Update of the guidelines for the pharmacological treatment of rheumatoid arthritis by the Mexican College of Rheumatology 2023.

OBJECTIVE: To develop updated guidelines for the pharmacological management of rheumatoid arthritis (RA). METHODS: A group of experts representative of different geographical regions and various medical services catering to the Mexican population with RA was formed. Questions based on Population, Intervention, Comparison, and Outcome (PICO) were developed, deemed clinically relevant. These questions were answered based on the results of a recent systematic literature review (SLR), and the evidence's validity was assessed using the GRADE system, considered a standard for these purposes. Subsequently, the expert group reached consensus on the direction and strength of recommendations through a multi-stage voting process. RESULTS: The updated guidelines for RA treatment stratify various therapeutic options, including different classes of DMARDs (conventional, biologicals, and JAK inhibitors), as well as NSAIDs, glucocorticoids, and analgesics. By consensus, it establishes the use of these in different subpopulations of interest among RA patients and addresses aspects related to vaccination, COVID-19, surgery, pregnancy and lactation, and others. CONCLUSIONS: This update of the Mexican guidelines for the pharmacological treatment of RA provides reference points for evidence-based decision-making, recommending patient participation in joint decision-making to achieve the greatest benefit for our patients. It also establishes recommendations for managing a variety of relevant conditions affecting our patients.

The value of inquiring patients about local discomfort during blood pressure measurement for fibromyalgia detection. A cross-sectional study.

BACKGROUND: Fibromyalgia overlaps and/or mimics other rheumatic diseases and may be a confounding factor in the clinimetric assessment of these illnesses. Allodynia is a distinctive fibromyalgia feature that can be elicited during routine blood pressure measurement. For epidemiological purposes fibromyalgia can be diagnosed using the 2016 Wolfe et al. criteria questionnaire. No physical examination is required. OBJECTIVE: To evaluate the role of a straightforward question formulated during routine blood pressure measurement for fibromyalgia detection in a rheumatology outpatient clinic. PATIENTS AND METHODS: All adult patients attending our Rheumatology outpatient clinic were invited to participate. While awaiting their medical consultation, they filled-out the 2016 Wolfe et al. FM diagnostic criteria questionnaire. During the ensuing routine physical examination, the physician advanced the following guideline: "I am going to take your blood pressure; tell me if the cuff's pressure causes pain". Then, blood pressure cuff was inflated to 170 mm/Hg. Sphygmomanometry induced allodynia was defined as any local discomfort caused by blood pressure measurement. If a patient voiced any uneasiness, a follow-up dichotomic question was formulated "did it hurt much or little". Sphygmomanometry-induced allodynia was correlated with the presence of fibromyalgia according to the 2016 Wolfe diagnostic criteria. RESULTS: Four hundred and ninety-one patients were included in the study; most of them (84%) were female. The female cohort displayed the following features: Twenty five percent had fibromyalgia. Twenty seven percent had sphygmomanometry-induced allodynia. In women, sphygmomanometry-evoked allodynia had 63% sensitivity and 84% specificity for fibromyalgia diagnosis. The area under curve was 0.751. Moreover, having "much" local pain elicitation during blood pressure testing had 23% sensitivity and 96% specificity for fibromyalgia diagnosis. Men behaved differently; 15% fulfilled the fibromyalgia diagnostic criteria, but only 2% had sphygmomanometry induced allodynia. CONCLUSIONS: Inquiring female patients about local discomfort during routine blood pressure measurement is a simple and efficient procedure for fibromyalgia detection. This undemanding approach could be implemented in all clinical settings. There is marked sexual dimorphism in the link between sphygmomanometry-induced allodynia and fibromyalgia diagnosis. The presence of fibromyalgia is almost certain in those individuals having substantial pain elicitation during blood pressure measurement.

Interferon-alpha regulates expression of lncRNA MALAT1 and interferon-stimulated genes, as well as chemokine production, in primary Sjögren's syndrome.

