Infarction and Shock Flashcards by Hannah Brule

What is infarction?

Ischemic necrosis within a tissue or organ

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What is infarction most often caused by?

Thrombotic or embolic occlusion

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What is white infarct?

Ischemic; turns pale, classic wedge shape

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What is red infarct?

Hemorrhagic; bleeding into tissue or organ

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What are the determining factors of clinical significance for infarction?

Nature of vascular supply
Rate of development of occlusion
Vulnerability of tissue to hypoxia

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If an occlusion has a very quick development, what is the likely result?

Necrosis

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If an occlusion develops over years, what is the likely result?

Tissue atrophy

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What tissues are vulnerable to hypoxia?

Heart, nerve, brain

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Infarction has margins lined by rim of…

hyperemia/inflammation

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The surface of an infarct is covered by…

fibrinous exudate

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Heart attack/myocardial infarction leads to what type of necrosis?

Coagulative necrosis

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What is the most common shape of an infarct?

Wedge-shaped

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What is shock?

Hypoperfusion of tissues

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What are five major subtypes of shock?

Cardiogenic
Hypovolemic
Septic
Anaphylactic
Neurogenic

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Myocardial infarction and myocarditis lead to what type of shock?

Cardiogenic

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Cardiac tamponade and pulmonary embolus lead to what type of shock?

Cardiogenic

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Hemorrhage leads to what type of shock?

Hypovolemic

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Diarrhea and dehydration lead to what type of shock?

Hypovolemic

Burns lead to what type of shock?

Hypovolemic

A severe infection will lead to what type of shock?

Septic

Type 1 hypersensitivity reactions lead to what type of shock?

Anaphylactic

Brain damage and/or spinal cord injury lead to what type of shock?

Neurogenic

What are three results of myocardial pump failure?

Decreased blood volume
Increased vasodilation
Increased vascular permeability

What happens during cardiogenic shock?

Heart fails as a pump

After myocardial infarction, necrotic tissue will appear ___ and scar tissue will appear ___

necrotic tissue = dark scar tissue = pale/white

What is cardiac tamponade?

Survival of heart attack leads to tear in myocardium and bleeding into pericardial sac; atria will collapse

Is cor pulmonale acute or chronic?

Acute

What is cor pulmonale?

Right ventricular dilation (fills with blood that can't leave) and hypertrophy

Cor pulmonale is an extension of...

what happens with embolized deep vein thrombosis: saddle embolus

What is hypovolemic shock?

Not enough blood due to blood loss

What are potential causes of cardiogenic shock?

* Myocardial infarction * Cardiac tamponade * Cor pulmonale

What are potential causes of hypovolemic shock?

* Hemorrhage * Severe trauma * Extensive burns (2nd and 3rd degree)

How does an extensive burn lead to hypovolemic shock?

Blisters are filled with edema fluid which is derived from blood plasma, thus decreasing blood volume

What is septic shock?

Sock due to blood borne infection

#septic shock Endotoxins are released from gram ___ bacteria (role of LPS)

gram **negative** bacteria

#septic sock Endotoxins stimulate release of ___

cytokines (IL-1, 6, and 8, TNF)

#septic shock Cytokines trigger the release of...

PAF, NO, bradykinin, complement, prostaglandins, and leukotrienes

#septic shock What is the result of released PAF, NO, bradykinin, complement, prostaglandins, and leukotrienes by cytokines?

Systemic vasodilation

What are the stages of shock?

* Non-progressive stage * Progressive stage * Irreversible stage

What is the non-progressive stage of shock?

Compensatory mechanisms are maintaining blood pressure: SNS, RAA axis, autoregulation

What is the progressive stage of shock?

Tissue hypoxia and metabolic acidosis but the tissue is not dying yet

What is the irreversible stage of shock?

Enzyme leakage and organ shutdown over a short time course

If increased BUN, creatinine, and decreased GFR are found in the blood, what is the likely cause?

Irreversible stage of shock due to kidney failure

If increased troponin, pancreatic lipase, and amylase are found in the blood, what is the likely cause?

Irreversible shock