complex regional pain syndrome

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Current Orthopaedics (2005) 19, 155–165

KEYWORDComplex rpain syndrReflex symdystrophy;Causalgia

0268-0890/$ - sdoi:10.1016/j.c

�Correspondifax: +44 117 92

E-mail addr(A. McBride), r

www.elsevier.com/locate/cuor

PAIN

Complex regional pain syndrome

Andrew McBride�, Roger Atkins

University Department of Trauma & Orthopaedic Surgery, Bristol Royal Infirmary, Marlborough Street,Bristol, BS2 8HW, UK

Segionalome;pathetic

ee front matter & 2005uor.2005.02.011

ng author. Tel.: +44 1178 4206.esses: [email protected]@ubht.swest

Summary Complex regional pain syndrome (CRPS) is a disabling chronic paincondition of unknown aetiology. Traditionally it has been thought to be a rarecomplication following trauma; however prospective studies demonstrate it to be acommon disabling complication of both trauma and operative procedures involving theupper and lower limbs. The condition is usually self-limiting, causing significantdisability for up to a year. Unfortunately in a minority of patients CRPS does notresolve, causing life-long misery. Modern research is aimed at understanding theinteractions of processes occurring locally at the site of injury with changes observed inthe peripheral and central nervous systems, as well as future preventative measuresand treatments. A bewildering array of proposed treatment modalities, both tested andexperimental, have been proposed. Despite differences between researchers and thespecialities involved in the management of CRPS, early recognition with sympatheticyet aggressive treatment is agreed to be vital to expedite optimal outcome.& 2005 Elsevier Ltd. All rights reserved.

Introduction

Complex regional pain syndrome (CRPS) is adisabling chronic pain condition of unknown aetiol-ogy. It is most commonly encountered followingtrauma to a limb and is diagnosed clinically by thepresence of abnormal pain, sensory changes,swelling, vasomotor instability (VMI), joint stiff-ness, motor dysfunction, trophic changes andincreased sudomotor activity. Research work overthe last 20 years has demonstrated that CRPS is nota rare sympathetically mediated condition seen

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bristol.ac.uk.nhs.uk (R. Atkins).

only in psychologically abnormal patients, rather itis a common and probably inevitable sequel oftrauma, including surgery. Understanding of thecondition has been progressed by the establishmentof internationally agreed diagnostic criteria com-bined with progress in clinical and basic scienceresearch. This article will summarise currentunderstanding within an orthopaedic context.

Terminology

The origins of CRPS can be traced to the AmericanCivil War; soldiers who had sustained nerve injurieswere reported on by Mitchell and colleagues whoobserved a post-injury burning pain they termed

ed.

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A. McBride, R. Atkins156

causalgia. Since then the condition has beendescribed under a number of different guises eachone having been popularised depending on theprecipitating factor, the country concerned or bythe speciality treating the patient (Table 1). To avoida term suggesting aetiology or site the InternationalAssociation for the Study of Pain (IASP), in 1994,agreed on the new nomenclature of CRPS.1 Two typesof CRPS are currently recognised: type 1, wherethere is no discernable nerve damage present(formerly termed Reflex Sympathetic Dystrophy)and type 2, where there is a discernable nerve injury(formerly termed causalgia).

Diagnosis

The diagnosis of CRPS is a clinical one and there isno single diagnostic test. Despite the IASPdiagnostic criteria agreed on nearly a decade ago(Table 2) a lack of consensus remains. Validationstudies have lead to refinement of these criteria in

Table 1 Previous terms for CRPS.

CRPS type 1 (no discernablenerve injury)

CRPS type 2(discernablenerve injury)

Reflex sympathetic dystrophy(RSD)

Causalgia

Sudeck’s atrophy Major causalgiaAlgodystrophy Mitchell’s

causalgiaShoulder hand syndromePainful post traumaticosteoporosisMinor causalgiaAlgoneurodystrophyPost traumatic pain syndromePainful post traumaticdystrophyTransient migratoryosteoporosis

Table 2 IASP diagnostic criteria for CRPS.

