Milton Cohen

A classification of chronic pain for ICD-11

Chronic pain has been recognized as pain that persists past normal healing time5 and hence lacks the acute warning function of physiological nociception.35 Usually pain is regarded as chronic when it lasts or recurs for more than 3 to 6 months.29 Chronic pain is a frequent condition, affecting an estimated 20% of people worldwide6,13,14,18 and accounting for 15% to 20% of physician visits.25,28 Chronic pain should receive greater attention as a global health priority because adequate pain treatment is a human right, and it is the duty of any health care system to provide it.4,13 The current version of the International Classification of Diseases (ICD) of the World Health Organization (WHO) includes some diagnostic codes for chronic pain conditions, but these diagnoses do not reflect the actual epidemiology of chronic pain, nor are they categorized in a systematic manner. The ICD is the preeminent tool for coding diagnoses and documenting investigations or therapeutic measures within the health care systems of many countries. In addition, ICD codes are commonly used to report target diseases and comorbidities of participants in clinical research. Consequently, the current lack of adequate coding in the ICD makes the acquisition of accurate epidemiological data related to chronic pain difficult, prevents adequate billing for health care expenses related to pain treatment, and hinders the development and implementation of new therapies.10,11,16,23,27,31,37 Responding to these shortcomings, the International Association for the Study of Pain (IASP) contacted the WHO and established a Task Force for the Classification of Chronic Pain. The IASP Task Force, which comprises pain experts from across the globe,19 has developed a new and pragmatic classification of chronic pain for the upcoming 11th revision of the ICD. The goal is to create a classification system that is applicable in primary care and in clinical settings for specialized pain management. A major challenge in this process was finding a rational principle of classification that suits the different types of chronic pain and fits into the general ICD-11 framework. Pain categories are variably defined based on the perceived location (headache), etiology (cancer pain), or the primarily affected anatomical system (neuropathic pain). Some diagnoses of pain defy these classification principles (fibromyalgia). This problem is not unique to the classification of pain, but exists throughout the ICD. The IASP Task Force decided to give first priority to pain etiology, followed by underlying pathophysiological mechanisms, and finally the body site. Developing this multilayered classification was greatly facilitated by a novel principle of assigning diagnostic codes in ICD-11, termed “multiple parenting.” Multiple parenting allows the same diagnosis to be subsumed under more than 1 category (for a glossary of ICD terms refer to Table ​Table1).1). Each diagnosis retains 1 category as primary parent, but is cross-referenced to other categories that function as secondary parents. Table 1 Glossary of ICD-11 terms. The new ICD category for “Chronic Pain” comprises the most common clinically relevant disorders. These disorders were divided into 7 groups (Fig. ​(Fig.1):1): (1) chronic primary pain, (2) chronic cancer pain, (3) chronic posttraumatic and postsurgical pain, (4) chronic neuropathic pain, (5) chronic headache and orofacial pain, (6) chronic visceral pain, and (7) chronic musculoskeletal pain. Experts assigned to each group are responsible for the definition of diagnostic criteria and the selection of the diagnoses to be included under these subcategories of chronic pain. Thanks to Bedirhan Ustun and Robert Jakob of the WHO, these pain diagnoses are now integrated in the beta version of ICD-11 (http://id.who.int/icd/entity/1581976053). The Task Force is generating content models for single entities to describe their clinical characteristics. After peer review overseen by the WHO Steering Committee,39 the classification of chronic pain will be voted into action by the World Health Assembly in 2017. Figure 1 Organizational chart of Task Force, IASP, and WHO interactions. The IASP Task Force was created by the IASP council and its scope defined in direct consultation of the chairs (R.D.T. and W.R.) with WHO representatives in 2012. The Task Force reports to ... 2. Classification of chronic pain Chronic pain was defined as persistent or recurrent pain lasting longer than 3 months. This definition according to pain duration has the advantage that it is clear and operationalized. Optional specifiers for each diagnosis record evidence of psychosocial factors and the severity of the pain. Pain severity can be graded based on pain intensity, pain-related distress, and functional impairment. 2.1. Chronic primary pain Chronic primary pain is pain in 1 or more anatomic regions that persists or recurs for longer than 3 months and is associated with significant emotional distress or significant functional disability (interference with activities of daily life and participation in social roles) and that cannot be better explained by another chronic pain condition. This is a new phenomenological definition, created because the etiology is unknown for many forms of chronic pain. Common conditions such as, eg, back pain that is neither identified as musculoskeletal or neuropathic pain, chronic widespread pain, fibromyalgia, and irritable bowel syndrome will be found in this section and biological findings contributing to the pain problem may or may not be present. The term “primary pain” was chosen in close liaison with the ICD-11 revision committee, who felt this was the most widely acceptable term, in particular, from a nonspecialist perspective.

