Summary's Chapter 4: Hemodynamic Disorders, Thromboembolism, and Shock

Question 1

What is edema? (for dutchies: oedeem)

Answer 1

Edema results from the movement of fluid from the vasculature into the interstitial spaces; the fluid may be protein poor (transudate) or protein rich (exudate).

Question 2

What may edema be caused by?

Answer 2

• Increased hydrostatic pressure
• Increased vascular permeability
• Decreased colloid osmotic pressure resulting from reduced plasma albumin
• Lymphatic obstruction
• Sodium retention

Question 3

Decreased colloid osmotic pressure can be because of 2 causes. What are these?

Answer 3

• Decreased synthesis

* Increased loss

Question 4

What is an example of increased hydrostatic pressure that causes edema?

Answer 4

Heart failure

Question 5

What is an example of increased vascular permeability that causes edema?

Answer 5

Inflammation

Question 6

What is an example of decreased synthesis and what is an example of increased loss causing a decreased colloid osmotic pressure, resulting from reduced plasma albumin?

Answer 6

• Decreased synthesis (e.g., liver disease, protein
malnutrition)
• Increased loss (e.g., nephrotic syndrome)

Question 7

What is an example of lymphatic obstruction causing edema?

Answer 7

Inflammation or neoplasia

Question 8

What is an example of sodium retention causing edema?

Answer 8

Renal failure

Question 9

Fill in: Endothelial injury exposes the underlying basement membrane ECM (=extracellular matrix); platelets adhere to the ECM primarily through the binding of platelet … receptors to …

Answer 9

GpIb, VWF (von willebrand factor) (respectively)

Question 10

Fill in: Adhesion leads to …, an event associated with secretion of platelet granule contents

Answer 10

platelet activation,

Question 11

Which platelet granule contents are secreted during platelet activation?

Answer 11

Calcium (a cofactor for several coagulation proteins) and ADP (a mediator of further platelet activation); dramatic changes in shape and membrane composition; and activation of GpIIb/IIIa receptors.

Question 12

With what molecule can GpIIb/IIIa receptors on activated platelets bind? How do they do this?

Answer 12

Bridging crosslinks with fibrinogen, leading to platelet aggregation.

Question 13

Fill in: Concomitant activation of thrombin promotes … deposition, cementing the platelet plug in place.

Answer 13

fibrin

Question 14

True/false: Coagulation occurs via the sequential enzymatic conversion of a cascade of circulating and locally synthesized proteins.

Answer 14

True

Question 15

Fill in: … elaborated at sites of injury is the most important initiator of the coagulation cascade in vivo.

Answer 15

Tissue factor

Question 16

Fill in: At the final stage of coagulation, thrombin converts fibrinogen into … that contributes to formation of the definitive hemostatic plug.

Answer 16

insoluble fibrin

Question 17

Coagulation normally is restricted to sites of vascular injury. By what pathways/mechanisms is that (4 answers)

Answer 17

• limiting enzymatic activation to phospholipid surfaces provided by activated platelets or endothelium,
• circulating inhibitors of coagulation factors, such as anti-thrombin III, whose activity is augmented by heparin-like molecules expressed on endothelial cells
• expression of thrombomodulin on normal endothelial cells,
which bind thrombin and convert it into an anti-coagulant,
• activation of fibrinolytic pathways (e.g., by association of
tissue plasminogen activator with fibrin)

Question 18

Thrombus development is usually related to one or more components of Virchow’s triad. What are these components?

Answer 18

• endothelial injury (e.g., by toxins, hypertension, inflammation,  or  metabolic  products)
• abnormal  blood  flow,  stasis,  or  turbulence  (e.g.,  resulting from aneurysms, atherosclerotic plaque)
• hypercoagulability:  either  primary  (e.g.,  factor  V  Leiden, increased prothrombin synthesis, anti-thrombin III deficiency)
or secondary (e.g., bed rest, tissue damage, malignancy)

Question 19

True/false: Thrombi may propagate, resolve, become organized, or embolize.

Answer 19

True

Question 20

Thrombosis causes tissue injury by …

Answer 20

local vascular occlusion or

by distal embolization.

Question 21

What is an embolus?

Answer 21

An embolus is a solid, liquid, or gaseous mass carried by the blood to a site distant from its origin; most are dislodged thrombi.

Question 22

Pulmonary emboli derive primarily from ….

Answer 22

lower-extremity deep vein thrombi

Question 23

The effects of pulmonary emboly depend mainly on ….

Answer 23

the size of the embolus and the location in which it lodges

Question 24

What are possible consequences because of a pulmonary emboli?

Answer 24

Consequences may include right-sided heart failure, pulmonary hemorrhage, pulmonary infarction, or sudden death.

Question 25

Where do systemic emboli derive from?

Answer 25

Cardiac mural or valvular thrombi, aortic aneurysms, or atherosclerotic plaques

Question 26

Does an embolus, per definition, cause tissue infarction?

Answer 26

No, it depends on the site of embolization and the presence/absence of collateral circulation

Question 27

How can fat embolism occur?

Answer 27

After crushing injuries to the bone

Question 28

What are the symptoms of fat embolism?

Answer 28

Pulmonary insufficiency and neurological damage

Question 29

Amniotic fluid embolism may follow childbirth and can give rise to ….

Answer 29

fatal pulmonary and cerebral manifestations.

Question 30

Air embolism can occur upon rapid decompression, most commonly in divers; it results from …

Answer 30

sudden bubbling of nitrogen dissolved in blood at higher pressures.

Question 31

What are infarcts and what are they caused by?

Answer 31

Infarcts are areas of ischemic necrosis most commonly caused by arterial occlusion (typically resulting from thrombosis or embolization); venous outflow obstruction is a less frequent cause.

Question 32

What colour are infarcts caused by venous occlusion or occurring in spongy tissues typically?

Answer 32

Red (because of hemorrhage)

Question 33

What colour are infarcts caused by arterial occlusion in compact tissues typically?

Answer 33

White (pale)

Question 34

Whether or not vascular occlusion causes tissue infarction is influenced by ….

Answer 34

collateral blood supplies, the rate at which an obstruction develops, intrinsic tissue susceptibility to ischemic injury, and blood oxygenation.

Question 35

What is shock?

Answer 35

A state of systemic tissue hypoperfusion resulting from reduced cardiac output and/or reduced effective circulating blood volume.

Question 36

What are the major types of shock?

Answer 36

cardiogenic (e.g., myocardial infarction), hypovolemic (e.g., blood loss), and septic (e.g., infections).

Question 37

True/false: shock always causes injury

Answer 37

False, but shock of any form can lead to hypoxic tissue injury if not corrected.

Question 38

What is septic shock caused by?

Answer 38

by the host response to bacterial or fungal infections;

Question 39

What is septic shock characterized by?

Answer 39

It is characterized by endothelial cell activation, vasodilation, edema, disseminated intravascular coagulation, and metabolic derangements.