(1) The presence of an initiating noxious event, or a caus(2) Continuing pain, allodynia, or hyperalgesia with which(3) Evidence at some time of oedema, changes in skin bloo

the pain.(4) This diagnosis is excluded by the existence of condition

and dysfunction.

an attempt to reduce the effect of over-diagnosis(Table 3).2 A different approach may be morerelevant for the orthopaedic surgeon (Table 4).3

Clinical features

Signs and symptoms

CRPS is a biphasic condition that begins up to amonth after the precipitating event. In the acutestage of the condition, the symptoms and signs ofregional inflammation affecting an area larger thanthe site of injury are characteristic (Fig. 1). Laterthis inflammatory picture is replaced by atrophyand contracture (Fig. 2).

Throughout the course of CRPS, the pain experi-enced is neuropathic. Spontaneous or burning pain,hyperalgesia, allodynia and hyperpathia (Table 5)are common but not universal.4 Pain is unremitting,worsening and radiating with time, although sleepis often unaffected. It is disproportionate to the tothe precipitating insult.

The distribution of pain tends to be distal to thesite of injury. It is often diffuse and not limited tothe territory of a single peripheral nerve.

The salient features of an inflammatory processin the early stage of the condition are due to VMI.These include skin colour changes (pink or red),swelling, altered skin temperature and changesin sudomotor function (Fig. 3). These symptomsmaybe variable and can be related to exercise,painful stimuli and changes in environment. Someclinicians and researchers subdivide the acutestage into two distinct groups depending on thetemperature difference findings; therefore theterms

’’

hot’’ and

’’

cold’’ CRPS are coined.Motor symptoms are present in the majority of

cases and can include tremor, weakness, exagger-ated tendon reflexes, dystonia and myoclonicjerks.5,6 Limited active range of movement is dueto pain and oedema initially, with contracturescontributing later on in the condition (Fig. 4).

e of immobilisation.the pain is disproportionate to any inciting event.d flow, or abnormal sudomotor activity in the region of

s that would otherwise account for the degree of pain

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Table 4 Suggested criteria for the diagnosis of CRPS within an orthopaedic setting.

The diagnosis is made clinically by the finding of the following abnormalities, which should not be readilyexplained by the underlying orthopaedic condition.(1) Neuropathic pain: Non-dermatomal, without cause, burning, with associated allodynia and hyperpathia.(2) Vasomotor instability and abnormalities of sweating: Warm red and dry, cool blue and clammy or an increase

in temperature sensitivity. Associated with an abnormal temperature difference between the limbs.(3) Swelling.(4) Loss of joint mobility:(5) Joint and soft tissue contracture.

These clinical findings are backed up by:(1) Radiographic evidence of osteoporosis after three months.(2) Increased uptake on bone scintigraphy early in CRPS.

Table 3 Modified IASP diagnostic criteria for CRPS.

(1) Continuing pain that is disproportionate to any inciting event.(2) Must report at least one symptom in each of the following categories:� Sensory: Reports of hyperaesthesia.� 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 movement and/or motor dysfunction (weakness, tremor,dystonia) and/or trophic changes (hair, nails, skin).

(3) Must display at least one sign in two or more of the following categories:� Sensory: Evidence of hyperalgesia and/or allodynia.� Vasomotor: Evidence of temperature asymmetry and or skin colour changes and/or asymmetry.� Sudomotor/Oedema: Evidence of oedema and/or sweating changes and/or sweating asymmetry.� Motor/Trophic: Evidence of decreased range of motion and/or motor dysfunction (weakness, tremor,dystonia) and/or trophic changes (hair, nails, skin).

Figure 1 Early CRPS affecting the right hand, following distal radial fracture. Note the discolouration and fingerswelling.

Complex regional pain syndrome 157

The atrophic stage of the condition commencesas the VMI and oedema resolves but marked motorand trophic changes occur. The skin is thin with

joint creases and subcutaneous fat disappearing.brown-grey scaly pigmentation develops in a highproportion of patients. Hairs become fragile,

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uneven and curled while nails are pitted, ridged,brittle and discoloured brown. Palmar and plantarfascias can thicken and contract manifesting asDupuytren’s disease (Fig. 5).7 Tendon sheathsconstrict with triggering and increased resistanceto movement. Muscle contracture combined withtendon adherence leads to reduced tendon excur-sion. Joint capsules and collateral ligaments be-come shortened, thickened and adherent, causing

Figure 2 (a, b) Late CRPS affecting the left hand. Notethe muscle atrophy and finger contractures.

Table 5 IASP Pain definitions.

� Pain: An unpleasant sensory and emotional experiencedescribe in terms of tissue damage or both.

