Current concepts in the pathophysiology of abnormal pain perception in fibromyalgia

Low-dose naltrexone's utility for non-cancer centralized pain conditions: a scoping review

BACKGROUND

At low doses, naltrexone (LDN) has been shown to modulate inflammation through the interruption of microglial cell activation within the central nervous system. One of the most likely contributors to centralized pain is changes in microglial cell processing. Therefore, it has been postulated that LDN can be used to manage patients with pain resulting from central sensitization due to this relationship. This scoping review aims to synthesize the relevant study data for LDN as a novel treatment strategy for various centralized pain conditions.

METHODS

A comprehensive literature search was conducted in PubMed, Embase, and Google Scholar, guided by the Scale for Assessment of Narrative Review Articles (SANRA) criteria.

RESULTS

Forty-seven studies related to centralized pain conditions were identified. Many of the studies were case reports/series and narrative reviews, but a few randomized control trials have been conducted. Overall, the body of evidence revealed improvement in patient-reported pain severity and in outcomes related to hyperalgesia, physical function, quality of life, and sleep. Variability in dosing paradigms and the time to patient response was present in the reviewed studies.

CONCLUSIONS

Evidence synthesized for this scoping review supports the ongoing use of LDN for the treatment of refractory pain in various centralized chronic pain conditions. Upon review of the currently available published studies, it is apparent that further high-quality, well-powered randomized control trials need to be conducted to establish efficacy, standardization for dosing, and response times. In summary, LDN continues to offer promising results in the management of pain and other distressing symptoms in patients with chronic centralized pain conditions.

The Pain Outcomes Comparing Yoga vs. Structured Exercise (POYSE) Trial in Veterans With Fibromyalgia: Study Design and Methods

Background

Fibromyalgia is a common pain condition that often leads to significant disability. Unfortunately, the effectiveness of most medications for fibromyalgia is limited, and there is a need for alternative, non-pharmacological therapies. Yoga and aerobic exercise are both evidence-based non-pharmacological treatments for fibromyalgia. However, no prior studies have directly compared the effectiveness of yoga vs. exercise.

Objective

This article describes the study design and recruitment outcomes of the Pain Outcomes comparing Yoga vs. Structured Exercise (POYSE) Trial, a two-arm randomized comparative effectiveness trial.

Methods

Veterans with fibromyalgia, defined by the 2010 American College of Rheumatology diagnostic criteria, who also experienced at least moderate pain severity were enrolled. The participants were randomized to a 12-week yoga-based or a structured exercise program (SEP) and will undergo comprehensive outcome assessments at baseline, 1, 3, 6, and 9 months by interviewers blinded to treatment assignment. The primary outcome will be the overall severity of fibromyalgia as measured by the total Fibromyalgia Impact Questionnaire-Revised. Secondary outcomes included depression, anxiety, health-related quality of life, pain beliefs, fatigue, sleep, and self-efficacy.

Results

A total of 2,671 recruitment letters were sent to potential participants with fibromyalgia. Of the potential participants, 623 (23.3%) were able to be contacted by telephone and had their eligibility assessed. Three hundred seventy-one of those interviewed were found to be eligible (59.6%) and 256 (69.0%) agreed to participate and were randomized to the YOGA (n = 129) or the SEP (n = 127) arm of the trial.

Conclusions

Clinicians are faced with numerous challenges in treating patients with fibromyalgia. The interventions being tested in the POYSE trial have the potential to provide primary care and other care settings with new treatment options for clinicians while simultaneously providing a much needed relief for patients suffering from fibromyalgia.

Trial Registration

Funded by VA Rehabilitation Research and Development (D1100-R); Trial registration: ClinicalTrials.gov, NCT01797263.

Evaluation of fibromyalgia syndrome in patients with rosacea

Objectives

This study aims to investigate the frequency of fibromyalgia syndrome (FMS) in rosacea patients and the relationship between disease disability score of FMS and quality of life score of rosacea.

Patients and methods

This cross-sectional controlled clinical trial was performed between December 2017 and December 2018. One hundred female rosacea patients (mean age 43.2±10.1; range, 21 to 65 years) and 100 age- and sex-matched control subjects (mean age 41.2±11.1; range, 22 to 68 years) with no history of skin disease and systemic diseases including diabetes, cardiovascular, renal and hepatic diseases were recruited. Dermatology Life Quality Index (DLQI) scores were calculated using a 10-item self-administered questionnaire. The diagnosis of FMS was established according to 2010 American College of Rheumatology diagnostic criteria. Fibromyalgia Impact Questionnaire (FIQ) was used to determine the clinical severity and functional disability, while Visual Analog Scale (VAS) was used to determine pain severity in the patients with FMS.

Results

The frequency of FMS in patient group was significantly higher than control group (p=0.019). The mean duration of FMS in patient group was significantly higher than control group (p=0.001). There was no significant difference in terms of the age of onset of FMS, FIQ and VAS scores between groups (p=0.53, p=0.54, p=0.07, respectively). DLQI scores were significantly correlated with FIQ scores in the patient group (r=0.43, p=0.008).

Conclusion

The frequency of FMS in rosacea patients was significantly higher than control subjects without any skin disease and there was a correlation between disability score of FMS and quality of life score of rosacea. Investigating fibromyalgia symptoms in rosacea patients may be helpful for providing patient-based therapeutic approaches where neurologically based treatments may also be beneficial for rosacea.

Assessment of hand function and disability in fibromyalgia

OBJECTIVE

Fibromyalgia, a potentially debilitating chronic pain syndrome, is a chronic disease. We aimed to compare the hand function of fibromyalgia (FM) patients and healthy individuals and to demonstrate the relationship between hand disability and FM.

