Bleeding Disorders Flashcards
What are hte causes of hereditary vascualr abnormalities assoc. with priamry haemostasis issues?
Marfans; Ehler Danlos
What are the acquired causes of vascular abnormalities associated with priamry haemostasis problems?
vasculitis; old age; scurvy; steroids
Where is bleeding primary haemostasis seen?
mucous membranes andl ower limb
What is often the trigger for autoimmune thrombocytopenic purpura?
often viral: HIV; EBV
What are the causes of thrombocytopenia?
reduced production: marrow issue; increased destruction
what are the causes of increased destruction in thrombocyopenia?
IPD; DIC; hypersplenism
What are the causes of platelet functional defects?
drugs: aspiring; NSAIDs; renal failure
Why would von Willebrand factor deficiency lead to increase in APTT?
carries around factor VIII, so will have less VIII for the intrinsic pathway
What is the commonest cause of primary haemostatic failure?
thrombocytopenia
What are the causes of failure of fibrin clot formation?
multiple clotting factor deficiencies- acquried; single factor deficiency: haemophilia
What are the causes of multiple factor deficiencies?
liver failure; vit K deficiency/warfarin; DIC
What are the abnoramlities on blood tests with multiple factor deficiens?
prolonged PT and APTT
Where are coag factors synthesised?
in hepatocytes
What coag factors are carboxylated by Vit K?
II; VII; IX and X
What are the sources of vitamin K?
diet (green leafy veg); intestinal bacterial synthesis
What type of vitamin is Vit K?
fat-soluble
Where is vit K absorbed?
upper intestine
What are the causes of vit K deficiency?
poor dietary intake; malabsorption; obstructive jaundice; warfarin; haemorrhagic disease of the newborn
What is DIC?
excessive and inappropriate activation of the haemostatic system
What happens in DIC?
microvascular thrombus formation; clotting factor consumption
why are newborns vit k deficient?
no dietary vit K (very little in breast milk); no intestinal flora to synthesise; imature liver
What are the causes of DIC?
sepsis; obstetric emergencies; malignancy; hypovolaemic shock; multiple traum
What is the treatment for DIC?
treat underlying cause; platelets; plasma; fibrinogen
What is the inheritance of haemophilias?
x-linked
What is haemophilia A?
factor VIII deficiency
What is haemophilia B?
factor IX deficinecy
Which type of blood vessels is there typically bleeding from in haemophilia?
medium-large blood vessels
Which coag factor has the shortest half0life?
VII
Which test of fibrin clot formation is suually abnormal first in DIC?
PT then APTT
Which blood test is abnormal in haemophilia?
APTT
What are the clinical features of haemophilia?
recurrent haemarthroses; recurrent soft tissue bleeds; proonged bleeding after procedures
