Module 3-Path Continued Flashcards
What is a thrombus?
Occurs inside a vessel and attached to a wall
Platelets involved in formation
Always in alive people
Firm
What is the key histological feature of a thrombus?
Lines of Zahn (indicate blood flow)
-pale: platelets and fibrin
-dark: RBCs
(these alternate)
A thrombus is composed of what three components?
Platelets, fibrin and RBC
Arterial Thrombi is most commonly due to what?
most common due to endothelial injury
Arterial thrombi are usually pale when observed on gross specimen why?
because of high velocity of blood and more platelets then RBCs
(propagates retrograde to blood flow)
Venous thrombi are usually red when observed on gross specimen why?
red because slow velocity of blood and usually more RBCs then platelets
Venous thrombi is most commonly due to what?
Stasis
propagate anterograde to blood flow) (90% in deep veins of the legs
What are the three components of Virchows Triad?
Endothelial Injury
Hypercoagulability
Turbulent Blood Flow (loss of laminar flow)-> stasis (allows buildup of platelets and coagulative factors)
What are the genetic conditions that lead to hypercoagulability?
Factor V laden mutation (most common)
Protein C and S deficiency
Anti- Thrombin III deficiency
(check for these before thinking of an acquired reason for hypercoagulability)
What are some acquired reasons for hypercoagulability?
Cancer (Trousseau's syndrome) Heart Failure Severe Burns Trauma Pregnancy and Birth Control Pills
What are the 4 fates of a thrombus?
- Propagate–> accumulate platelets and obstruct vessel
- Embolize–>dislodge/fragment and carried by blood to a distant site
- Dissolution –> removed by fibrinolytic activity (By tissue plasminogen activator)
- Reorganization/Recanalization –> induce inflammation and fibrosis (organization) –> re-establish some degree of flow (recanalization)
If a patient develops a thrombus in the LV and forms an embolus where will this embolus travel?
Lower Limbs
Brain (CVA)
In regards to a clot what is a clot?
Has only one component –> fibrin formation
Fibrin + trapped cells
Platelets are not involved
Occurs outside vessel (test tube, hematoma)
Red
Gelatinous
Not attached to the vessel wll
If an arterial thrombi is in the heart what is it called?
Mural Thrombi
also called mural for aneurysm
Another site of thrombosis is aorta this is secondary to what?
Atherosclerotic plaque
Venous thrombosis occurs in what veins??
Deep veins of legs (90%)
deep calf veins (At or above the knee)
femoral, popliteal or iliac
note–> superficial veins of legs rarely embolize
What are some clinical features of deep leg venous thrombus?
Edema of ankle, foot, pain and tenderness
asymptomatic in 50% - due to collaterals
high risk of embolization
What is trousseau’s syndrome?
Unexplained thrombophlebitis, recurrent-> look for underlying abdominal malignancy like pancreatic cancer
Explain an acute vs slow arterial thrombus?
Acute -> Infarct
Slow –> atrophy and fibrosis (cells will adapt and start shrinking)
(heart = systemic emboli)
A patient has a DVT but has a co-existing history of a right to left shunt where is the most common location that the clot will go?
To the other leg (right to left) –> called a paradoxyl embolus so it goes to the artery in the other leg because it enters systemic circulation
What is a post-mortem clot?
No lines of Zahn and do not attach to the vessel
fibrin + trapped cells
On gross image of an artery with post mortem clot, the superior red part of the artery is representative of what?
yellow chicken fat appearance of coagulated plasma (supernatant)
On gross image of an artery with post mortem clot, the inferior cherry red part of the artery is representative of what?
currant jelly appearance of emmeshed RBCs (sediment) due to gravity