Tag: chronic pain

Could the fibromyalgia syndrome be triggered or enhanced by COVID-19?

Abstract:

Fibromyalgia (FM) is a complex disease with an uncertain aetiology and intricate pathophysiology. Although its genesis is not fully explained, potential environmental factors, such as viral infections might trigger FM or worsen patients’ clinical outcomes.

The SARS-CoV-2 virus may affect central and peripheral nervous systems, leading to musculoskeletal, neurological, and psychological disturbances. These symptoms might persist at least 12 months beyond the recovery, often referred to as post-COVID syndrome, which resembles FM syndrome. In this sense, we argued the potential consequences of COVID-19 exclusively on FM syndrome.

First, we have described post-COVID syndrome and its painful symptoms. Afterwards, we argued whether FM syndrome could be triggered or enhanced by COVID-19 infection or by numerous and persistent stressors imposed daily by the pandemic setting (isolation, uncertainty, depression, mental stress, generalized anxiety, and fear of the virus). In addition, we have demonstrated similarities between pathophysiological mechanisms and cardinal symptoms of FM and COVID-19, speculating that SARS-CoV-2 might represent a critical mediator of FM or an exacerbator of its symptoms once both syndromes share similar mechanisms and complaints.

Therefore, pharmacologic and non-pharmacological approaches commonly used to treat FM could serve as strategic therapies to attenuate painful and neurological manifestations of post-COVID syndrome. Although it is still theoretical, clinicians and researchers should be alert of patients who develop symptoms similar to FM or those who had their FM symptoms increased post-COVID to manage them better.

Source: Fialho MFP, Brum ES, Oliveira SM. Could the fibromyalgia syndrome be triggered or enhanced by COVID-19? Inflammopharmacology. 2023 Feb 27:1–19. doi: 10.1007/s10787-023-01160-w. Epub ahead of print. PMID: 36849853; PMCID: PMC9970139. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9970139/ (Full text)

Decolonization of staphylococcus aureus and therapeutic test to assist the diagnosis in me/cfs, long covid, post-vaccine covid syndrome and other diseases with fatigue and/or chronic pain

Abstract:

Nasal Decolonization is performed with an antiseptic such as Povidone-iodine. For the Therapeutic Test an Antibiotic such as Flucloxacillin plus Probiotics or other supplements with an effect against S.aureus is indicated.

There is a Subgroup of patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Long COVID Syndrome or PACS who present a persistent bacterial infection that affects the upper respiratory tract, and especially at the level of the nostrils.

We estimate that this Subgroup of patients presenting this persistent infection as a causal or contributing factor would be around a third of all cases.

The most frequent causative agent of these persistent and/or recurrent infections is the Staphylococcus aureus bacterium. According to the studies carried out, this bacterium is present in the nasal passages of between 16 and 36% of the general population, who are asymptomatic carriers of Staphylococcus aureus, and are often unaware of it.

In health professionals who carry out care work, the percentage of carriers can exceed 50%. In a recent study carried out in health workers and medical students, 65% of nasal carriers of S. aureus were reported, and of these, 74% were multidrug-resistant (MDR) bacteria and 69% were biofilm-forming bacteria [1].

Source: Gustavo Aguirre Chang and Aurora Natividad Trujillo Figueredo. Decolonization of staphylococcus aureus and therapeutic test to assist the diagnosis in me/cfs, long covid, post-vaccine covid syndrome and other diseases with fatigue and/or chronic pain. ResearchGate [Preprint] 2/17/23. https://www.researchgate.net/publication/368646387_DECOLONIZATION_OF_STAPHYLOCOCCUS_AUREUS_AND_THERAPEUTIC_TEST_TO_ASSIST_THE_DIAGNOSIS_IN_MECFS_LONG_COVID_POST-VACCINE_COVID_SYNDROME_AND_OTHER_DISEASES_WITH_FATIGUE_ANDOR_CHRONIC_PAIN (Full text)

