chronic pain syndromes in the emergency department: identifying guidelines for management
TRANSCRIPT
Emergency Medicine Australasia
(2005)
17
, 57–64
Blackwell Science, LtdOxford, UKEMMEmergency Medicine Australasia1035-68512005 Blackwell Science Pty Ltd20051715764Original Article
Chronic pain managementK Baker
Correspondence: Dr Kylie Baker, Ipswich Emergency Department, Ipswich General Hospital, Chelmsford Ave, Ipswich, QLD 4305, Australia. Email: [email protected]
Kylie Baker, MBBS, Senior Medical Officer.
R
EVIEW
A
RTICLE
Chronic pain syndromes in the emergency department: Identifying guidelines for management
Kylie BakerIpswich Emergency Department, Ipswich General Hospital, Chelmsford Ave, Ipswich, Queensland,
Australia
Abstract
Objectives:
To explore current literature on chronic pain syndromes and develop ED recommendationsfor the management and minimalization of chronic non-cancer pain.
Methods:
A focused literature review.
Results:
Chronic pain is a common presentation to the ED but is poorly understood and managed.Research into the psychophysiology of chronic pain shows that there are definite changesin the receptive and processing pathways in patients suffering chronic pain syndromes.Evidence shows the effectiveness of early recognition with multimodal treatment, howeverhigh level evidence is lacking. All experts recommend balanced drug therapy, cognitiveand behavioural interventions. Certain interventions are appropriate to the ED setting.
Conclusions:
Emergency Medicine lacks a cohesive, informed strategy for management of chronic pain.The proposed guidelines represent the first step toward establishing consistency in themanagement of patients with chronic pain syndromes. Further work needs to be under-taken at a national level in developing evidence based guidelines.
Key words:
emergency treatment
,
pain and chronic disease
.
Chronic pain: Introduction
Pain is a common reason for presentation to the ED.
1
Emergency physicians deal with acute pain gener-ously, using the wide range of therapeutic optionsat their disposal.
2
Likewise, terminal cancer patientswith pain are treated with utmost sympathy. In con-trast, for a number of reasons, physicians may feela sense of anger and helplessness when confronted
with chronic unexplained pain.
2–4
First, chronic painsufferers are difficult to differentiate from narcoticseekers, particularly after hours with limited timeavailable. Second, they may be suffering from anintercurrent acute illness or stress. Most have oftenundergone extensive investigations, have multiplehealth care professionals involved, and rarely have aprewritten health plan available.
4
Finally, the mecha-nisms of chronic pain are poorly understood and this
K Baker
58
may engender a sense of disbelief in emergencyphysicians.
Research demonstrates that chronic pain is preva-lent in Western Society (Table 1) Cordell
et al
. recordedpain as the ‘chief complaint for visit’ in 52% of 1665consecutive ED visits.
1
Of these, 38% were identifiedas having specific chronic pain syndromes. Thisequates to almost one fifth of emergency visits in hisstudy.
The purpose of this literature review is to summarizethe recent advances in the management of chronic painsyndromes. I would like to change the perspective ofthe ED physician. Differentiating the various phenom-ena such as pseudoaddiction, neuropathic pain, com-plex regional pain, viceral, somatoform and chronicunexplained pain has little clinical advantage to thebusy ED physician but the common ‘rescue medicationoptions’ are vital. In this article, I will review currentemergency department research and non-emergencydepartment research, and then propose a practical guideto ED care of chronic pain. Background research intoneurophysiological advances is written up as a separateoccasional report.
Methods
Literature was searched via Medline, Cochrane, Cinahl,and PsycINFOR from 1996 to 2004, under ‘chronic painand emergency management’. Medline from 1996 wassearched for ‘chronic pain and prevention’, ‘chronic painand emergency’, ‘breakthrough pain’, and ‘chronic pain’.This was extended back to 1966 under ‘chronic pain andemergency’. Bibliographies were manually searched forolder keynote articles. Four major emergency medicinetextbooks (two Australian), the Australian TherapeuticGuidelines (Analgesia) and eMedicine Clinical Knowl-
edge Base were likewise scanned. Articles focusing onacute pain, cancer or non-cancer terminal pain werediscarded.
