03 - Hemodynamic disorders Flashcards
Accumulation of fluid in tissues or body cavities.
Edema (tissues) or effusion (body cavities)
Four main mechanisms of edema formation.
A. Increased hydrostatic pressure
B. Decreased oncotic pressure
C. Increased vascular permeability
D. Lymphatic obstruction
General morphologic appearance of edema.
Clearing and separation of ECM, and subtle cell swelling
It is an active process resulting from augmented blood flow due to arteriolar dilation; affected tissue is redder than normal, because of engorgement with oxygenated blood.
Hyperemia
It is a passive process resulting from impaired venous return out of a tissue; tissue has a blue-red color due to accumulation of deoxygenated hemoglobin in the affected tissue.
Congestion
Characterized by alveolar capillaries engorged with blood, with associated alveolar septal edema or focal minute intra-alveolar hemorrhage.
Acute pulmonary congestion
Pulmonary septa are thickened and fibrotic, with hemosiderin-laden macrophages in alveolar spaces.
Chronic pulmonary congestion
The central vein and sinusoids of the liver are distended with blood, with central hepatocyte degeneration; periportal hepatocytes are better oxygenated.
Acute hepatic congestion
The central regions of the hepatic lobules are grossly red-brown, slightly depressed, and are accentuated against the surrounding zones of uncongested tan, sometimes fatty liver (nutmeg liver); presence of centrilobular necrosis with hepatocyte drop-out, hemorrhage, and hemosiderin-laden macrophages.
Chronic hepatic congestion
Pathologic form of hemostasis.
Thrombosis
Components of Virchow triad (abnormalities that lead to thrombus formation).
Endothelial injury, Stasis, Hypercoagulability
It is a major contributor to the development of arterial thrombi.
Turbulence or endothelial injury
It is a major contributor to the development of venous thrombi.
Stasis
Any alteration of the coagulation pathway that predisposes to thrombosis; can be primary (e.g. Factor V Leiden, Protein C and S deficiency) or secondary (e.g. Cancer, atrial fibrillation, and prolonged immobilization)
Hypercoagulability
Laminations composed pale platelet and fibrin deposits alternating with darker red cell_rich layers; signifies formation of thrombus in flowing blood; present in antemortem thrombosis.
Lines of Zahn