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)

Neuropathology and Neurological Manifestations in ME/CFS and Long COVID with focus on Post-Exertional Symptom Exacerbation: a Literature Review

Summary:

Many of the people that get infected with the Coronavirus develop long-lasting complaints and are diagnosed with Long COVID after the acute infection is gone. These complains can last several months or years and include fatigue, cognitive impairment, sleeping problems and post-exertional symptom exacerbation (PESE). Research shows that COVID-19 patients with an acute infection have abnormalities in their brain, which could potentially lead to long-lasting neurological problems and symptoms. However, although many researchers are trying to uncover the underlying mechanisms, Long COVID is still very new.
The underlying mechanisms causing and maintaining the disease are therefore unclear. A large group of Long COVID patients resembles patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) in terms of symptoms and, in many cases, the viral trigger of the disease. A core symptom of ME/CFS is PESE, which is uncommon in other fatiguing illnesses, but frequently seen in Long COVID patients. PESE involves an abnormal worsening of symptoms and cognitive and physical functions after any type of normal activity. Because of the large symptom overlap and lack of knowledge regarding PESE, underlying brain-mechanisms associated with Long COVID and ME/CFS in general as well as after physical exertion were investigated.
The findings of this review indicate that ME/CFS is associated with several abnormalities in the brain which are also proposed to be present in Long COVID patients. Such abnormalities include inflammation of the brain, shrinkage of the brain and less blood flow to the brain. After physical exertion, these abnormalities might be exacerbated in ME/CFS patients. This results in a brain that needs to work harder than the healthy brain to complete a task. It is demonstrated by increased brain activity in several brain regions after physical exertion and general symptom exacerbation. Since the two diseases seem to have a large overlap in symptoms and underlying brain-mechanisms, this finding might apply to patients with long COVID as well. Importantly, Long COVID seems to consist of different subgroups of which a large part fulfills the criteria for ME/CFS.
Treatment and therapy for ME/CFS patients is therefore likely transferable to this subgroup of Long COVID patients, with explicit attention towards the PESE phenomenon. More research is needed to uncover the underlying mechanisms as well as correct treatment approach of these diseases. Future research should take subgroups of Long COVID into account.
Source: Rodenburg, Sanne. Neuropathology and Neurological Manifestations in ME/CFS and Long COVID with focus on Post-Exertional Symptom Exacerbation: a Literature Review. Master Thesis, Utrecht University. March 14, 2023. https://studenttheses.uu.nl/bitstream/handle/20.500.12932/43647/Rodenburg_7433050_Neuropathology%20and%20neurological%20manifestations%20in%20MECFS%20and%20Long%20COVID%20with%20focus%20on%20PESE.pdf (Full text)

Clinical and radiological outcomes of longCOVID: Is the post-COVID fibrosis common?

Abstract:

Introduction: COVID-19 survivors may take longer to regain full well-being. This study aimed to investigate clinical and functional evaluation and radiologic changes in the third month after COVID-19.

Materials and methods: A total of 126 patients were assessed in the third month for symptoms, pulmonary function, exercise capacity, radiologic imaging, and quality of life after being discharged following COVID-19 treatment. Two radiologists evaluated the initial and follow-up images.

Result: At the third month follow-up visit, the most common persisting symptoms were shortness of breath (32.5%), cough (12.7%), and muscle pain (12.7%). At the follow-up visit, oxygen saturations at rest and after a six min walking test were lower in patients with prior intensive care hospitalization compared to those without (p<0.001, p= 0.004). Computed tomography (CT) scans revealed persisting pulmonary pathologies in 64.6% of patients at the third month follow-up. The most common pathologies on follow-up thoracic CT were fibrotic-like changes in 44.2% and ground-glass opacities (GGO) in 33.3%. Regression analysis unveiled that age [95% confidence interval (CI), 1.01 to 1.15; p= 0.020], male sex (95% CI, 4.06 to 95.3, p<0.001), first CT severity score (95% CI, 1.02 to 1.41, p= 0.028), duration of hospitalization (95% CI, 1.02 to 1.18, p= 0.012), oxygen saturation (95% CI, 0.86 to 0.96, p<0.001) were independent predictors of fibrotic-like changes.

Conclusions: In the third month following COVID-19, the most common symptom was dyspnea, and the most common radiological findings were fibrotic-like changes and GGO. Longer follow-up studies of COVID-19 survivors are needed to observe lasting changes.

