Haemorrhage & Thrombosis

Question 1

petechiae

Answer 1

pinpoint haemorrhages
minor vascular damage

Question 2

ecchymosis

Answer 2

2-3cm diameter haemorrhage
more extensive vascular damage

Question 3

suffusive haemorrhage

Answer 3

larger areas of haemorrhage

Question 4

haematoma

Answer 4

haemorrhage in a confined sapce

Question 5

haemoperitoneum

Answer 5

blood in peritoneal cavity

Question 6

haemothorax

Answer 6

blood in thoracic cavity

Question 7

haemopericardium

Answer 7

blood in pericardial sac

Question 8

aneurysm

Answer 8

bulge in artery wall due to defect

coronary - right coronary artery aneurysm, more common in males

copper deficiency –> aorta, pulmonary artery and coronary artery aneurysm in turkeys

horses - aortic aneurysms in breeding stallions –> sudden death

seen in developmental collagen disorders - ehlers-danlos and marfan

vitamin C deficiency –> smaller haemorrhages in guinea pigs

Question 9

endothelial injury to vessel wall

Answer 9

endotoxemia
infectious agents - canine adenovirus 1
uremic toxins
trapped immune complexes between cells - FIP

Question 10

steps of hemostasis

Answer 10

artery vasoconstriction - mediated by reflex neurogenic mechanisms

primary hemostasis - platelet plug formation

secondary hemostasis - clotting factors and fibrin production

resolution - thrombus and antithrombotic events

Question 11

primary hemostasis

Answer 11

adhesion - vWF released by endothelium, coats collagen to act as bridge with platelet surface receptor

activation - thrombin and ADP - release of thromboxane

aggregation - binding of fibrinogen and stabilisation of fibrin

Question 12

secondary hemostasis

Answer 12

coagulation factor - plasma proteins - liver
intrinsic pathway - factors 11 and 12
extrinsic - factor 12
common pathway - factor 10
vitamin K dependant factors - used across all pathways - 2,7, 9, and 10

Question 13

primary hemostasis - congenital disroders

Answer 13

vWF deficiency - from reduced amounts to none
chediak-higashi - defective ADP storage
glanzmans thrombasthenia - affects calcium binding of vWF

Question 14

primary hemostasis - acquired disorders

Answer 14

NSAID induced - COX inhibition –> reduced thromboxane
uremia
idiopathic immune-mediated thombocytopenia

Question 15

testing primary hemostasis

Answer 15

buccal mucosal bleeding time

wrap strip around maxilla for engorgment, small cut, measure bleeding time

normal 2-4 mins in dogs, 1-2.5 mins incats

Question 16

secondary hemostasis - congential disorders

Answer 16

hemophilia A - factor 13 deficiency
hemophilia B - factor 9 deficiency

tend to be more severe in larger dogs and horses

Question 17

secondary hemostasis - acquired disorders

Answer 17

liver disease - can’t form plasma proteins
vitamin k deficiency - rodentidice poisoning - affects vitamin K dependent factors

Question 18

testing secondary hemostasis

Answer 18

Prothrombin time - extrinsic and common
- early indicator of vitamin K deficiency

Activated partial thromboplastin time - intrinsic and common
- prolonged with heritable factor deficiencies or DIC

Question 19

virchows triad of thrombosis

Answer 19

intravascular wall damage
stasis of blood flow
hypercoagulability

Question 20

thombus

Answer 20

ante mortem lump of blood in vessel

Question 21

thromboembolism

Answer 21

section of a thrombus that has broken off and lodged elsewhere

Question 22

causes of thrombosis

Answer 22

abnormal blood flow -
local stasis or reduced flow - GDV, torsion, compression of vessel
valvular disease
heart disease
shunts
aneurysms - copper deficiency in pigs, strongylus vulgaris
hypovolemia - shock, diarrhoea, burns
torsions

hypercoagulability -
glomerular disease - loss of antithrombin 3
metabolic disease - aortic trifurcation thrombosis in cushings
inflammation
platelet activation - neoplasia

endothelial injury -
infectious disease
free radicals - vitamin E/selenium deficiency
toxins
trauma

Question 23

endothelial cell functions

Answer 23

diffusion and transport
local vasoconstriction and dilation
coagulation - anti cogulant but become procoagulant when needed, produce vWF
inflammation
wound healing and angiogenesis

Question 24

DIC

Answer 24

caused by -
endothelial injury - acidosis, hyperthermia, hypoxia, neoplasia, sepsis, shock
massive tissue destruction - burns, neoplasia, pancreatitis, parturiency, surgery, trauma
severe inflammation - immune disease, infection, neoplasia

physiology - factor 3 release and spread around –> microthrombi in small vessels –> multi organ failure and widespread haemorrhage

Question 25

Infarction

Answer 25

local area of acute ischemia
coagulative necrosis
can be secondary to thrombosis or thromboembolism

Question 26

venous thrombi

Answer 26

slower flowing blood so will completely occlude

Question 27

post mortem clot

Answer 27

chicken fat clot
product of stasis and clotting post mortem