Fibromyalgia Syndrome Subjects Research Articles

Cluster analysis in fibromyalgia: a systematic review.

The multifaceted nature of Fibromyalgia syndrome (FM) symptoms has been explored through clusters analysis. To synthesize the cluster research on FM (variables, methods, patient subgroups, and evaluation metrics). We performed a systematic review following the PRISMA recommendations. Independent searches were performed on PubMed, Embase, Web of Science, and Cochrane Central, employing the terms "fibromyalgia" and "cluster analysis". We included studies dated to January 2024, using the cluster analysis to assess any physical, psychological, clinical, or biomedical variables in FM subjects, and descriptively synthesized the studies in terms of design, cluster method, and resulting patient profiles. We included 39 studies. Most with a cross-sectional design aiming to classify subsets based on the severity, adjustment, symptomatic manifestations, psychological profiles, and response to treatment, based on demographic and clinical variables. Two to four different profiles were found according to the levels of severity and adjustment to FMS. According to symptom manifestation, two to three clusters described the predominance of pain versus fatigue, and thermal pain sensitivity (less versus more sensitive). Other clusters revealed profiles of personality (pathological versus non-pathological) and psychological vulnerability (suicidal ideation). Additionally, studies identified different responses to treatment (pharmacological and multimodal). Several profiles exist within FMS population, which point out to the need for specific treatment options given the different profiles and an efficient allocation of healthcare resources. We notice a need towards more objective measures, and the validation of the cluster results. Further research might investigate some of the assumptions of these findings, which are further discussed in this paper.

Fibromyalgia is associated with hypersensitivity but not with abnormal pain modulation: evidence from QST trials and spinal fMRI.

Widespread pain and hyperalgesia are characteristics of chronic musculoskeletal pain conditions, including fibromyalgia syndrome (FM). Despite mixed evidence, there is increasing consensus that these characteristics depend on abnormal pain augmentation and dysfunctional pain inhibition. Our recent investigations of pain modulation with individually adjusted nociceptive stimuli have confirmed the mechanical and thermal hyperalgesia of FM patients but failed to detect abnormalities of pain summation or descending pain inhibition. Furthermore, our functional magnetic resonance imaging evaluations of spinal and brainstem pain processing during application of sensitivity-adjusted heat stimuli demonstrated similar temporal patterns of spinal cord activation in FM and HC participants. However, detailed modeling of brainstem activation showed that BOLD activity during "pain summation" was increased in FM subjects, suggesting differences in brain stem modulation of nociceptive stimuli compared to HC. Whereas these differences in brain stem activation are likely related to the hypersensitivity of FM patients, the overall central pain modulation of FM showed no significant abnormalities. These findings suggest that FM patients are hyperalgesic but modulate nociceptive input as effectively as HC.

Efficiency of pain inhibition and facilitation of fibromyalgia patients is not different from healthy controls: Relevance of sensitivity-adjusted test stimuli.

Pain is a dynamic phenomenon dependent on the balance of endogenous excitatory and inhibitory systems, which can be characterized by quantitative sensory testing. Many previous studies of pain modulatory capacity of patients with fibromyalgia syndrome (FM) have reported decreased pain inhibition or increased pain facilitation. This is the first study to assess pain modulation, including conditioned pain modulation (CPM) and temporal pain summation, in the same healthy control (HC) and FM participants. Only sensitivity-adjusted stimuli were utilized for testing of conditioned pain modulation (CPM) and temporal pain summation in 23 FM patients and 28 HC. All subjects received sensitivity-adjusted ramp-hold (sRH) during testing of pain facilitation (temporal summation) and pain inhibition (CPM). CPM efficacy was evaluated with test stimuli applied either concurrently or after application of the conditioning stimulus. Finally, the effects of CPM on pressure pain thresholds were tested. FM subjects required significantly less intense test and conditioning stimuli than HC participants to achieve standardized pain ratings of 50 ± 10 numerical rating scale (NRS) (p = 0.03). Using such stimuli, FM subjects' temporal pain summation and CPM efficacy was not significantly different from HC (all p > 0.05), suggesting similar pain facilitation and inhibition. Furthermore, the CPM efficacy of FM and HC participants was similar regardless of whether the test stimuli were applied during or after the conditioning stimulus (p > 0.05). Similar to previous studies, FM participants demonstrated hyperalgesia to heat, cold, and mechanical stimuli. However, using only sensitivity-adjusted stimuli during CPM and temporal summation testing, FM patients demonstrated similarly effective pain inhibition and facilitation than HC, suggesting that their pain modulation is not abnormal.