Source: Sarıoğlu N, Aksu GD, Çoban H, Bülbül E, Demirpolat G, Arslan AT, Erel F. Clinical and radiological outcomes of longCOVID: Is the post-COVID fibrosis common? Tuberk Toraks. 2023 Mar;71(1):48-57. English. doi: 10.5578/tt.20239907. PMID: 36912409. http://tuberktoraks.org/managete/fu_folder/2023-01/2023-71-1-48-57.pdf (Full text)

The Prevalence of Psychiatric Symptoms and their correlates as part of the Long-Covid Syndrome.

Abstract:

The Long COVID syndrome has now been documented clearly in the literature, but whether or not psychiatric symptoms are prominent is unclear. We performed a retrospective chart review of all patients receiving medical care during the pandemic in an outpatient Long-COVID specialty clinic that serves a large racial and ethnic minority population. As many as 44% of patients had symptoms that necessitated referrals to psychiatrists, predominantly depression or anxiety. Spanish speaking patients had greater COVID severity (48%) than did predominantly English speakers (15%). We conclude that the long COVID syndrome is predominantly a cluster of physical symptoms that are sequelae of the viral infection.

Source: Clifton Chow, Will Schleyer, Lynn E DeLisi. The Prevalence of Psychiatric Symptoms and their correlates as part of the Long-Covid Syndrome. Psychiatry Research, 2023, 115166, ISSN 0165-1781, https://doi.org/10.1016/j.psychres.2023.115166. https://www.sciencedirect.com/science/article/pii/S0165178123001178

Effect of laser acupuncture on immunomodulation and dyspnea in post-COVID-19 patients

Introduction: The post-COVID-19 syndrome is characterized by post-viral chronic fatigue syndrome as well as multi-organ complications. Its usual clinical symptoms are exhaustion, dyspnea, and chest pain. This study examines the effect of laser acupuncture (LA), which implies laser application on acupuncture points, on boosting immunity and reducing the inflammatory symptoms in post-COVID syndrome patients.

Material and methods: A total of 80 patients of both sexes with post-COVID symptoms were enrolled and randomly divided into the LA group (n = 40), which received LA three times/week for 12 weeks, and a placebo group (n = 40) which received sham LA. The following measures were taken for both groups before and after the study: Total lymphocyte count (TLC), Interleukin 6 (IL-6), dyspnea using the modified Medical Research Counseling Dyspnea Scale (mMRC), and fatigue using the Chalder Fatigue Scale (CFQ-11).

Results: LA group showed a significant elevation in TLC (p < 0.001) as well as a significant reduction in IL-6 levels, dyspnea, and fatigue scale (p < 0.001). On the other hand, the placebo group demonstrated a significant increase in TLC (p < 0.05).

Conclusions: The use of lasers at particular acupuncture points related to lung and immunity showed promising results in dealing with the typical main symptoms post-COVID, including chronic fatigue and dyspnea.

Source: Algitany SI, Fouad SA, Nassif AA, Guirguis SA. Effect of laser acupuncture on immunomodulation and dyspnea in post-COVID-19 patients. Advances in Rehabilitation / Postępy Rehabilitacji. 2023. doi:10.5114/areh.2023.125836. http://www.advrehab.org/Effect-of-laser-acupuncture-on-immunomodulation-and-dyspnea-in-post-COVID-19-patients,125,50340,0,1.html (Full text available as PDF file)

Increased insulin resistance due to Long COVID is associated with depressive symptoms and partly predicted by the inflammatory response during acute infection

Abstract:

Background: Some months after the remission of acute COVID-19, some individuals show depressive symptoms, which are predicted by increased peak body temperature (PBT) and decreased blood oxygen saturation (SpO2). No data indicate whether Long COVID is associated with increased insulin resistance (IR) in association with neuroimmune and oxidative (NIO) processes.

Methods: This case control and retrospective cohort study used the homeostasis Model Assessment 2 (HOMA2) calculator© to compute β-cell function, insulin sensitivity and resistance (HOMA2-IR) and measured the Beck Depression Inventory (BDI) and the Hamilton Depression Rating Scale (HAMD) in 86 Long COVID patients and 39 controls.

Results: Long COVID (3-4 months after the acute infection) is accompanied by increased HOMA2-IR, fasting blood glucose, and insulin levels; 33.7% of the patients versus 0% of the controls had HOMA2-IR values >1.8, suggesting IR. Increased IR was predicted by PBT during acute infection, and associated with depressive symptoms above and beyond the effects of NIO pathways (NLRP3 inflamasome, myeloperoxidase, protein oxidation). There were no significant associations between increased IR and the activated NIO pathways during Long COVID.

