Tag: pain

Experiences of pain in paediatric chronic fatigue syndrome/myalgic encephalomyelitis: a single-centre qualitative study

Abstract:

Background: Moderate to severe pain affects up to two-thirds of children with chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) and is associated with worse fatigue and physical functioning. This research aims to gain a greater insight into pain experienced by these children.

Methods: Thematic analysis of qualitative data from semistructured interviews with 13 children with CFS/ME (mean age=15.3 years, 67% female) was completed.

Results: Thematic analysis enabled construction of three themes: children’s wide-ranging experiences of pain, negative impact of pain and lack of effective treatment for pain and nine subthemes. The first theme demonstrated highly varied pain experiences, ranging from ‘like [being]… on fire’, like ‘being stabbed’ to ‘like…lead’. Children experienced pain in multiple sites and with wide-ranging frequency and severity. The second theme highlighted the profound negative impact of pain on multiple aspects of children’s lives. Physical activity was severely impaired; some children ‘couldn’t leave bed’ or ‘couldn’t…brush [their] own hair’. Abdominal pain meant some would ‘go…days without eating’. Pain substantially impacted on mental health, leaving children feeling ‘agitated’, experiencing ‘really bad panic attacks’ or making them ‘[want to] breakdown’. Children felt they ‘can’t do the things that everyone else can do’, had ‘missed out’ and are ‘behind everyone’. Some avoided socialising as they ‘don’t want to stop everyone else’. The final theme demonstrates the absence of adequate treatment for pain, with participants reporting ‘nothing has ever really got rid of it’ and only ‘slightly [takes] the edge off’ and other experiencing side effects.

Conclusions: Pain in paediatric CFS/ME is highly variable, common and often results in severe physical limitation and poor mental health. Effective treatments for pain represent an unmet need.

Source: Serafimova T, Ascough C, Parslow RM, Crawley E. Experiences of pain in paediatric chronic fatigue syndrome/myalgic encephalomyelitis: a single-centre qualitative study. BMJ Paediatr Open. 2022 Feb;6(1):e001201. doi: 10.1136/bmjpo-2021-001201. Epub 2022 Feb 15. PMID: 36053633. https://bmjpaedsopen.bmj.com/content/6/1/e001201 (Full text)

Musculoskeletal symptoms in patients with Long COVID: A cross-sectional study on Iranian patients

Abstract:

Background and objectives: Latest studies have revealed that an increasing number of Corona Virus Disease of 2019 (COVID-19) patients may continue to feel symptoms after the acute phase. This study aimed to evaluate the prevalence of musculoskeletal symptoms after the acute phase of COVID-19 and its associated factors.

Methods: We designed a cross-sectional study from January 2021 to April 2021. An online questionnaire was designed and sent to patients who had recovered from COVID-19. The questionnaire contained questions on participants’ demographic characteristics, COVID-19 course at its acute phase, and musculoskeletal symptoms after recovering from COVID-19. Musculoskeletal symptoms associations with patients’ characteristic and COVID-19 course was evaluated.

Result: 239 patients, including 72 (30.1%) males and 167 (69.9%) females with a mean age of 37.96 years (SD=11.19), were included in the study. 98.74% of our patients had experienced at least one musculoskeletal symptom after recovering from COVID-19, and the most common symptom was fatigue, as 91.2% of participants experienced this symptom, followed by myalgia, headache, and low back pain. High BMI, hospitalization, and ICU admission were associated with a higher risk of musculoskeletal symptoms.

Conclusion: This study indicated a high prevalence of persistent musculoskeletal symptoms among patients who recovered from COVID-19. Modifiable factors, such as BMI, can be targeted to reduce the prevalence of musculoskeletal symptoms in COVID-19 survivors and reduce its burden.

