Vascular Disorders & Thrombosis 4 Flashcards
An aggregate of platelets, fibrin, and other blood elements formed on a vessel wall or within the heart
Thrombus
Any material (thrombus, gas bubble, fat, etc.) carried by the blood from its point of origin to a distant site
Embolus
A thrombus or fragment of a thrombus that breaks loose and enters the circulation
Thromboembolus
What is Virchow’s triad?
Triad = the 3 primary contributing factors to thrombosis
- Endothelial injury (most important!)
- Abnormal blood flow
- Hypercoagulability
Trauma, inflammation, invasive neoplasms, infectious agents, endotoxemia, uremic toxins, immune complexes, and collagen disorders are all causes of ____________ injury.
Endothelial
Reduced blood flow is also called…
Stasis
(E.g. GDV, torsion, cardiomyopathy, aneurysm)
Chaotic blood flow is also called…
Turbulence
(E.g. atherosclerosis)
Abnormally high tendency of blood to clot that is typically caused by alterations in coag factors; can be inherited or acquired
Hypercoagulability
(E.g. antithrombin III deficiency)
What is the pathogenesis of atrial thrombosis in hamsters?
- 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
What are the 4 possible fates/outcomes for a thrombus?
(Think in terms of what happens to the thrombus itself)
Propagation, embolization, dissolution, organization/recanalization
Outcomes of the thrombus:
What is “propagation”?
Enlargement of the thrombus
Outcomes of the thrombus:
What is “embolization”?
Part or all of the thrombus is dislodged and transported elsewhere in the vasculature
Outcomes of the thrombus:
What is “dissolution”?
Shrinkage of the thrombus through fibrinolysis
Outcomes of the thrombus:
What is “organization and recanalization”?
Thrombus is organized by the invasion fibroblasts and the formation of new vascular channels
What is the general morphology of a thrombus?
- 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
What is a “chicken fat clot”, and what is it often mistaken for?
Smooth, shiny, gelatinous post-mortem blood clots; can be mistaken for a thrombus
What is an easy way to distinguish a chicken fat clot from a thrombus in a post-mortem examination, aside from its appearance alone?
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
What pathology does bacterial endocarditis cause in cattle?
- Bacteria builds up in right AV valves, causing septic thromboemboli which will travel to the small branches of the pulmonary artery
- Result: pneumonia
What causes saddle thromboembolism in cats?
- 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
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…
Saddle thrombus
Widespread intravascular coagulation and platelet activation which results in consumption of platelets and coag factors; causes progressive thrombocytopenia and widespread hemorrhage
Disseminated Intravascular Coagulation (DIC)
What is a fibrocartilagenous emboli, and what does it cause?
Traumatic implantation of intervertebral disk material into spinal vessels; causes necrotizing myelopathy (spinal cord infarcts)
Bone fractures release microscopic fat globules into circulation, and this can cause a….
Fat embolism