Background research into the advances in under-standing of pathophysiology of chronic pain used‘chronic pain’ reviews from Medline searched from1996.
This is summarized in a separate article, althoughcertain references are used in both articles.
Relevant research has been grouped and reportedunder headings of1. Emergency medicine research in chronic pain
management2. Non-emergency research – treatment, risk identifica-
tion and rationalizing referral and investigation.Guidelines for the ED are proposed from the above
research.
1. Emergency medicine research in chronic pain management
The search of medical literature databases suggestedlittle input from emergency physicians into themanagement of chronic pain in their departments.There were no prospective trials; all were reviews orexpert opinion articles. In 1996, Afilalo, Cantees andDucharme
5
searched emergency medicine literaturefor any studies on pain. One textbook, two chaptersin other texts, and 60 articles were found. These weremostly clinical research, based around particularpainful conditions. They concluded that emergencyphysicians should do more research in early paincontrol.
Review of emergency medicine journals specificallyfor chronic pain research, reveals little else since 1996.Ten relevant references are summarized below.
In 1996, MacLeod and Swanson
3
wrote up anextensive but promising system for managingchronic pain in Calgary, Canada, however, neitherresearcher has reported on the outcome of theirintervention in emergency literature. Interestingly,they audited 1882 non-serious headache presentationsand estimated that only 29 patients were likely to bedrug seeking. Along with Ducharme,
2
they argue thatthe label of ‘drug-seeking’ is too often applied, nar-cotics are withheld and the patient either treated tooconservatively, or overinvestigated. Assuming all tobe drug seekers adversely affects the majority whopresent with genuine chronic pain. Stereotypic ‘drug-seeking’ behaviours that disappear with adequate
Table 1.
Studies quantifying prevalence of chronic pain syn-dromes in adults
Author Prevalence (estimatedpercentage of
general population)
Samplesize
Nielson
29
(quotes Millar
42
) 17% —Schochat
43
† 13.5% 3174Papageorgiou
44
† 10–11% 1386Elliot
45
46.5% 3605Singh and Patel
13
35% —
†
These studies surveyed only chronic widespread pain, exclud-ing regional pain syndromes.
Chronic pain management
59
pain management — narcotic or otherwise — istermed ‘pseudoaddiction’.
2
In a series of review articles entitled ‘Orthopaedicpitfalls in the ED’, Perron and associates note thatchronic pain may well follow misdiagnosis of scaphoidfractures, lunate and perilunate injuries, Lisfrancinjuries and osteomyelitis. They recommend earlydiagnosis and appropriate treatment of the acuteinjury.
6–9
One article by Ferrari,
10
in the Emergency MedicineJournal is excellent. It is the only article that acknowl-edges and tries to address the cognitive aspects ofchronic pain. It describes prevention of chronic painafter whiplash, using education and reassurance toencourage more healthy behaviours post injury.
Lummus and Thompson, in Emergency MedicineClinics of North America, review the management ofprostatitis, and its occasional progression to a chronicpain focus.
11
Suggested strategies for treatment of non-inflammatory, chronic prostatitis include diazepamand baclofen, antiadrenergics and psychotherapy. Thenature of the underlying abnormality is not addressedin any detail.
The Audio-Digest of Emergency Medicine
12
devotedone session to Professor Prager, lecturing on chronicpain management, in June 2003. He outlined neurostruc-tural changes, the addiction/pseudoaddiction/depen-dence quandary and the need for multimodal therapy.There was no emphasis on cognitive or behaviouralinterventions.
Ducharme
2
reviewed acute pain and pain control in2000. Of the 18 pages, one is devoted to chronic painand sets out very important general guidelines forapproach to these patients. He emphasizes the difficul-ties in identification of these patients, and the complex-ities involved with the chronic pain. Opioids may berequired, an exacerbating physical cause should beexcluded, depression should be treated and the physi-cian must explain the limitations of the ED with empa-thy. Very truly, he concludes that ‘Pain control isoptimized by increasing our understanding of the neu-robiology of pain combined with interaction with thepatient: science and knowledge combined with empathyand humanity’.
