Bleeding Disorders Flashcards
why are your blood vessels less efficient as you age?
lose collagen more easily
causes of vessel wall problems that affect platelet plug formation?
steroids ageing vasculitis eg HSP (antibodies stick to vessel wall) vitamin C deficiency inherited eg marfans
why can aspirin cause failure of platelet plug formation?
it is an antiplatelet so causes a reduced number
VW disease is more commonly presented in women/men
women
main clinical sign of thrombocytopenia
petechial rash in the lower limbs
thromocytopenia is more commonly hereditary/acquired
acquired
autoimmune is most common
causes of platelet destruction in thrombocytopenia
coagulopathy eg DIC
ITP
hypersplenism
what is ITP?
making antibodies against your own platelets
1st line Tx ITP
prednisolone
platelets last for _ days
7
why do you get hypersplenism in portal HT
blood backs up from the liver and diverts to the spleen
is acquired or hereditary VWF disease more common?
hereditary
inheritance for hereditary VWF disease?
AD
commonest cause of primary haemostatic failure
thrombocytopenia
multiple clotting factor deficiencies are generally acquired/hereditary
acquired
4 clotting factors need vitamin K activated to form, what are they?
2
7
9
10
what step do the vitamin K dependent CFs need and why?
carboxylation
makes them negative
causes of multiple factor deficiencies?
warfarin therapy
liver failure
coagulopathy eg DIC
why does warfarin therapy cause CF deficiency?
reduces vit K levels which is required for some CF formation
what does vitamin K need to be absorbed?
bile salts
where is vit K absorbed?
jejeunum
ileum
why can obstructive jaundice cause Vit K deficiency
gallstones block bile duct = reduced bile salt release = vit k deficiency
causes of reduced vit k?
poor diet malabsorption obstructive jaundice vit k antagonists eg warfarin haemorrhagic disease of newborn
define DIC
excessive activation of the haemostatic system (primary, secondary, fibrinolysis)
pathophysiology of DIC
TF expressed -> clotting -> more damage -> more clotting -> thrombus -> overuse of clotting factors = massive bleeding
screening test for extrinsic pathway (TF)?
PT
play tennis - outside
screening test for intrinsic pathway (8 etc)?
APTT
play table tennis - inside
if PT and PTT are low, where is the problem?
problem with 5, 10 or
multiple clotting factor deficiency
how are fibrin degradation products measured?
D dimers
high D dimers means..
using up clotting fibres to cause fibrinolysis eg in DIC
causes of DIC
sepsis eg meningitis/gram -ve
obstetric emergencies
malignancy
hypovolaemic shock
what obstetric emergencies cause DIC and why?
placental abruption
infarction from PET
triggers TF release, inducing DIC
Tx DIC
get a senior
treat cause eg antibiotics/delivery of placenta
REPLACE- platelets/plasma/fibrinogen transfusions
FFP can be used to replace what?
blood clotting factors
CFs are present in plasma
cryoprecipitate is good for replacing what?
fibrinogen (to make fibrin)
inheritance of haemophilia
X linked so only affects boys
where does bleeding most commonly present in haemophiliacs?
- ankle joint
- knee joint
- elbow joint
haemophilia A/B is more common
A
clinical features of haemophilia
haemarthrosis
recurrent soft tissue bleeds
bleeding after surgery/dental extractions
complications of haemophilia?
iron inflames the synovium from haemarthrosis and causes neovascularisation of new vessels which are prone to bleeding
haemophilia is a disruption of primary haemostasis T or F
F, secondary haemostasis as cant make factor 8/9 to form fibrin
what screening test will be abnormal in haemophilia?
APTT
medical term for a normal bruise
purpura
people with thrombocytopenia get a __ rash
petechial
thrombocytopenia means…
low platelets
what initiates the extrinsic pathway
tissue thromboplastin
what initiates the intrinsic pathway
contact activators
how is warfarin screened and why?
PT as factor 7 is most sensitive
how is heparin screened and why?
aPTT
VWF is carried around on…
factor 8
what age does VWF disease present?
adulthood
ideal INR?
2-3
