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Flashcards in Pathology Deck (37):
1

Definition: edema

Increased interstitial fluid

2

Terms regarding other sites of increased fluid:

1. Hydrothorax
2. Hydropericardium
3. Hydroperitoneum

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Causes of edema

1. Increased hydrostatic pressure

2. Reduced plasma osmotic pressure

3. Lymphatic obstruction

4. Sodium retention

5. Inflammation

4

Increased hydrostatic pressure causes edema through ___

Impaired venous return
Arteriolar dilation

5

What is hyperemia?
What kind of process? (Active or passive)

Arteriolar dilation leads to increased blood flow and engorgement of vessels with oxygenated blood

Active process

6

What is congestion?
What kind of process? (Active or passive)

Reduced outflow of blood causes increased volumes of deoxygenated blood, increased pressure, and stasis

Passive process

7

Classic sites of congestion

Lungs
Liver
Extremeties

8

Definition: hemorrhage

Hemorrhages in skin, mucous membranes, or serosal surfaces have specific names:

A release of blood into extravascular space

Petechiae 1-2 mm
Pupura >3 mm
Ecchymosis >1-2 cm

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Clinical significance of hemorrhage depends on ___ and ___

Volume and rate of blood loss

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Virchow's Triad

1. Endothelial injury
2. Stasis or turbulent blood flow
3. Hypercoagulability

Thrombosis: excessive clotting

11

Thrombi on heart valves are ___

Vegetations

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Thrombi are usually attached __
and tend to propagate towards __

Attached at their site of origin
Propagate towards the heart

13

What happens to thrombi?

Propagate
Embolism
Dissolve
Organize/recanalize
Microbial seeding >> mycotic aneurysm (rare)

14

Definition: emboli

Detached intravascular solid, semisolid, or gaseous mass carried by the blood to a site distant from the point of origin

15

Pulmonary emboli usually originate from __

DVT of leg above the knee

16

Fat emboli usually originate __

From marrow of broken long bones

17

Fat emboli are sometimes accompanied by __

Rash

18

Air emboli causes?

Decompression sickness from gas bubbling in tissues (esp. nitrogen)

Introduction of >100 cc of air into a vessel during a procedure

19

Amniotic fluid emboli causes

Rupture of membranes and concurrent year of uterine vessels

High maternal mortality rate

Pathognomic: items present in amnion (fetal squames, lanugo hairs, etc) are present in embolus

20

Definition: infarct

Coagulation necrosis corresponding to a particular vascular distribution caused by either arterial or venous occlusion

99+% are thromboembolic

21

Types of infarcts:

Red (hemorrhagic)
-venous
-loose tissues
-tissues with dual circulation (liver, lung, bowel)
-congested tissues
-can occur when flow is re-established to a site

White (occlusive)
-arterial
-more "solid" organs

22

Factors that influence the development of an infarct:

1. Nature of vascular supply
2. Rate of development of the occlusion
3. Tissue vulnerability to hypoxia
4. Oxygen content of blood

23

Definition: shock

Circulatory collapse with resultant hypo-perfusion and decreased oxygenation of tissue

24

Causes of shock:

Decreased cardiac output

Widespread peripheral vasodilation

25

4 major types of shock

1. Hypovolemic
2. Cardiogenic
3. Septic
4. Neurogenic

26

Hypovolemic shock
What is it?
Causes?

Circulatory collapse resulting from acute reduction of circulating blood volume

Caused by:
1. Severe hemorrhage or massive loss of fluid from the skin(injury, burns, trauma)
2. Loss of fluid from GI tract (vomiting, diarrhea)

27

Cardiogenic shock
What is it?
Cause?

Circulatory collapse

Resulting from:
Pump failure of the left ventricle

Most often caused by massive myocardial infarction

28

Septic shock
What is it associated with?

Gram - infections

Cause gram - endotoxemia

*also occurs with gram + infections
*TSS - staph aureus

29

What is MODS?

Multiple organ dysfunction syndrome

Can be an outcome of septic shock

Characterized by systemic shut down of vital processes

Requires major intervention

30

Neurogenic shock is most often associated with ___

Severe trauma
and
Reactive peripheral vasodilation

31

Stages of shock:

1. Nonprogressive (early) stage

2. Progressive stage

3. Irreversible stage

32

Non progressive (early) stage of shock
Characteristics

Compensatory mechanisms:
-Increased heart rate
-increased peripheral resistance

Maintain perfusion of vital organs

33

Progressive stage of shock
Characteristics

Tissue hypoperfusion
Circulatory and metabolic imbalance
-metabolic acidosis from lactic academia

*compensatory mechanisms are no longer adequate

34

Irreversible stage of shock
Characteristics

Organ damage and Metabolic disturbances are so severe that survival is not possible

35

Morphologic manifestations of shock

ACUTE TUBULAR NECROSIS OF THE KIDNEY

Others:
Brain necrosis
Liver necrosis
Fatty change in heart or liver
Patchy mucosal hemorrhages in colon
Depletion of lipid in adrenal cortex
Pulmonary edema

36

What is DIC?

Disseminated Intravascular Coagulation

Widespread microvascular thrombi because of endothelial damage

37

Causes of DIC

1. Major trauma (esp crush injuries)
2. Overwhelming infections (often gram -)
3. Obstetric complications
4. Mucin-secreting adenocarcinomas
5. Prostatic surgery
6. Venomous snake bites