High levels of cathepsin S and cystatin C in patients with fibromyalgia syndrome.

Although the etiopathogenesis of fibromyalgia syndrome (FM) is not yet clear, central sensitization is thought to be responsible for the pathogenesis of FM. The aim of this study was to compare the serum cathepsin S (CatS) and cystatin C (CysC) levels between patients with FM and healthy control subjects. This study was conducted in the Physical Medicine and Rehabilitation Clinic between January 2019 and October 2019. The study included 145 FM patients newly diagnosed with primary FM according to the 2010 American College of Rheumatology criteria and 129 healthy volunteers. The age, gender, and body mass index (BMI) of the participants were recorded. Venous blood samples were collected from both groups for the measurement of the levels of serum CatS and CysC. The functional status of FM patients was evaluated using the Fibromyalgia Impact Questionnaire (FIQ). No statistically significant difference was determined between the patient and control groups in terms of age, gender, and BMI (P>.05). A comparison of the serum CatS and CysC levels of the FM and control groups revealed a statistically significant difference (P=.001). No correlation was determined between FIQ and serum CatS and CysC levels (P>.05). Serum CatS and CysC levels were found to be higher in FM patients. However, there was no correlation between the functional status of FM patients and serum CatS and CysC levels. These results can be of guidance for further clinical studies of the etiopathogenesis and treatment of FM.

IS FIBROMYALGIA A SYNDROME OF HORMONAL IMBALANCE?

Objectives: The present study was conducted to estimate cortisol and thyroid-stimulating hormone (TSH) levels in patients with fibromyalgia syndrome (FMS) and to find correlation if any between hormone levels and pain duration in FMS.Methods: Plasma cortisol and TSH concentration were determined by electro chemiluminescence immunoassay in 89 female patients with FMS and 74 age-matched healthy women.Results: No significant difference in TSH level was observed between FMS and healthy subjects. Ten patients had higher cortisol levels than the standard reference range, 48 patients with reduced cortisol and 31 patients with normal cortisol levels. No significant correlation was observed between pain duration and levels of cortisol.Conclusion: The study has confirmed the equivocal data regarding cortisol/hypothalamic-pituitary-adrenal axis related dysfunction in FMS. To the best of our knowledge, it is the first Indian study on FMS which assessed the cortisol and TSH levels and their correlation with pain duration if any.

Embodied pain in fibromyalgia: Disturbed somatorepresentations and increased plasticity of the body schema.

Fibromyalgia syndrome (FMS) is a highly prevalent, chronic musculoskeletal condition characterized by widespread pain and evoked pain at tender points. This study evaluated various aspects of body awareness in a sample of 14 women with FMS and 13 healthy controls, such as plasticity of the body schema, body esteem, and interoceptive awareness. To this end, the Rubber Hand Illusion (RHI), the Body Esteem Scale (BES), and the Body Perception Questionnaire (BPQ) were used, respectively. Consistent with increased plasticity of the body schema, FMS patients scored higher, with large or very large effect sizes, across all three domains evaluated in the RHI paradigm, namely proprioceptive drift and perceived ownership and motor control over the rubber hand. Scores on all items addressed by the BES were consistently lower among FMS subjects (2.52, SEM .19 vs 3.89, SEM .16, respectively, p < .01, Cohen’s d = .38-.66). In the FMS sample, BES scores assigned to most painful regions also were lower than those assigned to the remaining body sites (1.58, SEM .19 vs 2.87, SEM .18, respectively, p < .01). Significantly higher scores (p < .01, Cohen’s d = .51-.87) were found in the FMS sample across awareness (3.57 SEM .15 vs 1.87 SEM .11), stress response (3.76 SEM .11 vs 1.78 SEM .11), autonomic nervous system reactivity (2.59 SEM .17 vs 1.35 SEM .07), and stress style 2 (2.73 SEM .27 vs 1.13 SEM .04) subscales of the BPQ. Intensity of ongoing clinical pain was found to be strongly correlated with interoceptive awareness (r = .75, p = .002). The results suggest a disturbed embodiment in FMS, characterized by instability of the body schema, negatively biased cognitions regarding one’s own body, and increased vigilance to internal bodily cues. These manifestations may be interpreted as related with the inability of incoming sensory inputs to adequately update negatively biased off-line somatorepresentations stored as long-term memory.