� Allodynia: Pain due to a stimulus that does not normall� Hyperaesthesia: Increased sensitivity to stimulation, ex� Hyperalgesia: An increased response to a stimulus that� Hyperpathia: Pain characterised by an increased reactioan increased threshold.

joint contracture. Bone loss and patchy osteoporo-sis occurs,8 but despite these changes osteoporoticfracture is uncommon.

Regions affected

The upper limb is more commonly affected thanthe lower. Distal involvement tends to predominateprobably due to the relatively higher occurrence ofinjuries at the wrist in the general population.When the entire arm is affected the elbow tends tobe spared. Patients with distal upper limb CRPShave a significant incidence of associated shouldercomplaints (the so-called shoulder-hand syn-drome). In most this is due to a biceps tendonitis.9

It is probable that a significant proportion of frozenshoulders can be considered a form of CRPS.10 Theclinical similarities between the two are supportedby changes observed on bone scans and plainradiographs.11 CRPS can occur following surgicalprocedures in the upper limb such as carpal tunnel

Figure 3 Increased sudomotor function in a foot affectedby CRPS.

that we primarily associate with tissue damage or

y provoke pain.cluding special senses.is normally painful.n to a stimulus, especially a repetitive one, as well as

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Figure 4 Joint stiffness affecting the right hand in earlyCRPS.

Figure 5 Early Dupuytren’s disease affecting the right-hand associated with the onset of CRPS following distalradial fracture.


decompression (whether performed endoscopicallyor as an open procedure), and Dupuytren’s release.CRPS affecting the lower limb is recognised follow-ing both trauma and surgery. These include tibialfractures, amputations and crush injuries to thefoot. As well as the periphery of the lower limb, theCRPS and its association with insults to the kneehave also been extensively reported on.12 Inpregnancy the hip can be affected. In otherspecialities CRPS affecting the face and thoracicwall have been described.

Incidence

The full-blown, severe form of CRPS is fortunate-ly rare, reflected by the low prevalence inretrospective studies.13 However prospective stu-dies show that a mild form of the condition occurscommonly following trauma or surgical insult. Anincidence of up to 37% is seen following distal radialfractures14 and 30% following tibial shaft frac-

tures.15 Following total knee replacement anincidence of 41% at 3 months and 19% at 6 monthsfollowing surgery has been reported.16

CRPS may occur at any age but it is more commonin middle-aged adults. It affects both sexes and allraces, but is more common in females.

Causation

Trauma is the commonest precipitating event,accounting for 30–77% of cases, the majorityfollowing minor insults to an extremity. A majordifficulty in the understanding of this condition hasbeen why one fracture or traumatic insult shouldgive rise to CRPS while an identical fracture orinsult in another patient or even in a different limbin the same patient does not. In up to 25% of casesno precipitant insult can be identified. Whilsttrauma is the commonest precipitant, CRPS is alsoreported following a wide range of disease pro-cesses including: cerebral vascular events, myo-cardial ischaemia and herpes zoster infection.

Natural history

The exact onset of CRPS following a precipitatinginsult is difficult to ascertain. The acute stages ofthe condition mimic those of acute inflammation, anexpected finding in the immediate time periodfollowing either trauma or surgery. It is probablethat the majority of cases begin within a month afterthe initial insult; some researchers report the onsetof some cases are delayed by up to several months.These, however, are a minority and certainlyquestion the relevance of the reported initial insult.

The clinical course and severity following onset isvaried, reflected by the reported lower incidencefollowing trauma in studies involving establishedcases. Although most cases resolve within a year,17

some features, particularly stiffness, remain sug-gesting CRPS may be responsible for significantlong-term morbidity even when mild.18

Pathogenesis

The development of CRPS probably involves at leasttwo linked pathophysiological processes, one oc-curring at the site of the injury, involving local softtissues and the peripheral nervous system, and thesecond occurring in the central nervous systemleading to altered reflexes and neuronal pathways.A number of theories have been investigated anddiscussed (Fig. 6):

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• Central sensitisation• Sympathetic nervous system

• Genetic predisposition

• Immobilisation

• Free radical damage• Neurogenic inflammation• Peripheral sensitisation

• Exaggerated inflammatory response

• Psychological factors

-Sympathetic mediated pain

OHO2

-

Figure 6 Proposed mechanisms involved in the development of CRPS.