PATIENTS AND METHODS

The study was consisted of 40 female patients with FM and 30 healthy controls. All participants were evaluated for pain threshold measurements, handgrip strength, and pinch strength. Functional states, hand disability, and hand skills and coordination were evaluated using the Fibromyalgia Impact Questionnaire (FIQ) form, the Disability of Arm-Shoulder-Hand (DASH) questionnaire and the Purdue Pegboard Test, respectively.

RESULTS

Handgrip strength values, DASH score, lateral pinch strength test, Pegboard placement time, and Pegboard collection time of the patient group were significantly lower than those of the control group (all p < 0.05). A negative correlation was found between FIQ score and handgrip strength, two-point pinch strength test, three-point pinch strength test, and lateral pinch strength test in patients with moderate FM (all p < 0.05). Furthermore, a correlation was observed between DASH score and handgrip strength, lateral pinch strength test, Purdue Pegboard placement time, and Purdue Pegboard collection time in patients with moderate FM (all p < 0.05).

CONCLUSIONS

Our results show that hand function was decreased in patients with FM compared to healthy controls and decreasing hand function was influenced by FIQ score. As a result, the evaluation of hand function should be taken into consideration in the management of FM.

Reference values for muscle strength: a systematic review with a descriptive meta-analysis

BACKGROUND

Muscle strength is an important component of health.

OBJECTIVE

To describe and evaluate the studies which have established the reference values for muscle strength on healthy individuals and to synthesize these values with a descriptive meta-analysis approach.

METHODS

A systematic review was performed in MEDLINE, LILACS, and SciELO databases. Studies that investigated the reference values for muscle strength of two or more appendicular/axial muscle groups of health individuals were included. Methodological quality, including risk of bias was assessed by the QUADAS-2. Data extracted included: country of the study, sample size, population characteristics, equipment/method used, and muscle groups evaluated.

RESULTS

Of the 414 studies identified, 46 were included. Most of the studies had adequate methodological quality. Included studies evaluated: appendicular (80.4%) and axial (36.9%) muscles; adults (78.3%), elderly (58.7%), adolescents (43.5%), children (23.9%); isometric (91.3%) and isokinetic (17.4%) strength. Six studies (13%) with similar procedures were synthesized with meta-analysis. Generally, the coefficient of variation values that resulted from the meta-analysis ranged from 20.1% to 30% and were similar to those reported by the original studies. The meta-analysis synthesized the reference values of isometric strength of 14 muscle groups of the dominant/non-dominant sides of the upper/lower limbs of adults/elderly from developed countries, using dynamometers/myometer.

CONCLUSIONS

Most of the included studies had adequate methodological quality. The meta-analysis provided reference values for the isometric strength of 14 appendicular muscle groups of the dominant/non-dominant sides, measured with dynamometers/myometers, of men/women, of adults/elderly. These data may be used to interpret the results of the evaluations and establish appropriate treatment goals.

Concomitance of fibromyalgia syndrome and cervical disc herniation

[Purpose] Fibromyalgia syndrome (FMS) and cervical disc herniation (CDH) are a common diseases commonly encountered in physical therapy clinics. There are also patients who have both of these diseases. In this study we aim to investigated whether FMS is a risk factor for cervical disc herniation and the frequency of their coincident occurrence. [Subjects and Methods] Thirty-five patients having a primary FMS diagnosis according to the American Rheumatism Association criteria are taken into consideration and a control group were the subjects of this study. The two groups were compared with respect to cervical disc hernia using cervical region MRI. [Results] The distribution of disc hernia of 6 fibromyalgia patients who had cervical discopathy was: 16.6% C2–3, 16.6% C5–6, 16.6% C6–7, 33.3% C4–5, C5–6 (two levels in two patients) and 16.6% C4–5, C5–6, C7–1 (three levels in one patient) . The herniation directions were given as: central in 5 levels, right paramedian in 1 level, and left paramedian disc hernia in 1 level. There were 4 cervical disk hernia in the control group. The herniation direction were central in two, right paramedian in one, and left paramedian in one patient. [Conclusion] In this study, the existence of cervical disc herniation in fibromyalgia patients was found to be not different from the normal population.

Review of overlap between thermoregulation and pain modulation in fibromyalgia

Fibromyalgia (FM) syndrome is characterized by widespread pain that is exacerbated by cold and stress but relieved by warmth. We review the points along thermal and pain pathways where temperature may influence pain. We also present evidence addressing the possibility that brown adipose tissue activity is linked to the pain of FM given that cold initiates thermogenesis in brown adipose tissue through adrenergic activity, whereas warmth suspends thermogenesis. Although females have a higher incidence of FM and more resting thermogenesis, they are less able to recruit brown adipose tissue in response to chronic stress than males. In addition, conditions that are frequently comorbid with FM compromise brown adipose activity making it less responsive to sympathetic stimulation. This results in lower body temperatures, lower metabolic rates, and lower circulating cortisol/corticosterone in response to stress--characteristics of FM. In the periphery, sympathetic nerves to brown adipose also project to surrounding tissues, including tender points characterizing FM. As a result, the musculoskeletal hyperalgesia associated with conditions such as FM may result from referred pain in the adjacent muscle and skin.