Singh and Patel, in their June 2004 update in eMedi-cine, give a well rounded general summary of chronicpain and management principles and some medicationsbut unfortunately stop short of a concrete plan orguidelines.
13
Our paper is the forerunner of original research com-mencing in our department this year.
2. Non-emergency medicine studies on chronic pain management
Studies were chosen if they outlined strategies thatcould be of relevance to the ED. They can be dividedinto three categories.1. Those examining treatment modalities2. Early identification of chronic pain sufferers and
those at risk3. Rationalizing referral or investigation via screening.
These articles are listed by descending level ofevidence.
2.1 Treatment modalities
Management of chronic pain centres on drug therapy,physiotherapy, rehabilitation and psychologicalinterventions.
There are two Cochrane Reviews on chronic painmanagement; one on the efficacy of anticonvulsantdrugs and one on the efficacy of psychological therapiesfor the management of chronic and recurrent pain inchildren and adolescents. The first concluded that car-bamazepine could be recommended for trigeminal neu-ralgia but that there was not a strong evidence base forother treatments. Gabapentin warranted further studyand might prove effective. Neither induced significantharm.
14
The study in adolescents found that there wasvery good evidence that psychological treatments wereeffective in reducing severity and frequency of chronicheadache in children and adolescents.
15
A structured abstract from the NHS centre forReviews and Dissemination
16
looked at Kingery’s criti-cal review of controlled clinical trials for peripheralneuropathic pain (PNP) and complex regional pain syn-dromes (CRPS). For PNP they found consistent supportfor the use of tricyclic antidepressants, intravenousand topical lignocaine, intravenous ketamine, carbam-azepine and topical aspirin. Intravenous morphine waslikely to be effective, while oral NSAID were thoughtto be probably ineffective. Magnesium, propranolol,lorazepam, phentolamine and oral codeine were foundto be ineffective. For CRPS, the only treatment consis-tently beneficial was oral corticosteroids. Guanethidineand reserpine regional blocks were found to be ineffec-tive. For both PNP and CRPS, clonidine was probablyeffective.
Dworkin
et al
., in Archives of Neurology, reviewedrandomized controlled trials on management of neuro-pathic pain and recommended five first line medicationsfor neuropathic pain.
17
Each one could be used as initialtreatment or added on, providing that drug interactions
K Baker
60
and patient susceptibility were considered. The recom-mended treatments were gabapentin, 5% lignocainepatch, opioid analgesics, tramadol and tricyclic antide-pressants. An important statement made was ‘concernsabout causing a substance abuse disorder when thereis no history of one do not justify refraining from usingopioid analgesics in patients with chronic neuropathicpain’.
Hocking and Cousins, in an evidence based review ofketamine in chronic pain management, conclude thatthere is limited level two evidence for the efficacy ofketamine in specific situations but in view of side-effects they can only recommend it as a ‘third line’ drug,‘where standard analgesic options have failed’.
18
Nielson and Weir systematically reviewed literatureon the effectiveness of biopsychosocial and multimodalapproaches to treatment of chronic musculoskeletalpain, primarily back pain.
19
They concluded that therewas level two evidence in support of the cognitive-behavioural and behavioural arms of biopsychosocialmanagements for chronic low back pain and other mus-culoskeletal pains for up to 12 months.
In two separate original research papers, Hering
et al
.
20
and Srikiatkhachorn
et al
.
21
looked at serotoninlevels in patients with chronic analgesic-induced head-ache. In single crossover studies, they showed that sero-tonin levels were decreased during long-term simpleanalgesic use (predominantly paracetamol), and thatserotonin levels increased again after abrupt discontin-uation of simple analgesics, with significant improve-ment in pain score, and headache-free days. They usedNSAIDs while withholding paracetamol.
