Path - Inflammation (Ischemia, Infarcts, Shock, & Atrophy)

Question 1

What areas in the brain are susceptible to hypoxia/ischemia and infarction?

Answer 1

ACA/MCA/PCA boundary areas;

Question 2

Explain the general blood supply of watershed areas. What are these areas protected from versus susceptible to in terms of hypoxia/ischemia and infarction? Give 2 organs and specific areas within them to which the concept of watershed areas applies.

Answer 2

Watershed areas (border zones) receive dual blood supply from most distal branches of 2 arteries, which protects these areas from single-vessel focal blockage. However, these areas are susceptible to ishcemia from systemic hypoperfusion; (1) Brain - ACA/MCA/PCA boundary areas (2) Colon - Splenic flexure, rectum

Question 3

What is HIE, and what cells/regions does it affect?

Answer 3

Hypoxic ischemic encephalopathy (HIE) affects pyramidal cells of hippocampus and Purkinje cells of cerebellum

Question 4

What area in the heart is susceptible to hypoxia/ischemia and infarction?

Answer 4

Subendocardium (LV)

Question 5

What 2 areas in the Kidney are susceptible to hypoxia/ischemia and infarction?

Answer 5

(1) Straight segment of proximal tubule (medulla) (2) Thick ascending limb (medulla)

Question 6

What area in the liver is susceptible to hypoxia/ischemia and infarction? Both describe/define and name this area.

Answer 6

Area around central vein (zone III)

Question 7

What 2 areas in the Colon are susceptible to hypoxia/ischemia and infarction?

Answer 7

(1) Splenic flexure (2) Rectum

Question 8

What causes reperfusion injury?

Answer 8

Reperfusion injury is due to damage by free radicals

Question 9

What is another name for red infarcts? In what setting/context do they occur? Give 3 examples of such organs.

Answer 9

Red (hemorrhagic) infarcts occur in loose tissues with multiple blood supplies, such as liver, lungs, and intestine; Think: “REd = REperfusion”

Question 10

In what setting/context do pale infarcts occur? Give 3 examples of such organs.

Answer 10

Pale infarcts occur in solid tissues with a single blood supply, such as heart, kidney, and spleen

Question 11

What is the first sign of shock?

Answer 11

First sign of shock is tachycardia

Question 12

What kind of presentation involving shock would suggest an etiology of sepsis?

Answer 12

Shock in the setting of DIC secondary to trauma is likely due to sepsis

Question 13

What are 3 types of distributive shock?

Answer 13

Distributive shock includes septic, neurogenic, and anaphylactic shock

Question 14

Compare/contract the output failure in Distributive versus Hypovolemic/Cardiogenic shock. Give the change in relevant variables in each case.

Answer 14

DISTRIBUTIVE: High-output failure (low TPR, high CO, high venous return); HYPOVOLEMIC/CARDIOGENIC: Low-output failure (high TPR, low CO, low venous return)

Question 15

Compare/contract the PCWP in Distributive versus Hypovolemic/Cardiogenic shock.

Answer 15

DISTRIBUTIVE: Low PCWP; HYPOVOLEMIC/CARDIOGENIC: PCWP high in cardiogenic & low in hypovolemic

Question 16

Compare/contract the vascular change in Distributive versus Hypovolemic/Cardiogenic shock. Give the relevant clinical presentation/findings in each case.

Answer 16

DISTRIBUTIVE: Vasodilation (warm, dry skin); HYPOVOLEMIC/CARDIOGENIC: Vasoconstriction (cold, clammy patient)

Question 17

Compare/contract the use of IV fluids in Distributive versus Hypovolemic/Cardiogenic shock.

Answer 17

DISTRIBUTIVE: Failure to increase blood pressure with IV fluids; HYPOVOLEMIC/CARDIOGENIC: Blood pressure restored with IV fluids

Question 18

What is atrophy?

Answer 18

Reduction in the size and/or number of cells

Question 19

What are 7 causes of atrophy?

Answer 19

Causes include: (1) low endogenous hormones (e.g., post-menopausal ovaries) (2) high exogenous hormones (e.g., factitious thyrotoxicosis, steroid use) (3) low innervation (e.g., motor neuron damage) (4) low blood flow/nutrients (5) low metabolic demand (e.g., prolonged hospitalization, paralysis) (6) high pressure (e.g., nephrolithiasis) (7) Occlusion of secretory ducts (e.g., cystic fibrosis)

Question 20

What hormonal changes cause atrophy? Give at least one example of each change.

Answer 20

(1) low endogenous hormones (e.g., post-menopausal ovaries) (2) high exogenous hormones (e.g., factitious thyrotoxicosis, steroid use)

Question 21

What change in innervation causes atrophy? Give an example of this.

Answer 21

low innervation (e.g., motor neuron damage)

Question 22

What change in blood flow/nutrients causes atrophy?

Answer 22

low blood flow/nutrients

Question 23

What change in metabolic demand causes atrophy? Give 2 examples of this.

Answer 23

low metabolic demand (e.g., prolonged hospitalization, paralysis)

Question 24

What change in pressure causes atrophy? Give an example of this.

Answer 24

high pressure (e.g., nephrolithiasis)

Question 25

What kind of occlusion causes atrophy? Give an example of this.

Answer 25

Occlusion of secretory ducts (e.g., cystic fibrosis)