Skeletal muscle-related symptoms are common in both acute coronavirus disease (Covid)-19 and post-acute sequelae of Covid-19 (PASC). In this narrative review, we discuss cellular and molecular pathways that are affected and consider these in regard to skeletal muscle involvement in other conditions, such as acute respiratory distress syndrome, critical illness myopathy, and post-viral fatigue syndrome. Patients with severe Covid-19 and PASC suffer from skeletal muscle weakness and exercise intolerance. Histological sections present muscle fibre atrophy, metabolic alterations, and immune cell infiltration. Contributing factors to weakness and fatigue in patients with severe Covid-19 include systemic inflammation, disuse, hypoxaemia, and malnutrition. These factors also contribute to post-intensive care unit (ICU) syndrome and ICU-acquired weakness and likely explain a substantial part of Covid-19-acquired weakness. The skeletal muscle weakness and exercise intolerance associated with PASC are more obscure. Direct severe acute respiratory syndrome coronavirus (SARS-CoV)-2 viral infiltration into skeletal muscle or an aberrant immune system likely contribute. Similarities between skeletal muscle alterations in PASC and chronic fatigue syndrome deserve further study. Both SARS-CoV-2-specific factors and generic consequences of acute disease likely underlie the observed skeletal muscle alterations in both acute Covid-19 and PASC.
There is ongoing discussion about whether preoperative obesity is negatively associated with inpatient outcomes of total hip arthroplasty (THA). The aim was to investigate the interaction between obesity and muscle strength and the association with postoperative inpatient recovery after THA. Preoperative obesity (body mass index (BMI)>30 kg/m2) and muscle weakness (hand grip strength <20 kg for woman and <30 kg for men) were measured about 6 weeks before THA. Patients with a BMI<18.5 kg/m2 were excluded. Outcomes were delayed inpatient recovery of activities (>2 days to reach independence of walking) and prolonged length of hospital stay (LOS, >4 days and/or discharge to extended rehabilitation). Univariate and multivariable regression analyses with the independent variables muscle weakness and obesity, and the interaction between obesity and muscle weakness, were performed and corrected for possible confounders.
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Background: Lipoedema is a chronic disorder of adipose tissue typically involving an abnormal build-up of fat cells in the legs, thighs and buttocks. Occurring almost exclusively in women, it often co-exists with obesity. Due to an absence of clear objective diagnostic criteria, lipoedema is frequently misdiagnosed as obesity, lymphoedema or a combination of both. The purpose of this observational study was to compare muscle strength and exercise capacity in patients with lipoedema and obesity, and to use the findings to help distinguish between lipoedema and obesity. Design: This cross-sectional, comparative pilot study performed in the Dutch Expertise Centre of Lymphovascular Medicine, Drachten, a secondary-care facility, included 44 women aged 18 years or older with lipoedema and obesity. Twenty-two women with lipoedema (diagnosed according the criteria of Wold et al, 1951) and 22 women with body mass index ≥30kg/m2 (obesity) were include in the study. No interventions were undertaken as part of the study. Results: Muscle strength of the quadriceps was measured with the MicroFET™, and functional exercise capacity was measured with the 6-minute walk test. The group with lipoedema had, for both legs, significantly lower muscle strength (left: 259.9 Newtons [N]; right: 269.7 N; p < 0.001) than the group with obesity. The group with lipoedema had a non-significant, but clinically relevant lower exercise-endurance capacity (494.1±116.0 metres) than the group with obesity (523.9±62.9 metres; p=0.296). Conclusions: Patients with lipoedema exhibit muscle weakness in the quadriceps. This finding provides a potential new criterion for differentiating lipoedema from obesity. We recommend adding measuring of muscle strength and physical endurance to create an extra diagnostic parameter when assessing for lipoedema.
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