Chronic Pain: Real or imaginary

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(No Transcript)
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Chronic Pain Real or imaginary

• Or
• Malingering

Dr Ian Yellowlees Consultant in Pain Management
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Aims

• Pain medicine a specialty in its own right
• (Why consult a pain Doc?)
• Pain mechanisms
• Pain assessment for treatment or medico-legal use
• (Treatment options)

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1866 Back pain described as pathology..
Railway spine
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20th Century mainstream.. Emphasis on diagnosis,
pathology quick fixes..
Pull Push
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Surgery pills failed1953- first textbook of
pain
Pain is no longer considered exclusively either
as a neurophysiological or a psychological
phenomenon. Such a rigid dichotomy is obsolete,
because pain is now recognised as the compound
result of physiopsychological processes whose
complexity is almost beyond comprehension.
The Management of Pain J Bonica Lea Febiger
1953
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Psychologists become a core part of pain medicine

• Pain Mechanisms a new theory. Melzack R Wall PD
  
• Science 1965 50 971-979
• Gate control theory

Pain is a complex perceptual process subject to
modulation and manifesting a disconcertingly
unreliable relationship to physical injury.
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The Biopsychosocial Model -1977

• Widely accepted in many specialties
• Google 178,000 refs
• 1990s Details are a core part of IASP
  post-graduate training in pain
• Undergraduate medical, nursing, physiotherapy
  curricula

Engel GL The need for a new medical model a
challenge for biomedicine. Science 1977 196
129-136
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Culture, social interactions, Sick role
SOCIAL
PAIN
PSYCHO
Illness behavior, Beliefs, Coping strategies,
Emotions Distress
Physiological dysfunction neurophysiological
changes
BIO
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Pain medicine is a specialty

• 2007 Faculty of Pain Medicine (RCA)
• Dont expect other specialties to understand pain
• Melzack Wall Textbook of Pain - 1280 pages
• Mercers Orthopaedic surgery, a standard
  postgraduate reference text - 6/1184 pages
• Bailey Loves Short Textbook of Surgery
  (worldwide sales gt 800,000') - 2/1332 pages

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What is pain?

• Definition
• Diagnosis
• Mechanisms

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The Chronic pain patient
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Definition
An unpleasant sensory and emotional experience...
...caused by actual or potential
tissue injury, ...or described in
terms of such injury.
International Association for the Study of Pain
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ICD10, DSM IV, (IASP)

• ICD10 classifies by causal agent, system,
  symptoms
• Chronic pain by definition is pain persisting
  beyond time of healing, therefore cant use a
  classification based on physical causes
• DSM IV pain disorder
• Diagnosis of exclusion
• IASP uses a classification based on description
• Limited ability to encompass combination of
  sensory and emotional factors

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Chronic pain syndrome

• Often used by non specialist Dr
• dustbin diagnosis as a result of failure to
  identify a physical cause for pain
• Often used to imply a psychological cause
• Not used by those working in the field

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Diagnosis if pushed!
No diagnosis in conventional sense. Describe in
terms 4 components or biopsychosocial model
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The 4 components of pain

• Sensory / Physical
• Action in pain nerves (actually just sensory
  nerves)
• NB Activity in pain nerves ? pain
• Beliefs
• Knowledge, expectations, fears, and attributions
• Behavioural
• The effect of pain on behaviour, physical and
  emotional
• coping strategies
• Emotions
• The effect of the other three on mood and mood on
  the other three

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• Assessment of pain problems

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Investigations

• X ray / MRI findings
• Changes seen on X-ray or MRI scan have no
  predictive value for future pain or disability
• Reflected in current guidelines
• Blood tests
• No value except to confirm inflammatory disease
  (rheumatoid arthritis)
• The absence of abnormal findings does not mean
  that there are no abnormal physical components,
  but simply that the tests used did not detect any

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Physical measurement

• Measured as changes in performance
• Performance relies on conscious drive to perform
• Greatly influenced by psychological components
• NB Treatment directed at the physical aspects of
  dysfunction only may not improve performance
• So what is going on?

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Physical Soft tissue physiology and dysfunction

• Abnormal muscular function, imbalance between
  muscle units, giving rise to localised stress
  concentrations
• Starts within hours (POP)
• Changes in muscle metabolism and
  electrophysiology
• Increased fatigue and reduced endurance

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• Disuse syndrome or deconditioning syndrome
• May give rise to pain directly, or to increased
  fatigue (TATT) and decreased function
• Altered patterns of movement and muscle function
  may also become learned responses and form a
  protective habit 

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Nervous system changes

• Connections between nerves within the spinal cord
  brain change in response to injury
• Interactions between different systems
• Weather effects
• Skin temperature changes
• The sensitivity of the cells also changes
• Increasing sensitivity spreads to surrounding
  areas
• Changes can become permanent
• Continue to cause pain long after the initial
  injury has apparently healed
• This process is termed neuroplasticity
• Eg CRPS

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CRPS
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Brain mapping
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An aside - Reversing neuroplastic changes

• Mirror therapy
• Phantom pains
• Arthritis
• Hypnosis
• Cognitive behavioural therapy
• Drug treatments

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Psychological Fear avoidance

• Fear of pain fear of damage
• Limits activities
• Limits treatment compliance
• Becomes self perpetuating
• Less activity more deconditioning
  pain increasing disability
• Starts within few days of injury

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Psychological Catastrophising

• I cant work because of the pain, therefore
• ? I cant earn any money
• ? I cant pay the mortgage
• ? I will lose my house
• ? My family will leave me
• ? I have nothing to live for
• ? There is no point in trying

