THE “MANTLE SIGN”: HOW THERMOGRAPHY CAN HELP TO SUPPORT THE CLINICAL DIAGNOSIS OF FIBROMYALGIA SYNDROME?
Marcos Leal Brioschi MD, Manoel Jacobsen Teixeira MD
Clinical Thermology and Thermography Postgraduate Specialty Hospital das Clinicas, University of São Paulo Medical School, São Paulo, Brazil.
Fibromyalgia (FM) syndrome is a chronic condition characterized by musculoskeletal pain that persists for many years and is unresponsive to anti-inflammatory and analgesic compounds. There is an overlap between thermoregulation and the modulation of nociception that are consistent with the symptoms of FM (Larson et al, 2013):
1. Cold intolerance.
2. Decreased body temperature (low metabolic rate).
3. Distribution of brown adipose tissue (BAT) resembles that of tender points (TP) (Jeschonneck, 2000).
4. BAT activity at rest and the incidence of FM are each relatively greater in females than males (whereas adaptive thermogenesis is greater in males than females).
5. Stress and cold each stimulate thermogenesis and aggravate symptoms of FM (whereas warmth suspends thermogenesis and temporarily relieves the symptoms of FM).
6. Regulation of thermogenesis and pain share several areas in the brain where they may influence each other.
7. Sensitive to sympatholytic maneuvers: injections of a local anesthetic into stellate ganglia (sympathetic projections to subclavicular BAT) reduce pain in patients with FM (Bengtsson, 1988).
8. Rekindles upon injection with norepinephrine.
9. Polymorphisms in catechol-o-methyl transferase have been linked toFM(faulty degradation of catecholamines increases the risk of developing FM)
10. Extended programs of exercise relieve symptoms of FM (improve thermoregulation, decrease adrenergic activity, and inhibit recruitment of BAT).
Nerves projecting to BAT are located near regions surrounding tender points (TP), primarily in the supraclavicular region, and also in supra axial, perirenal, and subcutaneous areas. Eighteen TP distributed symmetrically on the trunk and proximal regions of limbs rather than areas that are usually more sensitive to tactile stimulation in healthy individuals, such as hands, feet, genitals, and mouth were defined by the American College of RheuRheumatology. This anatomic overlap provides collateral innervation of tissue adjacent to BAT, for example, skin and muscle, by sympathetic and primary afferent nerves. Thermogenic activity is increased by the same conditions that exacerbate the symptoms of FM, that is, cold and mild daily stress. BAT undergoes “recruitment” (increased mass) in response to repeated cold, repeated stress and overfeeding with diets chronically high in calories. Consistent with this, when BAT is activated by injections of adrenaline in rats, muscles surrounding interscapular BAT have greater blood flow than in muscles of the anterior limbs indicating that adjacent tissues operate in synergy with BAT (Sbarbati, 2006). Sympathetic activity that induces thermogenesis is poised to induce hyperalgesia in tissues surrounding BAT by referred pain.
One model of FM based on repeated exposures of rodents to cold depends on spinal substance P activity for hyperalgesia (Nishiyori, 2008). Substance P, released from primary afferent C-fibers transmitting pain or temperature, causes vasodilation in skin to dissipate heat and induces hyperalgesia. Thus pain can result from the combined effect of substance P along nociceptive pathways together with sympathetically mediated hyperalgesia in skin and muscle surrounding BAT, similar to the pain of angina.
Interscapular brown fat can be readily seen using IR thermography in young rats during cold exposure, in bats during arousal from torpor, in human infants and in human adults (Jackson et al, 2000).
Recently Symonds et al (2012) demonstrated using IR thermography a consistent, and highly localized, increase in local temperature within the supraclavicular region that directly corresponds to the main site of BAT, previously established from PET/CT scans and biopsy studies (Lee et al, 2011).
This is compatible with rapid activation of the sympathetic nervous system, concomitant unmasking of guanodine diphosphate binding sites within uncoupling protein and the stimulatory effect of catecholamines on heat production both in the newborn and in adults. Only a modest standard cool challenge (by placement of the participant’s feet or hand inwater at 20o C) is required to cause a local temperature increase within this supraclavicular region.