Role of the MicroRNAs in the Pathogenic Mechanism of Painful Symptoms in Long COVID: Systematic Review

Abstract:

The ongoing pandemic of COVID-19 has caused more than 6.7 million tragic deaths, plus, a large percentage of people who survived it present a myriad of chronic symptoms that last for at least 6 months; this has been named as long COVID. Some of the most prevalent are painful symptoms like headache, joint pain, migraine, neuropathic-like pain, fatigue and myalgia. MicroRNAs are small non-coding RNAs that regulate genes, and their involvement in several pathologies has been extensively shown. A deregulation of miRNAs has been observed in patients with COVID-19.
The objective of the present systematic review was to show the prevalence of chronic pain-like symptoms of patients with long COVID and based on the expression of miRNAs in patients with COVID-19, and to present a proposal on how they may be involved in the pathogenic mechanisms of chronic pain-like symptoms.
A systematic review was carried out in online databases for original articles published between March 2020 to April 2022; the systematic review followed the PRISMA guidelines, and it was registered in PROSPERO with registration number CRD42022318992. A total of 22 articles were included for the evaluation of miRNAs and 20 regarding long COVID; the overall prevalence of pain-like symptoms was around 10 to 87%, plus, the miRNAs that were commonly up and downregulated were miR-21-5p, miR-29a,b,c-3p miR-92a,b-3p, miR-92b-5p, miR-126-3p, miR-150-5p, miR-155-5p, miR-200a, c-3p, miR-320a,b,c,d,e-3p, and miR-451a.
The molecular pathways that we hypothesized to be modulated by these miRNAs are the IL-6/STAT3 proinflammatory axis and the compromise of the blood–nerve barrier; these two mechanisms could be associated with the prevalence of fatigue and chronic pain in the long COVID population, plus they could be novel pharmacological targets in order to reduce and prevent these symptoms.
Source: Reyes-Long S, Cortés-Altamirano JL, Bandala C, Avendaño-Ortiz K, Bonilla-Jaime H, Bueno-Nava A, Ávila-Luna A, Sánchez-Aparicio P, Clavijo-Cornejo D, Dotor-LLerena AL, Cabrera-Ruiz E, Alfaro-Rodríguez A. Role of the MicroRNAs in the Pathogenic Mechanism of Painful Symptoms in Long COVID: Systematic Review. International Journal of Molecular Sciences. 2023; 24(4):3574. https://doi.org/10.3390/ijms24043574 https://www.mdpi.com/1422-0067/24/4/3574 (Full text)

Blunted short-term autonomic cardiovascular reactivity to orthostatic and clinostatic challenges in fibromyalgia as an indicator of the severity of chronic pain

Abstract:

Fibromyalgia is a long-term pain disorder that has been related to autonomic dysfunctions and reduced cardiovascular reactivity. We aimed to assess the dynamic short-term cardiovascular responses to postural changes in fibromyalgia. Thirty-eight women with fibromyalgia and thirty-six healthy women underwent the “Chronic Pain Autonomic Stress Test”.

Electrocardiogram, blood pressure and impedance cardiography were continuously recorded during active standing and lying down. Second-by-second values were derived over the first 30 s of each posture. Lower reactivity during the beginning of each position was observed in fibromyalgia sufferers compared to healthy women, with smaller responses seen during stand up in heart rate, blood pressure, cardiac output, total peripheral resistance, and pre-ejection period, and smaller changes during lying down in heart rate, cardiac output and total peripheral resistance. The magnitude of the autonomic adjustments to postural changes was inversely associated with the severity of clinical pain.

These findings indicate an early impaired autonomic cardiovascular response to orthostatic and clinostatic challenges in fibromyalgia, suggesting less autonomic flexibility and adaptability to situational demands and challenges. Short-term second-by-second cardiovascular measures may be useful in the clinical assessment of fibromyalgia.

