The morphological changes arising at a new koronavirusny infection (COVID-19) can be divided into two groups: the changes arising in lungs (as the main target organ at this pathology) and the changes arising in other bodies and fabrics.
If to speak about the changes arising in lungs, then it should be noted that for the present moment the specific macroscopic changes characteristic only of this koronavirusny infection are not defined. Nevertheless, many researchers characterize a morphological picture in lungs which arises at their defeat by a coronavirus as rather typical. If the patient had signs of the expressed respiratory insufficiency during lifetime, then on autopsy takes place to be a morphological picture typical acute respiratory a distress syndrome of adult (ORDS). At the same time such signs as diffusion consolidation of lungs and their plethora are noted. Outward of such morphological changes is very similar to those at flu H1N1 (so-called swine flu), but at the same time there is a defeat of vessels as the endoteliit and hemorrhagic changes of a pulmonary parenchyma. Lungs have dense or pasty consistence, they are increased in volume, color dark red. The lightness of a parenchyma is sharply reduced or is absent absolutely.
At survey of the affected lungs sites of the hemorrhages various by the size and also the centers of heart attacks on hemorrhagic type, meet blood clots in pulmonary vessels. It should be noted that signs of damage of a trachea are not observed, or they have secondary character and are connected with stay in a trachea of an endotracheal (tracheostomy) tube or accession of secondary hospital flora.
At microscopic examination of the drugs received from the affected lungs alveolar hypostasis is noted. In edematous liquid alveolotsita, erythrocytes, macrophages, lymphocytes and neutrophils in a small amount are found. Also at microscopic examination of lungs hyaline membranes which can extend to the internal surface of bronchioles are found. Epithelium desquamation takes place. Existence of alveolotsit of the second type which have larger kernel with the small kernels included in it is also described. In cells the inclusions characteristic of viral infections are described. Around vessels and bronchial tubes and also in interalveolar partitions and in a wall of small vessels the expressed infiltration by lymphocytes and macrophages is observed. If to speak about cells which are found in the specified cell inclusions then these are first of all T lymphocytes of CD3, CD2, CD5 and CD8. Also there are V-lymphocytes in a small amount. In the immunohistochemical analysis in a ciliate epithelium of bronchial tubes, an epithelium of bronchioles, in alveolotsita and macrophages and also in an endothelium of vessels the SARS-CoV-2 virus comes to light.
An important role at a new koronavirusny infection is played by defeat of the mikrotsirkulyatory course. At the same time in lungs such changes as a capillary plethora in the field of interalveolar partitions and also a plethora of branches of pulmonary arteries and veins are characteristic. Sladzh of erythrocytes, fibrinous blood clots, intrabronkhialny, intrabronkhiolyarny and intraalveolyarny hemorrhages causing a pneumorrhagia in patients are noted and also perivascular hemorrhages take place.
At easier course of a koronavirusny infection the nature of morphological changes of pulmonary fabric is precisely unknown for today.
In other bodies and fabrics certain changes also come to light. They are caused first of all by damage of the endothelium of vessels caused by a tsitokinovy storm and immediate effect of a virus. Also the autoimmune nature of defeat of an endothelium at COVID-19 is not excluded. This damage of an endothelium was already sustained by the own name: SARS‑CoV‑2-associated endoteliit and serves as the reason for development of a mikroangiopatiya of lungs and also other target organs: hearts (myocardium), brain and so on. Researchers noted that in series of observations the thrombovasculitis develops.
Thus we see that the morphological changes arising at a koronavirusny infection have various character, and it concerns both microscopic, and microscopic signs. It is characteristic that similar changes affect not only lungs, but also other bodies and fabrics that demonstrates the system nature of an infection. Further researches on this question which will help to understand more deeply character and an essence of morphological measurements are coming and consequently, to develop the perspective directions in diagnostics and treatment of COVID-19.