Effects of low dose corticosteroids on bone mass in rheumatoid arthritis: a longitudinal study.

Low dose corticosteroids are effective in suppressing synovitis in rheumatoid arthritis (RA), but there remains concern about their side effects, particularly osteoporosis. To examine the effects of low dose corticosteroids on bone loss in RA bone mineral density (BMD) was measured in the lumbar spine and hip for up to two years in 15 patients treated with these agents (mean dose prednis(ol)one 6.6 mg/day). 15 patients not receiving them, and 15 age matched controls. The initial BMD at both skeletal sites was significantly reduced in both patient groups compared with controls. The mean change in bone density was 0.2, 0.1, and -0.1% a year in the spine and -2.0, -1.9, and -1.0% a year in the hip respectively for the three groups. These rates of bone loss were not significantly different between groups at either site. These findings suggest that low dose corticosteroid treatment in RA is not associated with an increased risk of osteoporosis.

Psychophysical evidence for a neuropathic component of chronic neck pain

&NA; Recent studies into the common complaint of chronic neck pain have focused on its anatomical origin, identifying especially the cervical zygapophysial joints. However the pathophysiology of chronic neck pain remains poorly understood. In this psychophysical study, responses to electrocutaneous stimulation in subjects with chronic neck pain were examined. In an ascending method of limits design, electrical stimuli at 100 Hz with variation in current from 0 to 45 mA and in pulse width from 100 to 1000 &mgr;s were delivered transcutaneously to two points 2 cm from the midline bilaterally at the levels of C5/6 and C7/T1 in 35 subjects with chronic neck pain and 22 pain‐free volunteers. There was a small difference in detection threshold between the two groups; both pain threshold and pain tolerance were significantly lower in the pain group compared with pain free controls. These findings define hyperalgesia psychophysically and, taken together with the absence of tissue damage at the sites of testing, suggest that these painful cervical regions may be examples of secondary hyperalgesia which, in turn, implies central sensitisation of nociceptive pathways. These results are compatible with studies which identify potential anatomical origins of chronic neck pain but provide evidence that central sensitisation may be the relevant mechanism of pain production.

Referred pain of peripheral nerve origin: an alternative to the "myofascial pain" construct.

The theory of myofascial pain syndrome (MPS) has been constructed around the trigger point (TrP), a region within a muscle from which local and remote pain can be evoked by palpation. Although their pathophysiology is obscure, TrPs have been regarded as the cause of myofascial pain. Spread and chronicity of pain are attributed to the activation of latent, secondary, and satellite TrPs. Although it lacks internal validity, this tautological concept has given rise to a system of empirical treatment that has been uncritically accepted by many. However, not only does the anatomical distribution of pain referred from TrPs bear a close relationship to the course of peripheral nerves, but the pain of MPS is also similar to nerve trunk pain, which is an example of somatic referred pain. Pain of peripheral nerve origin can be present without neurological deficit and with normal findings on conventional electrodiagnostic examination. In contrast to the theory of MPS, which considers the TrPs to be sites of primary hyperalgesia, this article argues that all MPS phenomena are better explained as secondary hyperalgesia of peripheral neural origin.