Source: Azadvari M, Haghparast A, Nakhostin-Ansari A, Emami Razavi SZ, Hosseini M. Musculoskeletal symptoms in patients with Long COVID: A cross-sectional study on Iranian patients. Heliyon. 2022 Aug 11:e10148. doi: 10.1016/j.heliyon.2022.e10148. Epub ahead of print. PMID: 35971463; PMCID: PMC9367176. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9367176/ (Full text)

Autoimmune Autonomic Dysfunction Syndromes: Potential Involvement and Pathophysiology Related to Complex Regional Pain Syndrome, Fibromyalgia, Chronic Fatigue Syndrome, Silicone Breast Implant-Related Symptoms and Post-COVID Syndrome

Abstract:

The pathophysiological mechanisms involved in chronic disorders such as complex regional pain syndrome, fibromyalgia, chronic fatigue syndrome, silicone breast implant-related symptoms, and post-COVID syndrome have not been clearly defined. The course of the pain in some of the syndromes, the absence of evident tissue damage, and the predominance of alterations in the autonomic nervous system are shared similarities between them.

The production of autoantibodies following a trigger in the syndromes was previously described, for instance, trauma in complex regional pain syndrome, infectious agents in fibromyalgia, chronic fatigue syndrome, and post-COVID syndrome, and the immune stimulation by silicone in women with breast implants. In fact, the autoantibodies produced were shown to be directed against the autonomic nervous system receptors, leading to the amplification of the perception of pain alongside various clinical symptoms seen during the clinical course of the syndromes. Therefore, we viewed autoantibodies targeting the autonomic nervous system resulting in autonomic dysfunction as likely the most comprehensive explanation of the pathophysiology of the disorders mentioned.

Based on this, we aimed to introduce a new concept uniting complex regional pain syndrome, fibromyalgia, chronic fatigue syndrome, silicone breast implant-related symptoms, and post-COVID syndrome, namely “autoimmune autonomic dysfunction syndromes”. Due to its etiological, pathophysiological, and clinical implications, the suggested term would be more precise in classifying the syndromes under one title. The new title would doubtlessly facilitate both laboratory and clinical studies aimed to improve diagnosis and make treatment options more directed and precise.

Source: Mahroum N, Shoenfeld Y. Autoimmune Autonomic Dysfunction Syndromes: Potential Involvement and Pathophysiology Related to Complex Regional Pain Syndrome, Fibromyalgia, Chronic Fatigue Syndrome, Silicone Breast Implant-Related Symptoms and Post-COVID Syndrome. Pathophysiology. 2022 Jul 28;29(3):414-425. doi: 10.3390/pathophysiology29030033. PMID: 35997389. https://www.mdpi.com/1873-149X/29/3/33/htm (Full text)

Histamine production by the gut microbiota induces visceral hyperalgesia through histamine 4 receptor signaling in mice

Abstract:

The gut microbiota has been implicated in chronic pain disorders, including irritable bowel syndrome (IBS), yet specific pathophysiological mechanisms remain unclear. We showed that decreasing intake of fermentable carbohydrates improved abdominal pain in patients with IBS, and this was accompanied by changes in the gut microbiota and decreased urinary histamine concentrations.

Here, we used germ-free mice colonized with fecal microbiota from patients with IBS to investigate the role of gut bacteria and the neuroactive mediator histamine in visceral hypersensitivity. Germ-free mice colonized with the fecal microbiota of patients with IBS who had high but not low urinary histamine developed visceral hyperalgesia and mast cell activation. When these mice were fed a diet with reduced fermentable carbohydrates, the animals showed a decrease in visceral hypersensitivity and mast cell accumulation in the colon. We observed that the fecal microbiota from patients with IBS with high but not low urinary histamine produced large amounts of histamine in vitro.

We identified Klebsiella aerogenes, carrying a histidine decarboxylase gene variant, as a major producer of this histamine. This bacterial strain was highly abundant in the fecal microbiota of three independent cohorts of patients with IBS compared with healthy individuals. Pharmacological blockade of the histamine 4 receptor in vivo inhibited visceral hypersensitivity and decreased mast cell accumulation in the colon of germ-free mice colonized with the high histamine-producing IBS fecal microbiota. These results suggest that therapeutic strategies directed against bacterial histamine could help treat visceral hyperalgesia in a subset of patients with IBS with chronic abdominal pain.

