Cell Death and Perfusion Disorders 3 Flashcards
Define congestion
Accumulation of blood in a vascular bed due to reduced or obstructed outflow.
Define hypostatic congestion
Gravitational pooling of blood in a dead animal.
What kind of heart failure leads to chronic passive congestion of the liver?
Right sided heart failure.
Essentially, when the right side of the heart is not moving fluid, the liver is the first capillary bed where blood backs up.
How can right heart failure cause liver issues?
Elevated central venous pressure - venous back up - congestion in zone 3 - progresses to zone 3 ischemic necrosis. cells in zone 1, around the portal tract, are spared but necrosis occurs in zone 3.
What is nutmeg liver
Chronic passive congestion of the liver from right heart failure causes the liver to look like a nutmeg.
Where do you see lack of blood flow in left sided heart failure?
In the lungs
What kind of fluid can ooze from the liver with chronic passive congestion?
Proteinaceous fluid can ooze from the surface due to elevated central venous pressure. Fibrin polymerizes on the surface. Ascites may accumulate in the peritoneal cavity.
What do lungs look like when the — side of the heart is in failure?
Chronically congested lungs due to left heart disease (not moving blood forward) cause heart failure lung, which isn’t very common in vet med.
Colour rusty due to hemosiderin in alveolar macrophages. Red cells leak to alveoli, macrophages.
What do heart failure cells look like (LS)?
Alveolar macrophages containing phagocytosed red blood cells, which have leaked from pulmonary capillaries congested by left heart failure. Hemosiderin (rusty colour) in such cells acts as a microscopic marker of congestion. Also get edema in alveoli which is bad for gas exchange.
What are the thing that contribute to the significance/sequelae of congestion?
- signals circulatory problem
- predisposes to thrombosis (blood not flowing properly promotes clotting)
- leads to edema
- dependent on degree and duration of vascular obstruction, oxygen depletion may lead to hypoxic necrosis/infarction of cells/tissue (how large area affected, how long, how profound hypoxia)
What can cause hyperaemia of sclera?
Dilated capillaries on the scleral surface of conjunctivitis. Mediators of acute inflammation promote vasodilation and increased blood flow (and exudation of inflammatory cells to where needed). Try to increase blood flow to tissue for inflammation.
What are the cells that often make up dirty brown coagulated material?
-neutrophils
-dead cells
-debris
-fibrin leaked from open dilated cells
Dirty yellow exudate leaks from damaged vessels and covers inflamed, eroded mucosal surface
How does the signalling of adaptive circulatory phenomenon have a role in hyperaemia?
- increased oxygen demand
- heat dissipation (increased cutaneous vascular flow)
- Inflammation (most important)
Define hyperemia
The opposite of coagulation. The active physiological increase in flow of bright red oxygenated blood into a tissue. Results from arteriolar dilation
Define hemorrhage
Extravasation of blood. Leakage of erythrocytes and plasma into the interstitial space. RBCs outside the vascular system treated as a foreign body.
How can hemorrhage be recognized grossly?
- free blood in space or cavity
- bright red to deep red-blue colour in tissue in a distribution not conforming to vascular pattern, often accompanies congestion and may be difficult to differentiate
How can hemorrhage be recognized microscopically?
RBCs outside vessels, free in tissue
What is the differenced between petechiae and ecchymoses?
Both are types of hemorrhage. Petechiae are smaller, often pinpoint.
What diseases are petechiae and ecchymoses patterns often seen with?
Bacterial septicemia, systemic viral infection, thrombocytopenia (not enough platelets), vasculitis (inflammation of blood vessels), DIC
What does focal hemorrhage imply?
Local vascular damage sufficient to permit red cells to leak.
What lesion is often present in dogs with canine parvovirus infection?
Petechial to ecchymotic and/or paintbrush hemorrhages on the serosal surface of a segment of canine small intestine.
What property of muscle gives the ability of paintbrush hemorrhage to form?
The fibrous nature. Vascular damage and consumption coagulopathy leads to hemorrhage.
Define hemopericardium
Leakage of blood into pericardial sac.
What can hemopericardium result in?
Cardiac tamponade
Define cardiac tamponade
A modest volume of blood in the pericardial sac physically preventing the heart from pumping blood.