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Psychological Control

• Influences reaction to illness and adversity
• Tolerance of lack of control is a product of
  genetics, learning social conditioning
• Ability to gain a sense of control is fundamental
  to ability to cope
• Learned helplessness

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Psychological Depression

• Some symptoms in common with pain
• Diagnosis difficult
• Generally secondary to pain
• Waddell
• Learned helplessness in the face of persistent
  pain which the patient cannot control, and which
  impacts on the patients whole life

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Psychological Social interactions

• Pain occurs in a social context that may be
  helpful or destructive
• Village collection

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Presentation Illness behaviour
Functional overlay

• What people say and do that communicates to
  others that they are ill Related to
• Distress they feel
• Who they are communicating with
• Important in MLA (Orthopaedic surgeons,
  neurologists..)
• May become part of the problem by further
  reducing performance and function
• May be connected with malingering

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Non-organic signsWaddell signs

• Clinical signs that do not fit with anatomy or
  physiology
• Should prompt the examiner to look for the cause
• Do not simply assume malingering

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Illness behaviour
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Predictors of chronicity

• Age gt 50, genetics
• Previous history of back pain
• Nerve root pain
• Pain intensity / disability
• Poor perception of general health
• Distress depression

• Fear avoidance
• Catastrophising
• Pain behaviour (non-physical illness behaviour)
• Job dissatisfaction
• Duration of sickness absence
• Expectations about return to work

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• Marital / family status
• Single parent with young children, partner
  retired or disabled
• Health status
• Mental health, musculoskeletal conditions,
  comorbidities
• Occupational / educational level

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Malingering

• Malingering is a deliberate behaviour for a known
  external purpose.
• Not considered a form of mental illness or
  psychopathology
• can occur in the context of other mental
  illnesses.
• Malingering can be expressed in several forms
• pure malingering falsifies all symptoms
• V rare. All the PI clients will have at least
  some activity in pain nerves
• partial malingering has symptoms but exaggerates
  the impact upon daily functioning.

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Assessment

• Try to explain the mechanisms underlying changes
  from pre accident to now
• Physical
• Psychosocial
• Take history into account
• Were these changes going to happen anyway?
• Predisposing factors (risk factors)

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The essential ingredients
Review of history ALL NOTES Looking for
physical, behavioural and psychological events
Eg LBP events
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Objective assessment - questionnaires

• Many well validated questionnaires
• Beck Depression inventory
• Self efficacy
• Sickness impact profile
• Tampa scale of Kineasophobia
• Fear avoidance
• Pathological somatic focus
• Decide if medical, physical and psychological
  assessments fit with questionnaires history
• Coherent story hard to fake

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The investigators video what can it add?
What it tells us She hung out the washing, once
, for x minutes.
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What it doesnt tell us

• Was the movement painful ?
• would you expect it to be?
• How long can she do it?
• How often can she do it?
• good days bad
• weather dependence?
• What happened afterwards?
• pacing
• pain killers
• Is she simply showing motivation to do as much as
  she can?
• Is this relevant to her employment?

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However if the video captures this
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Evidence?

• Extent of surveillance
• 24/7 big brother style vs 20 minutes once in 4
  years
• Likely to add
• highly selected, edited single snapshot picture
• can not assess prior, concurrent, or post
  activity pain or function
• no context
• Should be predictable from good assessment

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Assessment Timing

• Single expert may be ok lt6 months (?weeks)
• Multidisciplinary approach needed after this time

NB legal processes may prevent effective
treatment
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Conclusions

• Pain is a specialty
• Physical changes are always present, but often as
  physiological rather than pathological
• Psychological changes are always present
• Presentation is dependant on client and assessor
• Assessment requires multidisciplinary
  investigation of the 4 components
• Cognitive
• Sensory
• Affective
• Behavioral

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Pain is a complex perceptual process subject to
modulation and manifesting a disconcertingly
unreliable relationship to physical injury.
Pain Mechanisms a new theory. Melzack R Wall PD
Science 1965 50 971-979
Dr Ian Yellowlees Ian.Yellowlees_at_painco.co.uk www.
painco.co.uk
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Treatment
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No need for us pain Docs..
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If established chronic pain

• Full assessment
• Make non-diagnosis
• Rarely any place for invasive techniques
• subsequent nerve damage pain
• dependence
• need long term view
• Window of opportunity injections
• Review of / optimise drugs
• Neuropathic pain may need long term drugs
• ordinary pain killers do not work
• antidepressants, antiepileptics, ketamine,
  cannabinoids
• ?? opiates

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Requires a team approach

• Doctor
• Psychologist
• Physiotherapist
• Occ Therapist
• Nurse

• Pacing
• Goal setting
• Drug use
• Physical fitness
• Readiness for change
• Family issues
• Work issues
• Ergonomics
• Assertiveness
• Sleep

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• Pain management programme
• cognitive behavioural restructuring
• philosophy of coping with rather than curing
  problem
• May need windows of opportunity
• (NB recent link to brain physiology / anatomy)
• functional rehabilitation
• Occupational reassessment / training

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This is not easy or quick..
cycles of change
Note that relapse is not failure, simply part of
the process
Permanent exit
Relapse
Pre contemplation
Contemplation
Maintenance
Preparation
Action
Prochaska, J.O. DiClemente, C.C. (1982)
Pscychotherapy theory, research and practice,
19 276-288.
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The big problems

• For us
• Nerve damage pain
• shingles
• phantom limb
• post stroke
• Cancer pain
• widespread
• 20 uncontrolled pain
• Back pain

• For patients
• Accepting no cure
• Accepting no diagnosis
• Learning to change
• Maintaining change

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Ian.yellowlees_at_painco.co.uk WWW.painco.co.uk