Vascular disorders Flashcards
thrombus
solid mass of blood constituents formed during life
virchows triad
predisposing factors for thrombus formation
- endothelial injury
- abnormal blood flow
- hypercoagulability
endothelial injury: changes in vessel wall
inflammation
trauma
atherosclerosis
abnormal blood flow
stasis
turbulence
aneurysms
hypercoagulability: changes in blood constituents
viscosity
clotting factors
atheroma
collection of lipid filled cells within the wall of the blood vessel
lines of zahn
alternating layers of blood constituents
arterial thrombosis
most commonly caused by thrombi formed superimposed on atheroma
consequences: tissue infarct
venous thrombosis
most commonly caused due to stasis and immobilisation e.g. DVT
consequences: collection of fluid
consequences of thrombi (4 to consider)
- lysis and resolution
the thrombus will lyse and become broken down - organisation
inflammation resulting in tissue loss there may be scar tissue or organisation and that may lead to narrowing of blood vessels - recanalisation
some blood manages to filter through and restore some limited blood supply leaving behind scar and residual thrombus. - embolism
thrombus breaks off and travels further downstream and travels in the direction of the blood flow until it reaches a a vessel through which it cannot pass through
embolism
an intravascular mass and is not always a thrombus but it can be a broken fragment from a thrombus
it can also be solid, liquid or gas
it is a mass that has travelled away further downstream from its site of origin.
embolism consequences
obstruction
metastases (in the case of a tumour)
spread of infection
tissue destruction
pulmonary embolism
origin is the veins and right side of the heart. destination is anywhere along the pulmonary artery.
systemic embolism
origin is the arteries and left side of the heart. destination is systemic
ischaemia
the inadequate perfusion of blood to an organ or part of it
infarction
death of tissue due to ischemia
this cell death is necrotic and pathological
doesnt have to be a complete block of the blood supply but sufficient block that the tissue is not adequately perfused.
factors influencing ischaemia
rate of occlusion
tissue vulnerability
anatomy of the vascular supply
shape of infarction
typically wedge shaped with apex at point of occlusion
in the lung/kidney it is conical
brain it is fluid filled cyst
classification of infarction
red/haemorrhagic:
in the lung, intestine, liver
in organs that are composed of loose tissue.
occurs where there is a venous occlusion i.e. doesn’t occur because of inadequate perfusion but because of poor drainage
pale/anaemic:
heart, kidney, spleen
can be seen in solid organs containing dense tissue
seen in end arterial circulation i.e. circulation only having singular blood supply
types of shock
cardiogenic: low cardiac output
hypovolaemic: reduction in circulating volume
septic shock: infection resulting in systemic inflammatory response
neurogenic: loss of vascular tone due to spinal injury
anaphylactic shock: systemic vasodilation and increased vascular permeability.
phlebothrombosis vs thrombophlebitis
phlebothrombosis is a thrombosis of the veins.
thrombophlebitis is an inflammatory reaction to phlebothrombis.