Pressure pain thresholds of tender point sites in patients with fibromyalgia and in healthy controls

Pressure pain threshold (PPT) is defined as the minimum force applied which induces pain. This measure has proven to be commonly useful in evaluating tenderness symptom. Our aim was to study the intra-examiner reproducibility of PPT measurement, define cutoffs in normal groups, and compare these results with patients with fibromyalgia (FM). Fifty healthy females, 50 healthy males, and 20 patients with FM participated in the study. PPTs were assessed for 18 specific tender point sites by a dolorimeter. The intra-individual coefficient of variation determined by a test-retest PPT measurement procedure with 3-days interval reached, respectively, 17% and 13% in healthy females and males, versus 24% in patients with FM. PPTs were significantly lower in healthy females than in healthy males (p<0.01). Statistical analysis failed to show any differences between the dominant and nondominant side for both normal groups. PPTs were lower over all examined areas in patients with FM than those obtained in healthy females (p<0.000). Lower cutoff levels were calculated from normal values for all specific tender point sites. On average, 14 tender point sites in patients with FM were under the established lower cutoffs. In conclusion, pressure pain sensitivity was influenced by the anatomical localization of tender point and gender differences. Lowest PPTs were localized in trapezius, occiput, anterior cervical, and second rib. The reduction of total tender point score in patients with FM averaged 60% comparatively with normal values. PPT reproducibility and discrimination between the two groups were optimal for the gluteal and knee sites.

ATP, calcium and magnesium levels in platelets of patients with primary fibromyalgia

OBJECTIVES

To evaluate the intracellular levels of the high energy adenosine triphosphate nucleotide ATP and essential divalent cations, calcium and magnesium, in platelets of patients affected by primary fibromyalgia syndrome (FMs).

DESIGN AND METHOD

Platelet ATP and cation concentrations were measured in 25 patients affected by FMs and 25 healthy volunteers through a chemiluminescent and a fluorimetric assay, respectively.

RESULTS

Significant lower ATP levels were observed inside platelets of FM patients (fmol ATP/plt: 0.0169+/-0.0012 vs. healthy controls, fmol ATP/plt: 0.0306+/-0.0023, mean+/-SEM) (*** P<0.0001). A trend towards higher calcium concentrations (P=0.06) together with significant increased magnesium levels were also reported in platelets of patients by comparison with controls (P=0.02).

CONCLUSIONS

This preliminary study suggests that disturbances in the homeostasis of platelet ATP metabolism-signaling and calcium-magnesium flows might have a relevance in the pathogenesis of FMs.

Fibromyalgia: nosography and therapeutic perspectives

Fibromyalgia (FM) is an important cause of morbidity and health expenditure. Severe widespread extra-articular chronic pain, along with nonrestorative sleep, dominates the clinical syndrome. The pathogenesis of FM remains unclear. While dysfunction in serotoninergic neurotransmission is believed to play an important role, several neurologic and immuno-endocrine mechanisms may also be relevant. A theory is advanced based on an inherited imbalance in neuro-vegetative systems resulting from increased sympathetic tone because of a metabolic deficiency in the serotoninergic system that, when exposed to a precipitating event, leads to the development of the clinical manifestations of FM. The importance of both nonpharmacological treatments and multimodal medication management is stressed.

Characteristics of fibromyalgia in Muslim Bedouin women in a primary care clinic

BACKGROUND

Fibromyalgia (FM) has been described and studied in various sociocultural settings in both developed and developing countries.

OBJECTIVES

To study the clinical manifestations of FM and to describe its effect on quality of life in the unique setting of Muslim Bedouin women in the southern Israel Negev desert area.

METHODS

One hundred two Bedouin women were recruited from a primary health care clinic in the Negev area. All patients fulfilled American College of Rheumatology criteria for the diagnosis of FM. Tenderness was assessed by manual dolorimetry and the fibromyalgia impact questionnaire was utilized to estimate the severity of FM symptoms. Anxiety and depression were assessed by the Arthritis Impact Measurement Scales subscales and quality of life was evaluated by the SF-36 questionnaire.

RESULTS

The study population was characterized by a low educational level, a high rate of consanguinity, a high number of children per mother, and a high rate of polygamy. There was a high frequency of classic FM symptoms such as pain and fatigue, as well as anxiety and depression. The overall impact of FM on quality of life was exceedingly high (8.9 on a scale of 0 to 10).

CONCLUSIONS

FM is relatively common in the unique setting of Muslim Bedouin women and has a very significant impact on their quality of life as well as on their dependents. Physicians involved in the primary care of this population should be attentive to the manifestations of FM and related disorders.

Serum ghrelin levels but not GH, IGF-1 and IGFBP-3 levels are altered in patients with fibromyalgia syndrome

INTRODUCTION

Both hypothalamo-pituitary-insulin-like growth factor-1 (IGF-1) axis and ghrelin levels may be altered in fibromyalgia syndrome (FMS) due to increased somatostatin tone. The aim of this study is to compare hypothalamo-pituitary-IGF-1 axis, ghrelin concentrations and their relations in premenopausal women with FMS and premenopausal healthy controls.

METHODS

Seventy-five women (47 FMS and 28 healthy women) were enrolled in the study. Fasting plasma glucose, serum growth hormone (GH), insulin, C-peptide, IGF-1, insulin-like growth factor binding protein-3 (IGFBP-3) and ghrelin levels were measured. Depressive symptoms were assessed using beck depression inventory. Pain intensity and sleep disturbance were recorded on a visual analog scale. The activity of daily living was assessed by fibromyalgia impact questionnaire.

RESULTS

There were no significant differences in GH, IGF-1, IGFBP-3, glucose, insulin, and C-peptide levels between patients and controls (p>0.05), whereas ghrelin levels were significantly lower in patients than controls (p<0.05). Ghrelin levels were not correlated with GH, IGF-1, IGFBP-3, glucose, insulin, and C-peptide levels while they were positively correlated with tender point score and sleep disturbance score and negatively correlated with pain intensity score.

CONCLUSION

Our results suggest that low levels of ghrelin in FMS are not related to the changes in hypothalamo-pituitary-IGF-1 axis but may be related to some symptoms of FMS. Our results need to be clarified by further studies.

