Path X: Congestion and hyperemia

Question 1

What is the difference between hyperemia and congestion?

Answer 1

both describe localized incr. vol. of blood. Hyperemia is the result of incr. flow of blood into the tissue due to arteriolar dilation (this leads to more blood flow out into the tissue without necessarily more absorption back into the vasculature later).
congestion: decr. outflow of blood from the tissue due to local or systemic incr. in venous bp.

Question 2

What are examples of the functions physiological active hyperemia?

Answer 2

remember: hyperemia = localized incr. in vol. of blood as a result of arterial dilation.
examples of functions of physiological hyperemia include dissipation of of excess heat, as in exercise or fever, or fight or flight resposnes where we see hyperemia in skeletal muscle, heart, and liver.
also in local tissue hypoxia resulting from active metab (exercise)

Question 3

What are examples of pathological cases of active hyperemia?

Answer 3

acute inflammation, as after a bug bite or sunburn
granulation tissue (new capillaries being laid down)
neoplasia (again, probably some angiogenesis/incr. O2 and energy demands)

Question 4

If I only learn one thing about passive congestion and pathology, what should it be?

Answer 4

passive congestion is almost always pathological and often leads to edema.

Question 5

What are some common causes/sequelae of chronic passive congestion in the lungs?

Answer 5

mechanical outflow obstruction in the left atrium- leads to a backup of fluid in the pulmonary circ. Pulmonary edema is often a result.

Question 6

What might you see in chronic pulmonary congestion?

Answer 6

engorged, tortuous alveolar capillaries, small intralaveolar hemorrhages, hemosiderin-laden macrophages (“heart failure cells:” red cells in alveouls have been eaten by a macrophage), thickened fibrotic alveolar space.

Question 7

What is a cause of chronic passive congestion of the liver?

Answer 7

Right heart failure leads to decreased venous return in the inferior VC and hepatic veins: systemic backup.

Question 8

What are some gross and histologic features of chronic passive congestion of the liver?

Answer 8

Gross-
“nutmeg” liver: dark red brown central vein and nearby hepatocytes are surrounded by light brown periportal hepatocytes.
central hemorrhagic necrosis
and “cardiac cirrhosis:” fibrous thickening of central veins extending into the lobule.

Question 9

What is edema?

Answer 9

abnormal accumulation of fluid in intercellular spaces or body cavities due to disturbances in normal mechanisms of fluid exchange.

Question 10

What is anascara?

Answer 10

Severe generalized edema causing diffuse swelling of all tissues and serous cavities.

Question 11

What is pitting edema?

Answer 11

swelling of sufficient degree that the skin survafe can be visibly indented by pressure and remain so for several seconds after the pressure is released.

Question 12

What is dependent edema?

Answer 12

swelling which occurs in gravity dependent portions of the body, like feet and ankles in ambulatory pts or sacral regions of bedridden pts.
typical in congestive heart patients (among others)

Question 13

What is ascites?

Answer 13

edema localized to the peritoneum

Question 14

What are names for edema in the lungs?

Answer 14

hydrothorax or pleural effusion

Question 15

What is the name for edema in the pericardial sac?

Answer 15

hydropericardium or pericardial effusion

Question 16

What are the five most common factors that cause or contribute to edema?

Answer 16

1. incr. capillary hydrostatic pressure
2. reduced plasma oncotic pressure
3. incr. tissue osmotic pressure (salt in wound)
4. incr. endothelial permeability (inflammation)
5. lymphatic obstruction

Question 17

What happens during congestive heart failure in terms of fluid dynamics?

Answer 17

usually due to atherosclerosis: increased systemic pressure leads to inadequate LV output. Increased left end diastolic pressure leads to poor venous return from the pulmonary vasculature and incr. pulmonary capillary pressure (25-30 instead of 6-10 mmHg). net fluid movement into the alveolar spaces.

Question 18

What are the clinical characteristics of pulmonary edema?

Answer 18

dyspnea, cough, orthopnea (SOB when lying down), white or pink frothy sputum, rales, abnormal chest X-ray, hypoxia.

Question 19

What is the gross morphology of pulmonary edema?

Answer 19

heavy lungs, frothy, bloody fluid on cut surface

Question 20

What is the microscopic morphology of pulmonary edema?

Answer 20

granular pink ACELLULAR material in the alveoli, “heart failure cells”

Question 21

What role does the renin-angiotensin-aldosterone system play in congestive heart failure?

Answer 21

renin-angiotensin-aldosterone system triggers salt and fluid retention. this is supposed to increase cardiac output via starling forces of the heart. However, in the failing heart, increased fluid retention actually just makes every thing worse in terms of pulmonary and peripheral edema.

Question 22

What is cirrhosis?

Answer 22

severe liver disease characterized by diffuse fibrosis/scarring. typically results from alcoholism. leads to deranged hepatic circulation. leads to incr. hydrostatic pressure in the portal system and edema formation in the the peritoneum (ascites).
another example of incr. capillary pressure (congestion)

Question 23

Localized edema: what might cause it?

Answer 23

impaired venous drainage.

think tumor, thrombus, incompetent venous valves.

Question 24

How does reduced plasma oncotic pressure relate to tissue edema? What are some causes?

Answer 24

albumi is responsible for maintaining plasma oncotic pressure. Without it, you would see fluid leakage due to decr. oncotic pressure (either due to decr. production or incr. loss).
examples of causes:
liver failure/cirrhosis
nephrotic syndromes caused by glomerulonephritis (inc. loss)
protein losing enteropathies (inc. loss)
malnutrition/kwashiorkor (decr. production)

Question 25

What are three examples of cases where you see increased endothelial permeability?

Answer 25

1. allergic/immunologic reactions (urticaria, hay fever)
2. inflammation/infection (cellulitis, bug bite)
3. physical/chemical injury (burns, toxic gases)

Question 26

What are four reasons you might see lymphatic obstruction?

Answer 26

1. tumor
2. surgery (ex. mastectomy with lymph node dissection)
3. radiation
4. inflammation (filariasis/elephantiasis)

Question 27

What happens with sodium/water retention and edema? What are common causes?

Answer 27

this increases hydrostatic pressure and decreases vascular oncotic pressure, promoting edema. acute renal failure is a common cause. this will affect all parts of the body, not just dependent ones. may initially affect sites with loose CT: periorbital edema.

Question 28

What is the main clinical significance of peripheral edema?

Answer 28

may indicate major underlying disease state

may also impair local would healing/resistance to infection.

Question 29

What is dangerous about cerebral edema?

Answer 29

lack of room to expand. herniation of the brain into the foramen magnum is RAPIDLY fatal.

Question 30

What is the difference between transudate and exudate? Which is more common in edema?

Answer 30

transudate is protein poor- proteins are kept within the vasculature. exudate is rich in proteins and cells, and is commonly seen in inflammation as vascular permeability increases