Haemorrhage & Thrombosis Flashcards
(27 cards)
petechiae
pinpoint haemorrhages
minor vascular damage
ecchymosis
2-3cm diameter haemorrhage
more extensive vascular damage
suffusive haemorrhage
larger areas of haemorrhage
haematoma
haemorrhage in a confined sapce
haemoperitoneum
blood in peritoneal cavity
haemothorax
blood in thoracic cavity
haemopericardium
blood in pericardial sac
aneurysm
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
endothelial injury to vessel wall
endotoxemia
infectious agents - canine adenovirus 1
uremic toxins
trapped immune complexes between cells - FIP
steps of hemostasis
artery vasoconstriction - mediated by reflex neurogenic mechanisms
primary hemostasis - platelet plug formation
secondary hemostasis - clotting factors and fibrin production
resolution - thrombus and antithrombotic events
primary hemostasis
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
secondary hemostasis
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
primary hemostasis - congenital disroders
vWF deficiency - from reduced amounts to none
chediak-higashi - defective ADP storage
glanzmans thrombasthenia - affects calcium binding of vWF
primary hemostasis - acquired disorders
NSAID induced - COX inhibition –> reduced thromboxane
uremia
idiopathic immune-mediated thombocytopenia
testing primary hemostasis
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
secondary hemostasis - congential disorders
hemophilia A - factor 13 deficiency
hemophilia B - factor 9 deficiency
tend to be more severe in larger dogs and horses
secondary hemostasis - acquired disorders
liver disease - can’t form plasma proteins
vitamin k deficiency - rodentidice poisoning - affects vitamin K dependent factors
testing secondary hemostasis
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
virchows triad of thrombosis
intravascular wall damage
stasis of blood flow
hypercoagulability
thombus
ante mortem lump of blood in vessel
thromboembolism
section of a thrombus that has broken off and lodged elsewhere
causes of thrombosis
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
endothelial cell functions
diffusion and transport
local vasoconstriction and dilation
coagulation - anti cogulant but become procoagulant when needed, produce vWF
inflammation
wound healing and angiogenesis
DIC
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
