Myopathy as a cause of fatigue in long-term post-COVID-19 symptoms: Evidence of skeletal muscle histopathology

Abstract:

Background: Among post-COVID-19 symptoms, fatigue is reported as one of the most common, even after mild acute infection, and as the cause of fatigue, myopathy diagnosed by electromyography has been proposed in previous reports. This study aimed to explore the histopathological changes in patients with post-COVID-19 fatigue.

Methods: Sixteen patients (mean age:46 years) with post-COVID-19 complaints of fatigue, myalgia or weakness persisting for up to 14 months were included. In all patients, quantitative electromyography and muscle biopsies analysed with light and electron microscopy were taken.

Results: Muscle weakness was present in 50%, myopathic electromyography in 75% while in all patients, there were histological changes. Muscle fiber atrophy was found in 38%, and 56% showed indications of fiber regeneration. Mitochondrial changes, comprising loss of COX activity, subsarcollemmal accumulation and/or abnormal cristae, were present in 62%. Inflammation was found in 62%, seen as T-lymphocytes and/or muscle fiber HLA-ABC expression. In 75%, capillaries were affected involving basal lamina and cells. In two patients, uncommon amounts of basal lamina were found, not only surrounding muscle fibers but also around nerves and capillaries.

Conclusions: The wide variety of histological changes in this study suggest that skeletal muscles may be a major target of SARS-CoV-2 causing muscular post-COVID-19 symptoms. The mitochondrial changes, inflammation and capillary injury in muscle biopsies can cause fatigue in part due to reduced energy supply. Since most patients had mild-moderate acute affection, the new variants that might cause less severe acute disease could still have the ability to cause long-term myopathy.

Source: Hejbøl EK, Harbo T, Agergaard J, Madsen LB, Pedersen TH, Østergaard LJ, Andersen H, Schrøder HD, Tankisi H. Myopathy as a cause of fatigue in long-term post-COVID-19 symptoms: Evidence of skeletal muscle histopathology. Eur J Neurol. 2022 Jun 6. doi: 10.1111/ene.15435. Epub ahead of print. PMID: 35661354.  https://pubmed.ncbi.nlm.nih.gov/35661354/ https://pubmed.ncbi.nlm.nih.gov/35661354/ (Full text available as PDF file)

An Unexpected Journey: The Lived Experiences of Patients with Long-Term Cognitive Sequelae After Recovering from COVID-19

Abstract:

This current study explored the lived experiences of patients with long-term cognitive sequelae after recovering from COVID-19. A qualitative design with in-depth interviews and an analysis inspired by Ricoeur’s interpretation theory was utilised. Contracting COVID-19 and suffering long-term sequelae presented as a life-altering event with significant consequences for one’s social, psychological and vocational being in the world in the months following the infection.

Patients living with long-term cognitive sequelae after COVID-19 were in an unknown life situation characterised by feelings of anxiety, uncertainty and concerns about the future, significantly disrupting their life trajectory and forcing them to change their ways of life. While awaiting studies on treatment, symptom management and recovery after persistent sequelae of COVID-19, clinicians and researchers may find inspiration in experiences of other health conditions with similar phenomenology, such as ME/chronic fatigue syndrome and chronic headaches.

Source: Loft MI, Foged EM, Koreska M. An Unexpected Journey: The Lived Experiences of Patients with Long-Term Cognitive Sequelae After Recovering from COVID-19. Qual Health Res. 2022 May 21:10497323221099467. doi: 10.1177/10497323221099467. Epub ahead of print. PMID: 35603563. https://pubmed.ncbi.nlm.nih.gov/35603563/

Risk factors and multidimensional assessment of long COVID fatigue: a nested case-control study

Abstract:

Background: Fatigue is the most prevalent and debilitating long COVID symptom, however risk factors and pathophysiology of this condition remain unknown. We assessed risk factors for long COVID fatigue and explored its possible pathophysiology.

Methods: Nested case-control study in a COVID recovery clinic. Individuals with (cases) and without (controls) significant fatigue were included. We performed a multidimensional assessment evaluating various parameters, including pulmonary function tests and cardiopulmonary exercise testing, and implemented multivariable logistic regression to assess risk factors for significant long COVID fatigue.

Results: Total of 141 individuals were included. Mean age was 47 (SD 13) years; 115 (82%) were recovering from mild COVID-19. Mean time for evaluation was 8 months following COVID-19. Sixty-six (47%) individuals were classified with significant long COVID fatigue. They had significantly higher number of children, lower proportion of hypothyroidism, higher proportion of sore throat during acute illness and long COVID symptoms, and of physical limitation in daily activities. Individuals with fatigue had poorer sleep quality and higher degree of depression. They had significantly lower heart rate [153.52 (22.64) vs 163.52 (18.53), p=0.038] and oxygen consumption per Kg [27.69 (7.52) vs 30.71 (7.52), p=0.036] at peak exercise. The two independent risk factors for fatigue identified in multivariable analysis were peak exercise heart rate (odds ratio [OR] 0.79 per 10 beats/minute, 95% confidence interval [CI] 0.65-0.96, p=0.019); and long COVID memory impairment (OR 3.76, 95% CI 1.57-9.01, p=0.003).

Conclusions: Long COVID fatigue may be related to autonomic dysfunction, impaired cognition and decreased mood. This may suggest a limbic-vagal pathophysiology. Clinical Trial registration: NCT04851561.

Source: Margalit I, Yelin D, Sagi M, Rahat MM, Sheena L, Mizrahi N, Gordin Y, Agmon H, Epstein NK, Atamna A, Tishler O, Daitch V, Babich T, Abecasis D, Yarom Y, Kazum S, Shitenberg D, Baltaxe E, Elkana O, Shapira-Lichter I, Leibovici L, Yahav D. Risk factors and multidimensional assessment of long COVID fatigue: a nested case-control study. Clin Infect Dis. 2022 Apr 11:ciac283. doi: 10.1093/cid/ciac283. Epub ahead of print. PMID: 35403679.  https://pubmed.ncbi.nlm.nih.gov/35403679/

Neural Dysregulation in Post-Covid Fatigue

Abstract:

Following infection from SARS-CoV-2, a substantial minority of people develop lingering after-effects known as ‘long COVID’. Fatigue is a common complaint with substantial impact on daily life, but the neural mechanisms behind post-COVID fatigue remain unclear. We recruited volunteers with self-reported fatigue after a mild COVID infection and carried out a battery of behavioural and neurophysiological tests assessing the central, peripheral and autonomic nervous systems. In comparison to age and gender matched volunteers without fatigue, we show underactivity in specific cortical circuits, dysregulation of autonomic function, and myopathic change in skeletal muscles. Cluster analysis revealed no sub-groupings, suggesting post-COVID fatigue is a single entity with individual variation, rather than a small number of distinct syndromes. These abnormalities on objective tests may indicate novel avenues for principled therapeutic intervention, and could act as fast and reliable biomarkers for diagnosing and monitoring the progression of fatigue over time.

Source: Anne M.E. Baker, Natalie J. Maffitt, Alessandro Del Vecchio, Katherine M. McKeating, Mark R. Baker, Stuart N. Baker, Demetris S. Soteropoulos. Neural Dysregulation in Post-Covid Fatigue.
medRxiv 2022.02.18.22271040; doi: https://doi.org/10.1101/2022.02.18.22271040 https://www.medrxiv.org/content/10.1101/2022.02.18.22271040v1.full-text (Full text)