Chronic Pain

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Chronic Pain

• Andrew Skinner
• South Tees Hospitals
• UHNT

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IASP definition of pain

• An unpleasant sensory and emotional experience
  associated with actual or potential tissue
  damage, or described in terms of such damage

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Definition

• Pain that outlasts the normal healing process
• or
• 12 weeks!

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How common is it?

• About 50 of the population
• Back pain
• Arthritis
• Fewer have severe pain 15 of those with pain
• Numerous papers of course
• Elliott AM, Smith BH, Penny KI, Smith WC,
  Chambers WA. The epidemiology of chronic pain in
  the community. Lancet 1999 Oct 9354(9186)1248-52
  

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But that is rather a lot

• JCUH pain clinic covers about 500000 people, so
  that makes
• 250000 with pain and
• Perhaps 20000 with severe pain

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What causes chronic pain?

• Chronic clear cut problems that wont heal up by
  themselves
• Arthritis
• Cancer
• Limb ischaemia
• Things that are out of proportion
• Funny things you cannot explain
• Injuries to the nervous system
• PHN
• Tic
• PSCP

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What is the difference between acute and chronic
pain?
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Damage Pain Disability
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Disease Symptoms Illness
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Bio Psycho Social
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What does this?

• Fear
• Anxiety
• Health beliefs (toe vs chest angina)
• Anger
• Guilt
• Depression
• Learned behaviour (kids)
• Litigation
• Secondary gain

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Chronic clear cut problems that wont heal up by
themselves

• Easy
• Diagnose
• Treat
• Cure
• Pain killers!

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Pain killers

• We all know what comes next

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Pain killers
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Pain killers

• Do you trust someone who cannot tell a staircase
  from a ladder?
• Did you know it is only really intended as a
  teaching aid for cancer pain the pain tends to
  worsen?
• Dont forget acute pain gets better more a
  snake than a ladder

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Step one

• Non opioids
• Paracetamol basically
• Aspirin?
• The other NSAIDs?
• Nefopam
• (and just what the hell is nefopam?)

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Step one

• Paracetamol basically
• It is safe, cheap and pretty side effect free
• Regular might be better than as needed
• Seems to have an opioid sparing effect
• Which means opioid side effects sparing
• I think aspirin is pretty good, but most people
  cannot take it long term
• BNF Nefopam may have a place in the relief of
  persistent pain unresponsive to other non-opioid
  analgesics. It causes little or no respiratory
  depression, but sympathomimetic and
  antimuscarinic side-effects may be troublesome.

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Step two

• Weak opioids and co-whatsamols
• Codeine
• Dihydrocodeine
• Tramadol (or is this step two and a bit?)
• Meptazinol (or is this step one and a bit?)
• The NSAIDs? (opinion varies)

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Step two

• Codeine and dihydrocodeine
• Codeine is probably a prodrug
• Morphine or C-6-G
• Which is important as only the former has been
  studied in detail
• But it doesnt seem to suit everyone
• Dihydrocodeine
• Opinion varies even more
• But it might be stronger addicts seem to know
• And you can get it MR

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Step two

• Tramadol suits some people
• Meptazinol is an indicator we were running out of
  ideas, but occasionally hits the spot
• Weak opioids seem to buy all the opioid side
  effects with fewer and lesser benefits

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NSAIDs

• Non-steroidal anti-inflammatory drugs, usually
  abbreviated to NSAIDs, are drugs with analgesic,
  antipyretic and anti-inflammatory effects
• They are the least safe of all analgesics and a
  lot of people rarely prescribe them long term

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NSAIDs

• GI bleeding and perforation
• One of my long term patients died from this
• Renal failure
• Asthma
• CVS risks
• COX2?

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NSAIDs

• Used to be said they were good for
  musculoskeletal pains not visceral
• But actually they just seem to be good pain
  killers
• And patient killers
• People argue about where on the WHO staircase
  they fit

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Step three

• Strong opioids
• Morphine basically
• Others

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Step three

• There is little convincing evidence that anything
  is reliably better than morphine
• Some drugs suit some people, others other people
• But you cannot predict which by type of person or
  type of pain

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Step three

• Not working?
• Underdosed?
• Adverse effects?

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Step three

• Sedation
• Nausea
• Constipation
• Addiction or dependence
• Itch
• Hallucinations
• Respiratory depression
• Are they over treated?

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Step three

• Oxycodone
• Fentanyl
• Buprenorphine
• Hydromorphone
• Pethidine
• Diconal
• Palfium

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Step three

• Stick with one agent
• Get the dose up
• Treat the side effects
• Jolly them along
• Opioid switching isnt magic
• Or perhaps it is?