Source: De Palma G, Shimbori C, Reed DE, Yu Y, Rabbia V, Lu J, Jimenez-Vargas N, Sessenwein J, Lopez-Lopez C, Pigrau M, Jaramillo-Polanco J, Zhang Y, Baerg L, Manzar A, Pujo J, Bai X, Pinto-Sanchez MI, Caminero A, Madsen K, Surette MG, Beyak M, Lomax AE, Verdu EF, Collins SM, Vanner SJ, Bercik P. Histamine production by the gut microbiota induces visceral hyperalgesia through histamine 4 receptor signaling in mice. Sci Transl Med. 2022 Jul 27;14(655):eabj1895. doi: 10.1126/scitranslmed.abj1895. Epub 2022 Jul 27. PMID: 35895832. https://pubmed.ncbi.nlm.nih.gov/35895832/

Histamine-producing gut bacteria can trigger chronic abdominal pain

Press Release: Hamilton, ON (July 27, 2022) – Researchers from McMaster University and Queen’s University have discovered a gut bacterial ‘super-producer’ of histamine that can cause pain flare-ups in some patients with irritable bowel syndrome (IBS).

The culprit is what has now been named Klebsiella aerogenes, the McMaster-Queen (MQ) strain, identified in up to 25 per cent of gut microbiota samples from patients with IBS. Researchers examined stool microbiota samples from both Canadian and American patient cohorts.

“We followed up these patients for several months and found high levels of stool histamine at the time when the patients reported severe pain, and low stool histamine when they were pain-free,” said senior author Premysl Bercik, professor of medicine of McMaster’s Michael G. DeGroote School of Medicine and a gastroenterologist.

The McMaster-Queen’s research team pinpointed the bacterium Klebsiella aerogenes as the key histamine producer by studying germ-free mice colonized with gut microbiota from patients with IBS. They also colonized some mice with gut microbiota from healthy volunteers as a control group.

The study found that the bacterium Klebsiella aerogenes converts dietary histidine, an essential amino acid present in animal and plant protein, into histamine, a known mediator of pain.

The bacterial histamine then activates the gut immune system through histamine-4 receptor, which draws immune mast cells into the intestines. These activated mast cells produce even more histamine and other pain-signalling mediators, triggering inflammation and pain.

“Now that we know how the histamine is produced in the gut, we can identify and develop therapies that target the histamine producing bacteria,” said first author Giada de Palma, assistant professor of medicine at McMaster.

The study found that when the mice colonized with histamine producing bacteria were fed a diet low in fermentable carbohydrates, bacterial histamine production dramatically decreased. This was due to change in bacterial fermentation and acidity within the gut, which inhibited the bacterial enzyme responsible for histamine production.

Bercik said that these results explain the beneficial effects of a low fermentable diet observed in patients with IBS.

It is known that patients with IBS have more mast cells in their intestines, and that some of them improve with treatments targeting mast cells or histamine, such as mast cell stabilizers or antihistamines.

“Although mast cell treatment in IBS has been explored, a novel approach based on our research would be targeting the bacterial histamine production or H4R pathways,” Bercik said.

The McMaster-Queen’s study explains why increased mast cells are found in IBS and suggests that H4 receptor pathway plays a major role in this process.

“If we block the H4 receptors, then we can prevent recruitment of mast cells to the colon and subsequently the development of abdominal pain,” said senior co-author Stephen Vanner, professor of medicine at Queen’s University.

“Many but not all IBS patients will benefit from therapies targeting this histamine driven pathway,” said co-first author David Reed, assistant professor of medicine at Queen’s. Reed said that one or more biomarkers of this pathway could be used to find the patients most likely to benefit.

The McMaster-Queens study was funded by the Canadian Institutes of Health Research.

The study was published in the journal Science Translational Medicine on July 27.

Click HERE to read the study.

