pathology of thrombosis and embolism Flashcards
describe Virchow’s triad?
Changes in the blood vessel wall
Changes in the blood constituents
Changes in the pattern of blood flow
define thrombosis
Formation of a solid mass from the constituents of blood within the vascular system during life
describe the pathogenesis of thrombosis
Atheromatous coronary artery
Turbulent blood flow (fibrin deposition, platelet clumping)
Loss of intimal cells, denuded plaque
Collagen exposed, platelets adhere
Fibrin meshwork, RBCs trapped
Alternating bands: lines of Zahn
Further turbulence and platelet deposition
Propagation
Consequences
examples of changes in the blood constituents?
hyperviscosity, post-traumatic hypercoagulability
what are the 2 changes in blood flow called and give an example of each
stasis: caused by inactivity so less flow such as being bed bound or ‘economy class syndrome’
turbulence: atheromatous plaque, aortic aneurism
describe embolism
Movement of abnormal material in the bloodstream and its impaction in a vessel, blocking its lumen
define embolus
detached intravascular mass, most are dislodged thrombi
where is the most common site for a systemic thromboembolism to travel?
lower limbs but can also spread to brain and other organs
the consequences of this depend on the vulnerability of tissues to ischaemia, calibre of the occluded vessel.
define venous thromboembolism
Originate from deep venous thromboses (lower limbs)
Most common form of thromboembolic disease
describe process of venous thromoemboli
Travel to the pulmonary arterial circulation
Depending on size, may occlude main pulmonary artery, bifurcation (saddle embolus), smaller arteries
Often multiple
Consequences of pulmonary thromboembolism depend on size of embolus: silent, pulmonary haemorrhage/infarction, right heart failure, sudden death
what are some of the complications if one presents with multiple PE over time?
pulmonary hypertension and right ventricular failure
what are some of the risk factors for DVT and PT? (think Virchow’s triad)
Cardiac failure, severe trauma/burns, post-op/post-partum, nephrotic syndrome, disseminated malignancy, oral contraceptive, older age, bed rest/immobilisation, obesity, PMH of DVT
describe 2 types of gas embolus
decompression sickness - N2 forms as bubbles which lodge in capillaries
air embolus - head and neck wounds, surgery, CV lines
describe rheumatic fever
Disease of disordered immunity
Inflammatory changes in the heart and joints, sometimes neurological symptoms
in rheumatic fever in the acute stage, pancarditis occurs. describe what this is and what sounds can be heard upon auscultation?
inflammation affecting endocardium, myocardium, pericardium
heart murmurs common