OBJECTIVES: This study aimed to explore the contribution of interferon-alpha (IFN-α) to MALAT1 expression in primary Sjögren's syndrome (pSS). METHODS: Peripheral blood mononuclear cells (PBMC) from pSS patients and healthy blood donors were stimulated with recombinant human IFN-α, and the expression levels of MALAT1 and several interferon-stimulated genes (ISGs) were measured by RT-PCR, while supernatant levels of interferon-regulated chemokines were measured using multiplex cytokine immunobead assay. RESULTS: In this work, we found that MALAT1 expression levels were increased in IFN-α-stimulated PBMC from pSS patients and healthy controls. As expected, ISG expression levels and interferon-regulated chemokine secretion levels were higher after IFN-α stimulation. However, the fold-change values for ISG15, Ly6E, OAS1, and OASL expression levels were higher in cells from pSS patients than in controls. Similarly, PBMC from pSS patients produced higher concentrations of chemokines than those from healthy controls after IFN-α stimulation. CONCLUSIONS: Our data provide insights into the abnormal IFN-α-mediated regulation of the lncRNA MALAT1 in pSS. Based on an unusually high capacity of PBMC to express ISG and to produce interferon-responsive chemokines, it is likely that targeted therapies to block these molecules may be of benefit to patients with pSS.

Clinical overlap between fibromyalgia and myalgic encephalomyelitis. A systematic review and meta-analysis.

Myalgic encephalomyelitis is an illness characterized by profound malaise after mental or physical effort occurring in patients already suffering from constant fatigue. On the other hand, widespread pain and widespread allodynia are the core fibromyalgia clinical features. There is controversy on these two syndromes alikeness. Through the years, different diagnostic and/or classification criteria have been put forward to appraise both fibromyalgia and myalgic encephalomyelitis. The epidemiology of these two illnesses, and their overlap, may vary accordingly to the used definition. The most recent Wolfe et al. 2016 fibromyalgia diagnostic criteria incorporates three myalgic encephalomyelitis features including fatigue, waking unrefreshed and dyscognition. The objective of this meta-analysis was to define the clinical overlap between fibromyalgia and myalgic encephalomyelitis based on a systematic literature review. METHODS: PubMed, Embase, Lilacs, and Cochrane data bases were searched on January 25, 2021 linking the medical subject heading "Fibromyalgia" to the following terms "chronic fatigue syndrome", "myalgic encephalomyelitis" and "systemic exertion intolerance disease". Our review included all original articles in which the clinical overlap between fibromyalgia and myalgic encephalomyelitis could be quantified based on recognized diagnostic or classification criteria. Articles scrutiny and selection followed the PRISMA guidelines. Each study quality was assessed according to GRADE recommendations. The global clinical overlap was calculated using a fixed effect model with inverse variance-weighted average method. RESULTS: Twenty one publications were included in the meta-analysis. Reviewed studies were highly dissimilar in their design, objectives, sample size, diagnostic criteria, and/or outcomes yielding a 98% heterogeneity index. Nevertheless, the clinical overlap between fibromyalgia and myalgic encephalomyelitis was a well defined outcome that could be reliably calculated despite the high heterogeneity value. All reviewed publications had moderate GRADE evidence level. Most evaluated articles used the old 1990 Wolfe et al. fibromyalgia diagnostic criteria. Myalgic encephalomyelitis and fibromyalgia diagnoses overlapped in 47.3% (95% CI: 45.97-48.63) of the reported cases. CONCLUSION: This meta-analysis found prominent clinical overlap between fibromyalgia and myalgic encephalomyelitis. It seems likely that this concordance would be even higher when using the most recent Wolfe et al. 2016 fibromyalgia diagnostic criteria.

Interferon Lambda 3/4 (IFNλ3/4) rs12979860 Polymorphisms Is Not Associated With Susceptibility to Systemic Lupus Erythematosus, Although It Regulates OASL Expression in Patients With SLE.

Systemic lupus erythematosus (SLE) is an autoimmune disease with a complex etiology. Various genetic factors are associated with susceptibility to developing SLE and contribute to its onset and progression. Different single-nucleotide polymorphisms (SNPs) have been associated with SLE in several populations. The rs12979860 SNP in interferon lambda 3/4 (IFNλ3/4) is significantly associated with SLE susceptibility in patients negative for nephritis in Taiwanese people, and interferon-stimulated genes (ISGs) are differentially expressed in normal liver by the rs12979860 genotype. This study aimed to investigate whether rs12979860 is associated with the presence of SLE and lupus nephritis in Mexican individuals as well as with the expression of several ISGs in SLE patients. In total, 439 SLE patients and 358 healthy donors were genotyped for rs12979860 using real-time PCR, and allelic discrimination plots were constructed. Additionally, peripheral blood mononuclear cells (PBMCs) were isolated from the venous blood of SLE patients by centrifugation (n = 78). The mRNA levels of 2'-5'-oligoadenylate synthetase like (OASL), myxovirus resistance 1 (MX1), 2'5'-oligoadenylate synthetase 1 (OAS1), interferon-stimulated gene 15 (ISG15) and lymphocyte antigen 6 complex, locus E (LY6E) were determined using real-time PCR. The distributions of rs12979860 genotypes and allele frequencies were compared between SLE patients and healthy donors; case-control analysis revealed that rs12979860 was not associated with SLE susceptibility (OR 1.18, 95% CI 0.97-1.45, p = 0.08) or with the risk for lupus nephritis (OR 0.913, 95% CI 0.590-1.411, p = 0.682). However, OASL expression levels in PBMCs were significantly different between rs12979860 genotypes in SLE patients: median OASL mRNA levels were significantly higher in patients carrying the CC genotype (197.10, IQR 71.10-411.17) than in those with CT/TT genotypes (173.75, IQR 58.80-278.75, p = 0.016). Our results suggest that the SNP rs12979860 does not play a relevant role in susceptibility to SLE in Mexican individuals. However, IFNλ3/4 genotypes appear to be associated with OASL expression in PBMCs from patients with SLE.

