These findings are consistent with knowledge regarding clinical patterns of viral infection, development of hyperinflammation and hypercoagulability, and fibrosis. Moreover, patients can present with more than one pattern, either simultaneously or consecutively. The epithelial and vascular patterns can present in all stages of symptomatic COVID-19, whereas the fibrotic pattern presents starting at ~3 weeks. In lung samples ( n = 131 cases), we identified three main histological patterns: epithelial ( n = 110, 85%), with reactive epithelial changes and DAD vascular ( n = 76, 59%) with microvascular damage, (micro)thrombi, and acute fibrinous and organizing pneumonia and fibrotic ( n = 28, 22%) with interstitial fibrosis.

Using PRISMA-IPD guidelines, 42 articles reporting 198 individual cases were included in our analysis. Here, we systematically reviewed published case reports and case series in order to increase our understanding of COVID-19 pathophysiology by constructing a timeline and correlating histopathological findings with clinical stages of COVID-19. Although essential for therapeutic guidance, the pathophysiology of COVID-19 is poorly understood. Moreover, low and high elastance phenotypes can be distinguished in mechanically ventilated patients, based on lung mechanics, ventilation-to-perfusion ratio, and CT scans these two phenotypes have presumed differences in their underlying pathophysiology. Clinically, three stages have been identified based on viral infection, pulmonary involvement with inflammation, and fibrosis. Since the outbreak of the COVID-19 pandemic, much has been learned regarding its clinical course, prognostic inflammatory markers, disease complications, and mechanical ventilation strategy.

All the mods 3 progression