Embolism, infraction, shock Flashcards

1
Q

What are the 3 common circulatory disorders?

A
  • Embolism
  • Infraction
  • Shock
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2
Q

What is the concept of Embolism?

A
  • An embolus is a mass of material in the vascular system able to become lodged within a vessel and block its lumen
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3
Q

What is the most common type of embolism?

A
  • Pulmonary embolism, from deep leg vein thrombosis
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4
Q

Where does the term thromboembolism come from?

A
  • Most of the emboli are form dislodged thrombus, hence the term thromboembolism
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5
Q

What location is the outcome of Embolism?

A
  • The outcome depends on where the emboli originate and where they lodge
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6
Q

What are the sources of emboli?

A
  • Pieces of thrombus, mixed thrombus and blood clot
  • Infected lesions within the bloodstream
  • Gas bubbles e.g. air, N2 (divers transferred rapidly from high to low-pressure environments)
  • Fat, bone marrow (in bone fractures)
  • Tumour cells
  • Others: amniotic fluid (during labour)
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7
Q

What % of Pulmonary Embolism are small and clinically silent?

A
  • 60% - 80%
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8
Q

What can Pulmonary embolism cause?

A
  • Can cause sudden death, right heart failure, cardiovascular collapse
  • If the blockage is in a middle size vessel, it can cause pulmonary haemorrhage
  • Multiple emboli over time may cause pulmonary hypertension
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9
Q

What is Systemic arterial emboli?

A
  • Emboli arise in the arterial circulation
  • ~80% from intracardiac mural thrombi
  • ~10-15% of unknown origin
  • Can travel to a wide variety of sites
  • In general, arterial emboli cause tissue infraction
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10
Q

Systemic arterial emboli can travel to a wide variety of sites, what does the site of lodge depend on?

A
  • The site of lodge depends on the source and the relevant amount of blood flow that downstream tissues receive
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11
Q

What is infraction?

A
  • An infarct is an AREA of ISCHEMIC NECROSIS caused by OCCLUSION of either the ARTERIAL SUPPLY or the VENOUS DRAINAGE in a particular tissue
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12
Q

Explain the relationship of Tissue infraction and clinical illness and death

A
  • Tissue infraction is a common and very important cause of clinical illness and death
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13
Q

Is death of tissue from toxins or trauma infraction?

A
  • The death of tissue from other causes, such as toxins or trauma, is not infraction but simply necrosis
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14
Q

What do Infractions result from?

A
  • Nearly 99% of all infracts result from thrombotic or embolic events and almost all result from arterial occlusion
  • Other causes: vasospasm, haemorrhage into atheromatous plaque, vessel compression (by tumour), traumatic rupture
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15
Q

What does different shapes of infracts reflect?

A
  • Shape reflects the territory of occluded blood supply
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16
Q

Name the different shapes of infracts and name the location of the blood supply

A
  • Wedge-shaped: in lung
  • Triangular: in kidney
  • Scarred: in spleen
17
Q

What is Classification of infracts?

A
  • Classification: Based on their colour (reflecting the amount of haemorrhage) and the presence or absence of microbial infection
18
Q

Explain the different colours of infracts

A
  • White (anaemic): in solid organs with end arterial circulation (such as heart, spleen, and kidney)
  • Red (haemorrhagic)
  • Septic: Infected infract
  • Bland: uninfected infract
19
Q

Name and explain the major factors that influence the outcome of an infraction

A
  • The nature of the vascular supply: The availability of alternative blood supply
  • The rate at which an occlusion develops: Slow occlusion provides time for alternative perfusion pathways
  • Vulnerability to hypoxia: Neurons and myocardial cells are vulnerable
  • The oxygen content of the blood
20
Q

Explain the Evolution of myocardial infract

A
  • Infracted area varies in appearance depending on the time after infraction
21
Q

What is Shock?

A
  • A final common pathway for several lethal clinical events best described as inadequate tissue perfusion
22
Q

What is Shock characterised by and this is due to what?

A
  • Characterised by systemic hypotension due to:
  • Reduced cardiac output
  • Reduced effective circulating blood volume
23
Q

What is Cardiogenic shock caused by?

A
  • Cardiogenic shock: results from low cardiac output due to heart failure
24
Q

What is the cause of Hypovolaemic shock?

A
  • The result of low cardiac output due to the loss of blood or plasma volume
25
Q

What is the cause of Septic shock?

A
  • Results from vasodilation and peripheral pooling of blood as part of a systemic immune reaction to bacterial or fungal infection
26
Q

What are the symptoms of shock

A
  • Altered conscious state
  • Restlessness or irritability
  • Pale or bluish, cool moist skin
  • Excessive thirst
  • Rapid and weak pulse
  • Rapid breathing
  • Nausea and/or vomiting
27
Q

What is the first aid of shock?

A
  • Place the victim in a shock position
  • Keep the person warm and comfortable
  • Turn the victim’s head to one side if the neck injury is not suspected