Differences in Pressure-Pain Threshold Between Healthy Women and Patients with Fibromyalgia Syndrome, Systemic Lupus Erythematosus, and Rheumatoid Arthritis

Abstract

Objectives: The objective of this study was to assess potential differences in the pressure-pain threshold [PPT] between persons without pain and patients with systemic lupus erythematosus [SLE], fibromyalgia syndrome [FMS], and rheumatoid arthritis [RA], and to establish whether these differences depended on the type or location of pressure point evaluated or on the time of the assessment.

Methods: Sixty-five voluntary women were assigned to a control [no pain] group [n = 18], SLE group [n = 16], FMS group [n = 16], or RA group [n = 15]. The PPT was assessed using a portable electronic dolorimeter in three assessment sessions spaced 15 min and seven days from the first, respectively. Each session consisted of two consecutive trials in which 24 bilaterally located pressure points [18 tender points and six control points] were assessed.

Results: Results showed significantly lower PPT in patients compared with healthy women [p < 0.001]. No differences were found between the pathologies included in the study, although patients showed different PPT values. However, different patterns of evolution of PPT appeared over the course of assessment. Patients suffering from FMS showed the lowest PPT and the lowest stability in the PPT pattern, followed by RA patients.

Conclusions: Patients suffering from three different pain pathologies show different PPTs, which are lower than healthy subjects' PPTs. Mechanisms that may explain differences in PPT values and evolution are discussed.

KEYWORDS:

• Pain
• musculoskeletal disorders
• pressure-pain threshold
• algometry
• dolorimeter