Background/Purpose: Fibromyalgia is a diffuse chronic painful disease, with prevalence of 0.5% -12%, with a female:male ratio 3:10. Because of unexplained symptoms, particularly as disability pain, the primary differential diagnosis is inflammatory arthritis. Few studies have evaluated whether digital thermography can differentiate primary from secondary fibromyalgia with arthritis.

Our primary objective was identification of joint inflammation in patients with primary fibromyalgia; secondary objective, to correlate ultrasound findings hand with digital thermography, besides joint exploration of hands.

Methods: Methods: We selected patients with primary FM (Criteria ACR 2016) from January-April 2019. We  did a clinical, termographic and ultrasound evaluation of the carpal, metacarpophalangeal and proximal interphalangeal joints. The clinical evaluation was made by 2 blinded rheumatologists. For the thermographic evaluation we used a digital photograph of hands at 50 cm perpendicular distance with a thermal camera Flir-One -Pro; for the analysis, the software included in the thermography equipment was used; through the thermal delta of the average temperature of the hand with respect to the joints (we considered an inflamed joint with an increase of > 0.5 ° C). Finally, we did an articular ultrasound of 22 hand joints.

Results: Results: we included 22 patients with primary FM, of whom 3 showed inflammatory changes by thermography, the median age of these patients was 54 years (IQR 7.5) and median of BMI 23.1 (IQR 1.9). All patients had negative rheumatoid factor and anti-CCP, median erythrosedimentation rate 34 (IQR 15). With ultrasound 2 patients had joint effusion, 3 synovitis and 11 synovial hypertrophy, only 1 patient had the three features. We did not find any correlation between thermography and ultrasound (p = 0.9). Articular examination showed poor concordance between inflammed and painful joints (Kappa < 0.4); although with certain correlation in left  (kappa 0.42) and right carpal inflammation (kappa 0.49), as well as left (kappa 0.43) and right carpal pain (kappa 0.7).

Conclusion: Conclusion: In patients with primary fibromyalgia without joint pain, the use of tools such as digital thermography does not provide information for ruling out inflammatory arthropathy.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/hand-digital-thermography-findings-in-patients-with-primary-fibromyalgia/