Increased neural sympathetic activation in fibromyalgia syndrome

Fibromyalgia (FM) is a syndrome characterized by widespread musculoskeletal pain, although the mechanisms underlying the pain have not been fully elucidated. FM patients describe a number of nonspecific symptoms, such as anxiety, depression, fatigue, unrefreshing sleep, and gastrointestinal complaints, which appear after a flu-like illness, or after physical or emotional trauma in half of the patients, and are often exacerbated by exertion, stress, lack of sleep, and weather changes. There may also be symptoms of orthostatic intolerance, which suggests underlying abnormalities in cardiovascular neural regulation. Research suggests that various components of the central nervous system are involved, including the hypothalamic-pituitary-adrenal (HPA) axis, pain-processing pathways, and the autonomic nervous system (ANS). This review discusses the general aspects of the altered HPA and ANS, sympathetic overactivity, and alterations in cardiovascular autonomic responses to gravitational stimuli.

Hypothalamic–Pituitary–Adrenal and Autonomic Nervous System Functioning in Fibromyalgia

In general, there seems to be a reduction in some neuroendocrine and autonomic nervous system (ANS) responses to applied stresses in individuals who have fibromyalgia. This article presents an overview and discussion of these findings with respect to the role of the ANS and the neuroendocrine system in the response to stress, with emphasis on the hypothalamic-pituitary-adrenal axis and the possible implication to fibromyalgia.

Abnormality in the self-monitoring mechanism in patients with fibromyalgia and somatoform pain disorder

BACKGROUND

Auditory hallucinations and passivity experiences are associated with an abnormality in the self-monitoring mechanism that normally allows us to distinguish self-produced from externally produced sensations. It is unclear if chronic central pain disorders such as fibromyalgia and somatoform pain disorders also involve a defect of the self-monitoring mechanism.

METHODS

Responses to tactile stimulation were assessed in four groups of subjects (N = 40): patients with fibromyalgia, patients with somatoform pain disorder, patients with schizophrenia with auditory hallucinations and/or passivity experiences, and normal control subjects. The subjects were asked to rate the perception of a tactile sensation on their left and right hands. The tactile stimulation was either self-produced by movement of the subject's right or left hand or externally produced by the experimenter.

RESULTS

Normal control subjects experienced self-produced stimuli as less intense than identical, externally produced tactile stimuli. In contrast, patients with fibromyalgia, patients with somatoform pain disorder, and patients with schizophrenia with auditory hallucinations and/or passivity experiences gave the same perceptual ratings for tactile stimuli produced by themselves as those produced by the experimenter (intergroup difference, p = .043; 95% confidence interval [CI], 0.16-0.68). Post hoc tests revealed that this significance was mainly caused by the fibromyalgia (p = .046; 95% CI, -1.66-0.13) and the somatoform pain disorder group (p = .033; 95% CI, -1.71-0.06).

CONCLUSIONS

We conclude that central pain disorders such as fibromyalgia and somatoform pain disorders interfere with the correct functioning of the self-monitoring mechanism that normally allows us to distinguish self-produced from externally produced tactile stimuli.

The possible effect of clinical recovery on regional cerebral blood flow deficits in fibromyalgia: a prospective study with semiquantitative SPECT

OBJECTIVES

Regional deficits in cerebral blood flow have been reported in a few studies of fibromyalgia; however, there is no information on the effects of treatment and clinical recovery on these abnormalities. We evaluated the effects of amitriptyline treatment and consequent clinical recovery on cerebral blood flow changes in fibromyalgia.

METHODS

We assessed cerebral blood flow with a semiquantitative functional brain mapping technique of single-photon emission computed tomography in 14 patients with primary fibromyalgia before and after 3 months of amitriptyline treatment. Patients were followed by visual analog scale, tender point count, and Beck Depression Inventory for clinical improvement.

RESULTS

There was statistically significant improvement in visual analog scale and tender point count after treatment. Beck Depression Inventory did not change significantly. Statistically significant blood flow increase in bilateral hemithalami and basal ganglia and decrease in bilateral temporal, left temporo-occipital, and right occipital lobes were observed on single-photon emission computed tomography after treatment.

CONCLUSIONS

We speculate that these findings could indicate that deficits in cerebral blood flow in fibromyalgia improve parallel to clinical recovery.

Violence, mental health, and physical symptoms in an academic internal medicine practice

OBJECTIVE

To assess how physical and/or sexual intimate partner violence (IPV), child abuse, and community violence relate to long-term mental and physical problems; to examine the overlap between different forms of violence and the impact of experiencing multiple forms of violence.

DESIGN

Cross-sectional survey.

SETTING

Three general internal medicine practices affiliated with an academic medical center.

PARTICIPANTS

English-speaking women aged 25 to 60.

MEASUREMENTS

Telephone or in-person interview and chart review.

RESULTS

One hundred seventy-four women completed interviews. A majority of participants experienced more than one form of violence. In separate multivariate analyses, each form of violence was associated with depressive symptoms or with at least 6 chronic physical symptoms, after adjustment for demographic factors and substance abuse. The degree of association with health outcomes was similar for each form of violence (odds ratio [OR], 2.4 to 3.9; P < .003). The association with chronic physical symptoms remained significant for IPV (OR, 3.3; P < .002) and community violence (OR, 3.4; P < .003), even after adjustment for depression and posttraumatic stress disorder. There were dose-response relationships between the number of forms of violence experienced and the odds of depressive symptoms and the odds of multiple chronic physical symptoms.

CONCLUSIONS

Multiple types of victimizations may contribute to patients' current mental health and physical problems. Research or clinical protocols that only focus on one form of violence may underestimate the complexity of women's experiences and needs.

