Hemodynamic Disorders L16,17

Question 1

Fluid Distribution:

Answer 1

• 60% of lean body weight is water
  
  • 2/3 intracellular
  • 1/3 extracellular
    
    • Majority is interstitial fluid
    • 5% is in blood plasma

Question 2

2. What is the difference between anasarca and other types of edema?

Answer 2

Anasarca is a severe form of edema with extensive swelling of subcutaneous tissues and fluid accumulation in body cavities.

Question 3

3. What are the two main mechanisms of edema?

Answer 3

*Water extravasation (movement) out of the vascular wall into the interstitial spaces.
*imbalance between hydrostatic pressure forcing fluid out and colloid osmotic pressure pulling fluid in the capillaries.

Question 4

4. How do lymphatics contribute to edema?

Answer 4

Lymphatics drain excess interstitial fluid. A blockage in the lymphatic system can contribute to edema.

Question 5

5. What are the two main types of edema based on protein content?

Answer 5

*Inflammatory edema: protein-rich exudate, specific gravity > 1.020, caused by increased vascular permeability.

*Non-inflammatory edema: protein-poor transudate, specific gravity < 1.012, caused by reasons other than inflammation.

Question 6

1. What are the main forces influencing fluid movement across capillary walls?

Answer 6

Hydrostatic pressure (pushing fluid out) and osmotic pressure (pulling fluid in) are normally balanced, minimizing net fluid movement into the interstitial space

Question 7

2. What are the four main causes of non-inflammatory edema?

Answer 7

*Increased hydrostatic pressure

*Reduced plasma osmotic pressure

*Lymphatic obstruction (not covered in this excerpt)

*Sodium and water retention

Question 8

3. How can increased hydrostatic pressure cause localized edema?

Answer 8

*Deep vein thrombosis (DVT) in a leg hinders blood return, causing swelling in that leg.

*Portal hypertension due to liver cirrhosis leads to fluid buildup in the peritoneal cavity (ascites).

*Pressure from a pregnant uterus on iliac veins can cause congestion and edema in the lower limbs.

*Acute left ventricular failure causes acute pulmonary edema

Question 9

How can increased hydrostatic pressure cause generalized edema?

Answer 9

Congestive heart failure reduces cardiac output, leading to:

*Increased venous pressure throughout the body.

*Reduced kidney perfusion, triggering sodium and water retention, ultimately causing edema.

Question 10

Besides increased pressure, what can cause reduced plasma osmotic pressure leading to edema?

Answer 10

*A decrease in plasma proteins (like albumin) due to malnutrition or liver disease.

*Excessive fluid intake diluting plasma proteins.

Question 11

What protein is most responsible for maintaining fluid balance in the bloodstream?

Answer 11

Albumin

Question 12

What happens when albumin levels decrease?

Answer 12

Plasma osmotic pressure is reduced, causing a net fluid movement into the interstitial space and leading to edema.

Question 13

What are three situations that can cause reduced albumin levels?

Answer 13

*Albumin loss from leaky glomerular capillaries (e.g., nephrotic syndrome).

*Decreased albumin synthesis due to liver diseases (e.g., cirrhosis).

*Protein malnutrition.

Question 14

What is the typical effect of lymphatic obstruction on edema?

Answer 14

It usually causes localized edema.

Question 15

It usually causes localized edema.

Answer 15

*Inflammatory lesions

*Neoplastic lesions (cancers)

Question 16

How can breast cancer treatment lead to lymphedema?

Answer 16

Resection and/or irradiation of axillary lymph nodes can cause scarring and disrupt lymphatic drainage, leading to severe upper extremity edema.

Question 17

What is peau d’orange and how is it related to lymphatic obstruction in breast cancer?

Answer 17

*Peau d’orange is a French term meaning “orange peel” and refers to a dimpled appearance of the skin.

*It can occur in breast cancer when tumor cells infiltrate and obstruct superficial lymphatic vessels, causing fluid buildup and a characteristic pitted texture in the overlying skin.

Question 18

How does increased sodium and water retention contribute to edema?

Answer 18

It increases both hydrostatic pressure (due to more fluid in the blood vessels) and reduces osmotic pressure (diluting albumin’s effect).

Question 19

2. What are two situations where salt retention can occur and lead to edema?

Answer 19

*Poststreptococcal glomerulonephritis

*Acute renal failure

Question 20

What are the two main ways to recognize edema?

Answer 20

*Macroscopic observation of swelling

*Microscopic observation of:

-Clearing and separation of extracellular matrix elements

-Individual cell swelling

Question 21

In which tissues is edema most commonly encountered?

Answer 21

*Subcutaneous tissues

*Lungs

*Brain

Question 22

3. What is pitting edema and how is it caused?

Answer 22

*Pitting edema refers to a depression left in the skin after applying finger pressure.

*It occurs in edematous subcutaneous tissue where pressure displaces the interstitial fluid.

Question 23

Where does edema due to renal dysfunction or nephrotic syndrome often appear first?

Answer 23

Loose connective tissues, particularly around the eyelids (periorbital edema).

