Chronic Myofascial Pain

A Patient-Centered Approach

Caroline Ashley, Aileen Currie

• Publisher: CRC Press
• Year: 2018
• Print ISBN: 9781138448148
• eBook ISBN: 9781315344324
• Topic: Medicine
• Subtopic: Medical Theory, Practice & Reference

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1

The magnitude of the problem

Dag Bruusgaard and Søren Brage

Mrs Judith Smith, aged 55, has for the last 15 years been suffering from steadily increasing pain in her chest and shoulders. In recent years, her feet have also been terrible after a long day at work. She has taken painkillers for periods of time, but never finds any long-term relief from medication. The last few months, Judith Smith has felt exhausted with no energy whatsoever, but still kept on doing her work at the hospital laundry, where she has worked for the last 19 years. She has problems falling asleep, and during the night she is not able to get a good rest. She dreams a lot and wakes up with her head filled with worries and pain. Although her heart sometimes gives her palpitations, she does not really believe that the chest pain comes from her heart. However, her mother died from a heart attack, so she is somewhat concerned. She feels that strain at work and at home increases her muscular tension, but she is not able to change her situation and relieve her symptoms.

Yesterday, Judith Smith received a 20-page questionnaire from a research group, who knew that she had been sick-listed within the last year due to pain problems. She is puzzled about what to answer, when the researchers instruct her to choose between boxes of respectively widespread or localized pain. Actually, the pain is just all over, although it may differ from day to day. She also wonders whether she should agree to the suggestion that this is a chronic condition, because she desperately hopes that sooner or later she will get rid of her problems.

The problem

Symptoms from the musculoskeletal system are reasons for reduced quality of life for a substantial part of the population. They represent a great burden to society because of reduced working capacity, sick leave and disability pensions, and they are problematic for the healthcare system as a result of insufficient means to prevent and treat the conditions.

The concept of chronic myofascial pain

There is a confusing magnitude of names given to musculoskeletal pain complaints, reflecting diverging opinions and a lack of consensus on what it is all about. The International Classification of Diseases, latest edition (ICD10), illustrates the problem of classifying unspecific and widespread musculoskeletal complaints (Box 1.1). They are situated in two different chapters.

Under Chapter M, ‘Diseases of the musculoskeletal system and connective tissue’, we have to go down to M79, ‘Other soft-tissue disorders, not elsewhere classified, excluding: soft-tissue pain, psychogenic (F 45.4)’. Here we will find M79.0, ‘Rheumatism, unspecified’, which includes fibromyalgia and fibro-sitis. Chronic widespread muscle-pain syndromes should be included under this chapter, although not stated explicitly. Otherwise, if the musculoskeletal origin is questioned, generalized pain might be registered under Chapter R, ‘Symptoms, signs and abnormal clinical or laboratory findings, not elsewhere classified’. Under R52, ‘Pain, not elsewhere classified’ we find R52.9, ‘Pain unspecified, including generalized pain, not otherwise specified’ at the very end of the pain section.

The ICD chapter on diseases of the musculoskeletal system and connective tissue does not include injuries, tumors and malformations; however, these conditions are included in the chapter on musculoskeletal health problems in the International Classification for Primary Health Care (ICPC).

Box 1.1 International classification of diseases ICD 10

• Chapter M: Diseases of the musculoskeletal system and connective tissue
  • – M79 Other soft tissue disorders, not elsewhere classified, excluding soft tissue pain, psychogenic (F 45.4)
  • – M79.0 Rheumatism, unspecified
• Chapter R: Symptoms, signs and abnormal clinical or laboratory findings, not elsewhere classified
  • – R52 Pain, not elsewhere classified
  • – R52.9 Pain unspecified, including generalized pain, not otherwise specified

The International Association for the Study of Pain (IASP) suggests in the second edition from 1994 (Merskey and Bogduk, 1994) a detailed classification of chronic pain with five axes based on region, system, temporal characteristics, intensity and etiology. According to their definitions, fibromyalgia is classified as a ‘relatively generalized syndrome’ in the musculoskeletal system. They make a note to distinguish fibromyalgia from chronic myofascial pain (CMP) because they consider that the concept of myofascial pain syndromes also might include localized muscular pain. They also include what they call ‘Pain of psychological origin’, subdivided into:

• muscle tension
• delusional or hallucinatory
• hysterical, conversion, or hypochondriacal
• associated with depression.

