circulatory disorders part 2

Question 1

hemorrhage

Answer 1

defined as the escape of blood from the blood vessels (extravasion)

can be internal or external (within tissues or body cavities)

Question 2

causes of hemorrhage

Answer 2

trauma

sepsis, viremia, bacteremia, toxic conditions

coagulation abnormalities (defect or deficiencies)

abdominal neoplasia (hemoperitoneum can be caused)

Question 3

hemorrhage vs hyperemia

Answer 3

hemorrhage: blood outside vessel wall

hyperemia/congestion/ blood within vessels

Question 4

hemorrhage clinical significance

Answer 4

determined by location and severity

profuse blood loss is most common cause of hypovolemic shock

hemorrhage in the brain or heart can be fatal

Question 5

Answer 5

hemopericardium

leads to fatal cardiac tamponade

Question 6

hemorrhage by rhexis

Answer 6

due to substantial rent or tear in vascular wall (or heart)

Question 7

dissecting aneurysm

Answer 7

in additon to horses they are also reported in young male racing greyhounds

can lead to arterial rupture and fatal hemorrhage

Question 8

hemorrhage by diapedesis

Answer 8

due to small defect in vessel wall or rbc passing through a vessel wall in cases of inflammation or congestion (like in the lungs of animals with left sided CHF)

Question 9

hemorrhage diathesis

Answer 9

increased tendency to hemorrhage from usually insignificant injuries (seen in a wide variety of clotting disorders)

Question 10

hemothorax

hemoperitoneum

hemarthrosis

hemoptysis

Answer 10

hemothorax- blood in thoracic cavity

hemoperitoneum- blood in peritoneal cavity

hemarthrosis- blood within a joint space

hemoptysis: coughing up of blood or blood stained sputum form the lungs or airways

Question 11

epistaxis

Answer 11

bleeding from nose

Question 12

classification according to size

Answer 12

petechia

up to 1-2 mm in size. especially found on skin, mucosal and serosal surfaces

Question 13

classification according to size

Answer 13

ecchymosis

larger than petechia 1-2cm

bruise or small hematoma

Question 14

Answer 14

agonal hemorrhages

petechiae and ecchymoses associated with terminal hypoxia

Question 15

Answer 15

suffusive hemorrhage

larger than ecchymosis and contiguous

serosal surface of stomach, dog

Question 16

Answer 16

paint brush hemorrhage

looks like if red paint was hastily applied with a paint brush. most common on mucosal and serosal surfaces

Question 17

hemorrhage resolution small vs large amounts

Answer 17

small amounts can be absorbed

larger amounts require phagocytosis and degradation by macrophages

organizing hematoma: central mass of fibrin and red blood cells surrounded by supportive vascular connective tissue –> macrophages will eventually phagocytize this lesion

Question 18

cause of coloration

Answer 18

Question 19

hemostasis

Answer 19

arrest bleeding by physiological or surgical means

Question 20

the pathological form of hemostasis is ________ in which a ________ forms within a vessel which is not injured or only mildly injured

Answer 20

the pathological form of hemostasis is _thrombosis_______ in which a __a clot (thrombus)______ forms within a vessel which is not injured or only mildly injured

Question 21

general components necessary for normal hemostasis or thrombosis to occur

Answer 21

1. vascular wall
2. platelets
3. coagulation cascade

blood clotting is physiological necessity whereas thrombosis is a pathological manifestation of blood coagulation

Question 22

steps of normal hemostasis

Answer 22

initial injury

brief period of arteriolar vasoconstriction occurs

augmented by local secretion of factors such as endothelin

endothelial exposes highly thrombogenic subendothelial ECM allowing platelets to heal (glycoprotein 1b receptors to von willebrand factor and be activated)

platelet aggregation to form hemostatic plug; process is primary hemostasis

tissue factor III thromboplastin. acts to activate coagulation pathway with factor VII

thrombin cleaves fibrinogen to make insoluble fibrin creating a fibrin meshwork deposition

thrombin induces further platelet recruitment and granule release

secondary hemostasis lasts longer than initial platelet plug

Question 23

“Endothelial cells are key players in the regulation of _________, as the balance between the anti- and prothrombotic activities of endothelium determines whether __________, _________, or __________ occurs”