Question 24

How does the effect of edema vary depending on its location?

Answer 24

*It can have minimal effects in some locations.

*In subcutaneous tissue (e.g., with heart or kidney failure), it mainly indicates an underlying disease.

*In the lungs (pulmonary edema), fluid fills the air sacs and can cause life-threatening breathing difficulties.

*In the brain, edema can be localized (e.g., injury) or generalized (e.g., infections, high blood pressure).

Question 25

Why can pulmonary edema be life-threatening?

Answer 25

Fluid buildup in the lungs interferes with oxygen exchange, leading to severe breathing difficulties.

Question 26

What do hyperemia and congestion have in common?

Answer 26

Both indicate increased blood volume in a tissue.

Question 27

How do hyperemia and congestion differ in their cause?

Answer 27

*Hyperemia is an active process due to increased blood flow caused by arteriole dilation (e.g., inflammation, exercise).

*Congestion is a passive process due to impaired blood flow out of a tissue (e.g., heart failure, venous obstruction).

Question 28

How does the appearance of hyperemic tissue differ from congested tissue?

Answer 28

*Hyperemic tissue appears redder due to engorgement with oxygenated blood.

*Congested tissue has a blue-red color (cyanosis) due to deoxygenated blood buildup.

Question 29

What are the long-term consequences of chronic passive congestion?

Answer 29

*Chronic hypoxia (low oxygen supply) can lead to cell death and tissue fibrosis (scarring).

*Capillary rupture can cause small hemorrhages, and macrophage activity can lead to hemosiderin deposits.

Question 30

How does the macroscopic appearance of hyperemic/congested tissue differ?

Answer 30

Cut surfaces appear bloody and wet.

Question 31

How does acute pulmonary congestion manifest microscopically?

Answer 31

*Blood-engorged alveolar capillaries

*Alveolar septal edema (fluid buildup)

*Possible focal minor bleeding within alveoli

Question 32

How does chronic pulmonary congestion differ microscopically?

Answer 32

*Thickened and fibrotic alveolar septa

*Alveolar spaces with numerous hemosiderin-laden macrophages (“heart failure cells”)

Question 33

How does acute hepatic congestion differ from chronic hepatic congestion microscopically?

Answer 33

Acute: Central vein and sinusoids distended with blood, possible central hepatocyte degeneration.

*Chronic:

-Central regions appear grossly red-brown and depressed (cell loss).

-Peri portal areas (better oxygenated) show less severe changes, possibly fatty change.

-Overall appearance is called “nutmeg liver”.

*Microscopically: Centrilobular necrosis, hemorrhage, and hemosiderin-laden macrophages.

Question 34

What is Hemorrhage?

Answer 34

Hemorrhage is the leaking of blood from blood vessels into surrounding tissues, organs, body cavities, or externally

Question 35

What are the main causes of hemorrhage?

Answer 35

1.Trauma (most common)

2.Chronic congestion leading to capillary rupture

3.Coagulation disorders

4.Vascular injury (e.g., atherosclerosis, inflammation, tumors)

Question 36

Clinical Significance of Hemorrhage:

Answer 36

1.Blood loss tolerance varies:

-Healthy adults can handle losing up to 20% of their blood volume rapidly or even larger amounts slowly.

-Greater blood loss can lead to hemorrhagic shock.

2.Location matters:

Bleeding harmless in some tissues (subcutaneous) can be fatal in others (brain).

3.Chronic blood loss:

-Repeated external bleeding (e.g., peptic ulcer, menstruation) can lead to iron deficiency anemia.

Question 37

Types of hemorrhage

Answer 37

1. Hematoma
2. Petechiae
3. Purpura
4. Ecchymoses (Bruises)
5. Hemorrhage in Body Cavities

Question 38

What is a hematoma?

Answer 38

collection of blood confined within a

It can range from a minor bruise (insignificant) to a life-threatening bleed (aortic rupture).

Question 39

What is the size of petechiae

Answer 39

Tiny (1-2mm) hemorrhages

Question 40

Where can petechiae occur?

Answer 40

Skin, mucous membranes, or serosal surfaces.

Question 41

What are some causes of petechiae?

Answer 41

Increased local blood pressure, low platelet count, defective platelet function, or clotting factor deficiencies.

Question 42

What is the size of purpura?

Answer 42

Slightly larger (3-5mm) hemorrhages than petechiae.

Question 43

What are some causes of purpura?

Answer 43

Many of the same causes as petechiae, plus trauma and vascular inflammation (vasculitis).

Question 44

What is the size of ecchymoses?

Answer 44

Larger (1-2cm) subcutaneous hematomas.

Question 45

What happens to the blood in a bruise over time?

Answer 45

Macrophages remove red blood cells, and hemoglobin color changes occur (red-blue to blue-green to golden-brown) due to breakdown products.

Question 46

How are large blood accumulations in body cavities named?

Answer 46

are named based on the cavity involved:

*Hemothrax (chest)

*Hemoperricardium (pericardium sac)

*Hemoperitoneum (abdominal cavity)

*Hemarthrosis (joints)