Disorders of Circulation

Question 1

What are some differences between hyperemia and congestion?

Answer 1

Hyperemia is an active process resulting from arterial dilatation and increased blood flow. Congestion is a passive process resulting from impaired outflow of venous blood from a tissue.

Hyperemia makes tissues look “redder.”
Congestion gives tissues a “red-blue” color.

Question 2

What is a commonality between hyperemia and congestion?

Answer 2

Both refer to increased intravascular blood volume in a tissue, organ or body part

Question 3

What are two examples of hyperemia?

Answer 3

Sites of inflammation

Exercising skeletal muscle

Question 4

What is an example of congestion?

Answer 4

Right CHF leads to hepatic congestion

Question 5

Explain how CHF leads to ischemia and necrosis in the liver?

Answer 5

Blood is backed up at the central vein.
The sinusoids become engorged with blood, squeezing nearby hepatocytes –> ischemia
Thus, the impeded outflow leads to necrosis of hepatocytes around the central vein

Question 6

What causes edema?

Answer 6

Fluid moving out of capillaries into the interstitial space exceeds the body’s lymphatic drainage capacity

Question 7

Five reasons for edema:

Answer 7

1. Increased hydrostatic pressure
2. Decreased oncotic pressure due to reduced plasma albumin
3. Lymphatic obstruction
4. Increased vascular permeability
5. Na+ retention

Question 8

What could increase hydrostatic pressure?

Answer 8

a. Systemic - heart failure

b. Local - impaired venous return post DVT

Question 9

What 5 things could decrease plasma albumin (overlap with pharm)

Answer 9

Renal failure - excretion
Liver failure - not making enough albumin
Burns - protein leaks out into interstitial space
Cystic fibrosis
Pregnancy
Malnutrition

Question 10

What could obstruct the lymphatics?

Answer 10

a neoplasm

Question 11

What could cause increased vascular permeability?

Answer 11

inflammation

Question 12

What could cause sodium retention?

Answer 12

Renal failure

Question 13

What are the three pathophysiological categories for edema?

Answer 13

Heart failure
Renal failure
Malnutrition, decreased hepatic synthesis, nephrotic syndrome

Question 14

How does heart failure cause edema?

Answer 14

It increases capillary hydrostatic pressure, as there is a significant venous backup.

Because the heart’s not pumping much blood, there is decreased blood flow to the kidneys. This results in activation of the renin-ang.-aldo. system and retention of sodium and water.

Question 15

How does renal failure cause edema?

Answer 15

Sodium and H2O retention, increasing blood volume

Question 16

How do malnutrition, liver disease and nephrotic syndrome cause edema?

Answer 16

They decrease plasma albumin and, thus, oncotic pressure

Question 17

What causes transudate leakage?

Answer 17

High hydrostatic pressure, low oncotic pressure

Question 18

What causes exudate leakage?

Answer 18

Increased vascular permeability (inflammation)

Vasodilation and stasis

Question 19

f. Explain the pathogenesis, pathology and pathophysiology of HEMORRHAGE.

Answer 19

Pathology - Flow of blood from a ruptured blood vessel into tissue, into a body cavity or outside the body

Pathogenesis - Bleeding occurs when blood vessel is disrupted by either a mechanical force or a pathologic process, such as (congestion, inflammation, neoplastic erosion of vessel)

Pathophysiology - Abnormal hemostasis causes a predisposition to bleeding

Question 20

What could cause a thrombus?

Answer 20

1. Endothelial injury
2. Altered blood flow
3. Hypercoagulable state

Question 21

What would cause endothelial injury?

Answer 21

inflammation, advanced therosclerosis

Question 22

What would cause altered blood flow?

Answer 22

Turbulence, via atherosclerotic vessel narrowing, or stasis (a-fib, bed rest, scarred tissue on a heart doesn’t pump)

Question 23

What would cause a hypercoagulable state?

Answer 23

Predisposition to easy clot formation (inherited protein C deficiency, contraceptives and smoking, metastatic cancer, obesity)

Question 24

What factors influence the clinical outcomes of thrombosis?

Answer 24

1. Degree of occlusion of vessel lumen, collaterals, size of infarct
2. Survival of patient is determined by size and location of infarct as well as collateral circulation

Question 25

h. Define “Virchow’s Triad” - endothelial integrity is the most important factor

Answer 25

i. Endothelial integrity
ii. Abnormal blood flow
iii. Hypercoagulability

Question 26

Which is the most important factor of Virchow’s Triad

Answer 26

Endothelial integrity

Question 27

Define shock

Answer 27

Profound systemic hypoperfusion, resulting in impaired tissue function and hypoxia

Question 28

What are the three major types of shock?

Answer 28

Cardiogenic - low cardiac output due to myocardial pump failure

Hypovolemic - low cardiac output due to loss of blood or plasma volume

Septic - arteriolar vasodilation and venous blood pooling that stems from systemic immune response to microbial infection