Skeletal muscle weakness in patients with sarcoidosis and its relationship with exercise intolerance and reduced health status

Abstract

Background: Skeletal muscle weakness is assumed to be present in patients with sarcoidosis but has never been reported in a consecutive group of patients. Moreover, its relationship with previously observed exercise intolerance and reduced health status has never been studied in these patients. Methods: Pulmonary function, skeletal and respiratory muscle forces, peak and functional exercise capacity, health status, and the circulating levels of inflammatory and anabolic markers were determined in 25 patients with sarcoidosis who complained of fatigue (15 men) and in 21 healthy subjects (13 men). Results: Patients with sarcoidosis had lower respiratory and skeletal muscle forces, reduced exercise capacity and health status, higher anxiety and depression scores, and higher circulating levels of tumour necrosis factor-a than healthy subjects (all p(0.01). Its soluble receptor p75 tended to be higher (p = 0.04). Circulating levels of interleukin (IL)-6, IL-8, insulin-like growth factor I and its binding protein 3 were not significantly different between the two groups. Skeletal muscle weakness was related to exercise intolerance, depression, and reduced health status in patients with sarcoidosis, irrespective of age, sex, body weight and height (p(0.05). Quadriceps peak torque was inversely related to fatigue but not to the circulating levels of inflammatory or anabolic markers. The mean daily dose of corticosteroids received in the 6 month period before testing was related to quadriceps peak torque only in patients who received oral corticosteroids. Conclusion: Skeletal muscle weakness occurs in patients with sarcoidosis who complain of fatigue and is associated with reduced health status and exercise intolerance.

Physical activity and training in sarcoidosis: review and experience-based recommendations

“…In a study among 25 patients with sarcoidosis, only in the patients who received oral corticosteroid treatment (n = 11) was the quadriceps peak torque inversely related to the mean daily dose of corticosteroids received in the 6 months before testing [18]. Thus, steroid myopathy may be a clinically relevant entity in sarcoidosis, especially with intensified corticosteroid treatment.…”

“…In the broader context of medical management, physical therapy or rehabilitation can help to avoid a negative vicious circle of deconditioning and improve coping with the disease [18,22].…”

“…A growing body of evidence has demonstrated the impact of not only organ-specific symptoms but also nonspecific problems, including lack of energy, fatigue, pain, anxiety, depression, and cognitive symptoms, on patients' lives, inducing significant worsening of (health-related) quality of life (HR QoL) [10,[12][13][14]. Multifactorial influences include systemic inflammation, decreased pulmonary function, sleeping disorders, small fiber neuropathy (SFN), sarcoid myopathy, hypoxia or glucocorticoid use, and deconditioning [15][16][17][18]. This can lead to physical inactivity, loss of fitness and muscle strength, and thus increased fatigue [19,20].…”

Benefits of Physical Training in Sarcoidosis

“…Distance covered during the six-minute walk test (6MWD) is often reduced and correlates with forced vital capacity (FVC) and fatigue severity [7,8]. Fatigue may be explained by peripheral muscle weakness and exercise intolerance-each is influenced by multiple factors, including sarcoidosis-related skeletal muscle abnormalities, decreased pulmonary function, small fiber neuropathy, and deconditioning [9][10][11].…”

Effects of inpatient pulmonary rehabilitation in patients with interstitial lung disease

“…However, data supporting PR in patients with ILD are scarce and the effects of PR in patients with ILD are largely unknown. While ventilatory limitation and skeletal muscle dysfunction are present in both COPD and ILD, impaired pulmonary gas exchange and circulatory factors may be more important in ILD patients [10][11][12].…”