Long term pathological changes in lungs after COVID-19

World literature is paying increasing attention to the long-term course of COVID-19 and symptoms that appear after the acute coronavirus infection. The symptoms, functional state of the lungs, and the X-ray changes are assessed. Nevertheless, post-COVID lung histology has not been described yet. The aim of this article is to study the long-term pathological changes in the lungs after acute COVID-19. Methods. We analyzed autopsy lung material from 19 deceased who had COVID-19. The average age of the deceased was 68.82 ± 14.6 years. All patients were found to have IgG to SARS-CoV-2. The median time to death following viral interstitial pneumonia was 72 days. Results. The causes of death and thrombotic complications (infarctions of various organs and venous thrombosis) were analyzed. Histological examination revealed thrombosis of small pulmonary arteries and capillaries of interalveolar septa, microinfarctions, hemorrhages, foci of organizing pneumonia, and nonspecific interstitial pneumonia. Conclusion. The first assessment of histological changes in human lungs showed that the most common post-COVID pathologic changes are microcirculation disorders combined with small areas of acute lung damage. The obtained data are essential for understanding the pathogenesis of post-COVID syndrome, necessitate diagnostic of microvasculature disorders using laboratory tests, scintigraphy, and CT imaging, as well as search for the therapeutic strategies. © 2021 Vestnik Tomskogo Gosudarstvennogo Universiteta, Matematika i Mekhanika. All rights reserved.

Pathological Features in 100 Deceased Patients With COVID-19 in Correlation With Clinical and Laboratory Data.

Background: Autopsies on COVID-19 deceased patients have many limitations due to necessary epidemiologic and preventative measures. The ongoing pandemic has caused a significant strain on healthcare systems and is being extensively studied around the world. Clinical data does not always corelate with post-mortem findings. The goal of our study was to find pathognomonic factors associated with COVID-19 mortality in 100 post-mortem full body autopsies. Materials and Methods: Following necessary safety protocol, we performed 100 autopsies on patients who were diagnosed with COVID-19 related death. The macroscopic and microscopic pathologies were evaluated along with clinical and laboratory findings. Results: Extensive coagulopathic changes are seen throughout the bodies of diseased patients. Diffuse alveolar damage is pathognomonic of COVID-19 viral pneumonia, and is the leading cause of lethal outcome in younger patients. Extrapulmonary pathology is predominantly seen in the liver and spleen. Intravascular thrombosis is often widespread and signs of septic shock are often present. Conclusion: The described pathological manifestations of COVID-19 in deceased patients are an insight into the main mechanisms of SARS-CoV-2 associated lethal outcome. The disease bears no obvious bias in severity, but seems to be more severe in some patients, hinting at genetic or epigenetic factors at play.

A targeted study of pulmonary pathology and chest computed tomography (ct) findings in COVID-19

Introduction. In the context of the COVID-19 pandemic, one of the most important diagnostic methods is highresolution computed tomography of the lungs (HRCT), which is highly sensitive for diagnostics of viral pneumonia. Because of a variety of radiological changes in the lungs at different periods of the disease, it became necessary to compare the changes detected by HRCT with morphological features of the disease. The aim of the research is to compare the HRCT patterns and histological changes in the lungs in the deceased with COVID-19. Material and methods. We analyzed 45 pieces from 14 deceased with COVID-19 (7 men/7 women), with an average age of 77.1 ± 12.9 (49-90 years), which underwent HRCT no more than 5 days before death. On the fixed whole lungs, tissue sites were selected, according to the target localization selected by HRCT with 3- D reconstruction. The leading HRCT patterns such as 'ground glass' opacities, “crazy paving”, consolidation, and symptoms typical for organizing pneumonia were the points of interest. We performed routine hematoxylineosin stains for histopathologic evaluation. Results. “Ground glass” opacities in the majority of cases (57.1%) corresponded to an acute phase of diffuse alveolar damage (DAD) (intraalveolar edema, hyaline membranes, cellularity, interstitial infiltration). Mosaic histological changes with alternation of filled alveoli (intraalveolar edema, clusters of red blood cells, macrophages, lymphocytes, fibrin) and aerated alveoli were detected in the areas of “crazy paving” zones. Areas of consolidation were histologically represented by extensive intraalveolar hemorrhages and/or hemorrhagic infarcts in 45.5% of cases. Perilobular consolidation, subpleural cords, symptoms of “halo” and “reverse halo”, which we considered as part of the symptom complex of organizing pneumonia in 43% of cases morphologically corresponded to organizing pneumonia (the proliferative phase of DAD) and to distelectases. Conclusion. Herein, we established the correspondence of DAD histology phases with/ or without pulmonary intravascular coagulopathy to the main HRCT-patterns of viral pneumonia. The results obtained can be used to determine therapeutic tactics at different phases of viral pneumonia in COVID- 19.