Bleeding disorders Flashcards
describe thrombocytopenia
primary haemostatic disroder
describe haemophillia
coagulation disorder
what can cause bleeding defects
vascular defects
low platelet number
lowplatlet function
low coagulation
what is thrombocytopenia
low platlet count
bewo 50x10^9/L
causes of thrombocytopenia
failure of bone marrow production
short life span of RBC
what is ITP
idiopathic thrombocytopenia purpura
sudden onset of immunologica destruction of platlet
acute ITP
sudden onset in children after a trivial ilness
virus Ag bind to platlets and tag it as viral so its destroed
most will recover fine
chronic ITP
gradual onset in adults with no previous infection
autoAb agaisnt the plaatelet membrane
platelts destroyed in spleen very quickly
treatment for chronic ITP
reduce immune function with cortiocosteriods
splenectomy
what is TTP
thrombotic thrombocytopenic purpra
formation of vWF multimers leading to platlet aggegation (thrombosis) and therefore thrombocytopenia
acquired TTP
Ab block the protease breaking down vWF multimers
familiaral TTp
protease to break dwn vWF multimers absent or defective
DIC
disseminated intravascular cogulation
wide spread inapropriate deposition of fibrin leading to the consumption of coag factos and platlets leading to thrombocytopenia and bleedin
causes of DIC
infections
malignancy
hyersensitivity reactions
tissue damage
disorders of platlet function
inherited or acquired
platlet adhesion defects: VDW
von willebrand disease
low factor 8
very common
what are the three forms of VWD
quantitiative partial defieicnecy
functional abnormality
complete deficiency
diagnosis of VWD
prolonged bleeding
normal platlet number
aPPT long
PT normal
bernard-soulier syndrome
platler adhesion defects
isue with GP1b complex
rare
plaltelets cant bind to VWF, they dont stick down
secretion defects
lead to low coagulaion and therefore bleeding
grey platlet syndrome
platelts lack alpha granules and look grey and reduced agregation ability
secretion defect
aggregation defects of platlets
glanzmann thrombasthenia
inability of platlets to bind fibrinogen and form a platlet plug
prolonged bleeding time as they fail to aggregate when needed
platlet coagulation protein interaction defects
scott syndrome
inability of factors to bind to the platler surface resulting in lack of thrombin production
examples of inherited platler function disorders
- adhesion defects
- agonist receptr defects
- signalling defects
- secreton defects
- aggregation defects
- coagulation protein interaction defects