Complex Regional Pain Syndrome Evolving to Full-Blown Fibromyalgia: A Proposal of Common Mechanisms.

BACKGROUND: Spread of complex regional pain syndrome (CRPS) outside the affected limb is a well-recognized phenomenon; nevertheless, the actual evolution from CRPS to fibromyalgia is poorly documented. Similar mechanisms have been recently put forward to explain the development of CRPS and fibromyalgia including dorsal root ganglia (DRG) hyperexcitability and small fiber neuropathy. OBJECTIVES: The aims of this study were to describe 3 cases with typical CRPS evolving to full-blown fibromyalgia and to discuss the potential pathogenetic mechanisms linking these debilitating illnesses. METHODS: This was a review of medical records and PubMed search on the relationship between CRPS-fibromyalgia with DRG and small nerve fiber neuropathy. RESULTS: Our 3 cases displayed over time orderly evolution from CRPS to fibromyalgia. Dorsal root ganglion hyperexcitability and small fiber neuropathy have been recently demonstrated in CRPS and in fibromyalgia. Dorsal root ganglia contain the small nerve fiber cell bodies surrounded by glial cells. After trauma, DRG perineuronal glial cells produce diverse proinflammatory mediators. Macrophages, lymphocytes, and satellite glial cells may drive the immune response to more rostrally and caudally located DRG and other spinal cord sites. Dorsal root ganglion metabolic changes may lead to small nerve fiber degeneration. This mechanism may explain the development of widespread pain and autonomic dysfunction. CONCLUSIONS: Clinicians should be aware that CRPS can evolve to full-blown fibromyalgia. Spreading of neuroinflammation through DRG glial cell activation could theoretically explain the transformation from regional to generalized complex pain syndrome.

Correlation Between Corneal Nerve Density and Symptoms of Small Fiber Neuropathy in Patients With Fibromyalgia: The Confounding Role of Severe Anxiety or Depression.

OBJECTIVE: A consistent line of investigation proposes fibromyalgia as a dysautonomia-associated neuropathic pain syndrome. Comorbid anxiety or depression amplifies fibromyalgia symptoms. The recent recognition of small fiber neuropathy in fibromyalgia patients supports the neuropathic nature of the illness. Corneal confocal microscopy accurately identifies small nerve fiber pathology. The newly developed Small-Fiber Symptom Survey captures the spectrum of small fiber neuropathy symptoms. We aimed to correlate corneal nerve density with different fibromyalgia disease severity questionnaires including the Small-Fiber Symptom Survey. We defined the possible confounding role of comorbid anxiety or depression severity in the clinical-pathological association. METHODS: This is a case series of 28 women with fibromyalgia. A single ophthalmologist quantified corneal subbasal plexus nerve density. Corneal innervation was correlated (Spearman ρ) with the following clinical questionnaires scores: Small-Fiber Symptom Survey, Revised Fibromyalgia Impact Questionnaire, and COMPASS-31 (Composite Autonomic Symptom Survey 31-Item Score). Validated inquiry forms assessed the comorbid anxiety and/or depression severity. RESULTS: There were no clinical-pathological correlations in the group as a whole. In the subgroup of fibromyalgia women without severe anxiety or depression (n = 13), there was a strong negative correlation between corneal nerve density with the Small-Fiber Symptom Survey score (ρ = -0.771, p = 0.002) and COMPASS-31 score (ρ = -0.648, p = 0.017). Patients with profound anxiety or depression (n = 15) had more intense symptoms but had not clinical-pathological correlations. CONCLUSIONS: Small fiber neuropathy and dysautonomia symptoms correlate with corneal denervation in women with fibromyalgia without severe anxiety or depression. This clinical-pathological association reinforces fibromyalgia as a dysautonomia-related neuropathic pain syndrome. Severe anxiety or depression distorts fibromyalgia symptoms. PRACTICAL POINT: Corneal confocal microscopy may become a useful procedure to study fibromyalgia patients.

