Tag: muscle dysfunction

Reduced Muscle Strength in Patients with Long-COVID-19 Syndrome Is Mediated by Limb Muscle Mass

Abstract:

Understanding the impact of COVID-19 on muscle strength may help to elucidate the organ systems that contribute to acute and chronic COVID-19 sequelae. We questioned whether patients with postdischarge symptoms after COVID-19 had compromised muscle strength compared with a control group, and if this potential relationship was mediated by the lower appendicular lean mass index (ALMI).

A total of 99 patients with long-COVID-19 and 97 control participants were screened. Maximal grip strength was assessed with a TKK 5101 digital dynamometer, and leg extension 1RM was measured using EGYM Smart Strength machines. Body composition (fat mass percentage, lean mass, visceral fat and appendicular lean mass index) was determined using a whole-body dual-energy X-ray densitometer.

Results showed that grip strength and leg extension strength were significantly higher in controls than in COVID-19 survivors (mean [SD], 32.82 [10.01] vs. 26.94 [10.33] kg; difference, 5.87 kg; P < 0.001) and (mean [SD], 93.98 [33.73] vs. 71.59 [33.70] kg; difference, 22.38 kg; P < 0.001), respectively). The relationship between long-COVID syndrome and grip/leg strength levels was partly mediated by ALMI, which explained 52% of the association for grip strength and 39% for leg extension.

Our findings provide novel insights into the mechanisms underlying the relationship between long-COVID syndrome and grip/leg strength levels, supporting the negative effects of long-COVID syndrome on muscle function.

Source: Ramírez-Vélez R, Legarra-Gorgoñon G, Oscoz-Ochandorena S, García-Alonso Y, García-Alonso N, Oteiza J, Ernaga Lorea A, Correa-Rodríguez M, Izquierdo M. Reduced Muscle Strength in Patients with Long-COVID-19 Syndrome Is Mediated by Limb Muscle Mass. J Appl Physiol (1985). 2022 Nov 30. doi: 10.1152/japplphysiol.00599.2022. Epub ahead of print. PMID: 36448687. https://journals.physiology.org/doi/abs/10.1152/japplphysiol.00599.2022 (Full text available as PDF file)

Prevalence of peripheral neuropathy and myopathy in patients post-COVID-19 infection

Abstract:

Background: Severe acute respiratory syndrome (SARS-CoV-2), caused by the Coronavirus 2019 (COVID-19), has become a life-threatening epidemic, affecting multiple organs, including the nervous system. Recent studies have documented that COVID-19-associated peripheral neuropathy is a common and frequent problem, with central and peripheral nervous system complications.

Objective: This work aims to evaluate the peripheral nerves and muscle involvement after COVID-19 infection, in addition to studying the prevalence rate and risk factors of their affection.

Methods: The study involved 400 patients, divided into 2 groups, with a history of COVID-19 infection with or without symptoms of neuromuscular affection, and 30 gender- and age-matched healthy volunteers were involved as controls. They were referred to the Department of Rheumatology and Rehabilitation for electro-diagnosis. All participants performed complete clinical examination and laboratory measures with an electrophysiological study.

Results: The prevalence of peripheral neuropathy and myopathy in post-COVID-19 patients was 56.3% among all patients. A significant difference was detected among patients of both groups regarding serum creatine phosphokinase level, clinical signs, and electrophysiologic findings of neuropathy and myopathy compared to the control group, with more prominent features among the symptomatic group. Histories of hospitalization, severe and long-lasting respiratory symptoms were risk factors for developing neuromuscular complications.

Conclusions: The present study could indicate that muscle involvement and peripheral nerve affection are common problems even among asymptomatic patients after COVID-19 infection, especially in the presence of any risk factors.

Source: Saif DS, Ibrahem RA, Eltabl MA. Prevalence of peripheral neuropathy and myopathy in patients post-COVID-19 infection. Int J Rheum Dis. 2022 Aug 1. doi: 10.1111/1756-185X.14409. Epub ahead of print. PMID: 35915515. https://onlinelibrary.wiley.com/doi/10.1111/1756-185X.14409 (Full text)

Pathogenic tracks in fatigue syndromes

Abstract:

This review analyses the recent literature devoted to two related fatigue syndromes: chronic fatigue syndrome (CFS) and acute onset postviral fatigue syndrome (PVFS). The articles are grouped into five pathogenic tracks: infectious agents, immune system, skeletic muscle, hypothalamo-pituitary-adrenal (HPA) axis and psychiatric factors.

Although a particular infectious agent is unlikely to be responsible for all CFS cases, evidence is shown that host-parasite relationships are modified in a large proportion of patients with chronic fatigue. Antibody titres against infectious agents are often elevated and replication of several viruses could be increased.

Chronic activation of the immune system is also observed and could be due to the reactivation of persistent or latent infectious agents such as herpes viruses (i.e. HHV-6) or enteroviruses. It could also be favorised by an impaired negative feedback of the HPA axis on the immune system.

A model is proposed where the abnormalities of the HPA axis are primary events and are mainly responsible for a chronic activation of the immune system which in turn induces an increased replication of several viruses under the control of cellular transcription factors. These replicating viruses together with cytokines such as TNF-alpha would secondarily induce functional disorders of muscle and several aspects of asthenia itself.

 

Source: Moutschen M, Triffaux JM, Demonty J, Legros JJ, Lefèbvre PJ. Pathogenic tracks in fatigue syndromes. Acta Clin Belg. 1994;49(6):274-89. http://www.ncbi.nlm.nih.gov/pubmed/7871934

 

Persistent virus infection of muscle in postviral fatigue syndrome

Abstract:

Nucleic acid was extracted from muscle biopsy samples from a series of highly selected patients suffering from chronic muscle fatiguability following a viral infection (Postviral Fatigue Syndrome: PVFS).

Samples were examined for the presence of enteroviral RNA sequences or Epstein-Barr (EBV) virus DNA sequences by molecular hybridisation as these two agents have been implicated by retrospective serology in the aetiology of PVFS. We found enteroviral RNA in 24% of biopsy samples and EBV DNA in a further 9% of biopsy samples: no biopsy was positive for both enteroviral RNA and EBV DNA.

In addition, in the case of enteroviruses we found that the persisting virus is defective in control of RNA replication as both strands of enteroviral RNA are present in similar amounts: this is unlike the asymmetric synthesis of genomic RNA seen in a productive, cytolytic enterovirus infection. The implications of these data in relation to mechanisms of viral persistence and muscle dysfunction are discussed.

 

Source: Cunningham L, Bowles NE, Archard LC. Persistent virus infection of muscle in postviral fatigue syndrome. Br Med Bull. 1991 Oct;47(4):852-71. http://www.ncbi.nlm.nih.gov/pubmed/1665379