The Borg CR-10 scale is suitable to quantify aerobic exercise intensity in women with fibromyalgia syndrome

ABSTRACT Patients with Fibromyalgia syndrome (FMS) report higher ratings of perceived exertion (RPE) compared to healthy individuals for the same exercise intensity; however, to our knowledge, no studies have evaluated RPE at the ventilatory anaerobic threshold (VAT) for this population. This study aimed to assess RPE using the Borg CR-10 scale during a cardiopulmonary exercise test (CPET) in women with FMS. Twenty-four women with FMS and twenty healthy control subjects (HC) voluntarily participated in this study. Near the end of every 1-minute period during CPET, subjects were asked to report their RPE for fatigue in the lower limbs (RPE-L) and dyspnea (RPE-D), respectively, according to the Borg CR-10 scale. FMS subjects showed higher RPE-L and RPE-D compared to HC subjects at free wheel and at the first load increment. However, no significant difference was observed between groups for power output. There was no significant difference between groups for RPE-L and RPE-D reported at VAT and peak CPET. However, FMS subjects showed lower power output compared to HC subjects. The present results showed that FMS subjects present higher RPE compared to HC subjects. However, RPE reported at VAT and at peak CPET was not different between groups. The Borg CR-10 scale scores obtained at VAT can be used as an additional parameter for prescribing exercise intensity in aerobic training protocols for women with FMS.

FMRI of spinal and supra-spinal correlates of temporal pain summation in fibromyalgia patients.

Fibromyalgia syndrome (FM) is a debilitating chronic pain condition, which afflicts primarily females. Although the etiology of this illness is not completely understood, FM pain is thought to rely on enhanced pain sensitivity maintained by central mechanisms. One of these mechanisms is central pain amplification, which is characterized by altered temporal summation of second pain (TSSP). Here we use a TSSP paradigm and functional MRI (fMRI) of the spinal cord, brainstem, and brain to noninvasively examine the central nervous system contributions to TSSP in FM patients and normal controls (NC). Functional MRI of pain-free female adults (N = 15) and FM patients (N = 14) was conducted while brief, repetitive heat pain stimuli (0.33 Hz) were applied to the thenar eminence of the hand (C6 dermatome). The stimulus intensity was adjusted to each participant's heat pain sensitivity to achieve moderate pain. Data were analyzed by means of a General Linear Model and region-of-interest analyses. All participants demonstrated significant pain summation in the TSSP condition. FM subjects, however, required significantly lower stimulus intensities than NC to achieve similar TSSP. fMRI analyses of perceptually equal TSSP identified similar brain activity in NC and FM subjects; however, multiple areas in the brainstem (rostral ventromedial medulla and periaqueductal grey region) and spinal cord (dorsal horn) exhibited greater activity in NC subjects. Finally, increased after-sensations and enhanced dorsal horn activity was demonstrated in FM patients. In conclusion, the spinal and brainstem BOLD responses to TSSP are different between NC and FM patients, which may indicate alterations to descending pain control mechanisms suggesting contributions of these mechanisms to central sensitization and pain of FM patients.

Understanding the Association of Fatigue With Other Symptoms of Fibromyalgia: Development of a Cluster Model.

