Respiratory muscles dysfunction and respiratory diseases.

This review presents an analysis of the literature on the topic of respiratory muscle (RM) dysfunction in various forms of respiratory pathology: chronic obstructive pulmonary disease (COPD), asthma, community-acquired pneumonia, idiopathic pulmonary fibrosis (IPF), sarcoidosis and interstitial lung diseases (ILD), associated with systemic connective tissue diseases (polymyositis, dermatomyositis and systemic lupus erythematosus - SLE). Various clinical and pathophysiological aspects of RM dysfunction and general patterns of its pathogenesis were examined. It was proved that the role of RM in the development of respiratory failure depends on the form and stage of the pulmonary pathology and the severity of systemic manifestations of these diseases: excessive proteolysis, oxidative stress, hypoxia, chronic systemic inflammation. These factors modify the morphofunctional status of RM, worsens their contractile function, which is contributed to the development of respiratory failure. In some cases, the primary weakness of RM precedes the clinical manifestation of pulmonary pathology, which is distinctive for some variants of myositis-associated ILD and SLE. Endogenous intoxication syndrome plays a significant role in the development of RM dysfunction during community-acquired pneumonia. It is noted that sarcoid pulmonary ventilation disorders associate with the RM weakness, but not with the degree of lung damage. In most cases, secondary RM dysfunction predominates that contributes to respiratory failure progression, which is especially noticeable in case of COPD, asthma and IPF.