haematology Flashcards
how is it dynamic?
establishes an equilibrium
warfarin dose
1-15mg
warfarin mechanism
inhibits synthesis of vit K dependent clotting factors
- 2, 7, 9, 10 (also protein C and S - decrease rate of fibrin formation)
major disadvantage of warfarin
interactions
danger of warfarin
haemorrhage (1%)
what type of anticoagulant is warfarin?
coumarin
phenindione
vit K antagonist
indanediones
indications for anticoagulants
AF DVT heart valve disease mechanical valves thrombophilia pulmonary embolism
INR
prothrombin time ratio corrected for the Warfarin sensitivity of the thromboplastin reagent
risks of adjusting INR
fatal thromboembolic events
non-fatal thromboembolic events
rebound hyper coagulable state?
NOACs
no monitoring
shorter acting time
dabigatran
direct thrombin inhibitor
apixaban
FXa inhibitor
rivaroxaban
FXa inhibitor
unfractionated heparins
IV, hospital
makes you bleed more
short 1/2 life - controllable
low molecular weight heparins
doesn’t make you bleed more
SC injection
no monitoring
heparin mechanism
make blood not clot as well
inhibit FX and thrombin formation, by activating AT3
antiplatelets
aspirin, clopidogrel, dipyridamole, prasugrel
inhibit platelet aggregation and thrombus formation in arterial circulation
thrombophilia
increased risk of clots developing
inherited thrombophilia
protein C/S deficiency
F5 leiden
AT3 deficiency
acquired thrombophilia
antiphospholipid syndrome OCP surgery cancer pregnancy trauma smoking
platelet abnormalities
thrombocytopenia
qualitative disorders
thrombocythaemia
thrombocytopenia
idiopathic
drug related
secondary to e.g. leukaemia
qualitative disorders
rare
normal number but abnormal function
inherited/acquired e.g. cirrhosis
thrombocythaemia
often pre-malignant
what would platelet abnormalities vs a coagulation problem cause?
platelet abnormalities - immediate haemorrhage
coagulation problem - delayed haemorrhage
haemophilia B
F9 deficiency/Christmas disease NO IDB females carriers (sex linked recessive)
haemophilia A
F8 deficiency NO IDB F carriers (sex linked recessive)
haemophilia A tx
severe - recombinant F8
mild - DDAVP
v mild - TXA (antifibrinolytic)
inhibitors
antibodies which develop after being given factor concs
takes a while to dissipate
VW disease
most common reduced F8 and reduced platelet aggregation autosomal dominant T1 and 2 - dominant mild T3 - recessive severe
VW tx
DDAVP
TXA
severe - VW factor conc
F11 deficiency
less common
common in Ashkenazy Jew pop
haemophilia B tx
doesn’t respond to DDAVP
TXA
recombinant F9
blood tests
bleeding (platelets - FBC, bleeding time)
Clotting (INR), (APPT)
factor assay (only if above abnormal)
rare bleeding disorders
inherited
- defects of other factors
- defects of platelet no/fct
lack of clear correlation between bleeding and level of factor
DDAVP/Desmopressin
nasal
causes F8 stuck to blood vessels to be released into bloodstream
own factor so no inhibitors
txing pts with bleeding disorders
severe/mod - hospital except pros
mild/carriers - refer for ext, surgery, IDB, lingual infiltration
