Post Viral Pain, Fatigue, and Sleep Disturbance Syndromes: Current knowledge and Future Directions

Abstract:

Post-viral pain syndrome, also known as post-viral syndrome (PVS), is a complex condition characterized by persistent pain, fatigue, musculoskeletal pain, neuropathic pain, neurocognitive difficulties, and sleep disturbances1,2 that can occur after an individual has recovered from a viral infection. Much remains unknown regarding the pathophysiology of post-viral syndromes and few studies have provided a comprehensive summary of the condition, agents that cause it, and successful treatment modalities.

With the COVID-19 pandemic continuing to affect millions of people worldwide, the need for understanding the etiology of post-viral illness and how to help individuals cope with the sequalae is paramount.2 This narrative review provides a summary of the sequelae of post-viral syndromes, viral agents that cause it, the pathophysiology, treatment, and future considerations for research and targeted therapies.

Source: Caleb TackeyP. Maxwell SlepianHance Clarke & Nimish Mittal (2023) Post Viral Pain, Fatigue, and Sleep Disturbance Syndromes: Current knowledge and Future Directions, Canadian Journal of Pain, DOI: 10.1080/24740527.2023.2272999 https://www.tandfonline.com/doi/full/10.1080/24740527.2023.2272999 (Full text)

Fatigue in post COVID-19 patients: the P4O2 COVID-19 study

Abstract:

Background: Some patients do not fully recover after COVID-19 and have symptoms occurring 3 months after acute illness, lasting for >2 months, defined as post COVID-19. Fatigue seems most present in post COVID-19 and part of the patients might develop symptoms similar to chronic fatigue syndrome.

Aim: To determine the occurrence of fatigue and other symptoms in post COVID-19 patients.

Methods: In the prospective P4O2 COVID-19 cohort, post COVID-19 patients aged 40-65 years were recruited from outpatient post-COVID clinics in 5 Dutch hospitals between May 2021-September 2022. At 3-6 months post-COVID, patients completed the Fatigue Severity Scale (FSS). If the FSS score was ≥4 (the cut-off for severe fatigue), patients also completed the DePaul Symptom Questionnaire version 2 (DSQ-2). The FSS ranges from 1-7 and a higher score means more fatigued. The DSQ-2 rates frequency and severity of 79 symptoms on a 5-point Likert scale. Binary thresholds (if scored ≥2 on both severity and frequency, the threshold is met and the symptom is present) were calculated.

Results: The mean age of the 78 included patients was 53.9±6.2 and 51.7% were male. Median (IQR) FSS score was 5.6 (4.2-6.3) and 66 patients (84.6%) had a score ≥4. According to the DSQ-2 (n=61), patients reported a median (IQR) of 16 (8-23) symptoms. The majority of the patients experienced fatigue (85%). Furthermore, post-exertional malaise (PEM) (40%), sleep-related problems (37%), pain (21%) and neurocognitive problems (23%) were frequently reported.

Conclusion: The occurrence of severe fatigue 3-6 months after COVID-19 was 84.6% in our cohort. Patients with severe fatigue also frequently reported PEM, sleep related problems, pain and neurocognitive problems.

Source: Merel E.B. Cornelissen, Lizan D. Bloemsma, Nadia Baalbaki, Somayeh Bazdar, Jelle M. Blankestijn, Inés Beekers, Rosanne J.H.C.G. Beijers, Joop P. Van Den Bergh, Debbie Gach, J.J. Miranda Geelhoed, Sebastiaan Holverda, Laura Houweling, John J. Jacobs, Renée Jonker, Ivo Van Der Lee, Paulien M.A. Linders, Lieke C.E. Noij, Esther J. Nossent, Marianne A. Van De Pol, Daphne W. Schaminee, Annemie M.W.J. Schols, Lisanne T. Schuurman, Brigitte Sondermeijer, Anouk W. Vaes, Els J.M. Weersink, Yolanda De Wit-Van Wijck, Martijn A. Spruit, Anke H. Maitland-Van Der Zee. Fatigue in post COVID-19 patients: the P4O2 COVID-19 study.