IASP, in its focusing on pain, does not include chronic widespread pain (CWP) as a condition reaching further than fibromyalgia. Overall, the contribution from ICD and IASP to the classification and understanding of the CMP syndromes is limited. For the purpose of this chapter, a possible simple classification, focusing on the musculoskeletal system, could be:

• strain-related musculoskeletal complaints, including soft-tissue rheumatism, both localized as tendinitis and myalgia, and widespread as CMP and fibromyalgia
• inflammatory musculoskeletal complaints, including rheumatoid arthritis and ankylosing spondylitis (AS)
• degenerative musculoskeletal complaints, including osteoporosis and osteoarthritis
• other musculoskeletal complaints, including injuries, deformities, infections and tumors.

One problem with this grouping is where to put the chronic low back pain conditions. They are often considered strain related, but, on x-ray, have at the same time frequently degenerative signs. Textbooks include mostly the latter three categories, while the first one affects the greatest number of persons. In this chapter, we will focus on this first category, on what we have called the strain-related conditions, in particular CWP.

Chronic widespread pain includes fibromyalgia, but reaches further than the fibromyalgia concept. We will use the American College of Rheumatology’s (ACR) definition of fibromyalgia (Wolfe etal., 1990), if not stated explicitly otherwise. This definition is based on three dimensions:

• duration (at least three months)
• localization (widespread; that is, axial pain, pain on the left and right side, and pain above and below the waist)
• tender points (pain at 11 or more out of 18 specified anatomical locations).

Although the ACR definition is widely accepted and used, there is still a great controversy about the fibromyalgia concept. Some still claim that it is a distinct clinical entity with specific causes needing specific treatment, whilst others, including IASP, consider fibromyalgia at one extreme of a continuous spectrum of distress and pain, starting with localized complaints of short duration, and ending with chronic widespread complaints.

There is no commonly accepted definition of CMP. One solution to the lack of definition is to use the ACR definition without the tender-point criterion. A group in Manchester, UK, has suggested an alternative definition of widespread pain, hereafter referred to as CWP(M). For subjects to satisfy the definition, pain must be reported in at least two sections in each of two contralateral limbs and in the axial skeleton. CMP is first and foremost an epidemiological term, reflecting self-reported, long-lasting, widespread complaints of suspected muscular origin, while fibromyalgia is a term based on a clinical examination. In this chapter, we will use CMP synonymously with CWP.

The prevalence of musculoskeletal complaints

Musculoskeletal complaints are frequent in the population. Earlier studies focused primarily on localized pain as low back pain or shoulder/neck pain, often in association with working conditions. When Yunus introduced criteria for the diagnosis of fibromyalgia (Yunus et al, 1989), it opened a new area with focus also on widespread pain, a tendency supported by the ACR criteria. Such conditions are often called ‘diffuse’, in English often related to something that is spread, scattered and widespread as opposed to localized. In Norwegian ‘diffuse’ usually gives associations to something foggy or contourless, not to be grasped, clearly seen or even taken seriously.

Adults

A sample of the adult population in a Norwegian municipality received a mailed questionnaire, including the extensively used Nordic form on musculoskeletal complaints. 85.1% of 2361 responders reported pain or discomfort from at least one region of the body during the last 12 months (Natvig et al. 1994). Of the 10 regions marked on a body mannequin, low back (total 52.9%, female 54.7%, male 50.7%), head (total 48.9%, female 60.5%, male 36.3%), neck (total 47.9%, female 57.6%, male 37.3%), and shoulder (total 46.8%, female 56.2%, male 36.5%) were most frequently checked off.