Assessment of inflammatory activity in Takayasu's arteritis: performance of clinical scores and common biomarkers versus 18F-FDG PET/CT.

OBJECTIVES: There is no consensus on how to evaluate inflammatory activity in Takayasu's arteritis (TAK). Here we compare biochemical tests and three clinical scores, which evaluate inflammatory activity (IA) in TAK, versus quantitative 18F-FDG PET/CT as the gold standard. METHODS: This prospective study included patients with TA diagnosed according to the American College of Rheumatology (ACR) criteria. IA was assessed through laboratory tests, clinical scores of the National Institute of Health (NIH), Dabague-Reyes (DR) and the Indian Takayasu Clinical Activity Score 2010 (ITAS2010), and the result of these assessments was compared against 18F-FDG PET/CT Standardised Uptake Values (SUVmax). RESULTS: A total of 35 patients were studied, 86% were women. SUVmax had positive correlations with acute phase reactants and DR and NIH. Agreement of 18F-FDG PET/CT was significant with erythrocyte sedimentation rate (ESR) and DR score. Receiver Operating Characteristic (ROC) curve analysis showed diagnostic value for inflammatory activity in ESR, DR and NIH scores, which had higher specificity when they were estimated with new cut-off points for the Mexican population. CONCLUSIONS: ESR and other phase reactants have good sensitivity but low specificity to evaluate IA in TAK when compared against 18F-FDG PET/CT. Among all the clinical scores, DR had the best diagnostic value, with strong potential as a clinical tool to define the inflammatory status in TAK patients when the study image is not available. However, in complex TAK cases with doubtful diagnosis after assessment by clinical scores or laboratory, 18F-FDG PET/CT remains mandatory.

Ambroxol for fibromyalgia: one group pretest-posttest open-label pilot study.

A consistent line of investigation proposes that fibromyalgia is a sympathetically maintained neuropathic pain syndrome. Dorsal root ganglia sodium channels may play a major role in fibromyalgia pain transmission. Ambroxol is a secretolytic agent used in the treatment of various airway disorders. Recently, it was discovered that this compound is also an efficient sodium channel blocker with potent anti-neuropathic pain properties. We evaluated the add-on effect of ambroxol to the treatment of fibromyalgia. We studied 25 patients with fibromyalgia. Ambroxol was prescribed at the usual clinical dose of 30 mg PO 3 times a day × 1 month. At the beginning and at the end of the study, all participants filled out the Revised Fibromyalgia Impact Questionnaire (FIQ-R) and the 2010 ACR diagnostic criteria including the widespread pain index (WPI). At the end of the study, FIQ-R decreased from a baseline value of 62 ± 15 to 51 ± 19 (p = 0.013). Pain visual analogue scale decreased from 77 ± 14 to 56 ± 30 (p = 0.018). WPI diminished from 14.6 ± 3.1 to 10.4 ± 5.3 (p = 0.001). Side effects were minor. In this pilot study, the use of ambroxol was associated to decreased fibromyalgia pain and improved fibromyalgia symptoms. The open nature of our study does not allow extracting the placebo effect from the positive results. The drug was well tolerated. Ambroxol newly recognized pharmacological properties could theoretically interfere with fibromyalgia pain pathways. Dose escalating-controlled studies seem warranted.

HPV vaccination syndrome. A questionnaire-based study.

