Bleeding disorders Flashcards
Three main possible reasons for failure of the platelet plug (primary haemostasis)
Vascular disease
Reduced platelet number/function
Von Willbrand factor deficiency
What causes Henoch-Schonlein purpura?
IgA-mediated vasculitis following an infection
Features of HSP (4)
Palpable purpuric rash over buttocks and extensor surfaces
Polyarthritis
Abdominal pain
Possibly nephropathy
Causes of acquired thrombocytopenia (4)
Marrow failure
Disseminated intravascular coagulation
Immune thrombocytopenic purpura
Hypersplenism
Common causes of acquired reduced platelet function (2)
Antiplatelet drugs Renal failure (uremic platelet failure)
Most common inherited bleeding disorder, and its inheritance pattern
von Willebrand disease
Usually autosomal dominant
Why is coagulation affected by liver failure?
All clotting factors are synthesised by the liver
Causes of multiple clotting factor deficiencies (3)
Liver failure
Vitamin K deficiency/warfarin
DIC
Excessive and inappropriate activation of the haemostatic system
Disseminated intravascular coagulation
What does an elevated D-dimer suggest and which conditions have this as a feature?
Suggests there is active clotting happening in the body but does not indicate location or cause; DIC and VTE (such as DVT/PE) have this as a feature
Causes of DIC (4)
Sepsis
Obstetric emergencies
Malignancy
Hypovolaemic shock
Treatment of DIC (2)
Treat the underlying cause
Replace platelets/plasma
Cause of
a) haemophilia a
b) haemophilia b
a) factor VIII deficiency
b) factor IX deficiency
Clinical features of severe haemophilia (3)
recurrent haemarthroses
recurrent soft tissue bleeds
prolonged bleeding after dental extractions, surgery and invasive procedures
What measure of blood clotting is deranged in the haemophilias and why?
APTT.
Because APTT is affected by the intrinsic pathway, which is mediated by factors VIII (deficiency in haemophilia A) and IX (deficient in haemophilia B)