Pain, psychological variables, sleep quality, and natural killer cell activity in midlife women with and without fibromyalgia

In women with fibromyalgia (FM), central nervous system (CNS) dysfunction in pain, mood, and sleep processes could be associated with changes in immune system indicators. The primary purpose of this study was to compare pain, psychological variables, subjective and objective sleep quality, lymphocyte phenotypes and activation markers, and natural killer activity (NKA) in midlife women with and without FM. A secondary purpose was to explore relationships among these variables in a step-wise regression. Subjects had pain pressure tender points assessed, completed a psychiatric interview and questionnaires (Beck Depression Inventory, SCL-90, Profile of Mood States, subjective sleep), and underwent polysomnograhic assessment for two consecutive nights. Lymphocyte phenotypes, activation markers, and NKA were assessed from blood drawn the morning after sleep laboratory night 2. Compared to controls, women with FM had lower pain thresholds, more psychological distress, higher depression scores, and reduced subjective and objective sleep quality. They also had fewer NK cells (p <.009) and more NK cells that expressed the IL-2 receptor (p <.04), but these differences were not statistically significant after correction for multiple comparisons. NKA was not statistically significantly lower in the women with FM compared to controls. In a multiple regression of age, tender point threshold, depression, psychological distress, and sleep efficiency, only the effect of group was significant (F = 5.479, p <.03) on NKA. In conclusion, we found little evidence to support the hypothesis that pain, mood, and sleep symptoms are associated with changes in the enumeration of peripheral lymphocytes or function in FM.

Increased DNA fragmentation and ultrastructural changes in fibromyalgic muscle fibres

OBJECTIVE

To determine whether there is evidence of increased DNA fragmentation and ultrastructural changes in muscle tissue of patients with fibromyalgia (FM) compared with healthy controls.

METHODS

Muscle tissues from 10 community residents with FM and 10 age and sex matched healthy controls were examined "blindly" for the presence of DNA fragmentation by two different methods: terminal deoxynucleotidyl transferase (TdT) staining (TUNEL) and the FragEL-Klenow DNA fragmentation detection kit. Ultrastructural analysis of tissue was performed by electron microscopy.

RESULTS

DNA fragmentation was detected by both methods in 55.4 (SEM 2.5)% of the nuclei in muscle tissue of patients with FM compared with 16.1 (4.1)% (p<0.001) of the nuclei in healthy controls. Contrary to expectation, no typical features of apoptosis could be detected by electron microscopy. The myofibres and actin filaments were disorganised and lipofuscin bodies were seen; glycogen and lipid accumulation were also found. The number of mitochondria was significantly lower in patients with FM than in controls and seemed to be morphologically altered.

CONCLUSION

The ultrastructural changes described suggest that patients with FM are characterised by abnormalities in muscle tissue that include increased DNA fragmentation and changes in the number and size of mitochondria. These cellular changes are not signs of apoptosis. Persistent focal contractions in muscle may contribute to ultrastructural tissue abnormalities as well as to the induction and/or chronicity of nociceptive transmission from muscle to the central nervous system.

[Diagnosis and clinical signs of fibromyalgia]

According to the criteria of the American College of Rheumatology (ACR 1990) fibromyalgia can be classified as a complex of clinical symptoms. It is characterised by widespread muscle pain, and pain in at least 11 out of 18 defined so-called tender points. The widespread muscle pain must be present for at least 3 months. For the diagnosis of fibromyalgia many other rheumatological, neurological and psychiatric diseases have to be excluded; additional autonomic or functional symptoms are usual. Routine laboratory or radiological examinations yield normal results. From a pathogenetic point of view endocrine disturbances and psychosocial stress factors are found. In most cases the clinical course shows a slow development of generalised pain.

Tricyclic antidepressants and fibromyalgia: what is the mechanism of action?

Fibromyalgia is a chronic pain disorder of which other clinical features, such as persistent fatigue and disordered sleep, may be a secondary consequence. The initial pharmacological approach to treating the disorder is the management of the pain. Tricyclic antidepressants are the most effective drugs in use so far, especially when administered in combination with other therapies (e.g., selective serotonin re-uptake inhibitors), which suggests modulation of the neurotransmitters serotonin and noradrenaline. The effectiveness of amitriptyline and related tricyclic antidepressants, however, is consistent with the involvement of mechanisms, such as potassium channel modulation and NMDA receptor antagonism, in addition to or in place of the modulation of monoamine neurotransmitters. Investigation of the importance of each of the pharmacological properties of amitriptyline and related molecules in the management of fibromyalgia could provide clues for the rational design of new drugs.

Neuroendocrine abnormalities in fibromyalgia

Fibromyalgia is a disorder of unknown etiology characterized by chronic, widespread musculoskeletal pain and symptoms such as fatigue, poor sleep, gastrointestinal complaints, and psychologic problems that are similar to those experienced by patients with hormone deficiencies. This review summarizes the available data on the neuroendocrine function in fibromyalgia, including data on hormone secretion, circadian phase, and autonomic nervous system function. Studies suggest that there may be lower activity of a number of hypothalamic-pituitary-peripheral gland axes and altered autonomic nervous system function in patients with fibromyalgia. These reductions in activity are mild to moderate and do not result from alterations in circadian rhythms. The reduced hormonal and autonomic responses appear to reflect an impairment in the hypothalamic or central nervous system response to stimuli rather than a primary defect at the level of the pituitary gland or the peripheral glands. A combination of multiple, mild impaired responses may lead to more profound physiologic and clinical consequences as compared with a defect in only one system, and could contribute to the symptoms of fibromyalgia.

