Bleeding Disorders Flashcards
What are the anticoagulant defences in the normal haemostatic system?
Protein C and S
Anti-thrombin
What can cause failure of platelet plug formation?
Vascular - collagen issues
Platelets - thrombocytopenia, reduced function
Von Wilbrand Factor
What can cause vascular abnormalities that result in failure of primary haemostasisi?
Marfan’s syndrome (ghent criteria)
Vasculitis
HSP
Vit C deficiency - scurvy
What can cause thrombocytopenia?
Marrow problem; pancytopenia
Increased destruction - ITP
What is the commonest cause of thrombocytopenia?
Immune thrombocytopenic purpura
What can cause peripheral platelet destruction?
Coagulopathy; DIC
Autoimmune; ITP
Hypersplenism; liver dx, lymphoma
What blood results will DIC show?
Issue with secondary and primary haemostasis
Prolonged prothrombin and APTT
Thrombocytopenia
Raised d-dimer
What can cause an acquired platelet functional defect?
Drugs; aspirin, NSAIDs
Renal failure
What is vWF deficiency?
AD disease
Common
Variable severity
Failure of platelet sticking
How will a primary haemostatic problem present?
Bleeding from mucosal surfaces; nose bleeds, bleeding gums, menorrhagia, increased bleeding post operations
What can cause failure in secondary haemostasis (fibrin clot formation)?
Multiple clotting factor deficiencies: Acquired DIC Single clotting factor: Haemophilia
What is the difference between haemophilia A and haemophilia B?
A = factor 8 B = factor 9
What can cause multiple factor deficiencies?
Liver failure
Vit K deficiency/ warfarin therapy
DIC
What will multiple factor deficiencies lead to in terms of screening tests?
Prolonged PT time
Prolonged APTT
Where are all clotting factors synthesized?
Hepatocytes
Of all; factor 8 is least affected by liver failure
What clotting factors are carboxylated by vitamin K?
2,7,9,10
1972
What is the source of vitamin K?
Diet
Intestinal synthesis
Absorbed in upper intestine
Requires bile salts for absorption - fat soluable vitamin
What can cause vitamin K deficiency?
Poor dietary intake - green leafy veg Malabsorption Obstructive jaundice Vit K antagonists (warfarin) Haemorrhagic disease of newborn
In what part of the small bowel specifically is vitamin K absorbed?
Jejunum and ileum
How can haemorrhagic disease of the newborn be prevented?
All newborn babies are given a once off injection of vit K at birth
What is DIC?
Excessive and inappropriate activation of the haemostatic system - primary, secondary and fibrinolysis
Microvascular thrombus formation; end organ failure
Clotting factor consumption - bruising, purpura and generalised bleeding
What clotting factor has the shorted half life and therefore the screening test is most sensitive for warfarin therapy and liver failure?
7; prothrombin time
What can cause DIC?
Sepsis; tissue damage from bacterial endo/exo toxin
Obstetric emergencies - placenta rich in phospholipid and tissue factor
Malignancy - adenocarcinoma of bowel and prostate
Hypovolemic shock
How is DIC treated?
Treat underlying cause
Platelet transfusion
FFP
Cryoprecipitate
What is haemophilia?
An x-linked hereditary disorder in which abnormally prolonged bleeding recurs episodically at one or a few sites on each occasion
Which haemophilia is more common between A and B?
A (factor 8 deficiency)
What is the main consequence of haemophilia?
Formation of “target joints”
Iron in blood will irritate the synovium forming neovascularization which are fragile and prone to bursting
What aspect of secondary haemostasis will haemophilia affect?
Loss of amplification
Which screening test will be affected in haemophilia?
ONLY APTT
What are the clinical features of severe haemophilia?
Recurrent hemarthrosis
Recurrent soft tissue bleeds
Prolonged bleeding post dental extraction
How is severe haemophilia treated?
IV injections of clotting factor 8/9 every 2 days