 

Assessing sleep and pain among adults with myalgic encephalomyelitis/chronic fatigue syndrome: psychometric evaluation of the PROMIS® sleep and pain short forms

Abstract:

Purpose: To evaluate the psychometric properties of the patient-reported outcome measurement information system® (PROMIS) short forms for assessing sleep disturbance, sleep-related impairment, pain interference, and pain behavior, among adults with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

Methods: Data came from the Multi-Site ME/CFS study conducted between 2012 and 2020 at seven ME/CFS specialty clinics across the USA. Baseline and follow-up data from ME/CFS and healthy control (HC) groups were used to examine ceiling/floor effects, internal consistency reliability, differential item functioning (DIF), known-groups validity, and responsiveness.

Results: A total of 945 participants completed the baseline assessment (602 ME/CFS and 338 HC) and 441 ME/CFS also completed the follow-up. The baseline mean T-scores of PROMIS sleep and pain measures ranged from 57.68 to 62.40, about one standard deviation above the national norm (T-score = 50). All four measures showed high internal consistency (ω = 0.92 to 0.97) and no substantial floor/ceiling effects. No DIF was detected by age or sex. Known-groups comparisons among ME/CFS groups with low, medium, and high functional impairment showed significant small-sized differences in scores (η2 = 0.01 to 0.05) for the two sleep measures and small-to-medium-sized differences (η2 = 0.01 to 0.15) for the two pain measures. ME/CFS participants had significantly worse scores than HC (η2 = 0.35 to 0.45) for all four measures. Given the non-interventional nature of the study, responsiveness was evaluated as sensitivity to change over time and the pain interference measure showed an acceptable sensitivity.

Conclusion: The PROMIS sleep and pain measures demonstrated satisfactory psychometric properties supporting their use in ME/CFS research and clinical practice.

Source: Yang M, Keller S, Lin JS. Assessing sleep and pain among adults with myalgic encephalomyelitis/chronic fatigue syndrome: psychometric evaluation of the PROMIS® sleep and pain short forms. Qual Life Res. 2022 Jul 27. doi: 10.1007/s11136-022-03199-8. Epub ahead of print. PMID: 35896905.  https://pubmed.ncbi.nlm.nih.gov/35896905/

An online survey of pelvic congestion support group members regarding comorbid symptoms and syndromes

Abstract:

Objectives: Patients with pelvic congestion syndrome (PCS) often report overlapping somatic symptoms and syndromes. The objective of this study was to explore the prevalence of co-existing symptoms and self-reported syndrome diagnoses among women with PCS and to inform future research hypotheses.

Methods: A brief online survey was offered to members of a PCS support group website. Responses were assessed for self-reported co-existing symptoms and formal diagnoses, including: chronic fatigue syndrome, fibromyalgia, postural tachycardia syndrome, irritable bowel syndrome, migraines, interstitial cystitis, and temporomandibular joint dysfunction.

Results: Of a total of 6000 members, there were 398 respondents; 232 (59%) had not yet been treated for PCS. Among these, the most prevalent co-existing symptoms were as follows: severe fatigue (72%), dizziness (63%), IBS symptoms (61%), brain fog (33%), migraines (49%), polyuria or dysuria (41%), excessive sweating (31%), TMJ pain (31%), and loose skin or lax joints (18%). These are much higher than reported for the general female population. The most commonly self-reported comorbid syndrome diagnoses for the overall group of 398 were: irritable bowel syndrome (29%), fibromyalgia (13%), spinal nerve problems (18%), interstitial cystitis (10%), postural tachycardia syndrome (9%), hypertension (11%), chronic fatigue syndrome (10%), and Ehlers-Danlos syndrome (6%). Other than with hypertension, these rates are variably higher than in the general population.

Conclusion: Several self-reported co-existing symptoms and syndromes are more prevalent in members of a PCS support group relative to the reported prevalence in the general population. More formal investigation is warranted to evaluate this finding and to investigate potential etiologic links. Ehlers-Danlos Syndrome appears to be common in self identifying PCS women.

