What is CRPS? - The Norfolk & Norwich Medico

Complex Regional Pain
Syndrome (CRPS)
A Medicolegal Perspective
Dr. Jon Valentine
Consultant in Pain Medicine
What is CRPS?
Rare (uncommon)
condition most
typically affecting
the distal aspect
of the arm or leg.
What is CRPS?
• Characterised by
features including:
• Severe pain.
• Hypersensitivity.
 Swelling.
 Discoloration.
 Temperature change.
 Abnormal sweating.
Terms used for CRPS:
 Complex regional pain syndrome types I and II
 Reflex sympathetic dystrophy (RSD).
 Sudeck’s atophy.
 Algodystrophy.
 Causalgia.
 Chronic regional pain syndrome – Incorrect term for CRPS.
 CRPS is one type of “chronic pain syndrome”.
What CRPS is not:
 A ‘diagnosis’ for
medically unexplained
chronic pain affecting a
limb after an injury.
 A diagnosis wholly
based on the claimant’s
testimony and
subjective clinical signs.
What triggers the onset of CRPS?
• Trauma.
• Surgery.
• Crush injuries.
• Immobilisation in a cast.
• Soft tissue injuries,
sprains & strains.
• Peripheral nerve injuries.
• Fractures.
• Chemical & electrical
• Cervical spine and
shoulder injuries.
• Medical use of needles.
• Unknown / idiopathic.
CRPS – Risk / predisposing factors?
• None firmly established – definitely nothing that predicts the
onset of CRPS – except perhaps previous CRPS.
• Psychological factors – nothing definite – stressful life events?
• Autoimmune links – Autoimmunity against the β2-adrenergic
receptor and muscarinic-2 receptor – (PAIN 2011).
• HLA B62 & HLA DQ8 (CRPS with fixed dystonia – PAIN 2009).
• Links to asthma and migraine – proposed neurogenic
inflammation. Mast cell mediated neural-immune
• Smoking??
IASP diagnostic criteria for CRPS
Type I (1994):
The presence of an initiating noxious event or cause of
immobilisation – optional (!).
2. Continuing pain, allodynia or hyperalgesia with which the
pain is disproportionate to any inciting event.
3. Evidence at sometime of oedema, changes in skin blood flow
or abnormal sudomotor activity in the region of pain.
4. The diagnosis is excluded by the existence of conditions that
would otherwise account for the degree of pain and
• CRPS Type II – follows a named nerve injury.
Criticism of IASP criteria
• Criteria based on consensus of a panel of experts in 1994.
• Not clinically validated.
• Utilisation of these criteria in the medical literature has
been ‘sporadic at best’.
• Considered to be adequately sensitive, but with poor
specificity leading to over diagnosis of CRPS.
• Important medicolegal consequences (USA).
CRPS – diagnosis
International consensus group Budapest 2003:
• A “closed” workshop (by invitation only) was held in Budapest in
the fall of 2003. Revised clinical and research diagnostic criteria
for CRPS were proposed (Pain Medicine – 2007):
• Continuing pain that is disproportionate to any inciting event
• Patient must report at least one symptom in 3 of the 4 categories:
Sensory: Reports of hyperaesthesia and / or allodynia.
Vasomotor: Reports of temperature asymmetry and / or skin colour
changes and / or skin colour asymmetry.
Sudomotor / oedema: Reports of oedema and / or sweating changes and
/ or sweating asymmetry.
Motor / trophic: Reports of decreased range of motion and / or motor
dysfunction (weakness, tremor, dystonia and / or trophic change (hair,
nail, skin).
CRPS – diagnosis
International consensus group Budapest 2003:
• Must display at least one sign at time of evaluation in 2 or more of the 4
categories (N.B. research criteria = 3 or more):
1. Sensory: Evidence of of hyperaesthesia (to pinprick) and / or allodynia (to
light touch and / or deep somatic pressure and / or joint movement).
2. Vasomotor: Evidence of temperature asymmetry and / or skin colour changes
and / or skin colour asymmetry.
3. Sudomotor / oedema: Evidence of oedema and / or sweating changes and / or
sweating asymmetry.