To develop a symptoms cluster model that can describe factors of fibromyalgia syndrome (FMS) associated with fatigue severity as reported by the sample and to explore FMS clinical symptom subclusters based on varying symptom intensities. FMS individuals (n = 120, 82% ages 31-60 years, 90% women, 59% white) diagnosed with the 1990 or 2010 American College of Rheumatology diagnostic criteria were enrolled. Participants completed multiple validated self-report questionnaires to measure fatigue, pain, depression, anxiety, pain catastrophizing, daytime sleepiness, cognitive function, and FMS-related polysymptomatic distress. Cluster analysis using SPSS 19.0 and structural equation modeling using AMOS 17.0 were used. Final structural equation modeling the symptoms cluster model showed good fit and revealed that FMS fatigue was associated with widespread pain, symptoms severity, pain intensity, pain interference, cognitive dysfunction, catastrophizing, anxiety, and depression (χ(2) = 121.72 (98df), P > 0.05, χ(2) /df = 1.242, comparative fit index = 0.982, root mean square error of approximation = 0.045). Two distinct clinical symptom subclusters emerged: subcluster 1 (78% of total subjects), defined by widespread pain, unrefreshed waking, and somatic symptoms, and subcluster 2 (22% of total subjects), defined by fatigue and cognitive dysfunction with pain being a less severe and less widespread occurrence. Overall, subcluster 1 had more intense symptoms than subcluster 2. FMS symptoms may be categorized into 2 clinical subclusters. These findings have implications for an illness whose diagnosis and management are symptom dependent. A longitudinal study capturing the variability in the symptom experience of FMS subjects is warranted.

Health anxiety and depression in patients with fibromyalgia syndrome.

To investigate health anxiety and depressive symptoms in patients with fibromyalgia syndrome (FMS). Patients with FMS and healthy control subjects were recruited. All participants completed the Health Anxiety Inventory Short Form (HAI-SF) and Beck Depression Inventory (BDI). Pain was assessed in patients with FMS using the Fibromyalgia Impact Questionnaire (FIQ) and Visual Analogue Scale (VAS). This study involved 95 patients with FMS (15 male) and 95 healthy controls (17 male). Mean ± SD HAI-SF and BDI scores were significantly higher in patients with FMS = than in controls=. HAI-SF scores were 23.50 ± 10.78 and 9.38 ± 4.24 respectively; BDI scores were 18.64 ± 10.11 and 6.21 ± 4.05 respectively. There were highly significant correlations between FIQ and HAI-SF, FIQ and BDI, and HAI-SF and BDI. Patients with FMS had significantly higher HAI-SF and BDI scores than healthy controls. Psychiatric support is essential for patients with FMS. Treatment should include biological, psychological and social approaches.

Fear‐learning deficits in subjects with fibromyalgia syndrome?

Fibromyalgia syndrome (FMS) is frequently associated with psychiatric conditions, particularly anxiety. Deficits in contingency learning during fear conditioning have been hypothesized to increase anxiety and, consequently, pain sensation in susceptible individuals. The goal of this study was to examine the relationship between contingency learning and pain experience in subjects with FMS and rheumatoid arthritis (RA). Fourteen female FMS subjects, 14 age-matched female RA subjects and 14 age-matched female healthy controls (HCs) were included in a fear-conditioning experiment. The conditioned stimulus (CS) consisted of visual signs, the unconditioned stimulus (US) of thermal stimuli. CS- predicted low-temperature exposure (US), while CS+ was followed by low or high temperature. In the FMS group, only 50% of the subjects were aware of the US-CS contingency, whereas 86% of the RA subjects and all of the HCs were aware of the contingency. CS+ induced more anxiety than CS- in RA subjects and HCs. As expected, low-temperature exposure was experienced as less painful after CS- than after CS+ in these subjects. FMS subjects did not show such adaptive conditioning. The effects of the type of CS on heart rate changes were significant in the HCs and the aware FMS subjects, but not in the unaware FMS subjects. Contingency learning deficits represent a potentially promising and specific, but largely unstudied, psychopathological factor in FMS. Deficits in contingency learning may increase anxiety and, consequently, pain sensation. These findings have the potential to contribute to the development of novel therapeutic approaches for FMS.

Extreme Thermal Sensitivity and Pain-Induced Sensitization in a Fibromyalgia Patient

During the course of a psychophysical study of fibromyalgia syndrome (FMS), one of the subjects with a long history of headache and facial pain displayed an extraordinarily severe thermal allodynia. Her stimulus-response function for ratings of cutaneous heat pain revealed a sensitivity clearly beyond that of normal controls and most FMS subjects. Specially designed psychophysical methods showed that heat sensitivity sometimes increased dramatically within a series of stimuli. Prior exposure to moderate heat pain served as a trigger for allodynic ratings of series of normally neutral thermal stimulation. These observations document a case of breakthrough pain sensitivity with implications for mechanisms of FMS pain.