A single prospective double blind trial of 106 conser-vatively treated wrist fractures showed that post injuryvitamin C (500 mg) was associated with less occurrenceof Reflex Sympathetic Dystrophy.
22
In one single-blinded prospective comparison of 200chronic pain patients, randomized to receiving eitherketorolac and chlorpromazine, or meperidine andpromethazine, Mehl-Madrona
23
found that the regimeswere equally effective, with side-effects of respiratorydepression with meperidine and dizziness with chlor-promazine. However it is important to note that theketorolac/chlorpromazine doses were double that usedcommonly in Australia, while the meperidine was halfthat routinely used.
A randomized double blinded placebo-controlledcross-over study of 20 chronic pain patients used intra-nasal ketamine for episodes of breakthrough pain.
24
There were no major side-effects. Researchers foundsignificant relief of breakthrough pain and no use of
regular rescue medication. It is notable that 65% of theplacebo group also responded.
Two prospective outcome studies of multidisci-plinary pain clinics (Robbins
et al
.
25
— 201 patients andHubbard
et al
.
26
— 50 patients) found that specific,intensive, multimodal programmes improved outcomesfor chronic pain patients compared to unstructured orincomplete care. Brief descriptions of programmes out-lined on average 35 sessions with different therapists(Robbins) or a course averaging 8 weeks with four thentwo sessions of various therapies per week (Hubbard).There were no allusions to single visit or rescue modal-ities relevant to an ED.
An expert panel report by Stanton-Hicks
et al
.,
27
onan updated interdisciplinary clinical pathway for CRPS,continues to emphasize that psychological interventionsand rehabilitation have as much importance as pharma-cological treatments. They recommend tricyclic antide-pressants, gabapentin, and early short course oralsteroids. NSAIDs, opioids, calcitonin, alpha-1 adreno-ceptor antagonists, and other antidepressants can betried on an individual basis. Implantable therapies canbe effective provided screening is careful. Trial of trans-dermal clonidine is suggested.
Of interest, they propose a central neuroimmunedisorder as the cause of CRPS. There are no specificrecommendations for ED management.
In another report on assessment of pain prior toimplantable therapies, Prager outlines the types ofimplantable modalities, from peripheral nerve stimula-tors, central stimulators to spinal and epidural cathetersfor drug administration.
28
His flowchart of therapeuticmodalities begins with NSAIDs and simple analgesics,progresses through physical therapies with transcuta-neous endoneural stimulation (TENS), alternative ther-apies, corrective surgery if warranted, then long-termsystemic opioids, neuromodulation and neuroablation.There are no specific recommendations for ED manage-ment; however, questions from his screening processcould be incorporated into ED assessment.
Nielson reported strategies to reduce chronic pain,breaking them into primary injury prevention (essen-tially a workplace health and safety function) secondaryprevention (recognition of a subacute phase with highpain scores and the option of early intervention), andtertiary prevention – the damage control phase.
29
Hestates that ‘both biological and psychological founda-tion for long-term persistent pain is in place withinhours of injury’. This last statement attaches greatimportance to our ED management of acute injury. Herecommends early and appropriate acute pain manage-
Chronic pain management
61
ment which must include adequate explanations topatients. A flat denial of significant disease is ineffec-tive. There must be a positive explanation of symptoms.
2.2 Identifying at-risk and chronic pain patients
Pincus
et al
.
30
systematically reviewed six of 25 papersinvestigating psychological factors that predicted chro-nicity/disability in prospective cohorts of low backpain. The authors found persistence of symptoms morelikely among patients experiencing psychological dis-tress (e.g. worry, fear) or depressed mood, and amongpatients who reported many somatic symptoms. To alesser extent, they found that patients who coped withthe injury by ‘catastrophising’ were at risk of chronicpain.
Hasenbring, in ‘Nervous System Plasticity andChronic Pain’ summarizes the research on the variouscoping strategies used to address acute and chronicpain.