4. Motor / trophic: Evidence of decreased range of motion and / or motor
dysfunction (weakness, tremor, dystonia and / or trophic change (hair, nail,
• There is no other diagnosis that better explains the signs and
CRPS – diagnosis
International consensus group Budapest 2003:
• “IASP criteria” show high diagnostic sensitivity (1.00), but poor
specificity (0.41).
• Budapest “clinical criteria” retain the exceptional sensitivity of
the IASP criteria (0.99), but greatly improve on the specificity
• The Budapest “research criteria” result in the highest specificity
[Validation of proposed diagnostic criteria (the "Budapest Criteria") for
Complex Regional Pain Syndrome - PAIN 2010]
Fulfilled diagnostic criteria for
Early features of CRPS:
• Disproportionately severe pain
in the extremity (initially
limited to site of injury).
• Movement is painful so there is
a tendency for immobilisation.
• Localized swelling of the
• Skin changes in extremity (red
warm sweaty / blue cold dry).
• Mild forms probably not
uncommon in Orthopaedic
Medium term features of CRPS:
• Persistent pain and
hypersensitivity becomes more
severe & more diffuse:
Hyperalgesia / hyperpathia
• Swelling spreads away from the site
of injury & changes to hard
• Soft tissue and muscle atrophy.
Medium term features of CRPS:
• Hair becomes coarse &
nails grow faster.
• Abnormal sweating.
• Extremity becomes cold.
• Neglect of affected limb.
• Patchy bone thinning on
x-ray (osteopaenia).
Late features of CRPS:
• Pain remains constant (can
• Swelling changes to peri-articular
• Skin becomes atrophic, smooth,
glossy, tight with scanty hair. Nails
become brittle with slow growth.
• Stiff joints & muscle atrophy.
• Neuromuscular features - spasms,
dystonia, tremors, involuntary
movements and paresis.
• Osteoporosis becomes established.
Patterns of spread of CRPS:
• Contiguous spread (commonest): Enlargement of initial area from
distal to proximal.
• Independent spread (IS): To a non-contiguous distant site (6.4%).
• Bilateral or mirror image spread: Symmetrical, less (patchy) signs &
symptoms on opposite side.
• Generalized CRPS [Small % of patients]: affecting the entire body
• Maleki J et al - Patterns of spread in complex regional pain syndrome,
type I. Pain 2000 Dec 1;88(3):259-66.
Impact of CRPS and other
chronic pain syndromes
Disability & impact on life:
• Poor sleep – pain & hypersensitivity.
• Reduced mobility / problems with stairs – need for crutches / wheelchair.
• Reduced ability to stand / sit.
• Impact on upper limb function – limb neglect & disuse.
• Impact on ability to drive & travel etc.
• Impact on ability to work / perform domestic duties.
• Impact on close relationships / changing role – partner to carer etc..
• Social withdrawal / impact on leisure activities & holidays.
• Impact on concentration - medications / severe pain.
The psychosocial factors:
 Recognised to be important predictors of presentation with chronic
pain and pain-related disability. Can be pre-existing, accident and
litigation related, or unrelated to the accident and litigation.
 Psychological factors include:
Individual beliefs about pain.
Fear avoidance.
Low mood and depression.
Stresses – Domestic, litigation, work.
Investigation of CRPS
Investigations in CRPS
• Can assist in securing a diagnosis of CRPS, but:
• Negative results do not exclude the diagnosis.
• Unlikely to influence clinical management.
Plain radiography (x-ray):
 Mid to late stages of CRPS
 Patchy osteopaenia /
osteoporosis (thinning of
the bones).
 Spotty & localised bone
 Established osteoporosis.
Infrared thermography:
Three-phase isotope bone scan:
 Markedly increased blood
flow to the right hand
compared to the left.
 Blood pool images (Image
B) and delayed images
(Image C) show increased
uptake of tracer
throughout the right arm.
 Can exclude other causes
during the sub-acute
period (up to 1 year).
Future investigations in CRPS??
Functional MRI (f-MRI)
The MR signal of blood is slightly different depending on the level of oxygenation.
These differential signals can be detected using an appropriate MR pulse sequence as
blood-oxygen-level-dependent (BOLD) contrast.
Clinical Management
of CRPS:
Early medical management:
• Primary goal is restoration of function:
Pain relief – variable efficacy - pain has both nociceptive & neuropathic features:
Amitriptyline (antidepressant).
