COVID-19 associated myopathy

Abstract

Purpose of reviewThe global spread of severe acute respiratory syndrome coronavirus 2 resulted in many cases of acute and postacute muscular symptoms. In this review, we try to decipher the potential underlying pathomechanisms and summarize the potential links between viral infection and muscle affection. Recent findingsDisregarding single case studies that do not allow safe conclusions due to the high number of infections, histopathological evidence of myositis has only been reported in deceased individuals with severe COVID-19. Postacute myalgia and weakness seem to occur in a subset of patients up to one year after initial infection, reminiscent of postinfectious syndromes (PIS) described in prior epidemics and pandemics of the past. Summary COVID-19 associated myopathy likely comprises different entities with heterogeneous pathomechanisms. Individual factors such as disease severity and duration, age, sex, constitutional susceptibilities, and preexisting conditions are important to consider when formulating a diagnosis. Persisting symptoms show overlapping features with PIS or postintensive care syndrome. In lack of strong evidence for a direct infection of myocytes, inflammatory myopathies associated with COVID-19 are presumably immune-mediated. Differential diagnosis of rheumatological and nonmuscular neurological origin coinciding with the infection need to be considered, due to the extremely high numbers of newly occurring infections the last 2 years.

Post-COVID syndrome is associated with capillary alterations, macrophage infiltration and distinct transcriptomic signatures in skeletal muscles

“…Upper leg MRI also did not reveal signs of myositis, which is consistent with recently published radiological findings (50). However, biopsies were taken almost a year after acute infection and several case reports of biopsy-proven myositis after SARS-CoV-2 have been published (51)(52)(53), and we ourselves histologically diagnosed non-specific myositis in some patients in the subacute aftermath of mild or moderate COVID (Fig. S3F).…”

Skeletal muscle injury in COVID infection: Frequency and patterns

“…Very few studies have documented formal evaluation of muscle weakness in acute settings and none exist for acute COVID infections. 23 We found that most of our patients had demonstrable muscle weakness with around one third having a degree of weakness similar to other inflammatory myopathy cohorts. 24 Reduction in muscle strength by almost 30% in presymptomatic COVID-19 was reported in one patient.…”

“…Demonstrable muscle weakness, particularly of neck flexor muscles, and disability that limits daily activities were common. Very few studies have documented formal evaluation of muscle weakness in acute settings and none exist for acute COVID infections 23 . We found that most of our patients had demonstrable muscle weakness with around one third having a degree of weakness similar to other inflammatory myopathy cohorts 24 .…”

SARS-CoV-2 and the nervous system: current perspectives

“…Myopathy has also been reported in some patients during the acute phase of infection [ 60 ]. It is not clear if this is due to the direct effect of the virus on myocytes or due to the local and/or systemic immune response against the invading virus [ 75 ].…”