Robbins Ch. 4 - Part 1 - Edema, Effusion, Hyperemia & Congestion

Question 1

What is the difference between edema and effusions? What is the physical cause for both of these phenomena?

Answer 1

Both are accumulations of fluid, cause by increased hydrostatic pressure or decreased colloid osmotic pressure

Edema: fluid in tissues

pressure imbalance in tissues

Effusions: fluid in body cavities

pressure imbalance with serosal surfaces

Question 2

Normally, capillary hydrostatic pressure is greater than colloid pressure. How do tissues keep ‘dry’ with a pressure imbalance?

Answer 2

Normally, there’s a small net movement of fluid into interstitium, drained by lymph vessels and back into blood stream via thoracic duct.

Question 3

What often causes increased hydrostatic pressure?

Answer 3

Disorders that impair venous return

Question 4

What is the main contributor to plasma osmotic pressure? Where is it made?

Answer 4

Albumin - makes up ~half of plasma protein

Made in the liver, synthesis often dependent on liver health

Question 5

What does reduced plasma oncotic pressure lead to?

Answer 5

1. edema
2. reduced intravascular voume
3. renal hypoperfusion
4. secondary hypoaldosteronism

Question 6

Secondary hyperaldosteronism often follows low albumin levels leading to reduced colloid pressure. What problem(s) does this fail to correct?

Answer 6

Fails to correct

• plasma volume deficit
• exacerbates edema
• low plasma protein problem continues

Question 7

What does salt retention do to hydrostatic pressure and vascular colloid osmotic pressure? Why?

Answer 7

Increases hydrostatic pressure - increased intravascular fluid volume expansion

Decreases vascular colloid osmotic pressure - increased dilution of plasma proteins and constituents

Question 8

When does salt retention happen?

Answer 8

Whenever renal function is compromised

• primary kidney disorders
• cardiovascular disorders that decrease renal perfusion

Question 9

What is lymphedema?

Answer 9

Disruption of the lymphatic vessels that impairs the clearnace of interstitial fluid of a particular part of the body, leading to a localized edema

Question 10

What is the cellular process of pulmonary edema?

Answer 10

Fluid collects in alveolar septa around capillaries

Question 11

What often accompanies edema in the lungs? (Hint: not a disease)

Answer 11

Pulmonary effusions

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Question 12

What is another name for peritoneal effusions? What often causes it?

Answer 12

Ascites

Caused by portal vein hypertension

Question 13

What are 2 main reasons for increased hydrostatic pressure?

Answer 13

Impaired venous return

Arteriolar dilation

Question 14

What are 7 reasons for impaired venous return?

Answer 14

CHF

Constrictive pericarditis

Ascites - liver cirrhosis

Venous obstruction/compression

• thrombosis
• external pressure

lower extremity inactivity with prolonged dependency

Question 15

What are 2 causes for arteriolar dilation?

Answer 15

Heat

Neurohumeral dysregulation

Question 16

What are 4 causes for reduced plasma oncotic pressure?

Answer 16

protein-losing glomerulonephropathies (nephrotic syndrome)

liver cirrhosis (ascites)

malnutrition

protein-losing gastroenteropathy

Question 17

What are 4 causes for lymphatic obstruction?

Answer 17

Inflammatory

Neoplastic

Postsurgical

Postradiation

Question 18

What is hyperemia? What can it lead to?

Answer 18

An active process where arteriolar dilation leads to increased blood flow

-at sites of inflammation, or skeletal mm during exercise

Leads to redness - erythema - due to increased blood flow

Question 19

What is congestion?

Answer 19

Passive process from reduced outflow of blood from a tissue

• systemic - cardiaca failure

localized - isolated venous obstruction

Question 20

What does congestion commonly lead to?

Answer 20

Edema due to increased hydrostatic pressures