41.3 Embolism Flashcards
What are the different type of emboli?
*Thrombi
*Fat
*air
*pus
*material from atheromatous plaque
How may a fat embolism arise?
Soft tissue crush injury or rupture of marrow vascular sinusoids release fat globules into circulation
Occlude vasculature and trigger platelet aggregation from fatty acid release
What is an embolism?
The occlusion of a blood vessel, usually by a blood clot or thrombus (embolus) from a remote part of the circulation
What is an embolus?
A detached intravascular solid, liquid or gaseous mass that is carried by the blood from its point of origin to a distant site, where it often causes tissue dysfunction or infarction
What is an atheromatous plaque?
an abnormal accumulation of material in the inner layer of an arterial wall
*consists of mostly macrophage cells or debris, containing lipids, calcium and a variable amount of fibrous connective tissue
What does pulmonary embolism lead to?
-Blockage of major pulmonary arteries = sudden death
-Embolism in medium sized arteries can rupture and cause pulmonary haemorrhage
-Hypoxemia
-Pulmonary infarct (lungs do not receive oxygenated blood) if in small end -arteriolar vessels
-Right ventricular failure and pulmonary hypertension
What is systemic embolism, where does it typically originate and what are the causes?
- An embolism that lodges in a systemic artery (rather than the lungs) [CHECK]
- Typically originates in LHS of the heart
- Causes: Atrial fibrillation, Myocardial infarction, Infective endocarditis
What is the main consequence of systemic embolization?
Ischaemic necrosis of downstream tissues (infarction)
Describe the pathogenesis of pulmonary embolism.
An embolism travels to the pulmonary arteries, blocking them and thus cutting off perfusion of the lungs.
How do the sites of venous and arterial emboli differ?
Venous emboli = end up in the lung
Arterial emboli = diverse range of targets depending on flow rates (lower extremities and CNS)
What are the most common emboli?
Dislodged thrombus
What can be given to treat embolisms?
Warfarin = blocks reduction of vitamin K needed to make clotting factors
Heparin = stabilises AT-II increasing inactivation of Xa and IIa (thrombin)
What are the possible healing reactions in an embolised thrombus?
Clotting - usually associated with healing process + wound resolution when appropriate.
Platelet-derived GFs + promotion of fibroblast generation and activation –> reorganisation of surrounding tissue resulting in remodelling in area surrounding clot, impacting function chronically.
