Figure 3.

The relationship of general pathological processes in COVID-19. Two interrelated processes are depicted in the heuristic diagram of COVID-19 pathogenesis. In the left part of the scheme, the development of comorbid chronic pathologies, risk factors for SARS-CoV-2 infection, and chronic systemic low-grade inflammation (ChSLGI), which is a common, typical pathogenetic basis of chronic pathologies (in the form of allostasis), as well as comorbid chronic diseases are depicted. ChSLGI is linked to pro-inflammatory tissue stress, a subthreshold for the formation of focus of classical inflammation processes, and life-threatening “systemic inflammatory microcirculation”. In the center, the transformation of canonical pneumonia into Acute Respiratory Distress Syndrome (ARDS), which is already a sign of systemic inflammation (SI), is described. The source for ChSLGI development and stabilization (in the form of allostasis) are the extreme physiological processes in which tissue stress has limitations in its severity, time, and prevalence in the body.