Path 12: Thrombosis, embolism, and infracion

Question 1

Thrombosis is described as?

Answer 1

Pathologic formation of a blood clot. Solid structure formed by components of the blood within the circulatory system

Question 2

What can form thrombosis?

Answer 2

platelets

fibrin

leucocytes

Question 3

What are the necessary conditions for the Virchow triad?

Answer 3

Endothelial damage

Alteration of blood flow

Alteration of blood composition

you just need one to have thrombosis

Question 4

What are the requirements for thrombosis?

Answer 4

Blood must flow (stagnant blood clots, but do not form thrombi)

Decreased flow rate (permits contact of thrombocytes with endothelium)

Once attached to the endothelium, thrombocytes resist blood flow and current by forming “eddies” which allows more thrombocytes to adhere ad form a mass -> Thrombus

Question 5

Analyze this image

Question 6

Endothelial damage

Answer 6

Endothelial damage leading to platelet activation almost inevitably underlies thrombus formation in the heart and arterial circulation, where the high rates of blood flow impedes clot formation.

Endothelial damage or change to prothrombotic status (endothelial activation) > exposure of vWF and TF.

Endothelial activation: Physical injuries, infectious agents, abnormal blood flow, inflammatory mediators, metabolic abnormalities (hypercholesterolemia), toxins > prothrombotic state

Question 7

Answer 7

Endothelial damage: Most important factor. Endothelium must be damaged, physically ruptured, or dysfunctional to contribute to the development of thrombosis. Dysfunction eg: produce more clotting factors and less anticoagulants (hypertension, turbulent flow, endotoxins, radiation, hypercholesterolemia

Question 8

Alterations of the normal blood flow

Answer 8

Turbulence > endothelial injury or dysfunction and countercuurents, contributing to local formation of stasis
-Promotes endothelial activation (shift in genetic expression)
-Breaks laminar flow (platelets touch the endothelium)
-Promotes «washing» of activated clotting factors.

Stasis: major contributor to formation of venous thrombus

Question 9

Hypercoagubility
aka thrombophilia

Answer 9

Any disorder of the blood that predisposed to thrombosis

Important role in venous thrombosis

Primary (gnetic) and seconday (acquired)
P: factor V mutation, prothrombin mutation
S: prolonged immolization, myocardial infraction, atrial fibrillation, tissue injury, cancer, prosthetic cardiac valves, DIC, cardiomyopathy, nephrotic syndrome, Hyper-estrogenic states, others)

mass tissue destruction > release of large amounts of tissue thromboplastin

Question 10

Thrombi can develop where?

Answer 10

Anywhere in the cardiovasular system. Focally attached to underlying vascular surface

-arterial or cardiac: sites of turbulence or endothelial injury, tend to grow downstream from the site of attachment

-venous: characteristically occur at sites of statsis, tend to extend upstream from their point of origin

BOTH GROW AWAY FROM THE HEART

Question 11

Arterial or cardiac thrombi

Answer 11

Usually at sites of endothelial injury (atheroscerotic plaques) or turbulence (vessel bifurcation)

Tend to grow in downstream from point of attachment

Tend to be *occlusive**

Thrombi development on heart valves
- infective endocarditis: bacterial/ fungal infection
- sterile endocarditis: hyper coagulable states

Question 12

Analyze the photo

Answer 12

Spirocerca lupi

Question 13

Venous thrombi

Answer 13

Typically at sites of STASIS: contain more RBCs

Tend to grow against the direction of blood flow

Tend to be occlusive

May be confused with postmortem clots

More frequent than arterial thrombi. Hepatic abscesses >Thrombosis of caudal vena cava > pulmonary emboli.

Question 14

look at bottom of image

Answer 14

Abscess
-green

Happened from the outlined red line which is a venous thrombus

Question 15

Fate of thrombi?

Answer 15

If patient survives immediate effects of thrombotic vascular obstruction, thrombi may under one or more events

Propagation
Embolization
Dissolution
Organization & Recanalization

Question 16

What is occuring?

Answer 16

Recanalization Process

-Ingrowth of endothelial cells, smooth muscle cells, and fibroblasts

Formation of capillary channels -> channels anastomose to create conduits that re-establish limited blood flow continuity

With time -> contraction of mesenchymal cells -> connective tissue of organized thrombus incorporated as a subendothelial swelling of vessel wall

Question 17

Effects of Thrombosis (3)

Answer 17

Negligible no adverse effects (occurs in vessels that are not critical for life)

Beneficial it is needed to stop bleeding (important in hemostasis)

Damaging thrombosis in areas with inadequate collateral circulation > ischemia or infract

Question 18

How can you remember what occurs with DIC ?

Answer 18

Death is coming!!

not a disease but a CONSEQUENCE

Question 19

Embolism is described as?

Answer 19

Detached intravascular solid, liquid, or gaseous mass that is carried by blood to a site distant from its point of origin

ischemic necrosis of distal tissue = INFRACTION

Question 20

Embolism etiology is?

Answer 20

1. Thrombus (95%)
2. Fibrin
3. Bacteria
4. Parasites
5. Neoplasia
6. Fat embolism (in lungs due to fractures)
7. Gas embolism

Question 21

Describe Embolus and Embolism?

Answer 21

Embolus: Any foreign body (solid, liquid or gaseous) that circulates in the vascular or lymphatic system.

Embolism: An embolus is carried by the circulation, and is trapped in small caliber vessel > ischemia > infarct

Question 22

Infract is described as?

Answer 22

an area of schemic necrosis caused by occlusion of either arterial supply or venous drainage in a particular tissue

Question 23

Infractions can be caused by?

Answer 23

Nearly 99% of all infarcts result from thrombotic or embolic events, and almost all result from arterial occlusion
-Venous infarcts rare: bypass channels rapidly open after venous thrombosis
- Venous infarction more likely in organs with single venous outflow channels (kidney, heart, spleen, brain)

Question 24

How do you recognize of ATE?

Answer 24

Pain

Paralysis

Pulselessness

Poikilothermy

Pallor

Question 25

what is this?

Answer 25

Chronic infart