Source: Contreras-Merino AM, Davydov DM, Galvez-Sánchez CM, Reyes Del Paso GA. Blunted short-term autonomic cardiovascular reactivity to orthostatic and clinostatic challenges in fibromyalgia as an indicator of the severity of chronic pain. Int J Psychophysiol. 2022 May;175:61-70. doi: 10.1016/j.ijpsycho.2022.03.001. Epub 2022 Mar 11. PMID: 35283267. https://www.sciencedirect.com/science/article/pii/S0167876022000599?via%3Dihub (Full text)

The autoimmune aetiology of unexplained chronic pain

Abstract:

Chronic pain is the leading cause of life years lived with disability worldwide. The aetiology of most chronic pain conditions has remained poorly understood and there is a dearth of effective therapies. The WHO ICD-11 has categorised unexplained chronic pain states as ‘chronic primary pains’ (CPP), which are further defined by their association with significant distress and/or dysfunction. The new mechanistic term, ‘nociplasticic pain’ has been developed to illustrate their presumed generation by a structurally intact, but abnormally functioning nociceptive system.

Recently, researchers have unravelled the surprising, ubiquitous presence of pain-sensitising autoantibodies in four investigated CPP indicating autoimmune causation. In persistent complex regional pain syndrome, fibromyalgia syndrome, chronic post-traumatic limb pain, and non-inflammatory joint pain associated with rheumatoid arthritis, passive transfer experiments have shown that either IgG or IgM antibodies from patient-donors cause symptoms upon injection to rodents that closely resemble those of the clinical disorders. Targets of antibody-binding and downstream effects vary between conditions, and more research is needed to elucidate the molecular and cellular details.

The central nervous system appears largely unaffected by antibody binding, suggesting that the clinically evident CNS symptoms associated with CPP might arise downstream of peripheral processes. In this narrative review pertinent findings are described, and it is suggested that additional symptom-based disorders might be examined for the contribution of antibody-mediated autoimmune mechanisms.

Source: Goebel A, Andersson D, Helyes Z, Clark JD, Dulake D, Svensson C. The autoimmune aetiology of unexplained chronic pain. Autoimmun Rev. 2022 Mar;21(3):103015. doi: 10.1016/j.autrev.2021.103015. Epub 2021 Dec 10. PMID: 34902604. https://www.sciencedirect.com/science/article/abs/pii/S1568997221002974 (Full text)

Clinical Characteristics and Mechanisms of Musculoskeletal Pain in Long COVID

Abstract:

Objective: Musculoskeletal (MSK) pain is being increasingly reported by patients as one of the most common persistent symptoms in post-COVID-19 syndrome or Long COVID. However, there is a lack of understanding of its prevalence, characteristics, and underlying pathophysiological mechanisms. The objective of this review is to identify and describe the features and characteristics of MSK pain in Long COVID patients.

Methods: The narrative review involved a literature search of the following online databases: MEDLINE (OVID), EMBASE (OVID), CINAHL, PsyclNFO, and Web of Science (December 2019 to February 2022). We included observational studies that investigated the prevalence, characteristics, risk factors and mechanisms of MSK pain in Long COVID. After screening and reviewing the initial literature search results, a total of 35 studies were included in this review.

Results: The overall reported prevalence of MSK pain in Long COVID ranged widely from 0.3% to 65.2%. The pain has been reported to be localized to a particular region or generalized and widespread. No consistent pattern of progression of MSK pain symptoms over time was identified. Female gender and higher BMI could be potential risk factors for Long COVID MSK pain, but no clear association has been found with age and ethnicity. Different pathophysiological mechanisms have been hypothesized to contribute to MSK pain in Long COVID including increased production of proinflammatory cytokines, immune cell hyperactivation, direct viral entry of neurological and MSK system cells, and psychological factors.

