Chronic Pain: Real or imaginary Or… Malingering Dr Ian Yellowlees Consultant in Pain Management.
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Transcript of Chronic Pain: Real or imaginary Or… Malingering Dr Ian Yellowlees Consultant in Pain Management.
Chronic Pain: Real or imaginary
Or…
Malingering
Dr Ian YellowleesConsultant in Pain Management
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)
1866 Back pain described as pathology..
“Railway spine”
20th Century mainstream.. Emphasis on diagnosis, pathology &
quick fixes..
Pull & Push
Surgery & pills failed…1953- 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 Such a rigid dichotomy is obsolete, because pain is now recognised as the compound result of physiopsychological processes whose complexity is almost beyond comprehension.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
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.”
The Biopsychosocial Model* -1977
• Widely accepted in many specialties – Google – 178,000 refs
• 1990’s 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
Physiological dysfunction +
neurophysiological changes
Illness behavior, Beliefs, Coping strategies, Emotions Distress
Culture, social interactions, Sick role
BIO
PSYCHO
SOCIAL
Pain medicine is a specialty…
• 2007 Faculty of Pain Medicine (RCA)
• Don’t expect other specialties to understand pain– Melzack & Wall: Textbook of Pain - 1280 pages
– Mercer’s Orthopaedic surgery, a standard postgraduate reference text - 6/1184 pages
– Bailey & Love’s Short Textbook of Surgery (‘worldwide sales > 800,000') - 2/1332 pages
What is pain?
• Definition
• Diagnosis
• Mechanisms
The Chronic pain patient
Definition
An unpleasant sensory and emotional experience... An unpleasant sensory and emotional experience...
...caused by actual or potential tissue injury,...caused by actual or potential tissue injury, ...or described in terms of such injury....or described in terms of such injury.
International Association for the Study of Pain
ICD10, DSM IV, (IASP)
• ICD10 classifies by causal agent, system, symptoms– Chronic pain by definition is pain persisting beyond time of
healing, therefore can’t 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
“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
Diagnosis – if pushed!
Disorders
Degenerativeback pain
Worn outspine
Mechanicalback pain
Location
Leg pain
Toe pain
Sore balls
Aetiology
Crushed by abull pain
Post surgicalcock-up pain
Generalisedpain afteruse of bike
Psychology
Gross nasalobsession
You name ithe’s got itmad
No diagnosis in conventional sense. Describe in terms 4 components or biopsychosocial model
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
Assessment of pain problems
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
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?
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
• ‘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
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
CRPS
Brain mapping
An aside - Reversing neuroplastic changes
• Mirror therapy – Phantom pains– Arthritis
• Hypnosis
• Cognitive behavioural therapy
• Drug treatments
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
Psychological: Catastrophising
I can’t work because of the pain, therefore:
I can’t earn any money
I can’t 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
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
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 patient’s whole life
Psychological: Social interactions
• Pain occurs in a social context that may be helpful or destructive – Village collection
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
“Non-organic signs”“Waddell 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
PhysicalPsychological & behavioural
“Illness behaviour”
Illness behaviour Illness behaviour
Predictors of chronicity
• Age > 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
• Marital / family status– Single parent with young children, partner retired
or disabled
• Health status– Mental health, musculoskeletal conditions,
comorbidities
• Occupational / educational level
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.
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)
The essential ingredients
Review of history: ALL NOTES
Looking for physical, behavioural and psychological events
1985 1988 1989 1991 1993 1997 19991995
accident
Eg LBP events:
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
The investigator’s video – what can it add?
What it tells us:She hung out the washing, once , for x minutes.
What it doesn’t 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?
However if the video captures this…
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
Assessment Timing
NB: legal processes may prevent effective treatment
• Single expert may be ok <6 months (?weeks)
• Multidisciplinary approach needed after this time
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
“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 [email protected]
www.painco.co.uk
Treatment
No need for us pain Docs..
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
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
• “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
This is not easy or quick..
Contemplation
Preparation
Act
ion
Maintenance
Relapse
Permanent exit Pre contemplation
cycles of change
Prochaska, J.O. & DiClemente, C.C. (1982) Pscychotherapy: theory, research and practice, 19: 276-288.
Note that relapse is not failure, simply part of the process
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
[email protected] WWW.painco.co.uk