Metabolic Fingerprinting for the Diagnosis of Clinically Similar Long COVID and Fibromyalgia Using a Portable FT-MIR Spectroscopic Combined with Chemometrics

Abstract:

Post Acute Sequelae of SARS-CoV-2 infection (PASC or Long COVID) is characterized by lingering symptomatology post-initial COVID-19 illness that is often debilitating. It is seen in up to 30–40% of individuals post-infection. Patients with Long COVID (LC) suffer from dysautonomia, malaise, fatigue, and pain, amongst a multitude of other symptoms.
Fibromyalgia (FM) is a chronic musculoskeletal pain disorder that often leads to functional disability and severe impairment of quality of life. LC and FM share several clinical features, including pain that often makes them indistinguishable. The aim of this study is to develop a metabolic fingerprinting approach using portable Fourier-transform mid-infrared (FT-MIR) spectroscopic techniques to diagnose clinically similar LC and FM.
Blood samples were obtained from LC (n = 50) and FM (n = 50) patients and stored on conventional bloodspot protein saver cards. A semi-permeable membrane filtration approach was used to extract the blood samples, and spectral data were collected using a portable FT-MIR spectrometer. Through the deconvolution analysis of the spectral data, a distinct spectral marker at 1565 cm−1 was identified based on a statistically significant analysis, only present in FM patients. This IR band has been linked to the presence of side chains of glutamate.
An OPLS-DA algorithm created using the spectral region 1500 to 1700 cm−1 enabled the classification of the spectra into their corresponding classes (Rcv > 0.96) with 100% accuracy and specificity. This high-throughput approach allows unique metabolic signatures associated with LC and FM to be identified, allowing these conditions to be distinguished and implemented for in-clinic diagnostics, which is crucial to guide future therapeutic approaches.
Source: Hackshaw KV, Yao S, Bao H, de Lamo Castellvi S, Aziz R, Nuguri SM, Yu L, Osuna-Diaz MM, Brode WM, Sebastian KR, et al. Metabolic Fingerprinting for the Diagnosis of Clinically Similar Long COVID and Fibromyalgia Using a Portable FT-MIR Spectroscopic Combined with Chemometrics. Biomedicines. 2023; 11(10):2704. https://doi.org/10.3390/biomedicines11102704 https://www.mdpi.com/2227-9059/11/10/2704 (Full text)

A Thesis on Immune Differences in Chronic Fatigue Syndrome, Fibromyalgia and Healthy Controls

Abstract:

Background: Chronic Fatigue Syndrome (CFS) and Fibromyalgia (FM) are debilitating disorders that significantly affect the daily lives of those suffering from them, as well as their loved ones. Both conditions have overlapping clinical features that resemble inflammatory disorders, and overlapping symptoms, such as depression, suggest central nervous system (CNS) involvement. The role of the immune system’s soluble messengers in the pathogenesis of CFS and FM has been under investigation, but so far the results are inconclusive. In addition, there is growing evidence that the kynurenine pathway is involved in the pathology of diseases related to the CNS, yet the role of each metabolite is not clear. The relationship between kynurenine metabolism and CFS and FM has not been extensively explored. Few studies have simultaneously examined the immunological status in both CFS and FM, making this thesis the first to comprehensively evaluate the potential distinct immunological differences between the two disorders.

Objective: The objective of this study was to compare the CFS and FM with healthy controls, regarding the levels of several soluble blood markers related to the immune system. The markers chosen were:

  • The inflammatory marker high-sensitive CRP (hsCRP)
  • The following cytokines and chemokines: Interferon (IFN)-γ, Interleukin (IL)-1β, IL1ra, IL-4, IL-6, IL-8, IL-10, IL-17, Interferon gamma-induced protein (IP)-10, Monocyte Chemoattractant Protein (MCP)-1, Transforming Growth Factor (TGF)-β1, TGF-β2, TGF-β3 and Tumour Necrosis Factor (TNF)-α
  • The metabolites and their ratios of the kynurenine pathway: Tryptophan (Try), kynurenine (Kyn), kynurenic acid (KA), 3-hydroxykykynurenine (HK), anthranilic acid (AA), xanthurenic acid (XA), 3-hydroxyanthranilic acid (HAA), quinolinic acid (QA) and picolinic acid (Pic).

Method: The population consisted of three groups: CFS patients (n = 49), FM patients (n = 58), and healthy controls (n = 54). All participants were females aged 18–60. Patients were recruited from a specialised university hospital clinic and controls were recruited by advertisement among the staff and students at the hospital and university.

Plasma levels of hsCRP were analysed at the hospital. The cytokines and chemokines IFN-γ, IL-1β, IL-1ra, xii IL-4, IL-6, IL-8, IL-10, IL-17, IP-10, MCP-1, TGF-β1, TGF-β2, TGF-β3, and TNF-α were analysed by multiplex. Kynurenine metabolites were analysed by LC-MS/MS.

