93. thrombosis, embolism and infarction Flashcards
are blood clots and thrombosis the same thing
NO
where can you see blood clots
bruising etc
blood clot extravascular or intravascular
extravascular
what substances are involved in a blood clot
RBCs, fibrin, platelets etc
thrombus extravascular or intravascular
intravascular
Do thrombosis move around and circulate
NO - they are static
thrombosis - trigger of coagulation where?
WITHIN a blood vessel
what is thrombosis
excess intravascular coagulation
what is the end point of coagulation
aggregate of platelets, RBCs and fibrin etc
in coagulation what binds everything together
fibrin
what are the types of pathways in coagulation cascades
intrinsic
extrinsic
common
what is extrinsic pathway in coagulation cascade
produced through tissue factor
Factor 7 - factor 7a
which acts on
Factor 10- factor 10a
which acts on
prothrombin to thrombin
which acts on
fibrinogen to fibrin
which is more common in the coagulation cascade. The Intrinsic pathway or the extrinsic pathway
extrinsic
what is intrinsic pathway in coagulation cascade
produced through contact activation
Factor 12 - factor 12a
which acts on
Factor 11- factor 11a
which acts on
Factor 9 - factor 9a
which acts on
Factor 10 to 10a
prothrombin to thrombin
which acts on
fibrinogen to fibrin
explain the common cascade of coagulation
Factor 8 - factor 8a
which acts on
Factor 10 to 10a
prothrombin to thrombin
which acts on
fibrinogen to fibrin
what is the intrinsic coagulation cascade blood test
Prothrombin Time (PT)
what is the extrinsic coagulation cascade blood test
activated partial thromboplastin Time (APTT)
what does fibrin do?
binds everything together by forming the mesh of the net
thrombosis can occur anywhere but if favoured in locations with what 3 characteristics
- sites of endothelial injury
- turbulent blood flow
- hypercoagulative blood
- Sites of endothelial injury
- Turbulent blood flow
- Hypercoagulable blood
these together are known as…..
Virchow’s Triad
why would hypertension be associated with endothelial injury
lots of banging on the side of the vessel walls
what is primary vasculitis
autoimmune disease characterised by inflammation directed at vessel walls. specific antibodies.
what are some things that contribute to endothelial injury
- Hypertension
- Increased exposure to tissue factor
- Weak vessel walls
- Atheroma
- Aneurysms
- Lots of surface thrombosis
- Autoimmune disease
- Primary vasculitis
- Turbulence
- Stasis
describe laminar blood flow
most constituents are in center of vessel with slow flowing plasma peripherally
what is stasis
slowing or stagnation of blood circulation in blood vessels
what is hypercoagulability
increased tendency to develop blood clots
what causes hyperrcoaguability
lots and lots of causes
- anything causing increased viscosity
name some of the inherited disorders - primary causes
- factor V Lieden
- Protein C deficiency
- Protein S deficiency
- Antithrombin III deficiency
name some of the inherited disorders - secondary causes
- Prolonged immobility
- Significant tissue injury – burns, RTA
- Antiphospholipid syndrome –autoimmune
- Myocardial infarction
- Atrial fibrillation (irregular cardiac rhythm)
- cancer
- therapy
- marantic endocarditus
how is cancer a secondary cause of thrombosis
activate coagulation cascade through tumour produced TF, mucin, inflammatory cytokines
how is therapy a secondary cause of thrombosis
many chemotherapeutic agents injure endothelium and increase risk of thrombosis
what is an embolism
a thrombus that has been transported through the vasculature to a point where it gets stuck
most thrombosis is … arterial or venous?
venous
what is ischaemia
insufficient blood supply
what is infarction
death of tissue as a result of ischaemia
How does hypoxia cause cell injury and then acute inflammation?
No oxygen = no ATP
what is ATP used for
- ATP is the basic unit of currency for cellular energy
- ATP is required for anything that is not passive
- ATP required for most ion channel pumps
- Na/K ATPase
- Ca channels
what if there is no ATP
- Increased calcium stimulates
- ATPase (makes things worse)
- Phospholipase (membrane damage)
- Proteases (membrane and cytoskeleton damage)
- Endonuclease (DNA damage and breakdown)
Mitochondrial permeability (release pro death factors
are embolisms just blood constituents
no
what are the different types of embolism
amniotic fluid
fat
tumour
blood
septic
air
how much air is needed to get a air embolism
100ml
breathing at high pressure (like diving in sea) results in what
more dissolved gas
Breathing at high pressure results in more dissolved gas.
As pressure reduces ………….. comes out of solution
Nitrogen
- Breathing at high pressure results in more dissolved gas
- As pressure reduces nitrogen comes out of solution
Multiple bubbles which causes……? and what is this process called
- As pressure reduces nitrogen comes out of solution
decompression sickness
the bends
explain amniotic fluid embolism
A rare complication of childbirth
Tear in placenta or uterine vessels with secondary infusion of amniotic fluid or fetal material
Identify fetal skin (squamous cells) and hair etc in pulmonary vessels
what is a fat embolism made of
fat and marrow
after what kind of injury does fat embolisms occur
skeletal muscle injuries
large or small amounts of patients are symptomatic after injury (fat embolism)
small
describe a tumour emboli
- Usually associated with true thrombus
- Tumours are thrombogenic
- Some tumours have a propensity for vascular invasion
- Tumours are often friable by their nature
Failed metastases?
describe septic emboli
- Specific intravascular infections
- Thrombus forms in association with an infectious agent
- Abnormal cardiac valves
- Mycotic aneurysm
- In the heart – infective endocarditis
- Symptoms from numerous septic emboli