Isolated cases and small series have described the development of complex regional pain syndrome, postural orthostatic tachycardia, and fibromyalgia after human papillomavirus (HPV) vaccination. These illnesses are difficult to diagnose and have overlapping clinical features. Small fiber neuropathy and dysautonomia may play a major role in the pathogenesis of these entities. We used the following validated questionnaires to appraise the chronic illness that might appear after HPV vaccination: The 2010 American College of Rheumatology Fibromyalgia Diagnostic Criteria, COMPASS 31 dysautonomia questionnaire, and S-LANSS neuropathic pain form. These questionnaires and a "present illness" survey were e-mailed to persons who had the onset of a chronic ailment soon after HPV vaccination. Forty-five filled questionnaires from individuals living in 13 different countries were collected in a month's period. Mean (±SD) age at vaccination time was 14 ± 5 years. Twenty-nine percent of the cases had immediate (within 24 h) post-vaccination illness onset. The most common presenting complaints were musculoskeletal pain (66%), fatigue (57%), headache (57%), dizziness/vertigo (43%), and paresthesias/allodynia (36%). Fifty-three percent of affected individuals fulfill the fibromyalgia criteria. COMPASS-31 score was 43 ± 21, implying advanced autonomic dysfunction. Eighty-three percent of the patients who had ongoing pain displayed S-LANSS values >12, suggesting a neuropathic component in their pain experience. After a mean period of 4.2 ± 2.5 years post-vaccination, 93% of patients continue to have incapacitating symptoms and remain unable to attend school or work. In conclusion, a disabling syndrome of chronic neuropathic pain, fatigue, and autonomic dysfunction may appear after HPV vaccination.

Small fiber neuropathy in women with fibromyalgia. An in vivo assessment using corneal confocal bio-microscopy.

OBJECTIVE: A consistent line of investigation suggests that fibromyalgia is a neuropathic pain syndrome. This outlook has been recently reinforced by several controlled studies that describe decreased small nerve fiber density in skin biopsies of patients with fibromyalgia. The cornea receives the densest small fiber innervation of the body. Corneal confocal bio-microscopy is a new noninvasive method to evaluate small nerve fiber morphology. Our objective was to assess corneal small nerve fiber morphology in patients with fibromyalgia, and to associate corneal nerve microscopic features with neuropathic pain descriptors and other fibromyalgia symptoms. METHODS: We studied 17 female patients with fibromyalgia and 17 age-matched healthy control subjects. All the participants completed different questionnaires regarding the symptoms of fibromyalgia, including a neuropathic pain survey. A central corneal thickness scan was obtained with a confocal microscope. Nerve measurements were made by a single ophthalmologist without knowledge of the clinical diagnosis. Stromal nerve thickness was defined as the mean value between the widest and the narrowest portion of each analyzed stromal nerve. Corneal sub-basal plexus nerve density was also assessed. RESULTS: Patients with fibromyalgia had stromal nerve thickness of 5.0 ± 1.0 µm (mean ± standard deviation) significantly different from that of control's values (6.1 ± 1.3) p = 0.01. Patients also had decreased sub-basal plexus nerve density per square millimeter (85 ± 29) vs. 107 ± 26 of controls p = 0.02. When controls and patients were grouped together, there was an association between stromal nerve slenderness and neuropathic pain descriptors (Fisher's exact test p = 0.007). CONCLUSION: Women suffering from fibromyalgia have thinner corneal stromal nerves and diminished sub-basal plexus nerve density when compared to healthy controls. Nerve scarcity is associated with neuropathic pain descriptors. Small fiber neuropathy may play a role in the pathogenesis of fibromyalgia pain. Corneal confocal microscopy could become a useful test in the study of patients with fibromyalgia.

Sympathetic nervous system dysfunction in fibromyalgia, chronic fatigue syndrome, irritable bowel syndrome, and interstitial cystitis: a review of case-control studies.

BACKGROUND: Fibromyalgia often coexists and overlaps with other syndromes such as chronic fatigue, irritable bowel syndrome, and interstitial cystitis. Chronic stress has been implicated in the pathogenesis of these illnesses. The sympathetic nervous system is a key element of the stress response system. Sympathetic dysfunction has been reported in these syndromes, raising the possibility that such dysautonomia could be their common clustering underlying pathogenesis. OBJECTIVE: The objective of this study was to carry out a review of all published comparative case-control studies investigating sympathetic nervous system performance in fibromyalgia, chronic fatigue syndrome, irritable bowel syndrome, and interstitial cystitis. METHODS: Online databases PubMed and EMBASE were accessed using the following key words: autonomic (OR) sympathetic (AND) fibromyalgia, chronic fatigue syndrome, irritable bowel syndrome, and interstitial cystitis. All entries up to December 10th 2012 were reviewed by 2 independent investigators searching for case-control studies in humans. The Method for Evaluating Research and Guidelines Evidence adapted to the Scottish Intercollegiate Guidelines Network was used to rank the level of evidence contained in the selected articles. RESULTS: A total of 196 articles are included in this review. The most often used methods to assess sympathetic functionality were heart rate variability analysis, sympathetic skin response, tilt table testing, and genetic studies. The majority of studies (65%) described sympathetic nervous system predominance in these overlapping syndromes. In contrast, 7% of the studies found parasympathetic predominance. CONCLUSIONS: This review demonstrates that sympathetic nervous system predominance is common in fibromyalgia, chronic fatigue syndrome, irritable bowel syndrome, and interstitial cystitis. This concordance raises the possibility that sympathetic dysfunction could be their common underlying pathogenesis that brings on overlapping clinical features. The recognition of sympathetic predominance in these 4 syndromes may have potential clinical implications. It may be worth exploring the use of nonpharmacological measures as well as drug therapies aimed to regain autonomic balance.

