Circulatory Disorder: Thrombosis & Embolism Flashcards
Define thrombosis.
-inappropriate activation of the normal hemostatic process
-formation or presence of a solid mass/clot (thrombus) in CVS IN BLOOD VESSEL
-constituents: platelets, fibrin, entrapped blood cells
-can result in occlusion of vascular lumen
-adhered to vascular wall (opp to a blood clot)
Describe the Virchow Triad.
‘Father of pathology’
PATHOGENESIS:
1. Alterations (injury) in vascular endothelium
2. Alteration in blood flow
3. Alterations in constituents of blood
Describe normal VS thrombus formation.
Describe the pathogenesis of thrombosis.
Describe the classification of thrombosis.
Describe thrombosis examples.
- Dogs w renal glomerular disease -> protein losing nephropathy -> loss of anti thrombin III (inhibitor of thrombin)
- Verminous thrombosis = thrombus formation in cr mesenteric artery of horses w strongylus vulgaris infection
- Saddle thrombus in cats
Describe the outcome of thrombi.
- Lysis
- Propagation
- Embolization
- Abscessation
- Organization (fibrosis)
- Recanalization
Describe the effects of thrombosis.
- Beneficial effects = thrombosis of injured vessels assist in control of hemorrhage
- Negligible effects = thrombi present in blood vessel that aren’t required -> anastomosis
- Harmful effect = thrombosis of major blood vessel in vital organs -> insufficient or no collateral circulation
Describe PM clotting of blood.
- Red/currant jelly clot = rapid clotting of blood -> blood evenly distributed
- Yellow/chicken fat clot = prolonged coagulation time or inc sedimentation rate
-ventral portion red -> erythrocyte
-dorsal portion yellow -> fibrin & serum
Describe thrombus VS PM clot.
Describe hemostasis VS thrombosis.
- Hemostasis = vasoconstriction + primary hemostasis + secondary hemostasis
- Thrombosis = primary hemostasis + secondary hemostasis
*coagulation = secondary hemostasis
SUMMARY OF THROMBOSIS.
Describe embolism.
-pieces of thrombus break off from original mass & sail downstream to lodge at distant site = embolism
*mass that broke off is called embolus
Lodging -> obstruction -> local ischemia -> infarction -> necrosis
Describe the etiology of embolism.
- Thrombi (95%)
- Bacteria
- Parasites
- Neoplasia
- Fat embolism -> trauma
-complication of long bone fractures, prolonged surgery, & osteomyelitis - Gas embolism -> decompression illness (divers)
Describe other forms of embolism.
-parasites
>nematode larvae = s. Vulgaris, ascaris spp
>nematodes = Dirofilaria immitis
Describe thromboembolism.
-occlusion of a blood vessel by an embolus that has broken away from a thrombus
-travels until it gets stuck
-infectious causes = bacterial valvular endocarditis in cattle of R AV valve -> septic emboli that lodges into pulmonary arteries -> inflam/abscess formation (embolic pneumonia)
