SFP: embolism, infarction, and shock

Question 1

define embolus

Answer 1

a detached intravascular solid, liquid, or gaseous mass that is carried by the blood to a site that is distant from its origin

Question 2

where do most emboli come from

Answer 2

existing thrombus (thromboembolism)

Question 3

what are the rare origins of emboli

Answer 3

fat, air, amniotic fluid

Question 4

what are three big outcomes of embolism

Answer 4

1. occlusion of downstream vessels
2. infarct of tissues supplied by the vessel
3. ischemic necrosis

Question 5

what does venous occlusion lead to

Answer 5

congestion and infarction

Question 6

what does arterial occlusion lead to

Answer 6

infarct of tissues

Question 7

what is the most common pulmonary thromboembolism

Answer 7

DVT

Question 8

what are some risk factors for DVT

Answer 8

40+, prolonged immobility, surgery, trauma, cancer, clotting disorders, birth control

Question 9

what deficiencies can lead to DVT

Answer 9

FACTOR 5!!!!!

also protein C and protein S

Question 10

describe a saddle embolus

Answer 10

blocks the main pulmonary artery and its branches. this causes a sudden increase in pulmonary artery pressure, a drop in cardiac output, and sudden death

Question 11

what occurs if 60% of pulmonary vasculature is obstructed

Answer 11

sudden death, right ventricular failure, cardiovascular collapse

Question 12

multiple smaller emboli can occur as….

Answer 12

sequential or a showering

Question 13

what percentage of pulmonary emboli are clinically silent

Answer 13

60-80%

Question 14

how do most pulmonary emboli resolve

Answer 14

fibrinolytic activity and incorporation into the vascular wall

Question 15

describe how repeated pulmonary emboli can cause pulmonary hypertension

Answer 15

• showers of pulmonary emboli cause fibrosis in the lung
• it becomes difficult for the heart to pump blood into the lung due to scar tissue
• pulmonary hypertension occurs

Question 16

are those who had a previous embolism at increased risk for another?

Answer 16

yes

Question 17

describe systemic thromboembolism

Answer 17

emboli that originate in the arterial system. they result in infarct downstream of occluded vessels. the result of damage is highly tissue dependent

Question 18

where do 80% of systemic thromboemboli come from

Answer 18

cardiac mural thrombi; left ventricular wall with dilated left atrium and mitral valve disease

Question 19

where do 20% of systemic thromboemboli come from

Answer 19

aortic aneurysm, ulcerated atherosclerotic plaques, and fragmented valve vegetation

Question 20

where do the majority of systemic emboli go?

Answer 20

75% to lower extremities, 10% to the brain

Question 21

what is a paradoxical emboli

Answer 21

emboli originating from a thrombus in a vein that travels through the septal defect from vein to artery in the heart; travels from right atrium, to right ventricle, through the defect, left ventricle, and the aorta. ends up in systemic artery.

Question 22

describe fat embolism

Answer 22

can be caused by fracture of long bones or soft tissue trauma

Question 23

what is fat embolism syndrome

Answer 23

results from a fat embolism and can result in sudden onset of symptoms 1-3 days post injury. causes respiratory distress, neurologic symptoms, and anemia/thrombocytopenia

Question 24

what is a common hemorrhagic condition seen with fat embolisms?

Answer 24

petechiae from occlusion of cerebral and pulmonary vasculature

Question 25

describe an air embolism

Answer 25

more than 100 mL of air entering the vasculature. can be caused by chest wall injury, obstetric procedure, and sudden changes in atmospheric pressure. can cause focal ischemia, edema, hemorrhage, and necrosis.

Question 26

describe amniotic fluid embolism

Answer 26

amniotic fluid enters maternal circulation due to placental tear or rupture of uterine veins. results in 40% mortality.

Question 27

what is the pathogenesis of amniotic fluid embolism

Answer 27

pulmonary emboli and edema, systemic thrombogenesis with DIC

Question 28

what are the sudden onset symptoms of amniotic embolism

Answer 28

severe dyspnea, cyanosis, hypotensive shock, seizures and coma

Question 29

what is an infarct?

Answer 29

an area of ischemic necrosis caused by occluding arterial supply or venous drainage.

Question 30

___ causes infarct, while ___ causes obstruction and congestion

Answer 30

arterial events; venous occlusion

Question 31

what is the most common cause of infarct

Answer 31

thrombosis or thromboembolic events

Question 32

what is a red infarct

Answer 32

it occurs due to dual blood supply; it is an venous occlusion/congestion followed by arterial reperfusion. this can occur in loose tissues like the lungs and gut

Question 33

what is a white infarct

Answer 33

occurs in organs with single arterial supply. this occurs in solid organs such as heart, spleen, and kidney

Question 34

the majority of infarcts lead to…

Answer 34

coagulative necrosis

Question 35

what is shock

Answer 35

a common outcome for several lethal events. it is characterized by systemic hypo perfusion. this results in reduced cardiac output and circulating blood volume. this leads to hypotension, hypoxia, cell injury, irreversible injury, then death

Question 36

describe cardiogenic shock

Answer 36

failure of the pump. it has 70% mortality and can be from MI, ventricular rupture, cardiac tampenade, pulmonary embolism

Question 37

describe hypovolemic shock

Answer 37

loss of blood or plasma volume that results from hemorrhage, fluid loss from burns, vomiting or diarrhea

Question 38

what is septic shock

Answer 38

occurs from a microbial infection. the most common is gram-positive septicemia such as MRSA

Question 39

describe endotoxic shock

Answer 39

a type of septic shock

• bacterial cell wall segments get into vascularture
• segments bind macrophage
• TLR4 activates mononuclear cells
• TNF, IL1, IL6 release
• systemic acute phase reactions occur

Question 40

what are the fatal outcomes of endotoxic shock

Answer 40

DIC and multi-system organ failure

Question 41

what is neurogenic shock

Answer 41

can occur due to anesthetic accident or spinal cord injury and results in loss of vascular tone and peripheral pooling of blood

Question 42

what is anaphylactic shock

Answer 42

IgE hypersensitivity reaction that causes systemic vasodilation and increased permeability that leads to swelling of the throat and fluid loss

Question 43

what are the 3 stages of hypovolemic shock

Answer 43

• nonprogressive: reflex compensatory mechanisms try to make up for fluid loss and nervous system changes
• progressive: widespread hypoxia and dependence on glycolysis results in low pH, endothelial injury, and DIC
• irreversible: necrosis and organ failure