Genetic predisposition

Evidence for an inherited component to thedevelopment of neuropathic pain has been de-scribed in both animal and human studies.19–21

CRPS has been linked to certain variations (poly-morphisms) of genes encoding angiotensin-convert-ing enzyme (ACE) and human leucocyte antigen(HLA) class I and II molecules. These genes have ahigh amount of variation and, as they are inherited

in a Mendelian fashion, can be useful as geneticmarkers of disease.

Exaggerated inflammatory response

In the acute stages of CRPS the condition demon-strates all the classical symptoms and signs ofinflammation: rubor, calor, dolor, tumour andfunctio laesa.6 Sudeck first postulated that an

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exaggerated inflammatory response could contri-bute to the aetiology of the condition he describedin 1900. Over the last decade this theory has beenrevisited and investigated.

CRPS type 1 is associated with macromoleculeextravasation, reduced oxygen extraction andconsumption and tissue acidosis.22–24 Plasma mar-kers of cellular inflammation as well as histologicalstudies are normal; however an increase in inflam-matory mediators and mast cell activity have beendemonstrated in the skin of affected limbs of CRPSpatients.25

It has been known for some time that tissuedamage following acute inflammatory processes iscaused in part by free radical deposition.26,27

Evidence for the involvement of free radicals inthe development of the CRPS has been reported bya number of researchers. An animal model hasdemonstrated a CRPS-like limb following freeradical donor infusion directly into the limb.28

Amputated human specimens affected by CRPSshow basement membrane thickening consistentwith overexposure to free radicals.29 Treatment ofCRPS patients with topical free radical scavengersappears to provide some relief.30

Neurogenic inflammation

Stimulation by increased cytokine activity maintainsnociceptor reaction to an injury by a process calledneurogenic inflammation. During this process neu-ropeptides including substance P, calcitonin gene-related peptide (CGRP) and somatostatin arereleased. Peripherally these neuropeptides contri-bute to changes in vascular permeability whilstcentrally they have an excitatory affect.31 Infusionof exogenous substance P into the painful extremitypotentiates the symptoms of CRPS,32 whilst in ananimal model of CRPS a substance P receptorantagonist reverses the extravasation, warmth andoedema seen following sciatic nerve transection.33

Sympathetic nervous system abnormalities

The diagnosis of CRPS is dependent on the presenceof the symptoms and signs of VMI and trophicchanges suggesting sympathetic nervous system(SNS) dysfunction. Although the SNS is not normallyactive in the processing and transmission of noxiousstimuli in some cases of CRPS the phenomenon ofsympathetically maintained pain (SMP) is nowrecognised.1 SMP maybe relieved by stellate gang-lion block to the affected limb34 and then restoredby noradrenalin injection.35 Increasing sympatheticactivity worsens spontaneous pain and mechanical

allodynia.36 Pain can be enhanced or provoked,after sympathectomy, by injection of adrenergicagonists into the skin of the symptomatic limb.37

However intravenous regional sympathetic block-ade with guanethidine, traditionally a mainstay oftreatment in resistant cases, does not improve thesymptoms or alter the natural history of CRPS.38

The mechanism by which the SNS may be involvedin CRPS pain is not clear. Adrenergic supersensitivityin the affected limb may explain this in a number ofways. The density of a1 adrenoceptors is increasedin the non-vascular epidermal tissue of symptomaticlimbs. Following partial nerve injury, when bothinjured and uninjured somatic axons start toexpress a1 adrenoceptors.39 Cutaneous vasculatureshows increased responsiveness to noradrenalin inlimbs of CRPS patients. Thus adrenergic super-sensitivity could lead to sympathetic over-activitycausing the sensitisation of the somatic sensorynervous system to circulating catecholamines andnoradrenalin released from post-ganglionic sympa-thetic terminals. Adrenergic supersensitivity maycause vasoconstriction, aggravating tissue inflam-mation, causing a build up of nociceptive mediatorsproduced during the inflammatory process. Alter-natively adrenergic supersensitivity might interferewith the normal production of mediators such asnerve growth factor (NGF). a1 adrenergic activityincreases the secretion of NGF, an inflammatorymediator known to stimulate the growth of noci-ceptive afferents and to cause the release ofnociceptive mediators from mast cells, sympatheticneurones and macrophages.40 Increased a2 adrener-gic activity in the SNS stimulates the synthesis ofprostaglandins E and I both potent in increasing theexcitability of nociceptive afferent nerve fibres.41

Peripheral sensitisation

Changes in normal neuronal functioning, leading topain hypersensitivity, including allodynia have beenattributed to neuronal plasticity. This physiologicalprocess is an ongoing phenomenon that reflectschanges in neuronal environment and activity.42

The experience of pain occurs when small fibrenociceptors (C and Ad fibres in the skin) arestimulated. These fibres normally require signifi-cant energy and hence a stimulus that is tissuethreatening or damaging for a pain to be felt. Thesefibres are however activity dependent and ifstimulated at low intensity the perception is crudetouch.

