Trombosis, Embolism, infarction and Shock #4 (1/25/16) Flashcards Preview

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Flashcards in Trombosis, Embolism, infarction and Shock #4 (1/25/16) Deck (20):

What is a Thrombus?
What is Thrombosis?

Thrombus = An intravascular clot often impeding or preventing blood flow.

Thrombosis = Formation or presence of thrombus that may result in an infarction.


What is Virchow's Triad?

3 factors that can lead to a thrombus/thrombosis:
1. Endothelial injury
2. Alterations in blood flow = like turbulence or stasis (both lead to endothelial activation)
3. Hyper-coagulability


What conditions cause Hyper-coagulability?

1. Inherited Conditions
- Factor V leiden (Va cannot be cleaved)
- AT III deficiency
- Prothrombin Mutation

2. Acquired conditions
- prolonged bed rest
- extensive tissue injury
- pregnancy
- cancer
- anti-PL ab


Describe arterial Thrombosis....

- White (Because of fibrin)
- Often at sites of turbulence/endothelial injury
- Occlusive or mural
- Distinct lines of Zahn
- on heart valves (NBTE)


Describe venous thrombosis....

- Red
- Often at sites of stasis (Where blood slowed down) such as deep leg veins.
- Indistinct lines of Zahn


What are the 4 possible fates of Thrombi?

1. Propagation - whole thrombus moves.
2. Embolization - piece of thrombus breaks off and goes elsewhere.
3. Dissolution (resolution) - thrombus gets resorbed by body.
4. Organization/recanalization - thrombus gets holes in it so blood flow can be restored THROUGH thrombus.


What is DIC?

Disseminated Intravascular Coagulation
- Widespread activation of the coagulation cascade and fibrinolytic factors.
- Depletion of coagulation factors and platelets
- Elevation of fibrin spilt products
- Micro thrombi and hemorrhage
- Consumptive coagulopathy


What are the Etiologies of DIC? (7)

- Infection (gram negatives)
- Obstetric complications
- Placental abruption
- Retained dead fetus
- Neoplasm
- Shock
- Massive tissue injury.


Describe treatment for DIC....

Treatment is highly variable and dependent on management of underlying disorder. (Can be potentially life threatening)


What is an Embolus?

An intravascular solid, liquid or gaseous mass carried by the blood to a site distant from its point of origin. *The vast majority of Emboli are dislodged thrombus material.


Describe a Pulmonary Thromboembolism - Origin? Consequences?

Origin = Deep leg veins
Clinical consequences:
- No manifestations
- pulmonary hemorrhage
- Pulmonary infarction
- Sudden death
- Pulmonary Hypertension


Describe Systemic Embolization - Origin?

Origin = left atrium, left ventricle, atherosclerotic plaque.
*Paradoxical embolus = arises in a vein (Often leg vein) then crosses into the arterial side, often through patent foramen ovale.


What are the 5 types of Embolism?

1. Thrombus = most common by far
2. Fat
3. Air ("Bends" and caisson disease)
4. Amniotic fluid
5. Atherosclerotic plaque material


What is an Infarction?

Area of Ischemic Necrosis, secondary to occlusion of arterial supply or venous drainage.
*Major contributor to mortality associated with cardiovascular disease.


What are the 2 types of infarctions?

Red = hemorrhagic
- venous occlusion
- loose tissue
- dual blood supply
- previous congestion
- reflow of blood to infarcted area

White = pale
- Arterial occlusion in solid organ.


What factors influence Infarct development?

- Nature of vascular supply (Multiples, loose tissue)
- Rate of occlusion
- Vulnerability to hypoxia
- Oxygen carrying capacity of cardiovascular system


What is shock? What are the types of shock? (5)

Systemic Hypoperfusion (Not moving blood so well)
- Cariogenic shock
- Hypovolemic shock
- Septic shock (#1 cause of death in intensive care units)
- Anaphylactic shock
- Neurogenic shock


What is the most common cause of septic shock?

Gram + or Gram - Bacteria
* Activation of TLR on monocytes and neutrophils with release of IL-1, TNF and other mediators.
*Dose dependent effects, DIC in 50% of patients.


What are the stages of Shock?

1. Non-progressive = compensatory mechanism maintain perfusion.
2. Progressive = Inadequate perfusion, anaerobic metabolism, lactic acidosis, DIC.
3. Irreversible = Tissue injury unrecoverable, multiple organ failure, death.


What are the clinical manifestations of Shock?

- Tachycardia
- Tachypena
- Hypotension
- Cool clammy skin (septic may be warm)
- Pallor/cyanosis
- Confusion
- Low urine output
- Acidosis
- High lactic acid