A prospective open-label pilot study of fluvastatin on proinflammatory and prothrombotic biomarkers in antiphospholipid antibody positive patients.

OBJECTIVE: To determine if proinflammatory and prothrombotic biomarkers are differentially upregulated in persistently antiphospholipid antibody (aPL)-positive patients, and to examine the effects of fluvastatin on these biomarkers. METHODS: Four groups of patients (age 18-65) were recruited: (a) primary antiphospholipid syndrome; (b) systemic lupus erythematosus (SLE) with antiphospholipid syndrome (APS) (SLE/APS); (c) persistent aPL positivity without SLE or APS (Primary aPL); and (d) persistent aPL positivity with SLE but no APS (SLE/aPL). The frequency-matched control group, used for baseline data comparison, was identified from a databank of healthy persons. Patients received fluvastatin 40 mg daily for 3 months. At 3 months, patients stopped the study medication and they were followed for another 3 months. Blood samples for 12 proinflammatory and prothrombotic biomarkers were collected monthly for 6 months. RESULTS: Based on the comparison of the baseline samples of 41 aPL-positive patients with 30 healthy controls, 9/12 (75%) biomarkers (interleukin (IL)-6, IL1ß, vascular endothelial growth factor (VEGF), tumour necrosis factor (TNF)-α, interferon (IFN)-α, inducible protein-10 (IP10), soluble CD40 ligand (sCD40L), soluble tissue factor (sTF) and intracellular cellular adhesion molecule (ICAM)-1) were significantly elevated. Twenty-four patients completed the study; fluvastatin significantly and reversibly reduced the levels of 6/12 (50%) biomarkers (IL1ß, VEGF, TNFα, IP10, sCD40L and sTF). CONCLUSIONS: Our prospective mechanistic study demonstrates that proinflammatory and prothrombotic biomarkers, which are differentially upregulated in persistently aPL-positive patients, can be reversibly reduced by fluvastatin. Thus, statin-induced modulation of the aPL effects on target cells can be a valuable future approach in the management of aPL-positive patients.

Prevalence of fibromyalgia in vasovagal syncope.

BACKGROUND: Vasovagal syncope is an acute manifestation of autonomic nervous system dysfunction. This type of syncope is often associated with other dysautonomic expressions such as migraine, gastroparesis, or postural tachycardia syndrome. Autonomic nervous system dysfunction has been proposed as a key element in the pathogenesis of fibromyalgia. OBJECTIVES: The objectives of this study were to estimate the frequency of fibromyalgia in a sample of patients with vasovagal syncope and also to correlate the presence of syncope and fibromyalgia with different dysautonomic manifestations. METHODS: We studied 50 consecutive patients with vasovagal syncope seen at the Syncope Unit of the National Cardiology Institute of Mexico between June 2009 and June 2012. All individuals filled out the Composite Autonomic Symptoms and Signs questionnaire and the Fibromyalgia Impact Questionnaire. All cases underwent a head-up tilt test. A rheumatologist examined all participants to assess the presence of fibromyalgia. RESULTS: The median age of the studied population was 21 years. Sixty-eight percent of participants were women. Eight cases (16%) had concomitant fibromyalgia. Significantly, all fibromyalgia cases were female. This subgroup of fibromyalgia subjects had more secretomotor complaints (mainly dry eyes and dry mouth) and more bowel constipation than the remainder of the group. Also in this subgroup of fibromyalgia subjects, several significant associations were found between age, blood pressure, number of syncopal episodes, constipation, insomnia, pupillomotor impairment, and disability. In contrast, no correlations were found in the subgroup of fainters without fibromyalgia. CONCLUSIONS: Fibromyalgia was relatively frequent in these women with vasovagal syncope and could be associated with dysautonomic symptoms. Therefore, it seems important to search for dysautonomic comorbidities in patients with vasovagal syncope and/or fibromyalgia, to provide a patient-centered holistic approach, instead of the often currently used therapeutic partition.