Table 2.

Pathophysiological factors in COVID-19 disease

Systems or organs	Pathophysiological factors
Pulmonary	•Viral uptake into vascular endothelium and pneumocytes •Distinctive interstitial pneumonia with intra- and extravascular fibrin deposition, activation of megakaryocytes, intravascular trapping of neutrophils, proliferation of type II pneumocytes, intra-alveolar accumulation of lymphocytes and macrophages •Diffuse alveolar damage with overlapping phases, including hyaline membrane formation, alveolar fibrin deposits, hyper reactive type II pneumocytes with viral cytopathic effects, squamous metaplasia with syncytium, and later organizing phase •Thrombotic microangiopathy •Pulmonary thromboembolism
Cardiovascular system	•Viral uptake into interstitial, perivascular and endothelial cells •Endotheliitis •Microvascular dysfunction •Direct or indirect damage to cardiomyocytes •Myocarditis in some cases •Pericarditis in some cases
Hematologic system	•Virus induced procoagulant stage and coagulopathy •Virus invasion and damage of T lymphocytes resulting in lymphopenia •Depletion of white pulp of the spleen •Predisposition to deep vein thrombosis and pulmonary thromboembolism