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Introduction

  1. Top of page
  2. Introduction
  3. Subjects and Methods
  4. Results
  5. Discussion
  6. References

Juvenile primary fibromyalgia syndrome (JPFS) is a chronic pain disorder of unknown etiology. JPFS occurs primarily among females (similar to the adult syndrome) in the adolescent years and presents as widespread and diffuse musculoskeletal pain and numerous painful tender points upon palpation (1). Other symptoms, such as sleep disturbance, chronic anxiety or tension, fatigue, and abdominal pain, are also often present (2). Based upon studies of adult populations, the American College of Rheumatology (ACR) has published criteria for the classification of fibromyalgia (including widespread pain for at least 3 months and pain upon palpation of at least 11 of 18 tender points) (1). Buskila et al (3, 4) also used the ACR criteria for fibromyalgia in their study of a child and adolescent population and found that 21 (6.2%) of 338 healthy school children fulfilled the criteria. Some authors have argued that a separate set of diagnostic criteria may be necessary for younger populations with fibromyalgia because adolescents may have fewer painful tender points upon palpation. Specifically, it was suggested that a tender point criterion of at least 5 painful tender points should be used for juvenile fibromyalgia (2).

Unfortunately, studies in juvenile fibromyalgia continue to be limited by inconsistent use of criteria and lack of published data on all 18 tender point sites using standardized dolorimetry. The primary objective of this study was to conduct a standardized assessment of tender point count and tender point threshold at all 18 tender point sites in a clinical sample of adolescents with symptoms of juvenile fibromyalgia.

Subjects and Methods

  1. Top of page
  2. Introduction
  3. Subjects and Methods
  4. Results
  5. Discussion
  6. References

The study sample consisted of 22 adolescent females (20 white and 2 African American) from a pediatric rheumatology clinic who met Yunus and Masi's criteria for JPFS (2). These criteria include generalized musculoskeletal aching at 3 or more sites for at least 3 months; 5 or more typical tender points; and the presence of at least 3 other minor criteria such as chronic anxiety or tension, fatigue, poor sleep, chronic headaches, irritable bowel syndrome, subjective soft tissue swelling, numbness, and pain modulation by physical activities, weather factors, and/or anxiety/stress. The mean ± SD age was 15.62 ± 1.33 years (range 13–17 years). Adolescents with any other comorbid rheumatic diseases were not included in the study.

Subject recruitment was conducted in a rheumatology clinic in a tertiary hospital. The rheumatology clinic received referrals from community pediatricians and other subspecialties within the hospital (e.g., gastroenterology, orthopedics). All children and adolescents who met the Yunus and Masi criteria (2) for a classification of fibromyalgia syndrome were considered for the study. After preliminary chart reviews to determine eligibility, subjects' parents were contacted by research staff to request participation. If the parents agreed, they were scheduled for an appointment during which written informed consent from the parents and assent from the adolescent were first obtained. Subjects then underwent a standardized tender point examination and responded to self-report questionnaires assessing overall pain intensity. This study was conducted in accordance with the current guidelines and policies for research and was approved by the hospital institutional review board.

A board certified rheumatologist (SP or TBG) or trained occupational therapist performed the tender point examination in a standardized fashion. The examiners used exactly the same instructions for each subject and used a dolorimeter to ensure equivalence in application of pressure to the tender points. A licensed psychologist (SKZ) administered the measure of overall pain intensity ratings for each subject.

A demographics questionnaire was given to the parent to gather information about age, sex, ethnicity, and parental education. Information about the adolescents' pain duration and current pain medications was also obtained.

