Pathology Week 9 E

Question 1

Define effusion

Answer 1

The escape of blood or other bodily fluid into a cavity or tissue

The fluid that has escaped

Question 2

Define oedema

Answer 2

An effusion of serous fluid into the:

• tissue spaces (interstitial spaces)
• body cavities

The presence of excess fluid in the interstitial spaces of the body

Question 3

Define anasarca:

Answer 3

Severe and generalised oedema with profound subcutaneous tissue swelling

Question 4

Define transudate:

Answer 4

A collection of fluid that has formed after passing through a membrane, pore or interstice

Question 5

Define exudate

Answer 5

Fluid that has exuded out of a tissue or its capillaries due to injury or inflammation

Question 6

What are the types of local oedema?

Answer 6

Inflammatory oedema

Allergic oedema

Venous obstruction

Lymphatic obstruction

Question 7

What is capillary hydrostatic pressure? At which end of the system is it highest?

Answer 7

The pressure of fluid within a capillary

Highest at the arterial end than the venous end

Question 8

What is average capillary hydrostatic pressure in arterial end?

Answer 8

35mmHg

Question 9

What is average capillary hydrostatic pressure in the venous end?

Answer 9

15mmHg

Question 10

What is the purpose of higher capillary hydrostatic pressure at the arterial end?

Answer 10

It forces fluid into the interstitial space from the capillaries in the arterial end

Question 11

What is capillary osmotic pressure? Where does it tend to draw water?

Answer 11

Is the pressure exerted by the flow of water through the capillary wall (i.e. semipermeable membranes)

Occurs between regions with different concentrations of solute.

Tends to draw water into the capillary

Question 12

What is average capillary osmotic pressure?

Answer 12

28mmHg

Question 13

What are the only solutes which do not pass freely between the plasma and the interstitium?

Answer 13

Proteins in the plasma

Question 14

What is the most abundant plasma protein? How much of the capillary colloid pressure does it make up?

Answer 14

Albumin

21.8mmHg

Question 15

What is interstitial osmotic pressure?

Answer 15

A small amount of protein is present in the interstitium. This protein draws water out of the capillary and into the interstitial space.

Question 16

What is the average interstitial osmotic pressure?

Answer 16

8mmHg

Question 17

What is interstitial hydrostatic pressure?

Answer 17

May be positive or negative:

• When its positive it forces fluid into the capillary
• When its negative it forces fluid into the interstitium

Question 18

What is the average interstitial hydrostatic pressure in loose connective tissue?

Answer 18

3mmHg

Question 19

Define interstitial fluid in terms of comparison to plasma and where it comes from

Answer 19

It is derived from capillariesIt has solutes that are similar to plasma except for the protein content

Question 20

What is the lymphatic system and what is its purpose?

Answer 20

Is it a system of fine lymphatic channels throughout the body passing via lymph nodes to the thoracic duct.They collect fluid from the interstitial spaces and pass it back to the venous system to be filtered and excreted

Question 21

What are the causes of oedema?

Answer 21

Raised capillary hydrostatic pressure (e.g. Na+ retention)

Reduced plasma osmotic pressure (conditions reducing serum albumin)

Endothelial damage (inflammation)

Impaired lymphatic drainage (eg obstruction)

Question 22

What causes capillary hydrostatic pressure? What kind of oedema is it?

Answer 22

Cardiac failure:

• Right ventricle failure (Systemic/generalised oedema)
• Left ventricle failure (pulmonary oedema)
• Congestive heart failure (both Rv and Lv)

Local venous obstruction:-DVT

• External compression
• Superior vena cava obstruction

Constrictive pericarditis

It is usually a protein poor transudate

Question 23

What causes raised capillary pressure?

Answer 23

Excessive loss of albumin (renal failure with albumin lost across glomerulus.

Hepatic disease - inadequate albumin synthesis

Malnutrition - inadequate albumin synthesis

Question 24

Where is albumin made?

Answer 24

The liver

Question 25

What is the main cause of increased tissue hydrostatic pressure?What can also cause it?

Answer 25

Lymphatic obstruction Tumours Neoplasia Inflammation - parasites - fibrosis - congenital abnormality Post surgical Post irradiation

Question 26

What are the types of local oedema?

Answer 26

Inflammatory oedema Allergic oedema Venous obstruction Lymphatic obstruction

Question 27

What is inflammatory oedema?

Answer 27

Caused by increased capillary permeability and increased hydrostatic pressure as a result of local vasodilation

Question 28

What is allergic oedema?

Answer 28

Acute allergic reactions stimulate the release of vasoactive substances that cause increased capillary permeability and arteriolar dilation.

Question 29

What is venous obstruction?

Answer 29

Depends on the extent of the collateral circulation Can be caused by - thrombosis - increased hydrostatic pressure and capillary rupture

Question 30

What are the causes of generalised oedema?

Answer 30

Decreased oncotic pressure Increase vascular permeability to proteins Increased hydrostatic pressure Obstruction to lymph flow Inappropriate renal sodium and water retention

Question 31

What causes decreased oncotic pressure?

Answer 31

Nephrotic syndrome Cirrhosis Malnutrition

Question 32

What causes increased vascular permeability to proteins leading to generalised oedema?

Answer 32

Angioneurotic oedema (usually allergic)

Question 33

What causes increased hydrostatic pressure leading to generalised oedema?

Answer 33

Congestive heart failure Cirrhosis

Question 34

What causes an obstruction to lymph flow which can cause generalised oedema?

Answer 34

Congestive heart failure

Question 35

What can cause inappropriate renal sodium and water retention?

Answer 35

Renal failure Nephrotic syndrome

Question 36

What are the types of generalised oedema?

Answer 36

Cardiac oedema Oedema of hypoproteinaemia Renal oedema Pulmonary oedema

Question 37

Describe the process of congestive heart failure

Answer 37

Right ventricular output is reduced = decreased cardiac output = decreased renal perfusion =triggers renin-aldosterone-angiotensin axis =Na+ and water retention =OEDEMA

Question 38

How is renal oedema usually caused?

Answer 38

Nephrotic syndrome, albumin is lost through the kidneys

Question 39

In pulmonary oedema, what does the oedema often relate to?

Answer 39

Often relates to the increase in pulmonary artery pressure and decrease in lymphatic drainage.