Chapter 4.5 Embolism

Question 1

Define embolism.

Answer 1

intravascular mass that travels and occludes downstream vessels

symptoms depend on vessel involved

Question 2

What is most common source of embolism?

Answer 2

thromboembolus

get thrombus, thrombus breaks away, floats down bloodstream and lodges some place else

Question 3

Describe the mechanism of atherosclerotic embolus

Answer 3

patient has atherosclerosis, piece of plaque breaks off, travels down vessel and lodges somewhere else

due to plaque that dislodges

Question 4

When you look at embolus how do you know that it arose from an atherosclerotic plaque?

Answer 4

presence of cholesterol clefts in the embolus

Question 5

What can lead to fat embolus? When might it develop? What are some clinical presentations?

Answer 5

fat embolus is where you crack open bone (trauma and bone fracture) or soft tissue damage, fat released into blood supply and it lodges

develops while fracture is still present or shortly after repair

dyspnea and petechiae on skin overlying chest

Question 6

Why would a patient with a fat embolus experience dyspnea?

Answer 6

Bc classic location for fat embolus to travel is the blood vessels of lung

Question 7

What is gas embolus seen?

How does it present?

Answer 7

decompression sickness

pressure as dive increases as go deeper, forces nitrogen to dissolve in blood, when rapidly ascend N can precipitate out of the blood as small little gas bubbles which can lodge in various tissues

-presents with joint and muscle pain (N bubbles lodge there) "bends"
respiratory symptoms (lodge in lungs) = "chokes"

Question 8

What is the chronic form of gas embolus?

Answer 8

Caisson disease

characterized by multifocal ischemic necrosis of bone

Question 9

Besides the “bends”, what other things may cause a gas embolus?

Answer 9

laparoscopic surgery

air is pumped into abdomen during surgery, if some air gets into bloodstream that can result in embolus

Question 10

How might an amniotic fluid embolus occur?

Answer 10

enters maternal circulation during labor or delivery

usually lodges in mom’s lungs

Question 11

How does a patient with amniotic fluid embolus present?

Answer 11

shortness of breath (emboli in lung) 
neurologic symptoms (emboli going to brain), DIC (amniotic fluid is loaded w tissue thromboplastin which can activate coag. cascade and result in DIC)

Question 12

What is characteristic finding of emboli cells in the lung? (amniotic fluid embolus)

Answer 12

squamous cells and keratin debris from fetal skin in embolus

Question 13

What does a pulmonary embolus arise from?

Answer 13

usually due to thromboembolus from DVT of lower extremity (femoral, iliac, or popliteal veins)

DVT can dislodge and thromboembolus will enter pulmonary circulation and cause pulmonary embolus

Question 14

Most often when a patient gets a PE it is clinically silent, why?

Answer 14

lung has dual blood supply (pulmonary artery goes into lung and bronchial artery from aorta goes to lung tissue to keep it alive and healthy, even if occlude some area of lung the second blood supply can sustain lung)

embolus is usually small and self- resolves

Question 15

With PE sometimes infarction occurs; under what conditions might this occur? ?

Answer 15

need large embolus and obstruction of large or medium sized artery with pre-existing cardiopulmonary compromise (so lung is susceptible to this type of damage so dual blood supply is not as protective as normal)

10% of PEs cause pulmonary infarction

Question 16

Only 10% of PE’s cause pulmonary infarction; when they do occur, how do they present?

Answer 16

SOB, hemoptysis, pleuritc chest pain, and pleural effusion

V/Q scan shows mismatch; perfusion is abnormal

spiral CT shows a vascular filling defect in the lung

Question 17

How might a DVT (leading to PE) be detected clinically?

Answer 17

lower extremity Doppler US is useful to detect DVT

D-dimer is elevated (lysing PE and DVT so that elevates D dimer…whenever cut up thrombus that results in D-dimer being released in blood)

Question 18

What might gross exam reveal in the case of PE?

Answer 18

hemorrhagic, wedge shaped infarct

blood supply in lung dichotomous branching, if PE get infarction of everything that goes through following branches (looks like wedge which points to area of occlusion)

hemorrhagic bc dual blood supply and tissue is loose … blood to reenter dead tissue and tissue must be loose

Question 19

When might a patient suddenly die with PE?

Answer 19

large saddle embolus or significant occlusion of a large pulmonary artery

death due to electromechanical dissociation (heart pumping but blood supply totally dead

embolus has saddled and knocked out both pulmonary arteries, entire vascular supply occluded, heart will pump against it but blood cannot go any further

Question 20

What is a final consequence of PE?

Answer 20

chronic emboli over long period of time, PE can be reorganized and develop Pulmonary hypertension

Question 21

What happens when PE lodge in systemic circuit?

What is most common source?

Answer 21

usually due to thromboembolus most commonly arise in L heart

travel down systemic circulation to occlude flow to organs, most commonly the lower extremities