Functional abnormalities of the cervical cord and lower medulla and their effect on pain: observations in chronic pain patients with incidental mild Chiari I malformation and moderate to severe cervical cord compression

OBJECTIVE

Abnormalities of central sensory processing may play a role in the pathogenesis of chronic pain. The Chiari I malformation is a congenital hindbrain anomaly characterized by protrusion of the cerebellar tonsils into the upper cervical canal, with variable effects on the lower brain stem and cervical cord. The purpose of this study was to compare sensory function and pain among patients with chronic pain who had these disorders incidentally diagnosed, to assess the effect on pain in these patients in comparison with those without central nervous system disease.

DESIGN

Retrospective study in which pain, mood, and sensory function in 32 patients with chronic pain who had mild Chiari I malformation were compared with that in 53 patients with chronic pain who had moderate to severe compression of the cervical spinal cord and 52 patients with chronic pain who had no apparent central nervous system disorder. Data had been collected previously as part of standard clinical assessments, including clinical neurological examinations, quantitative sensory testing, pain drawings, and psychometric testing with the Symptom Checklist 90.

PATIENTS

All subjects were patients of a hospital-based pain management practice who had been accepted for treatment over a 5-year period.

RESULTS

Both the Chiari I and cervical compression groups had long tract signs evident on clinical neurological examination. Quantitative sensory testing indicated elevations in the trigeminal territory among patients with Chiari I malformation and on the neck, hands, and feet in both the Chiari I and cervical compression groups. The extent of pain and mood disturbance was greatest in the Chiari I group and least in the group with no central nervous system disorder. Complex regional pain syndrome, fibromyalgia, and temporal mandibular joint disorder were more common among the Chiari I malformation group than among the other groups.

CONCLUSIONS

Quantitative sensory analysis indicates sensory dysfunction associated with Chiari I malformation and cervical cord compression. The pattern of sensory abnormality is consistent with medullary dysfunction among the patients with Chiari I malformation and cervical cord dysfunction among cord compression patients. There were differences in the types and extent of pain and the associated disorders of mood observed among the cohorts defined above. These differences may be partly due to the presence and location of central sensory dysfunction.

Individualizing the exercise prescription for persons with fibromyalgia

"Exercise is good for you; you must exercise, and just do it" are common admonitions to fibromyalgia (FM) patients by health professionals. "I can't exercise; I hurt too much to exercise; and, I don't have enough energy to exercise" are equally common responses from patients with FM. Such exchanges can lead to frustration for both patient and provider. The factor that neither participant in the dialogue is addressing is that exercise carries both risks and benefits for persons with FM. Although for decades exercise has been acknowledged to be a key component of the treatment of FM, the majority of FM patients remain aerobically unfit, with poor muscle strength and limited flexibility. Unfit muscle is theoretically more prone to muscle microtrauma, which causes localized pain and may trigger widespread pain through disordered central processing. The purpose of this article is to provide practicing health care providers with guidelines for prescribing exercise to FM patients that take into account the risk/benefit ratio. A sample exercise prescription is included.

Evaluation and management of endocrine dysfunction in fibromyalgia

Fibromyalgia-like symptoms such as muscle pain and tenderness, exhaustion, reduced exercise capacity, and cold intolerance, resemble symptoms associated with endocrine dysfunction like hypothyroidism, and adrenal or growth hormone insufficiency. To investigate the potential of management of endocrine abnormalities for relieve of symptoms of patients with fibromyalgia, we reviewed experimental and clinical studies of endocrine functioning and endocrine treatment. Serum GH, androgen, and 24-hour urinary cortisol levels of patients with fibromyalgia tend to be in the lower part of the normal range, while serum levels of thyroid hormone, female sex hormones, prolactin, and melatonin are normal. With exception of GH, these conclusions are based on studies in small samples. With respect to dynamic responsiveness of the hypothalamic-pituitary-adrenal (HPA) axis, the dexamethasone suppression test and stimulation with ACTH show normal results, while patients show marked ACTH hypersecretion in response to severe acute stressors, perhaps indicative of chronic CRH hyposecretion. This finding and slightly altered responsiveness of growth hormone, thyroid hormone, and prolactin in pharmacologic stimulation tests suggest a central rather than peripheral origin of endocrine deviations. Because hormone level deviations were not severe, occurred in subgroups of patients only, and few controlled clinical trials were performed, there is--unless future research shows otherwise--little support for hormone supplementation as a general therapy in the common patient with fibromyalgia. In patients with clinically overt hormone deficiency, hormonal supplementation is an option. In patients with hormone levels that are in the lower part of the normal range, interventions aimed at pain, fatigue, sleep or mood disturbance, and physical deconditioning may indirectly improve endocrine functioning.

Rational and targeted pharmacologic treatment of fibromyalgia

Despite disappointing results when subjected to randomized clinical trials, pharmacologic agents remain an important component of FM management. Addressing the main symptoms of pain, disturbed sleep, mood disturbances, fatigue, and associated conditions is essential to improve patient functioning and enhanced quality of life. However, much work remains to design clinical trials which address the complexity of FM, while satisfying evidence based medicine paradigms.

Prescribing exercise for people with fibromyalgia

Fibromyalgia (FM) is a costly and debilitating pain syndrome which is commonly encountered by advanced practice nurses working in acute care settings. Fibromyalgia affects nearly 6 million people in the United States, approximately 80% to 90% of whom are women. Symptoms of FM include widespread and localized pain, disrupted sleep, fatigue, visceral pain and other pain syndromes, neurological symptoms (eg, dizziness, numbness, tingling, impaired cognition), and exercise-induced pain. Difficulties remaining active with FM may lead to extreme deconditioning, inability to remain employed, and eventually even impaired ability in complete activities of daily living. Exercise that combats deconditioning without triggering pain is, therefore, a key component in treating FM. Clinicians who understand FM pain and associated symptoms can minimize the negative impact of deconditioning by prescribing disease-specific exercise for people with FM.