Linear regression models of log-transformed data for hsCRP and the kynurenine metabolites were conducted for comparison of the three groups CFS, FM and controls. The Kruskal-Wallis test was used to analyse differences of cytokines between the three groups. Main findings were controlled for age, body mass index (BMI), and symptoms of anxiety and depression.

Results: hsCRP levels were significantly higher for both the CFS and FM groups compared to healthy controls when adjusting for age and BMI (p = .006). There was no difference between the two patient groups. Level of hsCRP was affected by BMI (p < .001) but not age.

MCP-1 was significantly increased in both patient groups compared to healthy controls (p < .001). IL-1β, Il-4, IL-6, TNF-α, TGF-β1, TGF-β2, TGF-β3 (all p < .001), IL-10 (p = .003) and IL17 (p = .002) all were significantly lower in the patient groups compared to healthy controls. IFN-γ was significantly lower in the FM group (p < .001). For IL-8, IP-10 and IL1ra there were no significant difference.

QA differed between CFS and FM patients (p = .036) and was related to higher levels of BMI (p = .002). The KA/QA ratio was lower for CFS patients compared to healthy controls (p = .016). The KA/HK ratio was lower for FM patients compared to healthy controls, and this lower ratio was associated with increased symptoms of pain (p = .002). The kynurenine aminotransferase II (KAT II) enzymatic activity given by XA/HK was lower for FM patients compared to healthy controls (p = .013). In addition, BMI was negatively associated with enhanced KAT II enzymatic activity (p = .039).

Symptoms of anxiety and depression were not associated with any of the immune markers studied.

Conclusion: In our material hsCRP and MCP-1 are increased in patients both with CFS and with FM, while several other cytokines are either similar or significantly lower in patients than controls. Our study also indicates associations between kynurenine metabolism and CFS and FM. Kynurenine also is associated with single symptoms such as fatigue and pain. Forthcoming studies indicating interactions and causative effects, or restoration of the inflammatory status, may place cytokines and kynurenine metabolites as a target for treatment as well as prevention of these conditions in the future.

Source: Groven, Nina. A Thesis on Immune Differences in Chronic Fatigue Syndrome, Fibromyalgia and Healthy Controls. PhD Thesis [Norwegian University of Science and Technology] https://ntnuopen.ntnu.no/ntnu-xmlui/handle/11250/3072207 (Full text available as PDF file)

Inflammation-induced pain and fatigue in fibromyalgia and ME/CFS and role of variant connective tissue

Abstract:

Background: Fibromyalgia and ME/CFS are multifaceted conditions with overlapping symptoms(1); the pathophysiological mechanisms are under debate. It remains unclear whether dysregulated inflammation, induced either by an exogenous stimulus (eg a virus or other stressor), or autoimmunity, is of prime importance [2].

Objectives: 1. To determine in a novel human model the effects of an in vivo inflammatory challenge in the induction of pain and fatigue in fibromyalgia and ME/CFS compared to controls. 2. Explore potential mediators and moderators involved.

Methods: Data were available for 48 patients with confirmed diagnoses of Fibromyalgia and/ or ME/CFS and 22 matched controls, who had undergone a placebo controlled inflammatory challenge (typhoid vaccination) as part of ISRCTN78820481. Participants underwent full research diagnostic evaluation including a hypermobility assessment. Subjective pain and fatigue were assessed after saline injection and typhoid vaccination (VAS). Linear regression models were used to explore predictors, with adjustment for potential confounders (age/gender) and baseline levels as appropriate.

Mediation analyses (looking for mechanistic effects) were conducted according to the method of Hayes (3) and mediation considered significant if bootstrapped confidence intervals of the estimated indirect effect did not cross zero. In these mediation analyses predictor variable was group membership (patient or control), outcome variable was change in 1) pain and 2) fatigue induced by challenge and mediators/moderators included change in IL-6 induced by inflammatory challenge and hypermobility features.

Results: Being a patient rather than control significantly predicted inflammation-induced fatigue (B=14.89 (95%CI 3.29-26.50), t=2.56, p=0.013) and pain (B=12.88 (95%CI 0.65-25.10), t=2.11, p=0.039) after adjusting for levels induced by placebo.

