Vascular Disorders & Thrombosis 4

Question 1

An aggregate of platelets, fibrin, and other blood elements formed on a vessel wall or within the heart

Answer 1

Thrombus

Question 2

Any material (thrombus, gas bubble, fat, etc.) carried by the blood from its point of origin to a distant site

Answer 2

Embolus

Question 3

A thrombus or fragment of a thrombus that breaks loose and enters the circulation

Answer 3

Thromboembolus

Question 4

What is Virchow’s triad?

Answer 4

Triad = the 3 primary contributing factors to thrombosis
- Endothelial injury (most important!)
- Abnormal blood flow
- Hypercoagulability

Question 5

Trauma, inflammation, invasive neoplasms, infectious agents, endotoxemia, uremic toxins, immune complexes, and collagen disorders are all causes of ____________ injury.

Answer 5

Endothelial

Question 6

Reduced blood flow is also called…

Answer 6

Stasis

(E.g. GDV, torsion, cardiomyopathy, aneurysm)

Question 7

Chaotic blood flow is also called…

Answer 7

Turbulence

(E.g. atherosclerosis)

Question 8

Abnormally high tendency of blood to clot that is typically caused by alterations in coag factors; can be inherited or acquired

Answer 8

Hypercoagulability

(E.g. antithrombin III deficiency)

Question 9

What is the pathogenesis of atrial thrombosis in hamsters?

Answer 9

• Renal amyloidosis, caused by chronic inflammation, leads to hypercoagulability and loss of antithrombin III
• Atrial thrombosis occurs as a result, which leads to congestive heart failure and SQ edema

Question 10

What are the 4 possible fates/outcomes for a thrombus?

(Think in terms of what happens to the thrombus itself)

Answer 10

Propagation, embolization, dissolution, organization/recanalization

Question 11

Outcomes of the thrombus:

What is “propagation”?

Answer 11

Enlargement of the thrombus

Question 12

Outcomes of the thrombus:

What is “embolization”?

Answer 12

Part or all of the thrombus is dislodged and transported elsewhere in the vasculature

Question 13

Outcomes of the thrombus:

What is “dissolution”?

Answer 13

Shrinkage of the thrombus through fibrinolysis

Question 14

Outcomes of the thrombus:

What is “organization and recanalization”?

Answer 14

Thrombus is organized by the invasion fibroblasts and the formation of new vascular channels

Question 15

What is the general morphology of a thrombus?

Answer 15

• Rough, red-tan, friable mass
• May have friable appearance due to alternate layers of platelets, fibrin, and other blood cells
• Can be occlusive or non-occlusive

Question 16

What is a “chicken fat clot”, and what is it often mistaken for?

Answer 16

Smooth, shiny, gelatinous post-mortem blood clots; can be mistaken for a thrombus

Question 17

What is an easy way to distinguish a chicken fat clot from a thrombus in a post-mortem examination, aside from its appearance alone?

Answer 17

Whether or not the clot is easily removed from the vessel; chicken fat clots are easily removed/not attached to vessels, thrombi are attached to vessels a difficult to remove

Question 18

What pathology does bacterial endocarditis cause in cattle?

Answer 18

• Bacteria builds up in right AV valves, causing septic thromboemboli which will travel to the small branches of the pulmonary artery
• Result: pneumonia

Question 19

What causes saddle thromboembolism in cats?

Answer 19

• Hypertrophic cardiomyopathy causes blood stasis in the enlarged left atrium, leading to an aortic thrombus
• Thromboembolism dislodges into aorta and travels to the bifurcation of the caudal abdominal aorta

Question 20

Acute paralysis, pain, weakness, lameness of hind limbs, and decreased/absent pulses in the femoral arteries of the rear legs are all clinical signs of…

Answer 20

Saddle thrombus

Question 21

Widespread intravascular coagulation and platelet activation which results in consumption of platelets and coag factors; causes progressive thrombocytopenia and widespread hemorrhage

Answer 21

Disseminated Intravascular Coagulation (DIC)

Question 22

What is a fibrocartilagenous emboli, and what does it cause?

Answer 22

Traumatic implantation of intervertebral disk material into spinal vessels; causes necrotizing myelopathy (spinal cord infarcts)

Question 23

Bone fractures release microscopic fat globules into circulation, and this can cause a….

Answer 23

Fat embolism