Shock

Question 1

define shock

Answer 1

state in which decreased cardiac output or effective circulating blood volume leads to hypoxia and impaired tissue function

Question 2

Types of shock

Answer 2

Hypovolemic

Cardiogenic

Distributive

Obstructive

Question 3

What are the phases of shock and describe them

Answer 3

Compensated “Pre-shock”- reflex compensatory mechanisms are activated so perfusion is maintained

“Progressive” Decompensated shock- tissue hypoperfusion and onset of worsening circulatory and metabolic imbalances (hypoxia leads to lactic acidosis)

Irreversible Shock- cellular and tissue injury to the point of impossible survival (lysosomal leakage and necrosis)

Question 4

Oxygen delivery equation and its components

Answer 4

CaO2= [Hb x 1.39 x SaO2) + PaO2 x 0.03)]

Question 5

What most commonly causes hypovolemic shock and examples of hypovolemic shock

Answer 5

decreased venous return

• hemorrhagic shock
• traumatic shock
• surgical shock
• burn shock

Question 6

Describe the sequelae of hypovolemic shock

Answer 6

Decreased intravascular volume leads to:

• decreased LVEDP
• Generalized vasoconstriction
• Sodium/water retention leading to the expansion of blood volume
• increased extraction of O2 from the blood

Question 7

describe cardiogenic shock

Answer 7

inappropriately low cardiac output, despite normal or high central venous (RA pressure)

Question 8

What causes cardiogenic shock and what are the consequences

Answer 8

• Decreased contractility leads to infarction
• Increased diastolic stiffness leads to ventricular hypertrophy and restrictive cardiomyopathy
• Increased afterload
• abnormal rate/ rhythm: V tach
• valve dysfunction leads to mitral regurg and rupture of IV shunt

Question 9

what is distributive shock and what are examples

Answer 9

condition of reduced oxygen delivery where the primary physiologic disturbances is a reduction in SVR

septic shock

adrenal crisis

endocrine shock

neurogenic shock

anaphylaxis

pancreatitis

liver failure

burns

Question 10

consequences of distributive shock

Answer 10

• compensatory increase in CO
• central venous pressure and pulmonary capillary wedge pressure are decreased

Question 11

most common sites of septic infection

Answer 11

respiratory tract

GU

abdomen

device implants

wound/ soft tissue infections

Question 12

explain the pathogenesis of septic shock

Answer 12

Question 13

Morphology of shock in the adrenal gland

Answer 13

cortical cell lipid depletion

hemorrhagic necrosis leading to Waterhouse Friedrichsen syndrome

Question 14

Morphology of shock in the lungs

Answer 14

Gross: congested/ firm tissue with frothy fluid exuding from the cut surface

Micro: diffuse alveolar damage with alveolar hyaline membranes

Question 15

Morphology of shock in the kidney

Answer 15

acute tubular necrosis

Question 16

Morphology of shock in GI

Answer 16

gastric mucosal erosions and superficial ischemic necrosis in the intestines with diffuse GI hemorrhage

Question 17

Morphology of shock in the liver

Answer 17

hepatomegaly with a mottled cut surface that reflects marked centrilobular congestion and necrosis of the blood

Question 18

Morphology of shock in the pancreas

Answer 18

impaired splanchnic circulation with ischemic damage to the exocrine pancreas

acute pancreatitis due to activated pancreatic enzymes

Question 19

Morphology of shock in the brain

Answer 19

watershed infarcts if severe