Abstract

The aim was to estimate the autopsy features of COVID-19 comparing with bacterial pneumonia.

Materials and methods: 15 patients died from COVID-19 pneumonia and 13 patients with CABP. 

On autopsy of COVID-19 patients macroscopically - enlarged, plethoric lungs, exudate with hemorrhagic components, areas of thrombosis, developing fibrosis (Figure 1A). Figure 1B - microscopical changes in COVID-19: artery of medium caliber, branching of the pulmonary artery, vascular endothelial integrity violation, the arrow indicates a pale pink non-nuclear mass in the form of threads – fibrin clot.

On autopsy of CABP patients macroscopically - compressed, dense, infiltrated lungs, filled with purulent exudate (Figure 1C). Figure 1D demonstrates an example of microscopical changes in CABP: mixed thrombi in the lumen of the arteries, more often in average caliber were found. This thrombus had a head (the structure of a white thrombus), a body (actually a mixed thrombus) and a tail (the structure of a red thrombus). The head was attached to the endothelial lining of the vessel, which distinguishes a thrombus from a posthumous blood clot or from an embolus.

Conclusions: 1) problems in fibrinolysis system, which is the main difference between CABP; in died patients with COVID-19 pneumonia the level of PAI-1 is associated with the disease severity and could be the crucial marker for patients’ distribution.