31
Including several of her own studies that mea-sure subjective pain ratings during and after noxiousinput, she reports that three common strategies wereoverexpressed in chronic pain patients. Catastrophizingthe incident, suppressing the incident and self distrac-tion were all associated with chronic pain. Suppressionwas a particularly common strategy as it increasedimmediate pain tolerance, but appeared to be followedby a rebound effect. She suggests that this is partly dueto the subject persisting in the painful task and over-taxing the damaged region. Self distraction helpedsomewhat in acute pain but seemed to lose efficacy inpatients with chronic pain. Sensory monitoring wasassociated with lower pain scores and less chronic pain.
An observational study by Kouyanou
et al
. of 125patients attending a chronic pain clinic found thatiatrogenic factors including over-investigation, inappro-priate advice, misdiagnosis, over treatment and inap-propriate prescription of medication were commonamong patients with chronic pain.
32
They suggest thatthese factors may be causative, rather than effect.
In a small prospective observational study, Dunbarfollowed chronic pain patients to determine if any socialfactors and behaviours could predict the developmentof narcotic abuse.
33
His findings reinforce the experience
of most emergency physicians, documenting that mul-tiple visits, multiple allergies, dose escalation, concur-rent polysubstance abuse and poor social support arerisks for narcotic addiction.
2.3 Screening and rational referral
In expert reports Mayou and Farmer,
34
Nielson,
19
Prager,
28
and Kroenke
4
all strongly recommend thebiopsychosocial approach that plots the patient’s riskfactors on a grid against precipitating, predisposingand perpetuating factors. (Table 2) This also helps todefine areas in which the physician might intervene,but seems somewhat lengthy for a screening EDassessment.
Mayou and Farmer reviewed functional somatic syn-dromes (including chronic pain) and symptoms. Theyplot the number of somatic symptoms reported by thepatient against the likelihood of psychiatric morbidity.In a reassuring graph, they illustrate that five or moresomatic symptoms have a greater than 50% associationwith psychiatric condition. Fifteen or more somaticcomplaints had a 100% chance of psychiatric comorbid-ity. These patients are less likely to require urgent afterhours investigation, and may benefit most from psychi-atric referral.
Kroenke looks at the prevalence of somatic symp-toms (including chronic pain) which remain medicallyunexplained, quoting studies with figures similar toMayou. He suggests a simple scheme for predicting ananxiety disorder using risk factors of;1. Stress in the preceding week2. Symptom count greater than five3. Self rated health as low4. Symptom reported as severe.
Non-organic aetiology is even more likely when thepatient is a frequent health care user, and also if thephysician rates the encounter as ‘difficult’.
Psychiatric referral is recommended by Kroenke butmust be prefaced by careful explanation. The authorsdo describe the role of non-specialist treatment, but it isdirected at a family physician. Their advice is general-ized and difficult to conceive within an ED. Theyemphasize the importance of correct information, sim-
Table 2.
Biopsychosocial matrix – example
K.B. Predisposing factors Precipitating factors Perpetuating factors
Biological Low IQ Minor fall Increasing obesityPsychological Family history of depression Stressed about pending court case Poor coping skillsSocial Abusive parent Lost job Increasing debt after losing job
K Baker
62
ple behavioural plans, anxiety management, diaries,graded exercise and antidepressants even in theabsence of depression.
Proposed guidelines for emergency department management of chronic pain
In the absence of consensus statements or managementguidelines in the literature, I open for debate the follow-ing guidelines for management of chronic pain syn-dromes in the ED.
Principles
1. Definitive treatment of chronic pain is not the roleof the ED.
2. ED management includes rescue medication, ratio-nal investigation and referral, given in an environ-ment which does not exacerbate chronic pain.
3. Pain should be treated aggressively, promptly andappropriately. Narcotics should not be withheldwithout definite evidence of addiction.
16,17
4. A focused search for precipitants (organic and psy-chologic) should be based on the individual’s riskprofile.
2
A thorough physical examination is itselfreassuring.
10,28
5. Emphasize that severe pain does not reliably pre-dict tissue damage, but address concerns and avoidsimplistic reassurance or denial of disease.