Gabapentin / Pregabalin (anticonvulsants).
Ketamine (anaesthetic agent).
Opioids (Morphine / Fentanyl / Oxycodone / Buprenorphine).
Pamidronate (bisphosphonate infusion).
• Physiotherapy, mirror-box therapy & home exercises.
• Avoid surgery.
• Vitamin C ???
Side effects of medication:
• Analgesic drug-related side effects are common:
Tiredness / fatigue.
Memory / concentration disturbance.
Bowel disturbance.
Sexual dysfunction.
Weight gain (Antidepressants/Gabapentin/Pregabalin).
Ankle swelling.
• Possible significant impact – ability to work / drive etc..
Local Anaesthetic Sympathetic Blocks:
 Without a good evidence base.
 Theoretically appropriate if performed
early for sympathetic component of
 Clear progress needs to be evident to
justify repeat procedures.
 Estimated cost in private sector approximately £2000.
 Unlikely to be appropriate by the time
of pain management medicolegal
Permanent Sympathetic Blocks:
 Performed with neurolytics
drugs (e.g. Phenol) or
radiofrequency lesioning (RF).
 Without an good evidence base.
 Possibly appropriate in limb
viability issues i.e. viability
severely threatened by cold &
 Estimated cost in private sector£2000 - £2500.
Spinal cord stimulation:
 CRPS a recognised indication for SCS
on the NHS (NICE). Increasingly used
in UK.
 High initial cost (£20-25k)
 High maintenance cost (£20k+ / 10 yrs):
 Need for (multiple) revision procedures.
 Replacement impulse generators.
 Variable functional improvement, but
can be very successful.
 Long-term efficacy???
What is SCS?
The use of an implanted epidural lead electrode to
stimulate the spinal cord.
Pain Management Programmes:
• Aim to optimise physical function and the selfmanagement of chronic pain.
• Entirely appropriate for genuine, well motivated
patients / claimants who are ready to change.
Cost £7k to £12k+.
• Unresolved secondary gains (litigation) can
have a negative impact on outcome. Best left
until after the‘stresses of litigation’ have been
• In many claimants, good evidence of the
measured‘improvement’ difficult to identify.
• Bath Centre for Pain Services – Young person’s
PMP & dedicated CRPS PMP.
• Surgery might need to be considered if there is an underlying or coexisting Orthopaedic problem, but typically makes CRPS worse.
• Surgery can be performed (if essential), but specialist Pain
Management / senior Anaesthetist involvement is very important.
• Amputation is not recommended in CRPS unless the limb is becoming
non-viable, which is rare.
• Chronic pain after amputation of CRPS affected limbs is a problem:
• Recurrence of CRPS in stump.
• Stump pain problems.
• Phantom pains.
• Variable and individual.
• Severe CRPS very likely to be permanent.
• Less severe forms with minimal objective physical signs can
improve significantly with the passage of time, treatment,
reduction in psychosocial stressors and motivation.
Chronic Pain and CRPS in
the medicolegal context
Time zero - The accident
Time zero + 60 minutes
Medicolegal issues
• Causation.
• Diagnosis.
• Objectivity.
• Chronic pain syndrome.
• Exaggeration.
• Any form of trauma or cause of immobilisation.
• STI / bony injury etc. to limb – trauma.
• Neck /shoulder injury – cause of immobilisation.
• Surgery:
• Clinical negligence issues can arise.
• Need good reason for operating if CRPS is present.
• Standard of care important – specialist Pain Management /
Anaesthetic involvement.
The importance of diagnosis:
 Clinical medicine:
 Patients want a diagnosis.
Doctors like to provide one.
 Diagnosis of CRPS can
influence treatment pathway.
 Diagnosis of ‘chronic pain
syndrome’ is close to irrelevant
(in Pain Medicine).
 Medicolegal practice:
 The diagnosis (especially of
of an organic condition)
strengthens the claim and
assists the Court in
understanding the problem.
 Monetary value is attached
to the diagnosis of CRPS /
chronic pain syndrome.
Features of CRPS at time of medicolegal
• Severe diffuse pain (deep /
• Discolouration - red / blue
/purple often ‘blotchy.
• Hypersensitivity (with
protection of limb).
• Nails growth changes.
• Excessive sweating.
• Hair growth – abnormal.