Conclusion: MSK pain is one of the most common symptoms in Long COVID. Most of the current literature on Long COVID focuses on reporting the prevalence of persistent MSK pain. Studies describing the pain characteristics are scarce. The precise mechanism of MSK pain in Long COVID is yet to be investigated. Future research must explore the characteristics, risk factors, natural progression, and underlying mechanisms of MSK pain in Long COVID.

Source: Khoja O, Silva Passadouro B, Mulvey M, Delis I, Astill S, Tan AL, Sivan M. Clinical Characteristics and Mechanisms of Musculoskeletal Pain in Long COVID. J Pain Res. 2022 Jun 17;15:1729-1748. doi: 10.2147/JPR.S365026. PMID: 35747600; PMCID: PMC9212788. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9212788/ (Full text)

Sexual dimorphism in a neuronal mechanism of spinal hyperexcitability across rodent and human models of pathological pain

Abstract:

The prevalence and severity of many chronic pain syndromes differ across sex, and recent studies have identified differences in immune signalling within spinal nociceptive circuits as a potential mediator. Although it has been proposed that sex-specific pain mechanisms converge once they reach neurons within the superficial dorsal horn, direct investigations using rodent and human preclinical pain models have been lacking.

Here, we discovered that in the Freund’s adjuvant in vivo model of inflammatory pain, where both male and female rats display tactile allodynia, a pathological coupling between KCC2-dependent disinhibition and N-methyl-D-aspartate receptor (NMDAR) potentiation within superficial dorsal horn neurons was observed in male but not female rats. Unlike males, the neuroimmune mediator brain-derived neurotrophic factor (BDNF) failed to downregulate inhibitory signalling elements (KCC2 and STEP61) and upregulate excitatory elements (pFyn, GluN2B and pGluN2B) in female rats, resulting in no effect of ex vivo brain-derived neurotrophic factor on synaptic NMDAR responses in female lamina I neurons. Importantly, this sex difference in spinal pain processing was conserved from rodents to humans.

As in rodents, ex vivo spinal treatment with BDNF downregulated markers of disinhibition and upregulated markers of facilitated excitation in superficial dorsal horn neurons from male but not female human organ donors. Ovariectomy in female rats recapitulated the male pathological pain neuronal phenotype, with BDNF driving a coupling between disinhibition and NMDAR potentiation in adult lamina I neurons following the prepubescent elimination of sex hormones in females. This discovery of sexual dimorphism in a central neuronal mechanism of chronic pain across species provides a foundational step towards a better understanding and treatment for pain in both sexes.

Source: Dedek A, Xu J, Lorenzo LÉ, Godin AG, Kandegedara CM, Glavina G, Landrigan JA, Lombroso PJ, De Koninck Y, Tsai EC, Hildebrand ME. Sexual dimorphism in a neuronal mechanism of spinal hyperexcitability across rodent and human models of pathological pain. Brain. 2022 Apr 29;145(3):1124-1138. doi: 10.1093/brain/awab408. PMID: 35323848; PMCID: PMC9050559. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9050559/ (Full text)

Altered Pain in the Brainstem and Spinal Cord of Fibromyalgia Patients During the Anticipation and Experience of Experimental Pain

Abstract:

Chronic pain associated with fibromyalgia (FM) affects a large portion of the population but the underlying mechanisms leading to this altered pain are still poorly understood. Evidence suggests that FM involves altered neural processes in the central nervous system and neuroimaging methods such as functional magnetic resonance imaging (fMRI) are used to reveal these underlying alterations. While many fMRI studies of FM have been conducted in the brain, recent evidence shows that the changes in pain processing in FM may be linked to autonomic and homeostatic dysregulation, thus requiring further investigation in the brainstem and spinal cord.

Functional magnetic resonance imaging data from 15 women with FM and 15 healthy controls were obtained in the cervical spinal cord and brainstem at 3 tesla using previously established methods. In order to investigate differences in pain processing in these groups, participants underwent trials in which they anticipated and received a predictable painful stimulus, randomly interleaved with trials with no stimulus. Differences in functional connectivity between the groups were investigated by means of structural equation modeling.