In awell-controlled ambient temperature lab Brioschi et al (2007) described in FM patients a consistent pattern called “mantle sign” that correspond of an exacerbated increase in temperature within the supraclavicular region that can extend to neck and trunk, observed by Biasi et al (1994) as a nonspecific hyperthermic pattern, corresponding to painful muscular areas. The authors also related a direct clinical correspondence of these findings with visual analog pain scale during the full body IR thermography of 226 patients and after validated with more 542 evaluations. Most of times, this finding was associated with symmetrical cold hands and periocular hyper radiation. Based on the count of hot spots, 74.2% of 252 subjects have been correctly diagnosed by Ammer et al (2011) described a high consistency of hot spots correlated with TP on upper body with 74.2% of precision in FM patients.
The supraclavicular “mantle sign” observed by IRthermography can be related to the vascular convection that carries in FM patients the overstimulated BAT heat to adjacent vital organs, such as the thoracocervical regions of the spinal cord, heart, and other thoracic organs. Although it is not a definitive diagnosis, the phenomenon of mantle sign can support the clinical dia. gnosis and play an important role in the following of FM patients.
Larson AA, Pardo JV, Pasley JD. Review of Overlap Between Thermoregulation and Pain Modulation in Fibromyalgia. Clin J Pain. 2013, Jul 24 (Epub ahead of print).
Jeschonneck M et al. Abnormal microcirculation and temperature in skin above tender points in patients with fibromyalgia. Rheumatology. 2000; 39:917-921.
Bengtsson A, Bengtsson M. Regional sympathetic blockade in primary fibromyalgia. Pain. 1988;33:161-167.
Martinez-LavinMet al. Norepinephrine-evoked pain in fibromyalgia.A randomized pilot study. BMC Musculoskelet Disord. 2002;3:2-8.
Martinez-Jauand M et al. Pain sensitivity in fibromyalgia is associated with catechol-O-methyl transferase (COMT) gene. Eur J Pain. 2013; 17:16-27.
Sbarbati A, Cavallini I, Marzola P, et al. Contrast-enhanced MRI of brown adipose tissue after pharmacological stimulation. Magn Reson Med. 2006;55:715-718.
Nishiyori M, Ueda H. Prolonged gabapentin analgesia in an experimental mouse model of fibromyalgia. Mol Pain. 2008;4:52-58.
Symonds ME, Henderson K, Elvidge L, Bosman C et al. Thermal imaging to assess age-related changes of skin temperature within the supraclavicular region co-locating with brown adipose tissue in healthy children. J Pediatr. 2012 Nov;161(5):892-8.
Lee P, Ho KK, Greenfield JR. Hot fat in a cool man: infrared thermography and brown adipose tissue. Diabetes Obes Metab 2011;13:92-3.
Brioschi ML, Yeng LT, Pastor EMH, Colman D, Silva FMRM, Teixeira MJ. Documentation of myofascial pain syndrome with infrared imaging. Acta Fisiatr 2007; 14(1): 41-8.
Brioschi ML, Yeng LT, Pastor EMH, Teixeira MJ. Infrared imaging use in rheumatology. Rev Bras Reumatol 47:42-51, 2007.
Brioschi ML. Índice termográfico infravermelho no diagnóstico complementar da fibromialgia. São Paulo, 2008. Tese (Pós-Doutorado) – Faculdade de Medicina, Departamento de Neurologia FMUSP, Universidade de São Paulo. 152 p.
Biasi G, Fioravanti A, Franci A, Marcolongo R. The role computerized telethermography in the diagnosis of fibromyalgia syndrome. Minerva Med 85:451-4, 1994.
Ammer, K., Engelbert, B., Kern, E. Reproducibility of the hot spot count in patients with fibromyalgia, an intra- and inter-observer comparison. Thermol. Int., 11, 143, 2001.
Ammer K. Thermal imaging: a diagnostic aid for fibromyalgia? Thermology International 18(2):45-50, 2008.
Brioschi ML, Silva FMRM, Yeng LT et al. Prevalência de artrite inicial em perícia de pacientes com fibromialgia. Estudo termográfico. Congressos Genival Veloso de França 2012 – I Congresso Brasileiro de Medicina Legal e Perícias Médicas e I Congresso Brasileiro de Termologia Clínica e Termografia. Fortaleza, 2012.
Brioschi ML, Abreu GF, Balbinot L et al. Identificação clínica, termográfica e ultrassonográfica de pontos-gatilho em pacientes com fibromialgia (OR015). XXIII Congresso Brasileiro de Medicina Física e Reabilitação, São Paulo, 2012.