• Temperature changes (cold).
• Localised muscle spasm /
tremor / dystonia etc.
• Tissue swelling (oedema).
• Muscle wasting.
Features of a ‘chronic pain syndrome’ at
time of medicolegal assessment:
• Disproportionately severe pain.
• High levels of pain-related distress.
• Disproportionately high disability.
• Pain behaviour / apparent overemphasis of pain,
sufferance, and disability.
• Inappropriate / non-organic clinical signs.
• No objective clinical features.
Chronic pain, not CRPS
• Most claimants reporting chronic pain in an
extremity do NOT have CRPS.
• The absence of objective clinical signs including
the features of CRPS does not exclude medically
and ‘medicolegally’ significant chronic pain.
• Pain is subjective in nature. Commonly no
objective clinical signs. Psychosocial factors are
very important (Biopsychosocial model).
Chronic pain, not CRPS
• In many instances, there is no diagnostic label to
adequately describe the claimant’s presentation.
• It is often appropriate to describe the claimant as
suffering from ‘chronic (xx) pain’ (i.e. provide no
formal diagnosis).
• The term ‘chronic pain syndrome’ is often used in
a medicolegal context – provides a diagnosis.
Chronic Pain Syndrome
• Has no formal definition and provides more of a label for a
clinical presentation rather than a true medical “diagnosis”.
• There are no established diagnostic criteria. There are no
clinical tests to confirm or refute the proposed diagnosis.
• Validity is dependent on the reliability of the claimant’s
testimony and the genuineness of their presentation at the time
of medical assessment.
• The term is most often used to provide a ‘diagnosis’ for patients
(commonly claimants) reporting chronic pain and disability that
is grossly disproportionate to the objective findings of physical
examination and clinical investigations.
Chronic Pain Syndrome
• The International Classification of Diseases.
• Chronic pain syndrome - ICD-10-CM Diagnosis Code G89.4
• G89.4 is a specific ICD-10-CM diagnosis code that can be used to
specify a diagnosis.
• Applicable to: “Chronic pain associated with significant
psychosocial dysfunction”.
ICD-9-CM will be replaced by ICD-10-CM beginning 1st October 2013, therefore,
G89.4 and all other ICD-10-CM diagnosis codes should only be used for training
or planning purposes until then.
What really matters is honesty!
Surveillance evidence – comparison with claimant’s testimony, clinical
records, presentation at time of assessment, findings of physical
examination, account of disability in DWP records.
Genuine presentation in CRPS:
• The absence of the objective features of CRPS does not exclude a
genuine pain syndrome.
• The clinical features of CRPS provide objective evidence of a
condition known to be chronically painful.
• The claimant’s reliability / honesty remains important.
• Objective features of CRPS at the time of medical assessment do
not exclude significant physical function – surveillance.
• Psychiatric diagnoses might need to be considered e.g. factitious
disorder / conversion disorder etc. in some cases.
Features supporting a genuine
presentation in CRPS:
• Evidence of initiating tissue injury.
• A clear medical history of regional pain with
hypersensitivity, temperature change, discolouration &
swelling etc.
• Objective clinical features, such as temperature
change, discolouration, swelling, muscle wasting,
dystonia, tremor & genuine hypersensitivity.
• Investigations were applicable support diagnosis.
CRPS Summary:
• CRPS is a genuine organic condition with clear diagnostic
• Early self-limiting CRPS (weeks / months) is perhaps not
uncommon after limb injuries & orthopaedic surgery.
• Persistent severe CRPS is rare. CRPS often proposed. Not
a common diagnosis in claimants with unexplained pain.
• Diagnosis is clinical using established diagnostic criteria.
• Investigations can assist in providing supporting evidence.
CRPS Summary:
• Treatment of CRPS is best carried out early.
• Physiotherapy & analgesia important.
• Injections can play a role in clinical management.
• Late and indefinite injection-based treatment can be
expensive and clinically unrewarding.
• Spinal cord stimulation should be considered.
• Specialist PMPs should be considered.
• Surgery should be avoided.
CRPS Summary:
• Psychosocial factors can be important in
determining pain-related disability.
• Claimants can suffer from genuine chronic pain in
the absence of a diagnosis of CRPS.
• Claimants with the objective features of CRPS can
exaggerate the severity and impact of their
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