Bleeding Disorders + Thrombophilia Flashcards
What is the most common cause of primary haemostatic failure?
Thrombocytopenia (usually acquired)
What are the two main mechanisms of thrombocytopenia?
Reduced production –> marrow problem
Increased destruction –> DIC, ITP, hypersplenism
What might cause function defects in platelets?
Drugs e.g. aspirin, NSAIDs
Renal failure
How is vWF deficiency inherited?
Autosomal dominant
Which conditions may cause a multiple factor deficiency?
Liver failure
Vitamin K deficiency / warfarin therapy
DIC
How would PT and APTT be affected by a multiple factor deficiency?
Both would be prolonged
Where are coagulation factors synthesised?
Hepatocytes (reduced in liver failure)
Which factors are carboxylated by vitamin K?
2, 7, 9, 10
What are the causes of vitamin K deficiency?
Poor dietary intake Malabsorption Obstructive jaundice (bile required for absorption) Warfarin (vitamin K antagonist) Haemorrhagic disease of newborn
What is DIC?
Excessive + inappropriate activation of the haemostatic system –> primary, secondary + fibrinolysis
What are the features of DIC?
Microvascular thrombus formation –> end organ failure
Clotting factor consumption –> bruising, purpura + generalised bleeding
What are some causes of DIC?
Sepsis
Obstetric emergencies
Malignancies
Hypovolaemic shock
How is DIC managed?
Treat underlying cause
Platelet + plasma transfusions
Fibrinogen replacement
What is the pattern of inheritance of haemophilia?
X-linked
Which type of haemophilia is most common?
Haemophilia A