An Evaluation of Mechanically Induced Neurogenic Flare by Infrared Thermography in Fibromyalgia

Abstract

Objectives: The purpose of this study was to compare the neurogenic flare between patients with fibromyalgia [FM] and healthy controls [HC] and to compare the visual tracing method [VTM] with thermography. Methods: The FM and HC groups [16 per group] were matched for age and sex. Two levels of pressure stimulation [3 kg and 6 kg] were applied by a dolorimeter to either side of the upper back of each subject in random order. The neurogenic flare was monitored by thermography for 30 minutes and outlined by the VTM at the second minute after stimulation. Results: The general baseline back temperature was found to be significantly lower in the FM group than the HC group [P = 0.04]. Significant differences were found between levels of stimulation on peak temperature change, peak area of flare, and flare area measured at the second minute after stimulation by thermography and the VTM [P < 0.05]. No statistically significant differences were found between the groups [P > 0.05]. A significant interaction was found between group and level of stimulation on the peak flare area measured by thermography [P = 0.03]. Conclusions: The significantly lower baseline skin temperature in FM patients implies that adrenergic sympathetic nerve activity in FM may be increased at rest. The significant interaction between group and level of stimulation indicates that the two mechanisms involved in producing the observable flare [sympathetic nervous system and the neurogenic inflammation] interact differently at different levels of stimulation.

KEYWORDS:

• Fibromyalgia
• Neurogenic flare
• Nociceptive
• Sympathetic activity