Source: Smith SJ, Sichlau M, Sewall LE, Smith BH, Chen B, Khurana N, Rowe PC. An online survey of pelvic congestion support group members regarding comorbid symptoms and syndromes. Phlebology. 2022 Jul 13:2683555221112567. doi: 10.1177/02683555221112567. Epub ahead of print. PMID: 35831253. https://pubmed.ncbi.nlm.nih.gov/35831253/

Altered serum bile acid profile in fibromyalgia is associated with specific gut microbiome changes and symptom severity

Abstract:

Alterations in the composition and function of the gut microbiome in women with fibromyalgia have recently been demonstrated, including changes in the relative abundance of certain bile acid metabolizing bacteria. Bile acids can affect multiple physiological processes, including visceral pain, but have yet to be explored for association to the fibromyalgia gut microbiome. In this study, 16S rRNA sequencing and targeted metabolomic approaches were used to characterize the gut microbiome and circulating bile acids in a cohort of 42 women with fibromyalgia and 42 healthy controls.

Alterations in the relative abundance of several bacterial species known to metabolize bile acids were observed in women with fibromyalgia, accompanied by significant alterations in the serum concentration of secondary bile acids, including a marked depletion of α-muricholic acid. Statistical learning algorithms could accurately detect individuals with fibromyalgia using the concentration of these serum bile acids. Serum α-muricholic acid was highly correlated with symptom severity, including pain intensity and fatigue.

Taken together, these findings suggest serum bile acid alterations are implicated in nociplastic pain. The changes observed in the composition of the gut microbiota and the concentration of circulating secondary bile acids seem congruent with the phenotype of increased nociception, and are quantitatively correlated with symptom severity.

This is a first demonstration of circulating bile acid alteration in individuals with fibromyalgia, potentially secondary to upstream gut microbiome alterations. If corroborated in independent studies, these observations may allow for the development of molecular diagnostic aids for fibromyalgia as well as mechanistic insights into the syndrome.

Source: Minerbi A, Gonzalez E, Brereton N, Fitzcharles MA, Chevalier S, Shir Y. Altered serum bile acid profile in fibromyalgia is associated with specific gut microbiome changes and symptom severity. Pain. 2022 May 19. doi: 10.1097/j.pain.0000000000002694. Epub ahead of print. PMID: 35587528. https://pubmed.ncbi.nlm.nih.gov/35587528/

Dorsal root ganglia: fibromyalgia pain factory?

Abstract:

This perspective article focuses on dorsal root ganglia (DRG) as potential fibromyalgia main pain source. Humans possess 31 pairs of DRG lying along the spine. These ganglia have unique anatomical and physiological features. During development, DRG are extruded from the central nervous system and from the blood-brain barrier but remain surrounded by meningeal layers and by cerebrospinal fluid. DRG house the pain-transmitting small nerve fiber nuclei; each individual nucleus is tightly enveloped by metabolically active glial cells. DRG possess multiple inflammatory/pro-nociceptive molecules including ion channels, neuropeptides, lymphocytes, and macrophages. DRG neurons have pseudo-unipolar structure making them able to generate pain signals; additionally, they can sequester antigen-specific antibodies thus inducing immune-mediated hyperalgesia. In rodents, diverse physical and/or environmental stressors induce DRG phenotypic changes and hyperalgesia.

Unfolding clinical evidence links DRG pathology to fibromyalgia and similar syndromes. Severe fibromyalgia is associated to particular DRG ion channel genotype. Myalgic encephalomyelitis patients with comorbid fibromyalgia have exercise-induced DRG pro-nociceptive molecules gene overexpression. Skin biopsy demonstrates small nerve fiber pathology in approximately half of fibromyalgia patients. A confocal microscopy study of fibromyalgia patients disclosed strong correlation between corneal denervation and small fiber neuropathy symptom burden. DRG may be fibromyalgia neural hub where different stressors can be transformed in neuropathic pain. Novel neuroimaging technology and postmortem inquest may better define DRG involvement in fibromyalgia and similar maladies. DRG pro-nociceptive molecules are attractive fibromyalgia therapeutic targets.

Source: Martínez-Lavín M. Dorsal root ganglia: fibromyalgia pain factory? Clin Rheumatol. 2021 Jan 6:1–5. doi: 10.1007/s10067-020-05528-z. Epub ahead of print. PMID: 33409721; PMCID: PMC7787228.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7787228/ (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)