Conclusion: Long COVID is associated with new-onset IR which may contribute to the onset of depressive symptoms due to Long COVID by enhancing overall neurotoxicity.

Source: Al-Hakeim HK, Al-Rubaye HT, Jubran AS, Almulla AF, Moustafa SR, Maes M. Increased insulin resistance due to Long COVID is associated with depressive symptoms and partly predicted by the inflammatory response during acute infection. Braz J Psychiatry. 2023 Mar 14. doi: 10.47626/1516-4446-2022-3002. Epub ahead of print. PMID: 36917827. https://pubmed.ncbi.nlm.nih.gov/36917827/ 

Comparison of Symptoms in Covid-19 Acute Infection and Long Covid-19

Abstract:

Background: Relatively little is known about the clinical course of covid-19 and the differences between the symptoms of covid-19 in acute phase of infection and the symptoms of long covid-19 in people with milder outpatient illnesses.

Objective: To compare clinical characteristics of covid-19 in acute infection with long covid-19 (presence of prolonged symptoms for at least 12 weeks, lasting at least 2 months, after acute covid-19 infection, and that are not explained by an alternative diagnosis).

Methodology: Comparison of secondary data among tow previous observational, longitudinal and prospective studies: 1) patients with post-acute covid-19 syndrome from March 15, 2020 to March 31, 2021; and 2) patients with Long covid-19 from March 15, 2020 to October 31, 2022, in the same population in general medicine.

Results: 33 covid-19 in acute phase, with 138 symptoms and 27 Long covid-19 cases with 44 symptoms were included. Respiratory symptoms predominated in both groups. Symptoms in Long covid-19 cases were significantly lower in general symptoms (X2= 5.9539. p= .014), and higher in Circulatory and Genitourinary system (Fisher exact test= 0.05).

Conclusion: Both in Long covid-19 and in covid-19 acute phase respiratory symptoms predominate. But they differ in that the symptoms of long covid-19 are less general than those of covid-19 acute phase, and present more symptoms of almost all organs and systems, those of the Circulatory and Genitourinary system being significant. The symptoms of Long covid-19 vs. acute phase are more debilitating and clinically heterogeneous.

Source: Turabian, Jose. (2023). Comparison of Symptoms in Covid-19 Acute Infection and Long Covid-19. 2694-5843. 10.36266/JCMHR/170.  https://www.researchgate.net/publication/369088222_Comparison_of_Symptoms_in_Covid-19_Acute_Infection_and_Long_Covid-19 (Full text)

Understanding Long COVID Syndrome: An Up to the Minute Fret

Abstract:

The Severe Acute Respiratory Syndrome Corona Virus 2 (SARSCoV-2) virus-induced corona virus disease 2019 (COVID-19) has had a global spread. Severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) rst emerged in Wuhan, China, in December 2019, and the infection spread rapidly across the world. The disease caused by the virus was named corona virus disease in 2019, and was declared a global pandemic by the World Health Organization (WHO) in March 2020. While the symptoms are mild or moderate in most patients, severe pneumonia can develop in 15%, and Acute Respiratory Distress Syndrome (ARDS), septic shock, and multiple organ failure in 5%. A comprehensive strategy for precautions includes hand washing, social distancing, isolation and mask-wearing. Besides, vaccines play an essential role in preventing the spread.

Long COVID or long-haul COVID (also known as post-COVID-19 syndrome, post-COVID-19 condition, post-acute sequelae of COVID-19 (PASC), or chronic COVID syndrome (CCS) is a condition characterized by long-term health problems persisting or appearing after the typical recovery period of COVID-19. Although studies into long COVID are under way, as of May 2022 there is no consensus on the definition of the term.

Long COVID has been described as having the potential to affect nearly every organ system, causing further conditions (sequelae) including respiratory system disorders, nervous system and neurocognitive disorders, mental health disorders, metabolic disorders, cardiovascular disorders, gastrointestinal disorders, musculoskeletal pain, and anemia. The most commonly reported symptoms of long COVID are fatigue and memory problems. Many other symptoms have also been reported, including malaise, headaches, shortness of breath, anosmia (loss of smell), parosmia (distorted smell), muscle weakness, low-grade fever, and cognitive dysfunction. Overall, it is considered by default to be a diagnosis of exclusion.

