Bleeding Disorders Flashcards
how is haemophilia A inherited?
X-linked
which factor is low in Haemophilia A?
Factor VIII
clinical features of haemophilia A
- joint and muscle bleeding
- prolonged bleeding after dental extractions
what determines the severity of haemophilia A?
the extent of the coagulation factor deficiency
investigations of haemophilia A
- APTT (prolonged)
- BT and PT (normal)
- factor VIII (low)
treatment of haemophilia A
factor VIII concentrates
which factor is deficient in haemophilia B?
factor IX
another name for haemophilia B
christmas disease
how is von Willebrand disease inherited?
autosomal dominant
what is deficient in von Willebrand disease?
von Willebrand factor
what happens in von Willebrand disease?
impaired platelet adherence to the subendothelium
clinical features of von Willebrand disease
- post-traumatic bleeding
- mucosal bleeding
- haemarthosis (rare)
what is haemarthosis?
bleeding into a joint cavity
investigations of von Willebrand disease
- bleeding time (prolonged)
- factor VIII (low)
- VWF antigen and activity (decreased)
- platelet aggregation with ristocetin (decreased)
management of von Willebrand disease
- DDAVP
- cryoprecipitate
- intermediate purity factor VIII
what is DDAVP?
desmopression (stops bleeding in von Willebrand disease and Haemophilia A)
characteristics of factor XII deficiency
- prolonged clotting time
- no clinically significant bleeding
characteristics of factor XI deficiency
- mild bleeding tendency
- prolonged bleeding episodes after surgery, dental procedures or trauma
characteristics of factor XIII deficiency
- severe bleeding tendency
- normal coagulation tests
what happens to coagulation in scenarios of liver disease?
- thrombocytopenia
- folate deficiency
- alcoholic toxic effect on haemolysis
- deficiency of vitamin K clotting factors
- decreased clearance of activated clotting factors
- decreased fibrinogen synthesis and dysfibrinoginaemia
- portal hypertension causing varices
- more sensitive to triggers of DIC
features of renal disease coagulopathy
- qualitative platelet defect
- prolonged bleeding time due to decreased platelet adhesion and aggregation
- anaemia
- deficiency of half molecular weight multimers despite increased VWF
- mild thrombocytopenia due to decreased platelet survival
management of renal-associated coagulopathy
- correction of anaemia
- DDAVP
- dialysis (may improve bleeding time)
what happens to coagulation in renal disesase?
- heparin effect; may develop ATIII deficiency
- vitamin K deficiency due to malnutrition
- loss of low molecular weight clotting factors through glomeruli
- tendency to chronic compensated DIC due to fibrin formation in glomeruli
what happens when a patient gets massive transfusions?
- blood deficient in clotting factors and platelets
- replacement of blood volume in 24hrs causes bleeding tendency
- dilution of clotting factors and dilutional thrombocytopenia
causes of vitamin K deficiency
- obstructive jaundice
- warfarin
- broad spectrum anitbiotics
where do you derive vitamin K?
- green vegetables
- bacterial synthesis in the gut
why can vitamin K levels be low in newborns?
- liver immaturity
- lack of gut bacterial synthesis of vitamin
- low quantities in breast milk
investigations of haemorrhagic disease in newborns
- APTT, PT (prolonged)
- fibrinogen (normal)
treatment of haemorrhagic disease of newborn
- vitamin K prophylaxis
causes of thrombocytopenia
- decreased marrow production
- increased consumption
what can cause decreased marrow production in thrombocytopenia?
- marrow infiltration
- marrow aplasia
- post radio/chemotherapy
what can cause increased consumption in thrombocytopenia?
- transfusion
- sepsis
- massive haemorrhage DIC
- hypersplenism
- microangiopathic haemolytic anaemias (TTP, HUS)
- autoimmune (ITP, HIT)
what happens in idiopathic thrombocytopenic purpura?
autoantibodies directed against GBIIIbIIa receptors
causes of idiopathic thrombocytopenic purpura?
- idiopathic
- viral infections
- drugs/vaccines
- lymphomas
- CLL
clinical features of childhood-type of ITP
- acute presentation
- viral aetiology
- outcome self-limiting
clinical features of adult-type of ITP
- chronic presentation
- usually idiopathic
- lifelong condition
investigations of ITP
- marrow aspirate (normal)
- blood film (no abnormal cells)
treatment of ITP
- immunosuppression
- immunomodulation
management of ITP
- steroids
- steroid-sparing agents (thiopurine)
- splenectomy
- rituximab
- lymphoma type chemotherapy
- avoid platelet transfusions if possible
- IVIG
- anti-D
