Sifting the wheat from the chaff? Evidence for the existence of an asymmetric fibromyalgia phenotype. (1st July 2020)

• Record Type: Journal Article
• Authors: H. Kaziyama, Helena; Barbour, Julio; Galhardoni, Ricardo; Aparecida da Silva, Valquíria; R. D. Tesseroli de Siqueira, Silvia; Listik, Clarice; dos Santos, Gabriel José; Yeng, Lin T.; Marcolin, Marco Antonio; Raicher, Irina; Teixeira, Manoel J.; Ciampi de Andrade, Daniel
• Is Part Of: European journal of pain. Volume 24:Number 8(2020)
• Page Start: 1635
• Page End: 1647
• Publication Date: 2020-07-01
• Subjects: Pain -- Periodicals; Pain -- Treatment -- Periodicals; Pain -- Physiological aspects -- Periodicals; 616.0472
• DOI: 10.1002/ejp.1620
• Languages: English
• ISSNs: 1090-3801

Abstract

Abstract: Background: The different phenotypic presentations of fibromyalgia (FM) have been infrequently studied and may have diagnostic and therapeutic implications. The aim of this study was to explore differences between FM patients with classical symmetric (s‐FM) presentation and FM patients with marked asymmetric (a‐FM) pain. Methods: We performed two consecutive cross‐sectional studies on FM patients and matched healthy volunteers (HV). FM patients were divided into a‐FM (and s‐FM groups according to their score of pain intensity on each body side; patients with a difference of ≥40 mm in VAS between left and right sides were classified as a‐FM, otherwise classified as s‐FM. Participants (FM = 32; HV = 31) were assessed for clinical, cortical excitability (CE), quantitative sensory testing (QST; study 1), and intraepidermal nerve fibre density (IENFD) determinations (study 2). Results: While pain intensity did not significantly differ between s‐FM and a‐FM patients, pain interference in daily activities was significantly higher in the a‐FM as compared to the s‐FM group (54.7 ± 8.9 and 37.6 ± 13.5; p < .0001). PPT was significantly lower in the more painful side of a‐FM as compared to the HV (27.7 ± 7.9 and 49.9 ± 13.0; p < .0001), while PPT in the less painful side of a‐FM was significantly higher than PPT values in the s‐FM (35.8 ± 8.3 and 27.7 ± 5.5; p = .031). S‐FM and a‐FM had significantly abnormal intracortical inhibition values on CE measurements compared to HV. There were no significant differences in IENFD between groups. Conclusions: Within the current FM criteria, there exist different phenotypes with clinical, psychophysics, and neurophysiological findings that are not related to peripheral IENFD abnormalities. Significance: Current fibromyalgia criteria may contain different phenotypes of fibromyalgia based on the lateralization of pain.