15.3% of the 2361 responders reported daily symptoms during the whole year. Daily symptoms increased with age, and were more common among women than men. In women, the fraction reporting daily symptoms increased from 7.7% in the 20–22 year-old group, to a maximum of 30.9% in the 60–62 year-old group; the corresponding figures for men were 4.9% and 20.8%.

Persons reporting low back pain as part of widespread pain were more often women, had more chronic complaints, reported in general more discomfort and more functional limitations compared to the ones reporting low back pain as their only musculoskeletal complaint.

A population study in the UK found a crude prevalence of CWP to be 15.6% among women and 9.4% among men, using the ACR criteria for social prevelance of symptoms (Croft et al., 1993). In contrast to most other studies, a study using the Manchester criteria did not find a statistically significant gender difference (5.3% among women and 3.7% among men) (Macfarlane et al., 1996).

In a study of the population aged 40–42 in a Norwegian county, 7127 persons responded (62% response rate). During the preceding year, 73.8% of the women and 62.4% of the men reported musculoskeletal complaints, with an increasing gender gap the more chronic and widespread the complaints. 32.6% and 23.6% reported chronic pain (lasting for at least three months), 13.5% and 4.7% reported CWP (affecting at least five out of nine regions, bilateral counting as one), 3.0% and 0.1% respectively claimed to have the diagnosis of fibromyalgia, giving sex ratio of 1.18, 1.38, 2.87 and 30.0 respectively (Aarflot and Bruusgaard, 1994).

Some studies have found female prevalence of CWP as high as 20% (Macfarlane, 1999). The prevalence of CWP has thus varied substantially according to what definition has been used. In contrast to CWP where criteria are lacking, the ACR criteria for fibromyalgia have been internationally accepted. The ACR criteria have been used in several surveys that have included clinical examinations. Prevalence rates from 2% to 13% among women have been reported. The great variation in prevalence of fibromyalgia reflects methodological difficulties rather than real differences in prevalence of the conditions. Different interpretations of the tender-point criterion could partly explain the variation.

One general conclusion from all these studies is that the majority of subjects with chronic widespread musculoskeletal pain do not meet the present fibromyalgia criteria.

Children

All schoolchildren in a local community aged 10, 13 and 15 were given questionnaires to be filled in during an ordinary school session (Smedbråten et al., 1998). 569 children answered (86.5% of all the pupils in the three age groups). They were asked if they usually felt pain anywhere in the body, regardless of location. Further, they were asked to register the pain on a map of the body. Here, 12 regions were marked and named, making no attempt to distinguish pain from the locomotor system from other types of pain.

73% answered ‘yes’ to the question of usually feeling pain, 82% of the girls and 64% of the boys. Knee, head and back were the regions most frequently reported. The number of regions reported was highest among girls, where it also increased with age. Among the ones reporting pain, 27% of the girls and 24% of the boys said they sometimes used medication for the symptoms.

Several studies among children, most of them from Scandinavia, showed the same high prevalence of the reporting of bodily pain (Kristjansdottir 1997; Mikkelsson et al, 1997). One study from Israel found a high number of children meeting the ACR criteria for fibromyalgia, although the symptoms and signs varied more over time than what was usually seen in adult fibromyalgia patients (Buskila et al., 1995).

Associated symptoms

Musculoskeletal pain has long been associated with other signs and symptoms, and Yunus required the existence of so-called minor criteria for the diagnosis of fibromyalgia (Yunus et al, 1989). These features were fatigue, poor sleep, anxiety/depression, irritable bowel syndrome, headache, swelling in fingers or...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Contents
• Series editors’ introduction
• About the authors
• Introduction
• 1 The magnitude of the problem
• 3 The illness experience
• 4 Understanding the whole person
• 5 The patient-clinician relationship
• 6 Management of chronic myofascial pain: finding common ground
• 7 The challenges of chronic myofascial pain: commitment to patient perspectives
• Index