The standardized tender point examination was conducted by a rheumatologist or a trained occupational therapist, using a dolorimeter (Pain Diagnostics & Treatment, Great Neck, NY). A maximum of 4 kg/cm2 of pressure was applied (1, 3–5), with pressure increasing at a rate of 1 kg/second (6, 7). Standardized instructions given to each subject were, “I am going to push on your body at 20 places. If you feel pain, not pressure, say ‘now’ and I will stop.” The examiner then demonstrated on himself/herself and began the tender point examination on the subject with 2 control points (right thumbnail and middle of the forehead), followed by the 18 tender points that have been outlined in the ACR criteria: right and left low cervical (at C5-C7); right and left second rib (at costochondral junctions); right and left lateral epicondyle (2 cm distal to the epicondyles); right and left knee (at the medial fat pad proximal to the joint line); right and left occiput (at the suboccipital muscle insertions); right and left trapezius (at the midpoint of the upper border); right and left supraspinatus (above the scapular spine near the medial border); right and left gluteal (upper outer quadrant of buttocks in anterior fold of muscle); and right and left greater trochanter (posterior to the trochanteric prominence). The examiner recorded dolorimeter readings for pain threshold at each tender point site on a body chart (Figure 1) and calculated the total tender point count.

thumbnail image

Figure 1. Average tender point threshold (kg/cm2) at each site (n = 22).

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Pain intensity was assessed using a 10-cm horizontal line with the words “no pain” and “worst imaginable pain” anchored at the 2 ends. The adolescent marked highest, lowest, and average pain in the past 2 weeks on separate visual analog scale (VAS) lines (8–10).

Descriptive data on tender point count, tender point threshold, and pain ratings were first computed. The relationship between tender point data and VAS and pain duration was then examined using Pearson product moment correlations. The power to detect a moderate Pearson correlation coefficient of 0.60 (2-tailed test, α = 0.05) was 0.87.

Results

  1. Top of page
  2. Introduction
  3. Subjects and Methods
  4. Results
  5. Discussion
  6. References

Subjects reported an overall duration of pain symptoms for >1 year, with 63.6% of subjects reporting pain for >2 years. The subjects took an average of 2.05 pain medications (90.9% were taking nonsteroidal antiinflammatory medications, 9% took analgesic medication, and 59.1% were taking antidepressant medication [64.3% taking selective serotonin reuptake inhibitors, 21.4% taking low-dose tricyclic antidepressants, and 14.3% taking other antidepressants such as venlafaxine and bupropion]). Subjects were not involved in any other forms of therapy at the time of assessment. Moderately high levels of average pain intensity were reported (mean ± SD VAS rating 5.39 ± 1.54) (Table 1).

Table 1. Tender point count, tender point threshold, and pain intensity ratings in 22 patients with juvenile primary fibromyalgia syndrome*
AssessmentRangeMean ± SD
  • *

    VAS = visual analog scale.

Tender point count(0–18)15.52 ± 2.62
Tender point threshold, kg/cm2(0–4)2.58 ± 0.41
Lowest VAS, cm(0–10)2.68 ± 1.79
Average VAS, cm(0–10)5.39 ± 1.54
Highest VAS, cm(0–10)7.93 ± 1.32

Subjects had a mean ± SD tender point count of 15.52 ± 2.62 out of 18 tender points. The mean ± SD tender point threshold was 2.58 ± 0.41 kg/cm2 (see Figure 1 for mean tender point threshold at each site). It should be noted that the tender point sites in the Yunus and Masi criteria include essentially the same tender point sites outlined in the ACR criteria but also include other sites on the body that have shown a high frequency of tenderness in individuals with fibromyalgia. This study assessed only the ACR tender point sites.

Correlations between tender point count and threshold and VAS were not significant (r = 0.08, P = 0.74 and r = −0.16, P = 0.48, respectively). Correlations between tender point count and threshold and pain duration were also not significant (r = −0.19, P = 0.41, and r = 0.13, P = 0.56, respectively).

