Acquired Blood dys Flashcards
what 3 things are required for clotting
platelets, vessel wall, clotting factors
what happens to clotting in massive blood loss
RBC’s can’t push platelets to vessel wall so they can’t adhere
describe what PT measures in clotting
prothrombin time - measures factors 2, 5, 7, 10 and fibrinogen which is the extrinsic pathway
time in seconds from exposure to clot formation
what is the only test that measures factor VII
prothrombin time
what are causes of prolonged PT test
deficiency in 2, 5, 7, 10 or fibrinogen (vit K deficiency) - they are on warfarin or have liver disease
what clotting tests give evidence of early liver disease
isolated prolonged PT but normal APTT
which clotting factor has the shortest half life
VII
what is an APTT and what does is measure
activated partial thromboplastin time
measure 2, 5, 8, 9, 10, 12, kallikrein, HMWK and fibrinogen
what can make a APTT test be abnormal without having bleeding problems
deficiencies in kallikrein, HMWK and factor 12
what can cause isolated APTT
UFH, lupus anticoagulant, haemophilia or deficiencies sin APTT clotting factors
what are common things that cause prolonged PT and APTT
deficiency in 2, 5, 10 or fibrinogen, DIC, HMWK, kallikrein deficiency
what does the thrombin time TT measure
function and amount of function of fibrinogen
what causes prolonged TT
dysfibrinogenaemia - none
low fibrinogen
heparin
DIC
what is LAC in coagulation
lupus anticoagulant - IgG/M autoantibody which prolongs the APTT
what type of drug is heparin
anticoagulant
what is the mode of action of heparin and its subtypes
wraps around antithrombin - inhibits factor X
LMWH - inhibits factor Xa
UFH - inhibits Xa and thrombin to switch of coagulation cascade
what is the efficacy ratio of LMWH
higher ratio of anti Xa compared to anti LLa (thrombin)
what are the two benefits of using LMWH
better bioavailability and longer half life
why do you want to avoid using UFH and what is it monitored using
badly monitored but with APTT
can be hard to anticoagulate in infants
what are some complications of heparin treatment
HIT - heparin induced thrombocytopenia
skin / allergic reactions and bleeding
what is given for patients with too much UFH from bleeding
protamine sulphate - derived from fish sperm - may have allergies
what is the mechanism of action of warfarin
inhibits vit K epoxide reducatase - prevents activation of vit K factors 2, 7, 9, 10 and protein C/S
another anticoagulant
what do you monitor treatment of warfarin
INR
how do you treat excessive bleeding on warfarin
stop warfarin
give prothrombin complex conc
vit K
what are DOAC’s used for and give examples
inhibitors of factor Xa (drugs that end in xaban)
drugs that inhibit thrombin IIa - dabigatran
what is fondaparinux
similar to heparin
anti-Xa
give examples of two types of anti-platelet agents
aspirin - inactivates platelet cyclooxyrgenase
P2Y12 antagonists - clopidogrel
what factors are inactive in VIT k deficiency and what is the treatment / cause
def in factor 2, 7, 9, 10 causes - obstructive jaundice, neonates treat with oral vit K
what is another name for bleeding in the liver
cirrhotic coagulopathy
in cirrhotic coagulopathy which factor is not deficient
VIII
what are the clinical features of cirrhotic caoguloppathy
impaired homeostasis
platelet dysfunction
excessive plasmin activity
what is the treatment for bleeding in the liver ie cirrhotic coagulopathy
platelet transfusion
prothrombin complex concentrate
what are the clinical features of bleeding with renal disease and what is the risk with hypertension
bruising, gum bleeding, nose bleeds
risk of intracerebral haemorrhage
what are the causes and features of bleeding with renal disease
anaemia - decreased platelet interaction with lining
penecillin blocking platelets
uraemia - disrupts platelet interactions and impaired binding
how to you prevent bleeding in renal disease
EPO and transfusion
desmopressin (stimulates vWF release)
in a major haemorrhage how much blood is needed for transfusion
equal to patients total blood volume in less than 24 hours
with HR greater than 110 and BP less than 90
what can massive haemorrhages lead to with clotting factors
DIC - become over active
what is DIC in bleeding
disseminated intravascular coagulation - overactive clotting leading to fibrin clots = organ failure
what is the pathogenesis and causes of DIC
excess thrombin generation - reduced natural anticoagulant activity and decreased fibrinolysis
acute cause - sepsis, trauma, acute liver haemolysis, live disease
chronic cause - malignancy
what test results signify DIC
low platelet, elevated d dimer, prolonged PT low fibrinogen
what is the management of `DIC
treatunderlying cause ie chemo, antibiotics
folic acid and VK supplementation