The Pain and Opioids IN Treatment study: characteristics of a cohort using opioids to manage chronic non-cancer pain

Abstract There has been a recent increase in public and professional concern about the prescription of strong prescription opioids for pain. Despite this concern, research to date has been limited because of a number of factors such as small sample sizes, exclusion of people with complex comorbidities, and studies of short duration. The Pain and Opioids IN Treatment is a 2-year prospective cohort study of 1500 people prescribed with pharmaceutical opioids for their chronic pain. This article provides an overview of the demographic and clinical characteristics of the cohort using the baseline data of 1514 community-based people across Australia. Participants had been in pain for a period of 10 years and had been on prescription opioids for approximately 4 years. One in 10 was on a daily morphine equivalent dose of ≥200 mg. Employment and income levels were low, and two-thirds of the sample reported that their pain had impacted on their employment status. Approximately 50% screened positive for current moderate-to-severe depression, and 1 in 5 had made a lifetime suicide attempt. There were a number of age-related differences. The younger groups experienced higher levels of pain and pain interference, more mental health and substance use issues, and barriers to treatment, compared with the older group. This study found that the people who have been prescribed strong opioids for chronic pain have very complex demographic and clinical profiles. Major age-related differences in the experiences of pain, coping, mental health, and substance use suggest the necessity of differential approaches to treatment.

A critical evaluation of the trigger point phenomenon

The theory of myofascial pain syndrome (MPS) caused by trigger points (TrPs) seeks to explain the phenomena of muscle pain and tenderness in the absence of evidence for local nociception. Although it lacks external validity, many practitioners have uncritically accepted the diagnosis of MPS and its system of treatment. Furthermore, rheumatologists have implicated TrPs in the pathogenesis of chronic widespread pain (FM syndrome). We have critically examined the evidence for the existence of myofascial TrPs as putative pathological entities and for the vicious cycles that are said to maintain them. We find that both are inventions that have no scientific basis, whether from experimental approaches that interrogate the suspect tissue or empirical approaches that assess the outcome of treatments predicated on presumed pathology. Therefore, the theory of MPS caused by TrPs has been refuted. This is not to deny the existence of the clinical phenomena themselves, for which scientifically sound and logically plausible explanations based on known neurophysiological phenomena can be advanced.

Improvement of yellow nail syndrome with oral zinc supplementation

An unusual case of yellow nail syndrome (YNS) is reported. Total resolution of yellow nails and lymphoedema was observed following oral zinc supplementation for 2 years. A few years later, the patient developed a classical seropositive rheumatoid arthritis (RA). YNS, alone or associated with RA remains a rare clinical condition. The reported beneficial effects of zinc supplementation in YNS, as well as in several other pathological conditions, raise interest about the role of this trace element and its potential therapeutic implications and suggest further investigations are necessary.

Management of acute whiplash: A randomized controlled trial of multidisciplinary stratified treatments

Summary This randomised trial showed that multiprofessional stratified management had no effect beyond usual care in reducing transition rates to chronicity in patients with acute whiplash. ABSTRACT Acute whiplash is a heterogeneous disorder that becomes persistent in 40% to 60% of cases. Estimates of recovery have not changed in recent decades. This randomized, single‐blind, controlled trial tested whether multidisciplinary individualized treatments for patients with acute whiplash (<4 weeks postinjury) could reduce the incidence of chronicity at 6 mo by 50% compared to usual care. Participants (n = 101) were recruited from accident and emergency centres and the community. It was hypothesized that better recovery rates were achievable if the heterogeneity was recognised and patients received individualised interventions. Patients randomized to pragmatic intervention (n = 49) could receive pharmaceutical management (ranging from simple medications to opioid analgesia), multimodal physiotherapy and psychology for post‐traumatic stress according to their presentations. The treatment period was 10 wks with follow‐up at 11 weeks and 6 and 12‐months. The primary outcome was neck pain and disability (Neck Disability Index (NDI)). Analysis revealed no significant differences in frequency of recovery (NDI ≤8%) between pragmatic and usual care groups at 6 months (OR 95%, CI = 0.55, 0.23–1.29), P = 0.163) or 12 mo (OR 95%, CI = 0.65, 0.28–1.47, P = 0.297). There was no improvement in current nonrecovery rates at 6 mo (63.6%, pragmatic care; 48.8%, usual care), indicating no advantage of the early multiprofessional intervention. Baseline levels of pain and disability had a significant bearing on recovery both at 6 and 12 mo in both groups, suggesting that future research focus on finding early effective pain management, particularly for the subgroup of patients with initial high levels of pain and disability, towards improving recovery rates.