Is fibromyalgia a neurologic disease?

Fibromyalgia (FM) is characterized by abnormal pain sensitivity in response to diverse stimuli as well as persistent widespread pain and other symptoms such as fatigue and sleep disturbance. Progress has been made in identifying factors that contribute to the etiopathogenesis of abnormal pain sensitivity, but there is no single model of pathophysiology or treatment of FM that has gained wide acceptance among health care professionals. We review the literature on the etiopathogenesis of abnormal pain sensitivity in FM and describe an explanatory model that serves as a source of testable hypotheses in our laboratory. This model posits that interactions of exogenous (e.g., environmental stressors) and endogenous (e.g., neuroendocrine dysfunction) abnormalities in genetically predisposed individuals lead to a final common pathway, i.e., alterations in central nervous system function and neuropeptide production that underlie central sensitization and abnormal pain sensitivity. This model also suggests that efforts to develop and evaluate treatments for FM should focus on interventions with direct or indirect effects on central functions that influence pain sensitivity.

Neuroendocrine mechanisms in fibromyalgia-chronic fatigue

Fibromyalgia and chronic fatigue syndrome are poorly understood disorders that share similar demographic and clinical characteristics. Because of the clinical similarities between both disorders it was suggested that they share a common pathophysiological mechanism, namely, central nervous system dysfunction. This chapter presents data demonstrating neurohormonal abnormalities, abnormal pain processing and autonomic nervous system dysfunction in fibromyalgia and chronic fatigue syndrome. The possible contribution of the central nervous system dysfunction to the development and symptomatology of these conditions is discussed. The chapter concludes by reviewing the effect of current treatments and emerging therapeutic modalities in fibromyalgia and chronic fatigue syndrome.

Pain complaints in patients with fibromyalgia versus chronic fatigue syndrome

Individuals with fibromyalgia (FM) and/or chronic fatigue syndrome (CFS) report arthralgias and myalgias. However, only persons with FM alone exhibit abnormal pain responses to mild levels of stimulation, or allodynia. We identify the abnormalities in the neuroendocrine axes that are common to FM and CFS as well as the abnormalities in central neuropeptide levels and functional brain activity that differentiate these disorders. These two sets of factors, respectively, may account for the similarities and differences in the pain experiences of persons with FM and CFS.

Pharmacologic treatment of fibromyalgia

Fibromyalgia is a chronic syndrome characterized by widespread pain, unrefreshed sleep, disturbed mood, and fatigue. Until such time as we have a clearer understanding of the trigger and/or pathophysiologic mechanisms producing these symptoms, pharmacologic treatment should be aimed at individual symptoms. Such treatment should ideally be offered as part of a multidisciplinary treatment program using both pharmacologic and nonpharmacologic treatment modalities. Critical components of any successful fibromyalgia treatment program include addressing physical fitness, work and other functional activities, and mental health, in addition to symptom-specific therapies. The main symptoms that should be addressed include pain, sleep disturbances including restless leg syndrome, mood disturbances, and fatigue. Pharmacologic therapy should also be considered for syndromes commonly associated with fibromyalgia including irritable bowel syndrome, interstitial cystitis, migraine headaches, temporomandibular joint dysfunction, dysequilibrium including neurally mediated hypotension, sicca syndrome, and growth hormone deficiency. This article provides general guidelines in initiating a successful pharmacologic treatment program for fibromyalgia.

[What happens to the fibromyalgia syndrome?]

OBJECTIVE

To realize a clarification about fibromyalgia, attempting to consider diagnostic criteria, prevalence, pathophysiology and therapeutic approach.

METHOD

A systematic literature search was conducted to select articles about fibromyalgia and connected diseases. The database are Premedline, Medline and Medlineplus.

RESULTS

Fifty-eight articles about fibromyalgia and twelve articles about connected diseases were selected to realize this review of literature.

DISCUSSION

Fibromyalgia constitutes a syndrome characterized by widespread musculo-skeletal pain, present above the waist and below the waist and in the axial skeleton. Widespread pain must have been present for at least three months. "Spasmophilie", chronic fatigue syndrome and myofascial syndrome represent diseases connected with fibromyalgia: differential diagnosis must be established. Researches related to fibromyalgia suggest a reduction of muscular performances associated with histological and biochemical anomalies. Patients are characterized by shorter and nonrestorative sleep. Psychological, neuroendocrine and central alterations appear often associated with fibromyalgia. The reduction of pressure tolerance and pain thresholds may be linked to the alterations of neuroendocrine substances. Literature recommend a multidisciplinary therapeutic approach in management of fibromyalgia.

CONCLUSION

The pathophysiologic mechanisms in fibromyalgia appear multiple and interdependent. With the aim to optimizing treatment, investigations are necessary to determine biochemical repercussions of various therapeutic approaches.

Psychological determinants of fibromyalgia and related syndromes

Fibromyalgia and other chronic pain and fatigue syndromes constitute an increasingly greater societal burden that currently is not being approached effectively by traditional Western medicine. Although the hallmarks of fibromyalgia--chronic widespread pain, fatigue, and multiple other somatic symptoms--have neurophysiologic and endocrinologic underpinnings, these biological aspects derive primarily from psychological variables. Female gender, adverse experiences during childhood, psychological vulnerability to stress, and a stressful, often frightening environment and culture are important antecedents of fibromyalgia. To understand fibromyalgia and related syndromes and to provide optimum care requires a biopsychosocial, not a biomedical, viewpoint.

