embolus and infarct Flashcards
define embolus
An intravascular solid, liquid, or gaseous mass that is carried by the blood to a site distant from its point of origin
Most emboli are derived from a dislodged?
thrombus (thromboembolism)
what are less common sources of emboli?
Fat, air, cholesterol, tumor fragments, bone marrow, amniotic fluid
Embolus results in?
partial or complete occlusion
Systemic and arterial emboli results in?
infarction
pulmonary emboli results in?
hypoxia, hypotension, right-sided heart failure
> 95% of pulmonary emboli arise from?
DVTs proximal to the popliteal fossa
pulmonary emboli cause how many deaths?
200,000 deaths/yr. in the US
T or F… Prior embolus decreases risk for additional emboli
FALSE. Prior embolus INCREASES risk for additional emboli
80% of systemic thromboembolism arise from?
intracardiac mural thrombi
what are common arteriolar embolization sites?
■ Lower extremities (75%)
■ CNS (10%)
■ Intestines, kidneys, and spleen are less often affected.
fat embolism etiology?
Soft tissue crush injury, long bone fracture
Fat and marrow emboli are common incidental findings after vigorous
CPR
Clinical findings of fat embolism in less than 10% of cases with severe?
skeletal injuries
Symptomatic Fat Embolism Syndrome clinical signs and symptoms show up?
**what are these signs?
1-3 days after injury
**Sudden onset of tachypnea, tachycardia, irritability, and restlessness, which may progress to delirium or coma. AND occlusion of pulmonary and cerebral microvasculature
Amniotic Fluid Embolism etiology
Placental tears and/or rupture of the uterine vein
clinical signs of amniotic fluid embolism?
Sudden severe dyspnea, cyanosis, and hypotensive shock, followed by seizures and coma
in woman that survive amniotic fluid embolism, what are possible side affects?
Pulmonary edema and possible DIC in those who survive
define air embolism
Obstruct vascular flow resulting in distal ischemic injury
air embolism eteology
CABG, neurosurgery, obstetric procedures and chest wall surgery
T or F… Small air emboli often have no significant effects
true
define and explain decompression sickness
Caused by sudden changes in atmospheric pressure
*increased amounts of gas (esp. nitrogen). Ascending rapidly from a deep dive causes expansion of nitrogen in the tissues ➔ gas emboli ➔ tissue ischemia
define infarction
An area of ischemic necrosis caused by occlusion of the vascular supply
40% of U.S. deaths are caused by cardiovascular disease, most from? caused by?
MI or CVA and CAUSED by arterial thrombosis or arterial embolism
**other exaples are pulmonary, bowel and gangrene
Types of infarcts?
Red and white
Red infarct occurs with?
venous occlusions, loose tissues, tissues with dual circulation, previously congested tissues, reperfusion post-infarction
white infarct occurs with
arterial occlusions in solid organs with end-arterial circulations or where there is limited ability for seepage of blood from adjoining vascular beds
common location and another name for white infarc?
pale infarcts and kidney is common location
4 factors the influence infarct development?
1) Anatomy of the vascular supply
2) Rate of occlusion
3) Tissue vulnerability to ischemia
4)
Anatomy of the vascular supply infarct development
Presence or absence of an alternative blood supply
Rate of occlusion infarct development
Slowly developing occlusions are less likely to cause infarction
Tissue vulnerability to ischemia infarct development
Neurons are especially vulnerable, myocardial cells intermediate vulnerability. Fibroblasts are more resistant
Hypoxemia of infarct development
increase risk with abnormally low blood O2