Discussion

  1. Top of page
  2. Introduction
  3. Subjects and Methods
  4. Results
  5. Discussion
  6. References

This is the first study to report the results of a standardized tender point assessment using dolorimetry in a clinical sample of juvenile fibromyalgia patients. These results provide important information that can be used in clinical research with JPFS samples and allow for comparisons with adult studies in fibromyalgia syndrome. Our results showed that tender point threshold in this clinical sample (mean 2.58 kg/cm2) is similar to that of a community sample (mean 2.5 kg) (3). However, the number of tender points was greater in our study than in that of Buskila et al (mean 15.52 versus 12.5) (4) suggesting that children and adolescents who present to a tertiary care center may have more severe symptoms than community samples. The greater number of tender points was found despite the fact that all of the subjects were taking medication at the time of tender point assessment. As compared with findings in adults with fibromyalgia, it appears that overall tender point threshold might be lower in juvenile fibromyalgia. In a study by Simms et al (7), 10 adults with fibromyalgia underwent tender point assessments using dolorimetry. The tender point threshold on nearly all respective tender points in that adult sample was higher as compared with the juvenile fibromyalgia sample in this study.

Another finding in this study was that subjects who were eligible for the study based upon Yunus and Masi's suggested criteria for juvenile fibromyalgia (which require at least 5 tender points) had an average of 15.52 of 18 tender points, thereby fulfilling the ACR criteria of 11 of 18 tender points. Although the ACR specifies manual palpation in their criteria, our study indicated that a standardized application of up to 4 kg/cm2 (which is often not practiced consistently with manual palpation, especially with pediatric patients) leads to identification of a greater number of tender points than might otherwise be found. Use of the established ACR criteria for children and adolescents would allow better comparison of research studies and equivalence of entry criteria and outcomes in intervention trials.

Limitations of this study included a relatively small sample size. In addition, this sample was a clinical sample in a tertiary setting, and caution is recommended in generalizing these results to all adolescents with fibromyalgia. Detailed documentation of all the major and minor Yunus and Masi criteria was not done because the primary focus of the study was to assess tender point data. Therefore, examination of differences between subjects on these additional criteria could not be assessed. Finally, all of the subjects were taking medications at the time of tender point assessment, which could have had some impact on the data.

Suggestions for future research include focusing on assessing the effects of different interventions (i.e., pharmacologic and nonpharmacologic therapies) on tender point assessment. In addition, future research should explore the relationship between emotional distress and tender point sensitivity to better understand the complex psychophysiologic relationship between emotional variables and pain in fibromyalgia.

References

  1. Top of page
  2. Introduction
  3. Subjects and Methods
  4. Results
  5. Discussion
  6. References
  • 1
    Wolfe F, Smythe HA, Yunus MB, Bennett RM, Bombardier C, Goldenberg DL, et al. The American College of Rheumatology 1990 criteria for the classification of fibromyalgia: report of the Multicenter Criteria Committee. Arthritis Rheum 1990; 33: 16072.
  • 2
    Yunus MB, Masi AT. Juvenile primary fibromyalgia syndrome: a clinical study of thirty-three patients and matched normal controls. Arthritis Rheum 1985; 28: 13845.
  • 3
    Buskila D, Press J, Gedalia A, Klein M, Neumann L, Boehm R, et al. Assessment of nonarticular tenderness and prevalence of fibromyalgia in children. J Rheumatol 1993; 20: 36870.
  • 4
    Buskila D, Neumann L, Hershman E, Gedalia A, Press J, Sukenik S. Fibromyalgia syndrome in children: an outcome study. J Rheumatol 1995; 22: 5258.
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  • 7
    Simms RW, Goldenberg DL, Felson DT, Mason JH. Tenderness in 75 anatomic sites: distinguishing fibromyalgia patients from controls. Arthritis Rheum 1988; 31: 1827.
  • 8
    Rosenberg BR, Degotardi PJ, Klass ES, Fox DG, Zemon V, Gottlieb BS. Cognitive behavioral treatment of juvenile primary fibromyalgia syndrome [abstract]. Arthritis Rheum 2002; 46 Suppl: S216.
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    Schanberg LE, Keefe FJ, Lefebvre JC, Kredich DW, Gil KM. Pain coping strategies in children with juvenile primary fibromyalgia syndrome: correlation with pain, physical function, and psychological distress. Arthritis Care Res 1996; 9: 8996.
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    Walco GA, Ilowite NT. Cognitive-behavioral intervention for junvenile primary fibromyalgia syndrome. J Rheumatol 1992; 19: 16179.