Source: Gomes, Richmond. (2023). Understanding Long COVID Syndrome: An Up to the Minute Fret. 04. 1-7.  https://www.researchgate.net/publication/369037934_Understanding_Long_COVID_Syndrome_An_Up_to_the_Minute_Fret (Full text)

Ambient air pollution exposure linked to long COVID among young adults: a nested survey in a population-based cohort in Sweden

Summary:

Background: Post COVID-19 conditions, also known as long COVID, are of public health concern, but little is known about their underlying risk factors. We aimed to investigate associations of air pollution exposure with long COVID among Swedish young adults.

Methods: We used data from the BAMSE (Children, Allergy, Environment, Stockholm, Epidemiology [in Swedish]) cohort. From October 2021 to February 2022 participants answered a web-questionnaire focusing on persistent symptoms following acute SARS-CoV-2 infection. Long COVID was defined as symptoms after confirmed infection with SARS-CoV-2 lasting for two months or longer. Ambient air pollution levels (particulate matter ≤2.5 μm [PM2.5], ≤10 μm [PM10], black carbon [BC] and nitrogen oxides [NOx]) at individual-level addresses were estimated using dispersion modelling.

Findings: A total of 753 participants with SARS-CoV-2 infection were included of whom 116 (15.4%) reported having long COVID. The most common symptoms were altered smell/taste (n = 80, 10.6%), dyspnea (n = 36, 4.8%) and fatigue (n = 34, 4.5%). Median annual PM2.5 exposure in 2019 (pre-pandemic) was 6.39 (interquartile range [IQR] 6.06–6.71) μg/m3. Adjusted Odds Ratios (95% confidence intervals) of PM2.5 per IQR increase were 1.28 (1.02–1.60) for long COVID, 1.65 (1.09–2.50) for dyspnea symptoms and 1.29 (0.97–1.70) for altered smell/taste. Positive associations were found for the other air pollutants and remained consistent across sensitivity analyses. Associations tended to be stronger among participants with asthma, and those having had COVID during 2020 (versus 2021).

Interpretation: Ambient long-term PM2.5 exposure may affect the risk of long COVID in young adults, supporting efforts for continuously improving air quality.

Source: Zhebin Yu, Sandra Ekström, Tom Bellander, Petter Ljungman, Göran Pershagen, Kristina Eneroth et al. Ambient air pollution exposure linked to long COVID among young adults: a nested survey in a population-based cohort in Sweden. The Lancet. Published: March 07, 2023 DOI:https://doi.org/10.1016/j.lanepe.2023.100608 (Full text)

Post-exertional malaise among people with long COVID compared to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)

Abstract:

Background: Long COVID describes a condition with symptoms that linger for months to years following acute COVID-19. Many of these Long COVID symptoms are like those experienced by patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

Objective: We wanted to determine if people with Long COVID experienced post-exertional malaise (PEM), the hallmark symptom of ME/CFS, and if so, how it compared to PEM experienced by patients with ME/CFS.

Methods: A questionnaire that asked about the domains of PEM including triggers, experience, recovery, and prevention was administered to 80 people seeking care for Long COVID at Bateman Horne Center. Their responses were compared to responses about PEM given by 151 patients with ME/CFS using chi-square tests of independence.

Results: All but one Long COVID respondent reported having PEM. There were many significant differences in the types of PEM triggers, symptoms experienced during PEM, and ways to recover and prevent PEM between Long COVID and ME/CFS. Similarities between Long COVID and ME/CFS included low and medium physical and cognitive exertion to trigger PEM, symptoms of fatigue, pain, immune reaction, neurologic, orthostatic intolerance, and gastrointestinal symptoms during PEM, rest to recover from PEM, and pacing to prevent PEM.

Conclusion: People with Long COVID experience PEM. There were significant differences in PEM experienced by people with Long COVID compared to patients with ME/CFS. This may be due to the newness of Long COVID, not knowing what exertional intolerance is or how to manage it.

Source: Vernon SD, Hartle M, Sullivan K, Bell J, Abbaszadeh S, Unutmaz D, Bateman L. Post-exertional malaise among people with long COVID compared to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Work. 2023 Mar 7. doi: 10.3233/WOR-220581. Epub ahead of print. PMID: 36911963. https://content.iospress.com/articles/work/wor220581 (Full text)