If the stimulus is repetitive and potentiallythreatening these nociceptors can become sensi-tised, decreasing their threshold to fire. This is a

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normal adaptive physiological response to injury.Unfortunately this response can become harmfulwhen the threatening environment recedes but thenociceptors remain sensitised. This pathophysiolo-gical state is further compounded by the fact thatthese small fibres proliferate in response to thepro-inflammatory soup of cytokines, neurotrans-mitters and growth factors that are released locallyduring the initial injury phase. A combination ofactivity dependent firing, an adaptive response to arepeated stimulus and proliferation in response toan injury environment leads to a vicious circle ofcontinuing pain without a noxious stimulus present.

Central processing changes

The unexplained pain of CRPS has been linked tocentral sensitisation. Following nerve injury, bothinjured and non-injured sensory afferents can firespontaneously. Prolonged input to the dorsal hornas a result of spontaneous firing in C fibrenociceptors sensitises dorsal horn neurons so thatthey abnormally respond to innocuous inputs. Thismay lead to an exaggerated dorsal horn response toA-fibre input and thus allodynia. Peripheral nerveinjury may also reduce the affect of centraldescending inhibitory pathways. The spread of painbeyond the territory of an affected nerve can bereversed by certain receptor antagonists impli-cated in central sensitisation.43

Fracture management

The incidence of CRPS following tibial shaftfracture is not affected by the method of fracturemanagement employed.15 Equally both the severityof the fracture and the quality of reductionfollowing distal radial fracture are not influential.14

Undue immobilisation has been proposed as acause of CRPS and CRPS features, except pain, areseen after cast immobilisation.44 Excessive plasterof paris cast tightness has been linked to thedevelopment of CRPS following distal radial frac-ture.45 Immobilisation has been proposed to causea

’’

neglect-like’’ phenomenon in which the patientsfind difficulty in initiating movement or accuratelydirecting it.46 Learned pain avoidance behaviour inresponse to allodynia may exacerbate changes ofdisuse since normal tactile and proprioceptiveinput are necessary for correct central nerve signalprocessing. Indeed, it has been suggested thatabnormal mobility is the entire cause, due to loss ofintegration between sensory input and motor out-put, in a manner akin to seasickness.47,48

Psychological factors

Some physicians may feel that the complex array ofsymptoms, the seemly innocuous

’’

minor trauma’’preceding the onset (or in deed lack of trauma) andthe lack of conclusive diagnostic tests or imagingpoints to CRPS being primarily of psychologicalorigin. This concept, however, is unsupported.49

Although several studies have linked certainpsychological factors with CRPS including emo-tional lability, low pain threshold, hysteria, depres-sion and antecedent psychological stress, mostCRPS patients are normal. One proposed theory isthat of a complex interaction between the, nowapparent, pathophysiological models for the dis-ease and certain psychological processes to explainthe progression and longevity seen in certainpatients.50

Investigations and differential diagnosis

Fortunately the severe and therefore obvious casesof CRPS are rare following trauma. The morecommon marginal case however does present adiagnostic dilemma. The differential diagnosis ofthe painful, swollen, hot limb in the orthopaedicsetting includes the direct effects of the originaltrauma, undiagnosed fracture, cellulitis, arthritisand malignancy. A carefully taken history and initialinvestigations in these marginal cases should bedirected to their exclusion.

CRPS does not cause elevation of the blood andserum markers of inflammation. All other routinebiochemical indices are also unchanged.

Plain radiography demonstrates features of rapidbone loss: visible demineralisation with patchy,subchondral or sub-periosteal osteoporosis, meta-physeal banding and profound bone loss (Fig. 7).51

Bone involvement is universal with increaseduptake on bone scanning in early CRPS (Fig. 8).This was originally thought to be peri-articular,suggesting arthralgia.52,53 However CRPS does notcause arthritis and recent studies have showngeneralised hyperfixation.54 Later the bone scanreturns to normal. A normal bone scan withoutradiographic osteoporosis virtually excludes adultCRPS. MRI can be helpful to exclude otherpathologies and in CRPS may demonstrate earlybone and soft tissue oedema, joint effusions andlate atrophy with fibrosis but is not diagnostic.

