Thrombophilia Flashcards
What is the most common thrombophilia?
Factor V Leiden, an autosomal dominant condition which presents with DVT in childhood or young adulthood.
What is the role of protein C and S?
Protein C, together with its cofactor protein S, inactivates clotting factors V and VIII
What are the coagulation studies?
PTT time
PT time
INR ratio
TT time
What does PTT time include?
PTT time, which includes antithrombin, Protein C and S
What is thrombin time?
Time taken for fibrinogen to convert to fibrin
What are the principles of thrombophilia testing?
Is not recommended after a first event as finding a genetic basis of thrombophilia does not accurately predict the risk of developing PE or DVT
May be considered if venous thromboembolism (VTE) occurs in an unusual site (eg. mesenteric vein or sagittal sinus), although this is not evidence-based
Should not be performed in the acute phase of a VTE or while taking anticoagulation due to false result but there are exception
When can testing for VTE while on anticoagulation be performed?
Factor V Leiden
Prothrombin gene mutation§
What is antiphosphopilipid syndrome
Antiphospholipid syndrome is an acquired autoimmune thrombophilia which is associated with arterial or venous thrombosis and recurrent miscarriages. The common sites of thrombosis are the lower limbs and cerebral arterial circulation.
Which antibodies is anti-phospholipid syndrome associated with?
Anti-cardiolipid antibodies
Lupus anticoagulant
What is the risk with LMWH therapy?
Heparin induced thrombocytopenia HIT typically presents 5-14 days after starting heparin therapy and can occur with LMWH like dalteparin. The absence of other symptoms and the isolated drop in platelets
What is the cause of neutrophilia unrelated to infection?
Severe stress with trauma, surgery, burns and haemorrhage
Use of corticosteroids
Inflammatory conditions like poly arthritis nodosa
MI
Malignancy
What causes neutropenia/
Severe sepsis
Viral ifnection
Felty’s syndrome
Which drugs cause agranulocytosis?
Carbamezapine
Carbimazole
Cloazipine
What causes lymphoctosis?
Acute viral infection, like EBV and CMV
Chronic atypical infection with tuberculosis and toxoplasmosis
Lymphoproliferative disorders
When is neutropenia a normal variant?
In African and Middle Eastern populations but this is only mild between 1 to 1.5 x 10/9
What is the most common cause of unprovoked PE in under 50’s?
Factor V Leiden mutation which causes resistance to inactivation by protein C resulting in accelerated thrombosis
Which conditions have complex inheritance?
Diabetes
Schizophrenia
Heart disease