Induced pain was independently predicted by level of IL-6 induced by inflammatory challenge (B=23.44 (95%CI 5.15-41.72),t=2.57, p=0.013) as was induced fatigue (B=10.63 (95%CI 2.84-18.41), t=2.73, p=0.008) Mediated moderation analyses suggested the link to induced pain and fatigue through induced inflammation was associated with hypermobility features (Index of mediated moderation 11.02 (95%CI 1.45-22.73) and 6.20 (95%CI 0.07-13.64) respectively))

Conclusion: To our knowledge this is the first human study to evaluate directly the effect of an exogenous inflammatory challenge (typhoid vaccination) in a combined group of Fibromyalgia and ME/CFS patients. Il-6 was shown to be a critical mediator. This work strongly supports the hypothesis that inflammation is key to the pathophysiology of ME/CFS. We are evaluating associated CNS inflammation in the model, as well as other associations, such as autonomic dysfunction and hypermobility. Further understanding the mediators involved in the condition should in future open the way to testing targeted anti-inflammatory therapy.

Source: Eccles J, Amato M, Themelis K, et alOP0194 INFLAMMATION-INDUCED PAIN AND FATIGUE IN FIBROMYALGIA AND ME/CFS AND ROLE OF VARIANT CONNECTIVE TISSUEAnnals of the Rheumatic Diseases 2023;82:129. https://ard.bmj.com/content/82/Suppl_1/129.2 (Full text)

Modulation of Beta-Adrenergic Autoantibodies Over Time in Post-Viral ME/CFS is Related to Fatigue and Pain Symptoms

Abstract:

Background: Myalgic encephalomyelits/chronic fatigue syndrome (ME/CFS) is an acquired disease with symptoms of fatigue and pain. In pathogenesis, the induction of autoantibodies (AAB) against G-protein coupled receptors (GPCR), such as β-adrenergic receptors (β-AdR), has been suspected. GPCR-AAB correlate with symptom severity and autonomic dysfunction in ME/CFS.

Objectives: To describe symptoms and treatment of a patient presenting with infection-triggered ME/CFS demonstrating that levels of β-AdR-AAB underlie modulation over time, correlating with the severity of symptoms.

Methods: At T1 and T2, GPCR-AAB were measured and questionnaires assessing symptom severity were completed. TSHDS-IgM-AAB were tested, and SF density was analyzed via skin probe.

Results: At T2, elevated levels of β-AdR-AAB were found, corresponding with an aggravation of fatigue and pain symptoms. Elevated TSHDS-IgM-AAB were found, which corresponded with reduced fiber density from the skin probe.

Conclusions: The levels of β-AdR-AAB in post-infectious ME/CFS can be modulated. Future studies might target interventions to reduce these AAB.

Source: Busch L, Schriek C, Paul M, Heidecke H. Modulation of Beta-Adrenergic Autoantibodies Over Time in Post-Viral ME/CFS is Related to Fatigue and Pain Symptoms. Isr Med Assoc J. 2023 Apr;25(4):259-264. PMID: 37129123. https://pubmed.ncbi.nlm.nih.gov/37129123/

Miscellaneous neuromuscular symptoms and signs in long Covid

Abstract:

We have completed the 3rd year of the Covid-19 pandemic. In the early stages of the disease, we were faced with a wide variety of symptoms and signs, including the neuromuscular system, as well as life-threatening cardiopulmonary, neurovascular and immune complications.

In our study, we questioned fatigue, myalgia, arthralgia, dyspnea, headache, dizziness, neck pain, back pain, low back pain, knee-hip-foot joint pain, vascular claudication (lower extremity pain/cramp), neuropathic pain, morning stiffness, joint swelling, pernio, imbalance in walking in patients (N=111; 65 female, 29 male) aged 20-59 years, who applied to our outpatient clinic in the last 1 year and had Covid-19.

The mean time after Covid-19 was 5.8 ±2.1 months. The duration of Covid-19 treatment was a minimum of 5 days and a maximum of 12 days (median=5 days). Weight loss in 14.4% (median=3.5 kg), anorexia 17.1%, myalgia 41.4% (visual analog scale, VAS=5.1±1.9 cm), arthralgia 24.3% (VAS=5.1±2 cm), fatigue 63.1%, joint swelling 1.8%, pernio sign 0.9%, morning stiffness 7.2% (median=15 min, min 5-maximum 60 min), headache 39.6%, neuropathic pain 15.3%, effort dyspnea 38.7%, 30 second chair stand test= 14.9 ±3.6, vascular claudication symptom 11.7%, neck pain 27.0%, low back pain 30.6%, back pain 36%, hip-knee-foot pain 18.0%, gait imbalance 1.8%, dizziness 18.9% were observed. While fatigue (p=0.05), headache (p=0.04), and dyspnea (p=0.021) complaints were higher in males; VAS (arthralgia) was found higher in females (p=0.026).

