Secondary haemostasis failure Flashcards
what is secodnary haemostasis failure?
-failure of fibrin clot formation
causes of secondary haemostasis failure?
clotting factor deficiency: either single or multiple
Multiple clotting factor deficiencies (acquired):
o liver failure (as all coagulation factors are synthesised in liver)
o vitamin K deficiency
o warfarin therapy
o disseminated intravascular coagulation
Single clotting factor deficiency :
o generally hereditary e.g. haemophilia A and B
causes of multiple clotting factor deficiency?
-Liver failure
- vitamin K deficiency
-warfarin therapy
-disseminated intravascular coagulation (DIC)
Liver failure (as all coagulation factors are synthesised in liver)
-Vitamin K deficiency (as this carboxylases the clotting factors and so makes them negative which allows them to bind to positively charged calcium on negatively charged platelet)
-Warfarin therapy (warfarin blocks Vit K step in clotting factors)
-Disseminated intravascular coagulation
causes of single clotting factor deficiency?
-usually hereditary e.g. Haemophilia A or B
what does haemophilia B interact with?
Haemophilia B
-interacts with clotting factor IX
what does haemophilia A interact with?
Haemophilia A- Ate- 8
-interacts with clotting factor VIII
APPT and PT of single vs multiple clotting factor deficiency?
Single:
APPT- prolonged
PT- normal
(unless only clotting factor VII involved which would cause prolongation of PT and normal APPT)
Multiple
APPT- prolonged
PT- prolonged
would Vitamin K deficiency cause a single or multiple clotting factor deficiency and why?
Multiple
Vitamin K is involved in carboxylation of clotting factors causing them to be negatively charged, allowing them to bind to the positively charged calcium ions on the platelet membrane
Vitamin K dependant clotting factors?
Vit K dependant clotting factors: II, VI, IX, X (2, 7, 9, 10)
where is Vit K absorbed?
absorbed in upper intestine
what is required for Vit K absorption?
Requires a bile source
(so will not be absorbed in obstructive jaundice)
sources of Vit K?
-Diet (leafy greens)
-Bacterial synthesis
causes of vitamin K deficiency?
-Malabsorption e.g. Chrons
-Diet (lack of leafy greens)
-Obstructive jaundice (require bile for absorption)
-Warfarin (Vit K antagonist)
-Haemorrhagic disease of newborn
What is disseminated intravascular coagulation (DIC)?
A multiple clotting factor deficiency cause of secondary haemastasis
-Excessive and inappropriate activation of the haemostatic system (primary, secondary and fibrinolysis)
-this causes both microvascular thrombus formation (which can lead to end organ failure) and clotting factor consumption
Causes of disseminated intravascular coagulation (DIC)?
-Sepsis
-Obstetric emergencies e.g. placental abruption
-Malignancy (usually slower + more chronic presentation)
-Hypovolaemic shock
-Road Traffic Accidents
Presentation DIC?
the underlying issue
e.g. sepsis, RTA, hypovolaemic shock, obstetrics emergency, malignancy
AND
-Bruising
-Purpura
-Generalised bleeding
Investigaitons of DIC?
-Raised d-dimer D dimer is a byproduct of fibrin degredation
-Decreased fibrinogen (also shown as increased Thrombin time)
-Thrombocytopenia
-Increased PT
-increased APTT
how to tell the difference between DIC and liver failure as a cause of failure of secondary haemastasis if both have increased PT and increased APTT?
Both:
-increased PT
-increased APTT
DIC- will have raised D dimers, decreased fibrinogen (increased thrombin time)
Liver failure- decreased albumin
treatment- DIC?
treat underlying cause + contact senior
-platelet transfusion
-plasma transfusion
-fibrinogen replacement
what is an example of a hereditary single clotting factor deficiency cause of secondary haemostasis failure?
-Haemophilia A
-Haemophilia B
what is Haemophilia?
An X linked hereditary disorder in which abnormally prolonged or spontaneous bleeding occurs
what is the inheritance of haemophilia and who is more likely to get it ?
X linked
-Men only really affected
-Women are carriers
What clotting factors do Haemophilia A and B affect?
Haemophilia A= factor 8 deficiency (5x more common)
8=8 ate= A
Haemophilia B= factor 9 deficiency
does haemophilia affect primary haemostasis?
No- haemophilia only affects secondary haemostasis (and so tends to affect medium to large vessels)