Temperature difference between the limbs isgreater in CRPS than other pain syndromes but thisis not usually applied in an orthopaedic con-text.55,56

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Figure 8 Bone scan changes affecting the left-hand seenin early CRPS.

Figure 7 Patchy osteopenia associated with CRPS affect-ing the foot.


Management

Early recognition of CRPS is the key to achieving thebest results. Aggressive, sympathetic multi-disci-plinary treatment is necessary. For those patientswith concomitant psychosocial factors an especiallyvigorous approach is required. Reassurance of theself-limiting natural history of the condition shouldbe emphasised. Increased function of the affectedlimb should be sought using a combination of simpleanalgesia and supervised physiotherapy to breakthe vicious cycle of disuse.57 Non-steroidal anti-inflammatory drugs appear to give better painrelief than opiates. Immobilisation and prolongedsplintage should be avoided where possible. Limbinactivity will not only slow the recovery but canproduce permanent disability through contrac-tures; therefore if used, splintage must be in the

safe position. For most orthopaedic patients whodevelop CRPS this approach will provide a goodoutcome.

If these simple measures do not result in rapidresolution, involvement of pain specialists iscrucial. Numerous second line measures have beenproposed but properly constructed scientific stu-dies are lacking58 and these treatments are oftenunsuccessful so that patients are left with pain anddisability.

Further treatments include centrally actinganalgesic medications such as amitriptyline, gaba-pentin or carbamazepine; regional anaesthesia; theuse of membrane stabilising drugs such as mex-ilitene; sympathetic blockade; desensitisation ofperipheral nerve receptors with capsaicin; transcu-taneous nerve stimulation or an implanted dorsalcolumn stimulator. Where the knee is affected,epidural anaesthesia and continuous passive motionmay be appropriate.

The role of surgery is limited. Where CRPSis caused by a surgically correctable nerve lesion,such as median nerve compression at the wrist,surgical intervention may provide relief, butthis should be undertaken cautiously in the pre-sence of active disease. Surgery is rarely indicatedto treat fixed contractures, which usually in-volve all of the soft tissues. Surgical releasemust therefore be radical and expectations limited.Surgery for contracture should be delayed untilthe active phase of CRPS has completely passedand ideally there should be a gap of at least ayear since the patient last experienced pain andswelling.

Amputation of a limb affected by severe CRPSshould be approached with great caution. In aseries of 28 patients who underwent 34 amputa-tions in 31 limbs, surgery was usually performed forrecurrent infection or to improve residual function.Pain relief was rare and unpredictable and neitherwas infection always cured nor function universallyimproved. CRPS often recurred in the stump,especially if the amputation level was symptomaticat the time of surgery.59

Generally, surgery represents a painful stimulus,which may exacerbate CRPS or precipitate a newattack. This risk must be balanced carefully againstthe proposed benefit. The risk of surgically pre-cipitated recurrence is greatest when the same siteis operated upon in a patient with abnormalpsychology in the presence of active disease andlowest when these conditions do not apply. Surgerymust be performed carefully with minimal traumawith excellent post-operative analgesia. Ideally theanaesthetist will have a particular interest in thetreatment of CRPS.

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CRPS in children

The condition in this age group differs from adultsboth in severity of symptoms and in response totreatment. For these reasons it has long been underreported. In a series of 70 cases, neither severedisabling pain nor trophic changes were common.60

The characteristic radiographic changes seen in theadvanced form of the disease in adults does notoccur. Psychological factors have been implicated.Symptom severity and the reaction of the family tothe symptoms of CRPS can be amplified by thepressures of academics or organised sports and bysubstantial family stress such as parental conflict,and sibling rivalry.

Good response to physical therapy makes this themainstay of treatment with an emphasis on func-tional goals as well as reduction of pain.

Research directions

� Further understanding of the pathophysio-logical processes occurring

� Exploring links with other chronic painstates. Is there a common localised initiat-ing pathological process occurring?

� Epidemiological studies to identify risk fac-tors for progression to long-term disability

� Validation of current proposed therapeuticand physical therapies through well de-signed randomised control trials

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