Low plasma levels of monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-alpha (TNFα), and vascular endothelial growth factor (VEGF) in patients with alpha1-antitrypsin deficiency-related fibromyalgia

Abnormalities in blood inflammatory markers have been associated with clinical manifestations and the pathogenesis of the fibromyalgia syndrome (FMS); a relationship between inherited alpha1-antitrypsin deficiency (AATD) and FMS has also been recently raised. In this study, plasma levels of inflammatory markers in FMS patients with and without AATD have been investigated. Blood samples from 138 age-matched females (79 FMS) and 59 general population (GP), with normal MM [n = 82 (59.4%)] and with MS, MZ, SZ, and ZZ AATD genotypes [n = 56 (40.6%)], were analyzed by ELISA for monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-alpha (TNFalpha), soluble TNFalpha receptors I and II, interleukin-8, and vascular endothelial growth factor (VEGF). Plasma levels of MCP-1, VEGF, and TNFalpha were significantly lower in FMS and GP subjects with AATD compared with those with normal MM-AAT genotypes. Moreover, plasma levels of MCP-1, VEGF, and TNFalpha were lower in AATD subjects with FMS than in those without FMS (P = 0.000, 0.000, and 0.046, respectively). No statistical differences were found for the other substances measured. Furthermore, a logistic regression model based on plasma MCP-1 cutoff value of <or=130 pg/ml allowed us to discriminate between FMS and GP subjects with a sensitivity of about 93% and a specificity of 79%. Low plasma levels of MCP-1, VEGF, and TNFalpha are related to AATD, although more markedly in FMS patients. Thus, hypotheses considering FMS as an inflammatory condition related to high plasma levels of inflammatory biomarkers cannot be supported.

Objective measures of disordered sleep in fibromyalgia.

Patients with fibromyalgia syndrome (FM) complain of inadequate sleep, which could contribute to common symptoms including sleepiness, fatigue, or pain. However, measures that consistently and objectively distinguish FM patients remain elusive. Fifteen women with FM and 15 age- and gender-matched controls underwent 3 nights of polysomnography; Multiple Sleep Latency Tests to assess sleepiness; testing of auditory arousal thresholds during non-REM stage 2 and stage 4 sleep; overnight assessment of urinary free cortisol; and analysis of 24-hour heart rate variability. On the second night of polysomnography, women with FM in comparison to controls showed more stage shifts (p = 0.04) but did not differ significantly on any other standard polysomnographic measure or on the Multiple Sleep Latency Tests. Alpha EEG power during deep non-REM sleep, alone or as a proportion of alpha power during remaining sleep stages, also failed to distinguish the groups, as did auditory arousal thresholds. Urinary free cortisol did not differ between FM and control subjects in a consistent manner. However, decreased short-term heart rate variability (HRV) and especially ratio-based HRV among FM subjects suggested diminished parasympathetic and increased sympathetic activity, respectively. Other HRV measures suggested decreased complexity of HRV among the FM subjects. Standard measures of sleep, a gold-standard measure of sleepiness, quantified alpha-delta EEG power, auditory arousal thresholds, and urinary free cortisol largely failed to distinguish FM and control subjects. However, HRV analyses showed more promise, as they suggested both increased sympathetic activity and decreased complexity of autonomic nervous system function in FM.

Treating patients with fibromyalgia in primary care settings under routine medical practice: a claim database cost and burden of illness study