The results demonstrate significant differences in brainstem/spinal cord network connectivity between the FM and control groups which also correlated with individual differences in pain responses. The regions involved in these differences in connectivity included the LC, hypothalamus, PAG, and PBN, which are known to be associated with autonomic homeostatic regulation, including fight or flight responses. This study extends our understanding of altered neural processes associated with FM and the important link between sensory and autonomic regulation systems in this disorder.

Source: Ioachim G, Warren HJM, Powers JM, Staud R, Pukall CF, Stroman PW. Altered Pain in the Brainstem and Spinal Cord of Fibromyalgia Patients During the Anticipation and Experience of Experimental Pain. Front Neurol. 2022 May 6;13:862976. doi: 10.3389/fneur.2022.862976. PMID: 35599729; PMCID: PMC9120571. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9120571/ (Full text)

The incidence and characteristics of chronic pain and fatigue after 12 months later admitting with COVID-19; The Post- COVID 19 syndrome

Abstract:

Introduction: This study aimed to evaluate chronic pain and fatigue in patients 12 months after hospitalization for Covid-19.

Methods: We studied the COVID-19 patients discharged from Hospital, March 10 and April 20, 2020.

Results: A total of 157 patients were included in this study. Forty-three patients (27.4%) complained of chronic fatigue and muscle weakness in the last six months. The visual analog fatigue scale (VAFS) score of 3.84 ± 1.48 was obtained. Forty patients (25.5%) were suspected of Chronic Fatigue Syndrome (CFS).Twenty-four patients (15.3%) had severe chronic pain or exacerbation of previous chronic pain, most of which were reported in the lower back (70.8%) and lower extremities (66.7%). Pain intensity had a mean score of 2.33 ± 0.87 and was mainly described as “muscle cramps,” “persistent dull pain,” and “boring and numbing.” In women, chronic pain and fatigue, extended hospital stays, ICU admission, and depressed mood were common than in men.For these pain and fatigue, 37% used nonsteroidal anti-inflammatory drugs, and 16.3% used antidepressants. Only one person had applied for physiotherapy, and none of the patients had received psychotherapy.

Conclusion: Fatigue and chronic pain in patients recovering from COVID-19 are common complications, even after 12 months of illness.

Source: Janbazi L, Kazemian A, Mansouri K, Madani SP, Yousefi N, Vahedifard F, Raissi G. The incidence and characteristics of chronic pain and fatigue after 12 months later admitting with COVID-19; The Post- COVID 19 syndrome. Am J Phys Med Rehabil. 2022 Apr 13. doi: 10.1097/PHM.0000000000002030. Epub ahead of print. PMID: 35473921.  https://pubmed.ncbi.nlm.nih.gov/35473921/

Chronic Fatigue Syndrome and chronic pain conditions – vitally protective systems gone wrong

Abstract:

Chronic Fatigue Syndrome (CFS) and chronic pain syndromes represent major health problems in society. These conditions are disabling and strongly associated with low quality of life. Even though CFS and chronic pain are separate conditions, they have strikingly much in common. Both pain and fatigue are important sensations with protective value in an acute situation. It can be life-threatening not to be aware of them.

However, as these symptoms become chronic, their protective roles decrease and instead they become health problems. Our understanding of the perception of pain and fatigue has shifted through the years, from a dualistic biomedical point of view to a holistic biopsychosocial understanding. This combined with the increasing evidence of how our brain works in a predictive/anticipatory manner, gives a deeper understanding of why treatments like cognitive behavior therapies and stress relief therapies can help these patients recover to better health.

Source: Pedersen M. Chronic Fatigue Syndrome and chronic pain conditions – vitally protective systems gone wrong. Scand J Pain. 2019 Jun 29. pii: /j/sjpain.ahead-of-print/sjpain-2019-0072/sjpain-2019-0072.xml. doi: 10.1515/sjpain-2019-0072. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/31256069