10,32,34
6. Emergency physicians must continue to gather bestavailable evidence based management protocolsfrom other specialty areas.
7. This field needs more original clinical research.
Recognition of chronic pain
8. Expect exaggerated avoidance, emotion, allodyniaand non-dermatomal spread of pain.
35,36
These areNOT signs of malingering.
9. Autonomic manifestations are common and donot guarantee new organic pathology nor drugwithdrawal.
28,37
10. Multiple somatic complaints are common.
4,34
11. Those at risk of developing chronic pain are thosewho are frightened or worried at the outset.
10,31,35
They tend to rate the initial pain as severe
38
theycatastrophize, suppress or try to distract them-selves,
31
and may have a pre-existing depression orother painful condition.
30
12. Behaviour AFTER adequate pain relief best differ-entiates addiction from pseudoaddiction.
2,39
Drug therapies
13. Rescue therapy should be multimodal, usingnarcotics, non-steroidal anti-inflammatory drugs,ketamine (all routes but watch dose), tramadol,paracetamol and local anaesthetics.
16–18,24,29
14. If a longer term change is unavoidable, manipulatethe five first line medications recommended forneuropathic pain. They are additive, side-effectspermitting. They are opioids, tramadol, gabapentin,tricyclic antidepressants and 5% lignocainepatches (not available yet in Australia).
17
15. Carbamazepine is recommended in trigeminalneuralgia.
14
16. Short course oral steroids can be used for chronicregional pain syndromes, if considered safe.
27
17. Vitamin C will do no harm and may assist acuteinjury, specifically Colles fracture.
22
Non-drug therapies
18. Advise against prolonged immobilization
10,32
—early return to altered work duty has the betteroutcome.
10
Exercise should be graded.
29
19. Where available, ensure referral of patient to mul-timodal pain clinic.
25,26
Failing this, utilize individ-ual psychology, psychiatric and physiotherapyservices. Urgent social work referral may provideeducation on correct coping strategies.
20. Minimize stress for the patient, circulating cate-cholamines can stimulate the altered neuroplasticadrenoreceptor expression.
40
21. Tabulation of the patient’s biopsychosocial-precipitant matrix is time-consuming but can reas-sure the patient and reveal further therapeuticopportunities.
10,28,34
22. A care path approach could speed management,with the patient filling out a questionnaire. Theplan should include an information booklet on cop-ing strategies and a follow up letter to the generalpractitioner detailing tests and treatment in the ED.Individualized care plans should be requested fromprimary care giver or pain clinic.
Conclusions
With limited time and resources, recognition of thechronic pain syndrome patient in the ED remains very
Chronic pain management
63
difficult. Many patients are afraid to admit their diag-nosis. The magic ‘Pain-o-meter’ does not yet exist, andpatients know that acute pain receives a far more sym-pathetic reception.
Balanced, detailed recommendations are avail-able,
13,41
yet lacking specificity for the demands,opportunities and limitations of a busy emergencydepartment.
Emergency physicians need to differentiate chronicpain breakthroughs from acute intermittent pain anddrug addiction. Ideally, emergency physicians shouldrecognize those at risk of chronic pain, forestall thesyndrome’s beginnings, and rationally exclude intercur-rent illness. Furthermore, the approach should linkevidence based medicine with the time limitations inemergency practice.
A better understanding of chronic pain, and knowl-edge of current management practices may reduceclinician angst, lead to more consistent, less prejudicialinterventions for patients presenting with chronic painsyndromes to emergency departments. In our modernsociety with high prevalence of chronic pain, furtherwork needs to be undertaken in developing consensusstatements and management guidelines.
Acknowledgements
I would like to thank librarians Ms Elisabeth Cash andMs Lyn Bogaarts for unparalleled search and retrievalservice. Also Drs Nigel Roberts, Stephen Brierley andDuncan Murray for editing suggestions.
This paper has been written with the support of theIpswich General Hospital in the form of study leave,library assistance and use of the information systems.
Competing interests
None declared.
Accepted 20 September 2004
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