interpret pain message and tolerate pain can be affected by the following:
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- emotional/psychological state
- upbringing
- gender
- memories of past
- beliefs/values
- social/cultural influences
- attitude
- expectations
What chronic about chronic pain?
- mild, short living pain typically causes few problems
- long lasting, intensive pain is a different matter (6 months often used as cut off)
- medication often becomes ineffective over time
- may be constant or come and go
- due to a chronic condition e.g. arthritis, cancer
- depression/anxiety
Describe the psychological interventions for managing chronic pain
- clinical trials have shown psychological interventions to give significant improvements
- do not undermine drugs approaches and not a sign of weakness, reassure patients you believe in them
- interventions might include combination of treatments
- pain clinics are likely to be multidisciplinary (pharmacology, clinician, physiotherapy, clinical psychology etc)
What are the two strands of intervention for chronic pain?
Cognitive - distraction - imagery - hypnosis - counselling Behavioural - relaxation exercises - biofeedback - physical activity/exercise
How do we measure pain?
Not easy as subjective - we cannot feel their pain - can male doctors understand childbirth Rely on indirect measures Two frequent measures - visual analogue scales (VAS) - McGill Pain Questionnaire (MPQ) Diaries Pain behaviours via observation
Describe the Visual Analogue Scale and its implications for practice
Frequently used, 10cm line Two ends of scale, no numbers on scale e.g. no pain at one end and worst possible pain at other Patient draws a line - easily administered - use with kids of 5yrs - can be used to measure severity and or improvement - sensitive to small changes
Describe the McGill Pain Questionnaire
How is it better than VAS?
VAS only measures intensity. Missing is quality of sensation and emotional impact
- MPQ examines different components of pain experience (questions and body map)
A: sensory (e.g. sickening, pulsing, throbbing, pounding)
B: affective (e.g. tiring-exhausting, fearful)
C: evaluative (e.g. annoying, troublesome)
What are the pros and cons of pain diaries?
Pros
- help doctor understand ‘causes’
- provide detailed daily picture
- help patient to see changes in pain and impact of behaviours on pain
Cons
- permanent record of pain - demolarising
- patients can be lazy/forget - incomplete info
- inconvenient - ‘just give be painkillers’
What is involved in measuring pain behaviour?
- patients can be asked to perform simple tasks to asses extent of pain e.g walking, bending
- can record and rate how often patient expresses pain
- more useful with chronic vs acute pain
- examples of behaviours e.g. groaning, grimacing, rubbing, stopping to rest, holding part of the body, distorted picture, irritability