Static magnetic fields for treatment of fibromyalgia: a randomized controlled trial

OBJECTIVE

To test effectiveness of static magnetic fields of two different configurations, produced by magnetic sleep pads, as adjunctive therapies in decreasing patient pain perception and improving functional status in individuals with fibromyalgia.

DESIGN

Randomized, placebo-controlled, 6-month trial conducted from November 1997 through December 1998.

SETTING AND SUBJECTS

Adults who met the 1990 American College of Rheumatology criteria for fibromyalgia were recruited through clinical referral and media announcements and evaluated at a university-based clinic.

INTERVENTIONS

Subjects in Functional Pad A group used a pad for 6 months that provided whole-body exposure to a low, uniform static magnetic field of negative polarity. Subjects in the Functional Pad B group used a pad for 6 months that exposed them to a low static magnetic field that varied spatially and in polarity. Subjects in two Sham groups used pads that were identical in appearance and texture to the functional pads but contained inactive magnets; these groups were combined for analysis. Subjects in the Usual Care group continued with their established treatment regimens.

OUTCOME MEASURES

Primary outcomes were the change scores at 6 months in the following measures: functional status (Fibromyalgia Impact Questionnaire), pain intensity ratings, tender point count, and a tender point pain intensity score.

RESULTS

There was a significant difference among groups in pain intensity ratings (p = 0.03), with Functional Pad A group showing the greatest reduction from baseline at 6 months. All four groups showed a decline in number of tender points, but differences among the groups were not significant (p = 0.72). The functional pad groups showed the largest decline in total tender point pain intensity, but overall differences were not significant (p = 0.25). Improvement in functional status was greatest in the functional pad groups, but differences among groups were not significant (p = 0.23).

CONCLUSIONS

Although the functional pad groups showed improvements in functional status, pain intensity level, tender point count, and tender point intensity after 6 months of treatment, with the exception of pain intensity level these improvements did not differ significantly from changes in the Sham group or in the Usual Care group.

Regional cerebral blood flow in fibromyalgia: single-photon-emission computed tomography evidence of reduction in the pontine tegmentum and thalami

OBJECTIVE

To determine whether regional cerebral blood flow (rCBF) is abnormal in any cerebral structure of women with fibromyalgia (FM), following a report that rCBF is reduced in the thalami and heads of caudate nuclei in FM.

METHODS

Seventeen women with FM and 22 healthy women had a resting single-photon-emission computed tomography (SPECT) brain scan to assess rCBF and a T1-weighted magnetic resonance imaging (MRI) scan to enable precise anatomic localization. Additionally, all participants underwent 2 manual tender point examinations and completed a set of questionnaires evaluating clinical features. SPECT scans were analyzed for differences in rCBF between groups using statistical parametric mapping (SPM) and regions of interest (ROIs) manually drawn on coregistered MRI.

RESULTS

Compared with control subjects, the rCBF in FM patients was significantly reduced in the right thalamus (P = 0.006), but not in the left thalamus or head of either caudate nucleus. SPM analysis indicated a statistically significant reduction in rCBF in the inferior pontine tegmentum (corrected P = 0.006 at the cluster level and corrected P = 0.023 for voxel of maximal significance), with consistent findings from ROI analysis (P = 0.003). SPM also detected a reduction in rCBF on the perimeter of the right lentiform nucleus. No correlations were found with clinical features or indices of pain threshold.

CONCLUSION

Our finding of a reduction in thalamic rCBF is consistent with findings of functional brain imaging studies of other chronic clinical pain syndromes, while our finding of reduced pontine tegmental rCBF is new. The pathophysiologic significance of these changes in FM remains to be elucidated.

Trauma and fibromyalgia: is there an association and what does it mean?

OBJECTIVES

The primary objective is to review current research with respect to the role of trauma in fibromyalgia (FM). A secondary objective is to hypothesize which steps need to be taken, first to determine whether such an association truly exists, and second to clarify what such an association might mean.

METHODS

An extensive literature review was undertaken, including Medline from 1979 to the present.

RESULTS

The strongest evidence supporting an association between trauma and FM is a recently published Israeli study in which adults with neck injuries had greater than a 10-fold increased risk of developing FM within 1 year of their injury, compared with adults with lower extremity fractures (P= .001). Several other studies provide a hypothetical construct for such an association. These include studies on (1) postinjury sleep abnormalities; (2) local injury sites as a source of chronic distant regional pain; and (3) the concept of neuroplasticity. There are, however, several primary arguments against such an association: (1) FM may not be a distinct clinical entity; (2) FM may be a psychological, rather than physical, disease; (3) the evidence supporting any association is limited and not definitive; (4) the Israeli study, itself, has some methodological limitations; and (5) other factors may be more important than the injurious event in determining chronic symptoms after an acute injury.

CONCLUSIONS

Although there is some evidence supporting an association between trauma and FM, the evidence is not definitive. Further prospective studies are needed to confirm this association and to identify whether trauma has a causal role.

Psychological and behavioral approaches to pain management for patients with rheumatic disease

This article reviews the efficacy of the psychological and behavioral pain management interventions that have been evaluated among adult patients with rheumatoid arthritis (RA), osteoarthritis (OA), and fibromyalgia (FM). Using published criteria for empirically validated interventions, it is concluded that cognitive-behavioral therapies and the Arthritis Self-Management Program represent well-established treatments for pain among patients with RA and OA. These interventions involve education, training in relaxation and other coping skills, and rehearsal of these skills in patients' home and work environments. There currently are no psychological or behavioral interventions for pain among FM patients that can be considered as well-established treatments. Future intervention research should use clinically meaningful change measures in addition to conventional tests of statistical significance, attend to the pain management needs of children, and assess whether outcomes produced in university-based treatment centers generalize to those in local treatment settings.