CLINICAL AND HISTOPATHOLOGICAL FEATURES OFLUNG INJURY IN COVID-19 INFECT

Abstract

The aim of the study was to evaluate the histopathological changes in the lungs of patients who died of a new coronavirus infection (COVID-19) in relation to the length of hospital stay. We evaluated lung autopsy material, autopsy reports, and death summaries of 39 patients who died of COVID-19. The length of hospital stay ranged from a few hours to 25 days. At all stages of the disease, lung alterations (desquamation of bronchial and alveolar epithelium), circulatory disorders (alveolar edema and hemorrhages, congestion in small blood vessels, thrombosis), compensatory response (fibrosis) were identified. The patients who died during the first week of hospitalization demonstrated predominant signs of circulatory disorders (alveolar edema, hyaline membranes, alveolar hemorrhages, congestion in small blood vessels). Fibrosis, usually not typical for the first week of acute respiratory distress syndrome, was detected in 46% of the deceased during the first week of hospitalization, which may be due to late hospitalization or patterns of fibrosis development in COVID-19. For those who died in the 2nd and 3rd weeks of hospitalization, the compensatory response and progression of fibrosis were noted. By the 3rd week, pulmonary fibrosis was detected in 91% of patients. Thrombotic complications (thrombosis, pulmonary artery thromboembolism) were observed in almost half of fatalities occurring during weeks 2–3. Hemorrhagic infarction was found in 43% (6 patients) who died during week 2 of hospitalization, three of them were diagnosed with pulmonary embolism, indicating progression of pulmonary vascular damage.