IntroductionThe objective of this study was to analyze health care and non-health care resource utilization under routine medical practice in a primary care setting claims database and to estimate the incremental average cost per patient per year of fibromyalgia syndrome (FMS) compared with a reference population.MethodsA 12-month cross-sectional and retrospective study was completed using computerized medical records from a health provider database. Analyses were conducted from the perspective of the provider and from the viewpoint of society. Health care and non-health care resource utilization included drugs, complementary tests, all types of medical visits, referrals, hospitalizations, sick leave, and early retirement because of disability due to FMS. Patients with a diagnosis of FMS in accordance with ICD-10 (International Statistical Classification of Diseases and Related Health Problems, 10th revision) criteria were included in the analysis if they had at least one claim for FMS during the 12 months prior to the end of May 2007. A non-FMS comparison group was also created with the remaining subjects.ResultsOf the 63,526 patients recruited for the study, 1,081 (1.7%) (96.7% of whom were women, 54.2 [10.1] years old) met the criteria for FMS. After an adjustment for age and gender, FMS subjects used significantly more health care resources than the reference population and had more sick leave and the percentage of subjects with premature retirement was also significantly higher (P < 0.001 in all cases). As a result, FMS subjects showed an incremental adjusted per-patient per-year total cost of €5,010 (95% confidence interval [CI] 3,494 to 6,076, +153%, P < 0.001) on average compared with non-FMS subjects. Significantly higher differences were observed in both health care and non-health care adjusted costs: €614 (404 to 823, +66%) and €4,394 (3,373 to 5,420, +189%), respectively (P < 0.001 in both cases). Annual drug expenditure per patient on average was considerably higher in FMS patients, €230 (124 to 335, +64%, P < 0.001), than the reference group.ConclusionsUnder routine medical practice, patients with FMS were associated with considerably higher annual total costs in the primary care setting compared with the reference population.

Sex‐specific Prenatal Programming

Women are four to eight times more likely to be affected by fibromyalgia syndrome (FMS). A lack of cortisol, potentially due to an adrenocortical deficit is postulated in FMS. The cause of such adrenal insufficiency is unknown. It could be assumed that stress exposure during critical periods contributes to vulnerability for FMS. These critical periods might include prenatal periods in which adversities may lead to an impaired development of the adrenal cortex, especially in females. More than 50% of FMS patients report major life events before the onset of the disease. Possibly due to adrenal insufficiency they may not be able to dampen their stress response by secreting sufficient glucocorticoids. Thus, stress mediators, such as catecholamines and pro-inflammatory cytokines, may be disinhibited and affect brain function. This might result in an enhanced responsiveness to external and internal pain- and fatigue-eliciting stimuli. In a study with female FMS patients (N= 93) those patients with a shorter gestational length (<38 weeks) showed a lower cortisol awakening response (CAR) than FMS subjects with a gestational length >38 weeks (F((3,31))= 2.94, P= 0.038). Additionally, more than 70% reported severe psychological stress alone or in combination with other factors at disease onset.

Sleep stage dynamics in fibromyalgia patients and controls

Objective To determine whether previously described sleep stage dynamics, reflecting the mean duration of specific sleep stages, may have clinical utility in a sample of patients with fibromyalgia syndrome (FMS) and controls. Methods Women with FMS ( n = 15, screened to exclude other sleep disorders) and age-matched women in good health ( n = 15) were studied with nocturnal polysomnography, multiple sleep latency tests, 2-week pain diaries, and a measure of current pain intensity. Results The FMS subjects, in comparison to controls, did not show differences in several common polysomnographic measures, except for increased numbers of stage shifts (126 ± 27 vs. 107 ± 22, p = .042). Mean durations for episodes of total sleep, stage 1 sleep, stage 3/4 sleep, and rapid eye movement sleep failed to distinguish FMS and control subjects (Wilcoxon rank sum tests, p > .10 for each), but those for stage 2 sleep were shorter in the FMS subjects ( p = .006), possibly because transitions to stage 3/4 sleep occurred more quickly ( p = .036). Shorter stage 2 sleep durations predicted higher pain diary scores (Spearman rho = −.56, p = .0014) and current pain intensity ( rho = −.71, p < 0.0001). Conclusions Sleep stage dynamic, and, more specifically, shorter durations of sleep stage 2 periods, distinguish FMS and control female subjects and may predict pain levels experienced in FMS. Analysis of the lengths of individual sleep stages, in addition to the usual sleep stage amounts and percentages listed in standard polysomnogram reports, may have clinical utility.