Experience of adjunctive cannabis use for chronic non-cancer pain: Findings from the Pain and Opioids IN Treatment (POINT) study

BACKGROUND There is increasing debate about cannabis use for medical purposes, including for symptomatic treatment of chronic pain. We investigated patterns and correlates of cannabis use in a large community sample of people who had been prescribed opioids for chronic non-cancer pain. METHODS The POINT study included 1514 people in Australia who had been prescribed pharmaceutical opioids for chronic non-cancer pain. Data on cannabis use, ICD-10 cannabis use disorder and cannabis use for pain were collected. We explored associations between demographic, pain and other patient characteristics and cannabis use for pain. RESULTS One in six (16%) had used cannabis for pain relief, 6% in the previous month. A quarter reported that they would use it for pain relief if they had access. Those using cannabis for pain on average were younger, reported greater pain severity, greater interference from and poorer coping with pain, and more days out of role in the past year. They had been prescribed opioids for longer, were on higher opioid doses, and were more likely to be non-adherent with their opioid use. Those using cannabis for pain had higher pain interference after controlling for reported pain severity. Almost half (43%) of the sample had ever used cannabis for recreational purposes, and 12% of the entire cohort met criteria for an ICD-10 cannabis use disorder. CONCLUSIONS Cannabis use for pain relief purposes appears common among people living with chronic non-cancer pain, and users report greater pain relief in combination with opioids than when opioids are used alone.

Pharmaceutical Opioid Use and Dependence among People Living with Chronic Pain: Associations Observed within the Pain and Opioids in Treatment (POINT) Cohort

OBJECTIVE There is increasing concern about the appropriateness of prescribing pharmaceutical opioids for chronic non-cancer pain (CNCP), given the risks of problematic use and dependence. This article examines pharmaceutical opioid dose and dependence and examines the correlates of each. DESIGN Baseline data were obtained from a national sample of 1,424 people across Australia (median 58 years, 55% female and experiencing pain for a median of 10 years), who had been prescribed opioids for CNCP. Current opioid consumption was estimated in oral morphine equivalent (OME; mg per day), and ICD-10 pharmaceutical opioid dependence was assessed using the Composite International Diagnostic Interview. RESULTS Current opioid consumption varied widely: 8.8% were taking <20 mg OME per day, 52.1% were taking 21-90 mg OME, 24.3% were taking 91-199 mg OME, and 14.8% were taking >= 200 mg OME. Greater daily OME consumption was associated with higher odds of multiple physical and mental health issues, aberrant opioid use, problems associated with opioid medication and opioid dependence. A significant minority, 8.5%, met criteria for lifetime ICD-10 pharmaceutical opioid dependence and 4.7% met criteria for past year ICD-10 pharmaceutical opioid dependence. Multivariate analysis found past-year dependence was independently associated with being younger, exhibiting more aberrant behaviors and having a history of benzodiazepine dependence. CONCLUSIONS In this population of people taking opioids for CNCP, consumption of higher doses was associated with increased risk of problematic behaviors, and was more likely among people with a complex profile of physical and mental health problems.