Chapter 4.5 Embolism Flashcards
Define embolism.
intravascular mass that travels and occludes downstream vessels
symptoms depend on vessel involved
What is most common source of embolism?
thromboembolus
get thrombus, thrombus breaks away, floats down bloodstream and lodges some place else
Describe the mechanism of atherosclerotic embolus
patient has atherosclerosis, piece of plaque breaks off, travels down vessel and lodges somewhere else
due to plaque that dislodges
When you look at embolus how do you know that it arose from an atherosclerotic plaque?
presence of cholesterol clefts in the embolus
What can lead to fat embolus? When might it develop? What are some clinical presentations?
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
Why would a patient with a fat embolus experience dyspnea?
Bc classic location for fat embolus to travel is the blood vessels of lung
What is gas embolus seen?
How does it present?
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"
What is the chronic form of gas embolus?
Caisson disease
characterized by multifocal ischemic necrosis of bone
Besides the “bends”, what other things may cause a gas embolus?
laparoscopic surgery
air is pumped into abdomen during surgery, if some air gets into bloodstream that can result in embolus
How might an amniotic fluid embolus occur?
enters maternal circulation during labor or delivery
usually lodges in mom’s lungs
How does a patient with amniotic fluid embolus present?
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)
What is characteristic finding of emboli cells in the lung? (amniotic fluid embolus)
squamous cells and keratin debris from fetal skin in embolus
What does a pulmonary embolus arise from?
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
Most often when a patient gets a PE it is clinically silent, why?
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
With PE sometimes infarction occurs; under what conditions might this occur? ?
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
Only 10% of PE’s cause pulmonary infarction; when they do occur, how do they present?
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
How might a DVT (leading to PE) be detected clinically?
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)
What might gross exam reveal in the case of PE?
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
When might a patient suddenly die with PE?
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
What is a final consequence of PE?
chronic emboli over long period of time, PE can be reorganized and develop Pulmonary hypertension
What happens when PE lodge in systemic circuit?
What is most common source?
usually due to thromboembolus most commonly arise in L heart
travel down systemic circulation to occlude flow to organs, most commonly the lower extremities
