THomboembolism Shock Flashcards
what is a thrombus
an Intravascular clot that often impedes or prevents blood flow
what is thrombosis
Formation or preence of a thrombus
what may thrombosis result in
Infarction
what is the pathogenesis of Thrombosis
Endothelial Injury
Alteration in blood flow
Hypercoagulability
what is the enothelial reason for causing THrombosis
- Loss of endothelial cell barrier
- Increased prothrombotic activity caused by:
- Hypertension
- Homocystinuria
- hypercholesterolemia
- radition
- cytokines
- endotoxin
what may alter blood flow to lead to thrombosis
Turbulence
Stasis
Aneurysms, Atherosclerotic plaques
how does turbulence lead to thrombosis
Induces endothelial dysfunction and activation
how does Stasis lead to thrombosis
creates hypoxic environment
Stasis disrupts laminar flow cuasing platelts to move to the periphery of the vessel
- allows concentration of clotting factors
- activates endothelial cells
- the major factor in venous thrombi and intra-cardiac thrombi
what is hypercoagulability
the increased risk of coagulation
what are the inherited conditions that may lead to hypercoagulability
Factor V leiden mutation
Porthrombin mutation
Deficiencies of anticoagulant proteins like AT III
what does a Factor V leiden mutation lead to
a factor V that cannot be degraded by protein C leading to hypercoagulability
what are the acquired conditions that may lead to hypercoagulability
Prolonged bed rest
Extensive tissue damage such as burns or surgery
Cancer
antiphospholipid antibody syndrome (lupus anticogulant
pregnancy
others
where does Arterial thrombi occur at
at sites of turbulence of endothelial injury/loss
what does Arterial thrombi look like
has a pale (white appearance
distinct lines of zahn
are arterial thrombi occlusal or mural
can be both
what does an arterial thrombi lodging in smaller arteries lead to
Often leads to infarction
what aresterile thrombi on heart valves
Nonbacterial thrombotic endocarditis
what does a venous thrombi look like
have a dark maroon color(red)
indistinct lines of Zahn
where do venous thrombi form
In the deep veins of the legs
why do venous thrombi tend to form
because of slow flow
how do Venous thrombi look like in the vein
Congealed jelly clot that is less organized
waht does thrombi in the heart lead to
Alternating lines due to degeneration of RBC
- less capacity of heart
what is the problem with deep vein thrombi
can grow, propogate and cause problems
- especially if it gets to the lung
what are the possible fates of thrombi
Dissolution (resolution)
Propagation
Embolization
Organization/recanalization
what causes Dissolution of thrombi
Lysis by fibrinolytic activity
what causes Propagation of thrombi
Enlarge by additional fibrin/platelet deposition
what is embolization of thrombi
entire thrombus dislodges or piece breaks loose
how does ORganization of thrombi occur
Ingrowth of fibroblasts and smooth muscle cells
- leads to deposition of collagen (replacing fibrin) and recantilizaation
what is the result of organization of thrombi
May re-establish some flow through the thrombus
what is Disseminated Intravascular Coagulation
- widespread activation of the coagulation cascade and fibrinolytic system
- leads to depletion of coagulation factors/platelets
- leads to a lot of Fibrin split products
- hemorrhage forms and can’t now clot correctly
what are some of the conditions of Disseminated Intravascular Coagulation
Infection (gram negative) obstetric complication (placenetal abruption, retained dead fetus) neoplasm - cascade for coagulation Shock Massive injury
how does One treat Disseminated Intravascular Coagulation
variable
- dependent upon management of underlying disorders
what is an embolism
A solid, liquid, or gas carried from one point to another point in the vascular system
what is often the origin of Pulmonary Thromboembolism
Embolism; Thrombi from deep veins of the legs (also pelvic veins, right heart chambers, amoung others)
what are the consequences of pulmonary thromboemboli
No clinical manifestations Pulmonary hemorrhage and hematemesis Pulmonary infarcation Suden death Gradual obstruction of many small pulmonary arteries
why would a pulmonary Thromboemboli have no clinical manifestation
Small emboli cause no ischeme due to the double blood supply to the lungs(bronchial and pulmonary arteries)
why would a pulmonary thromboemboli lead to a pulmonary hemorrhage and hematesmesis
Ischemic injury without infarcation
how would a pulmonary thrombooemboli lead to sudden death
Large emboli obstructing a large pulmonary artery
- straddling the bifurcation of the pulmonary arterial trunk
gradual obstruction of many small pulmonary arties causes what problem
Overtime can lead to pulmonary hypertension
what is a paradoxical embolus
An embolus that arises in a systemic vein and crosses a communication from the venous to arterial side of ciculation
where does Paradoxical embolus occure
usually through the heart via a patent foramen ovale, atrial septal defect, or another anomalous communication