A subset of fibromyalgia patients have findings suggestive of chronic inflammatory demyelinating polyneuropathy and appear to respond to IVIg

The aetiopathogenesis of the fibromyalgia syndrome (FMS) remains unknown. Recent reports, however, suggest that a subgroup of FMS subjects has an immune-mediated disease. Therefore, our primary objective was to study FMS subjects for evidence of an immune-mediated demyelinating polyneuropathy. Our secondary objective was to determine the effects of treating these FMS subjects with the immune modulator, intravenous immunoglobulin (IVIg). Fifty-eight FMS subjects, 26 rheumatic non-FMS subjects and 52 non-rheumatic non-FMS subjects were studied. Subjective measures of paraesthesias, weakness, stocking hypaesthesia, pain, fatigue and stiffness were made. Objective measures of tenderness, proximal muscle strength and electrodiagnostic (EDX) evidence of polyneuropathy and demyelination were also made. Eleven other FMS subjects underwent sural nerve biopsy. Paraesthesias, subjective weakness and stocking hypaesthesia were more common in FMS than in rheumatic non-FMS (P < or = 0.0001). Proximal muscle strength was less in FMS than in rheumatic non-FMS (P < or = 0.0001). EDX demonstrated a distal demyelinating polyneuropathy, suggestive of chronic inflammatory demyelinating polyneuropathy (CIDP), in 33% of FMS subjects. No rheumatic non-FMS subject had polyneuropathy (P = 0.005), or demyelination (P = 0.05). Fifteen FMS/CIDP subjects were subsequently treated with IVIg (400 mg/kg each day for 5 days). Pain (P = 0.01), tenderness (P = 0.001) and strength (P = 0.04) improved significantly. Fatigue and stiffness trended towards improvement. A significant subset of FMS subjects have clinical and EDX findings suggestive of CIDP. IVIg treatment shows promise in treating this subset. These observations have implications for better understanding and treating some FMS patients.

Generalized joint hypermobility: An issue in fibromyalgia and chronic fatigue syndrome?

Summary Joint hypermobility is defined as an increased mobility of small and large joints beyond the range of motion considered normal. Fibromyalgia Syndrome (FMS) and Chronic Fatigue Syndrome (CFS) are diagnostically different but overlapping disorders. Several researchers have examined the possible association between generalized joint hypermobility and chronic widespread muscle/joint pain in both FMS and CFS subjects. The present manuscript provides the reader with an overview of the published data addressing generalized joint hypermobility in FMS and CFS, with special emphasis on assessment strategy, prevalence, clinical importance, and conservative treatment. From the available scientific literature, it is concluded that generalized joint hypermobility is more common in both FMS and CFS patients compared to healthy volunteers.

Myofascial pain and fibromyalgia: Spatial summation of heat pain is not abnormal in patients with fibromyalgia syndrome

Spatial summation of heat sensations (SPAS) is positively correlated with the stimulated surface area and this effect has been clearly demonstrated for non-painful and painful stimuli in normal controls subjects (NC). In animal and human experiments the application of increasingly painful stimuli has been shown to recruit not only strong nociceptive but also anti-nociceptive mechanisms including diffuse noxious inhibitory controls (DNIC). In addition, pain coding by central nociceptive neurons is not only dependent on stimulus intensity but also on stimulated surface area. Abnormal pain modulatory and spatial summation mechanisms have been implicated in patients with fibromyalgia syndrome (FMS). We therefore applied thermal stimuli to the upper extremities (UE) to explore the hypothesis that FMS patients have abnormal SPAS mechanisms. 37 FMS patients and 22 NC immersed pre-determined areas of the UE in hot water (46C) for 5s and 20s in counterbalanced order. A mechanical visual analogue scale (VAS) was used for pain ratings. The area of thermal stimulation was varied across UE areas to test the contribution of dermatomes to SPAS. The results of pain ratings during 5s and 20s immersions were similar for each diagnostic group (p > .05). All experimental pain ratings of FMS patients were higher than NC (p < .05). Immersion of each individual finger (2-5) resulted in similar VAS ratings of pain (p > .5) within each group (baseline). Pain ratings, however, increased in NC and FMS subjects when the immersed areas were expanded within or across dermatomes (p < .04). The increase in pain ratings was greater within than across dermatomes. In addition, the increase in pain ratings during SPAS was comparable for FMS and NC subjects (p > .05) for all test conditions. Spatial summation of heat pain is not different between FMS patients and NC. A lack of difference between pain ratings after hot water immersions suggests effective anti-nociceptive mechanisms in both groups. These findings indicate that the clinical pain of FMS patients may not be related to abnormal spatial coding of peripheral nociceptive input.