Answer 23

“Endothelialcellsare key players in the regulation of homeostasis, as the balance between the anti- and prothrombotic activities of endothelium determines whether thrombus formation, propagation, or dissolution occurs”

Question 24

coagulation cascade

Answer 24

amplifying series of enzymatic conversions (culminating in thrombin formation)

at conclusion of proteolytic cascade thrombin converts soluble plasma protein fibrinogen into fibrin

coagulation factors are plasma proteins produced mainly by the liver

Question 25

thrombosis

Answer 25

formation or presence of a solid mass within the CV system

Question 26

pathogenesis of thrombosis

Answer 26

endothelial injury

alterations in blood flow

hypercoagulability (increase in coagulation factors and decrease in coagulation inhibitors)

Question 27

Answer 27

Question 28

Answer 28

pulmonary thromosis (dog)

seen in dogs with severe renal glomerular disease –> protein losing nephropathy –> significant loss of antithrombin III, a major inhibitor of thrombin

Question 29

Answer 29

verminous thrombosis

thrombus formation in the cranial mesenteric artery of horses with strongylus vulgaris infection

Question 30

Answer 30

strongylosis

colon, horse

Question 31

Answer 31

saddle thrombosis

cat with HCM

thrombis located in trifucation of abdominal aorta

Question 32

outcome of thrombi

Answer 32

lysis, propagation, embolization, organization/recanilization

Question 33

embolism vs embolus

Answer 33

embolism: when a piece of the thrombus breaks off from original mass and sails downstream lodging at a distant site. process is called emoblism
embolus: the mass that breaks off is called embolus

Question 34

Answer 34

fat embolism

could be complication of long bone fractures

picture: bone marrow emboli in pulmonary artery. secondary to CPR resusciation efforts

Question 35

Answer 35

infectious causes of thrombis/thromboembolism

bacterial valvular endocarditis in cattle and give rise to septic emboli that lodge in pulmonary arteries

Question 36

Answer 36

thrombotic meningoencephalitis

etiology: histophilus somni infection- results in vasculitis and thrombosis

Question 37

disseminated intravascular coagulation (DIC)

Answer 37

signs of tissue hypoxia, infarction or/and hemorrhage are seen

Question 38

Answer 38

fibrin thrombi within glomerular capillaries (disseminated intravascular coagulation)

PTAH stain

Question 39

infarction

Answer 39

localized area of ischemic necrosis in a tissue or organ caused by occlusion of either the arterial supply or the venous drainage

Question 40

Answer 40

venous infarct

intensely hemorrhagic as blood backs up into the affected tissue behind the obstruction

Question 41

Answer 41

arterial infarcts are often initially hemorrhagic but become pale as the area of coagulation necrosis becomes evident

Question 42

Answer 42

microscopically an infarct is a focal area of coagulation necrosis

Question 43

shock

Answer 43

cardiovascular collapse

shock is the final commonpathway for a number of potentially lethal clinical events (severe hemorrhage, trauma/burns, myocardial infarction, massive pulmonary embolism and microbial species)

shock gives rise to systemic hypoperfusion (caused by reduced cardiac output or reduced effective circulating blood volume)

can lead to multiorgan system failure

Question 44

types of shock

Answer 44

cardiogenic (heart doesn’t maintain normal cardiac output)

hypovolemic (fluid loss dur to hemorrhage/vomiting/diarrhea)

blood maldistribution (anaphylatic Type 1 hypersensitivity, neurogenic, septic)

Question 45

pathogenesis of septic shock

Answer 45

most cases of septic shock are caused by endotoxin producing gram negative bacilli (endotoxic shock)