what is the origin of systemic embolization
left atrium
Left ventricle (heart valve vegetation)
ulcerated atherosclerotic plaque
where can a systemic embolization travel
To any systemic artery
how may a fat emboli occure
Fracture of large long bone, soft tissue injury
what may cause of air emboli
Chest way injury
what can an air emboli cause
Decompression sickness due to bends and caisson disease
why would amniotic fluid cause an emboli
Rare, and often associated with DIC
what is Atherosclerotic amboli
Debris from the central core of an atherosclerotic plaque
what is an infarcation
An ischemic necrosis involving all cell types in a part of an organ or entire organ
why does an infarct occur
Most often due to arterial obstruction
less often due to vessel twisting, venous obstruction or slow flow
- also shock
what is infarcation a major contributor to the mortality of what disease
Cardiovascular disease
Types of Infarctions
Red
White
What type of INfarction is hemorrhagic
Red- Hemorrhage
what casues a Red infarction
Venous
loose tissue (lung)
Dual circulation or extenisve overlap of arterial supply (lung, small intestine)
Previous congestion
Infarcation followed by a reflow of blood to the area
where do White infarcts occur
With arterial occlusions in solid
- where tissue density limits blood seepage from adjacent vascular beds
what shape do infarcts tend to have
Wedge-shaped with the point of the wedge at the obstruction
when do histo changes of coagulation necrosis occur due to INfarcts
begin within several hours
peaks at 2-3 days
how does healing of infarcts occur
granulation tissue growth
, beginning at the infarct, followed by scar formation
what do infarcts in the brain lead to
liquefactive (non- coagulative) necrosis
how do Infarcts in the brain heal
formation of a cystic space
what can impact infarct development
Nauter of the vascular supply
Rate of development of occlusion
Vulnerability to hypoxia
O2 capacity of blood
what is beteer to limit the influence of an infarct, dual or single artery supply
Dual
where is dual supply found
Lungs
Liver(hepatic artery and portal vein flow)
Forearm (radial and ulnar arteries)
how does Rate of development of the infarct affect the infarct
Slow occlusion allows time for opening of collateral vessels
what tissues are more/less vulnerable to hypoxia
More vulnerable (heart, brain) Less vulnerable (arm, leg)
why would the blood be less good at carrying Oxygen
Anemia
Shock
Lung diseases
Congestive heart failure
what is Shock
Systemic hypoperfusion of tissue
what is Cardiogenic shock
The loss of pumping capacity of the heart
what is Hypovolemic shock
Blood loss
what is septic shock
BActerial infection
what is anaphylactic shock
Hypersensitivity reaction
what mediates Anaphylactic shock
IgE
what is neurogenic shock
Loss of vascular tone
what may cause Neurogenic shock
Anesthesia
Spinal cord injury
what is the numnber 1 cause of death in the ICU
septic shock -20% mortality with 750,000 death annually
what kinds of bacteria cause septic shock
Gram-positive or gram-negatiec bacteria associated with PMPS
what do PAMPS bind to
Bind to toll-like receptors (monocytes and neutrophils) with release of IL-1, TNF
- secondary release of IL-1 and TNF
what happens if you have too much PAMPS
leads to septic shock that may lead to DIC
what is the last response when going to Septic shock
Vasodilation
Hypotension
Endothelial cell activation and injury
reduced myocardial contractility
what are the stages of Shock
Nonprogressive
Progressive
Irreversible
why would shock be nonprogressive
Compensatory mechanisms maintain tissue perfusion by tachycardia, renal conservation of water, redistribution of blood to vital organs and away from skin by peripheral vasoconstriction
what are the compensatory mechanisms that allow nonprogressive shock to maintain tissue perfusion
Catecholamines
Renin
ADH
sympa nervous system stimulation
what is Progressive shock
when inadequate perfusion with metabolic imbalance(acidosis) reduces vasomotor response to symp stimulation
- lead to pooling of blood and reduced perfusion
what does hypoxic injury to epithelium during progressive shock lead to
DIC
what is Irreversible shock
Tissue injury that can not be reversed by reperfusion
what happens to brain in shock
Ischemic necrosis of neurons (hippocampus and cerebelum)
what happens to the heart in shock
Contraction band necrosis in the heart
what happens in the kidney during shock
Necrosis of tubular epithelial cells
what happens to the lungs in shock
Diffuse alveolar damage in the lungs due to endothelial injury
what is it called when sock cuasese endothelial injury in the lungs
Adult respiratory distress syndrom (ARDS)
what happens to the intestinal tract in shock
Mucosal hemorrhage and necrosis
what happens to the liver in shock
Centrizonal necrosis in the liver
what are the clinical manifestations of shock
Tachycardia Tachypnea Hypotension Cool clammy skin Decreased urinary outpur Confusion Low blood pH with elevated lactic acid
what type of shock does not result in cool clammy skin
Spetic shock