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Step three

• Easy to decide for cancer pain
• Less easy for chronic non cancer pain

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Step three
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Step three non cancer pain

• No injections
• Speak to primary/secondary care
• Previous addiction caution not a ban
• Medical practitioners only
• Consent and contract
• Single prescriber
• Regular assessment pain as the end point
• We control the dose
• No breakthrough doses
• No self escalation

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TENs

• Transcutaneous Electrical Nerve Stimulator
• Works for some chronic pains about half
• Harmless and cheap
• Doctor free
• Wears off
• Good advice and persistence
• Clearly ineffective for labour pains and acute
  pain

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Things that are out of proportion

• Bad back
• Bad neck
• Minor OA
• You know what it is, but

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Things that are out of proportionDisordered
interoception

• ? FM
• ?? CF
• ??? IBS
• ??? Chronic migraine
• ??? Chronic cystitis
• ??? Side effects of drugs
• I. M. Hunt, A. J. Silman, S. Benjamin, J. McBeth
  and G. J. Macfarlane The prevalence and
  associated features of chronic widespread pain in
  the community using the Manchester definition
  of chronic widespread pain. Rheumatology
  199938275279

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Funny things

• Headache (except migraine)
• Remember fear
• Remember MOH
• Facial pains (except Tic)
• Remember diagnosis
• Pelvic pains
• Abdominal pains
• Etc.
• Etc.
• You end up with symptomatic suggestions unless
  you get lucky

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Post surgical pain

• Is very common
• Macrae W A. Chronic pain after surgery Br J
  Anaesth 2001 87 8898
• And it is very difficult to treat
• And often omitted from consent (anger) and
  thought of as indicating a problem (fear)
• Recurrent pain after cancer surgery?

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Neuropathic pain

• Neuropathic isnt a synonym for difficult
• Plausible cause
• Right descriptors
• Right distribution
• Abnormal neurology
• Nothing wrong where it hurts

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Neuropathic pain

• Idiopathic trigeminal neuralgia
• PHN
• Post amputation pains
• Diabetic neuropathy
• Multiple sclerosis
• Pain following chemotherapy
• HIV infection
• Alcoholism
• Cancer
• Injury and surgery
• Various other uncommon nerve disorders.
• PSCP

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Neuropathic pain

• Antidepressants
• TCAs
• SSRIs etc
• Duloxetine
• Burning
• Nocturnal
• Sleep poor

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Neuropathic pain

• Anticonvulsants
• Gabapentin
• Pregabalin?
• The rest
• The funny ones

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Neuropathic pain

• Mexiletine
• Ketamine
• Opioids
• Oxycodone
• Methadone
• NMDA antagonist
• Capsaicin
• Cannabinoids
• NOT TENS!

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CRPS

• RSD
• Causalgia
• Disuse phenomenon in part
• OT physio
• Neuropathic pain agents
• Blocks

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So what do we do?

• Diagnosis
• 8 OA hip
• 6 vascular claudicants
• Sarcoma of rib
• Thalamic tumour
• Ca breast
• Myeloma
• PMR
• And refer of course

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So what do we do?

• Find out what the patient thinks and believes
• Is the patients cognition driving the illness?
• Are they depressed, anxious, angry etc?
• Can we treat this?
• Often psychologists are the first to really
  unearth patients beliefs

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So what do we do?

• Reconcile them that the orthodox medical model
  has failed
• Look for under and over activity, cycling of
  activity
• Consider rehabilitation or PMP

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So what do we do?

• Are there specific pain clinic treatments?
• Remember nerve blocking clinics
• TENs?
• Medication
• Support

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Une Lecon Clinique a la Salpetrie
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• Can we learn to shape illnesses towards recovery
  rather than towards chronicity?

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Actually of course modern medicine does just the
opposite

• Diagnostic puzzle
• Ultra specialists
• Repeated negative consultations
• Doctors despaired of me
• No one can find what is wrong
• Iatrogenic injury
• Perhaps wed be less dismissive if we remembered
  it was often our fault, not the patients

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Back pain - the clinical dilemma
Back pain can be a symptom of serious spinal
diseaseBUTMost back pain is due to backache,
not disease
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How the health care system contributes to chronic
pain

• inconsistent advice
• lack of clear, understandable information
• reluctance to abandon a curative model

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Some common beliefs about chronic pain
- that it is due to serious disease, which has
been overlooked- that it is due to
serious,irreversible damage- that it means
being vulnerable to further injury- that it
will inevitably lead to increasing disability
/ dependency- that health staff do not believe
they are in pain
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Underlying belief Hurt harm

• understandable
• true for acute conditions
• basis of the medical model

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Consequences of pain beliefs

• increased distress - anxiety, anger,
  depression
• changes in behaviour - increased consulting,
  seeking referrals or investigations, ill
  behaviour - bedrest
• poorer outcome - more likely to drop out from
  rehabilitation, less likely to return to work

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Fear avoidance model
Fear of pain (hurt, harm or both)
Avoidance - of whatever makes it worse
Survival value - evolutionary advantage
Acute conditions - limits damage, reduces
nociception
But Chronic conditions - barrier to
rehabilitation
(Lethem et al 1983)
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Expectation of pain
- avoidance- no increase in pain- avoidance
reinforced
eg Belief that muscle pain damage
- expect pain with activity -
reluctant to exercise - avoid
mobilisation - drop out of
rehabilitation
(Feuerstein 1991)
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Fear of pain
Confrontation
AvoidanceDesire to return to
Avoidance of physical /natural activities
social activitiesMobilise, exercise
Loss of spinal mobilityAccurate
interpretation Misinterpretation ofof pain
pain Effective
rehabilitation Increased disability
(Lethem et
al 1983)
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Assessment of fear avoidance beliefs

• Back Beliefs Questionnaire
  (Symonds et al 1996)
• Fear Avoidance Beliefs Questionnaire
  (Waddell et al 1993)

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