In the post-Covid-19 period, we see many neuromuscular symptoms and signs, especially fatigue, myalgia, headache and back pain. In addition, lower extremity vascular claudication and neuropathic pain related with chronic pain should not be overlooked in these patients.

Source: Koca TT, Erzurumluoglu O, Kocyigit BF. Miscellaneous neuromuscular symptoms and signs in long Covid. Med Science. 2023;12(1):238-43. https://www.medicinescience.org/article/3381 (Full text)

Not myopathic, but autonomic changes in patients with long-COVID syndrome: a case series

Abstract:

Introduction: Neurological sequelae following SARS-CoV-2 infection still represent a serious concern both for neurologists and neuroscientists. In our paper, we investigated pain, myalgia, and fatigue as symptoms in long-COVID patients with an electrophysiological approach, comprising the evaluation of sympathetic skin responses (SSRs) and quantitative electromyography (qEMG).

Materials and methods: Twelve patients were enrolled (mean age, 47.7 ± 11.6 years), referred to our attention because of myalgia, pain, or muscle cramps, which persisted about 6 months after the diagnosis of SARS-CoV-2 infection. They underwent conventional electroneurography (ENG), needle electromyography (EMG), and SSRs; moreover, qEMG was performed by sampling at least 20 motor unit potentials (20-30 MUPs) during weak voluntary contraction in deltoid and tibialis anterior muscles. The mean duration, amplitude, and percentage of polyphasic potentials were assessed and compared with healthy and age-matched volunteers.

Results: ENG did not disclose significant changes compared to healthy subjects; needle EMG did not reveal denervation activity. In addition, qEMG showed MUPs similar to those recorded in healthy volunteers in terms of polyphasia (deltoid: p = 0.24; TA: p = 0.35), MUP area (deltoid: p = 0.45; TA: p = 0.44), mean duration (deltoid: p = 0.06; TA: p = 0.45), and amplitude (deltoid: p = 0.27; TA: p = 0.63). SSRs were not recordable from lower limbs in seven patients (58%) and from the upper ones in three of them (25%).

Conclusion: Our data suggest an involvement of the autonomic system, with a focus on cholinergic efferent sympathetic activity, without any evidence of myopathic changes.

Source: Bocci T, Bertini A, Campiglio L, Botta S, Libelli G, Guidetti M, Priori A. Not myopathic, but autonomic changes in patients with long-COVID syndrome: a case series. Neurol Sci. 2023 Apr;44(4):1147-1153. doi: 10.1007/s10072-023-06637-8. Epub 2023 Feb 3. PMID: 36735149; PMCID: PMC9896447. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9896447/ (Full study)

Is Central Sensitisation the Missing Link of Persisting Symptoms after COVID-19 Infection?

Abstract:

Patients recovered from a COVID-19 infection often report vague symptoms of fatigue or dyspnoea, comparable to the manifestations in patients with central sensitisation. The hypothesis was that central sensitisation could be the underlying common aetiology in both patient populations. This study explored the presence of symptoms of central sensitisation, and the association with functional status and health-related quality of life, in patients post COVID-19 infection.

Patients who were previously infected with COVID-19 filled out the Central Sensitisation Inventory (CSI), the Post-COVID-19 Functional Status (PCFS) Scale and the EuroQol with five dimensions, through an online survey. Eventually, 567 persons completed the survey. In total, 29.73% of the persons had a score of <40/100 on the CSI and 70.26% had a score of ≥40/100. Regarding functional status, 7.34% had no functional limitations, 9.13% had negligible functional limitations, 37.30% reported slight functional limitations, 42.86% indicated moderate functional limitations and 3.37% reported severe functional limitations.

Based on a one-way ANOVA test, there was a significant effect of PCFS Scale group level on the total CSI score (F(4,486) = 46.17, p < 0.001). This survey indicated the presence of symptoms of central sensitisation in more than 70% of patients post COVID-19 infection, suggesting towards the need for patient education and multimodal rehabilitation, to target nociplastic pain.

Source: Goudman L, De Smedt A, Noppen M, Moens M. Is Central Sensitisation the Missing Link of Persisting Symptoms after COVID-19 Infection? J Clin Med. 2021 Nov 28;10(23):5594. doi: 10.3390/jcm10235594. PMID: 34884296; PMCID: PMC8658135. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8658135/ (Full text)

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)