Haemostasis, Thrombosis And Embolism Flashcards
What converts fibrinogen to fibrin?
Thrombin
Name some thrombin inhibitors
Anti-thrombin III
Alpha 1 anti-trypsin
Alpha 2 macroglobulin
Protein C and S
What are the 2 widely used fibrinolytic therapies?
Streptokinase
tPA (tissue plasminogen activator)
What anti-thrombotic substances are released from the endothelium?
Plasminogen activators
Prostacyclin
Nitric oxide
Thrombomodulin
Define thrombosis
The formation of a solid mass of blood within the circulatory system during life.
What are the components of Virchow’s triad for thrombosis?
Abnormalities of vessel wall
Abnormalities of blood flow
Abnormalities of blood components
Describe the appearance of an arterial thrombus
Pale
Granular
Lines of Zahn
Lower cell content
Describe the appearance of a venous thrombus
Soft
Gelatinous
Deep red
Higher cell content
What are the possible outcomes of thrombosis?
Lysis Propagation Organisation Recanaliastion Embolism
Define propagation of a thrombus
Progressive spread in the direction of blood flow
Describe organisation of a thrombus
Reparative process with an ingrowth of fibroblasts and capillaries
Lumen remains obstructed
What is a hyperaemic zone?
A junction between dead and alive tissue
Define embolism
Blockage of a blood vessel by solid, liquid or gas at a site distant from its origin
Apart from breaking off a thrombus, what can emboli be?
Air Amniotic fluid Nitrogen Medical equipment Tumour cells
Name some risk factors for DVT
Immobility Post-op Post-partum/pregnancy Oral contraceptives Severe burns Cardiac failure Disseminated cancer
What can we do to prevent DVT?
Move regularly if possible
Subcutaneous heparin
Leg compression stockings
What is the treatment for DVT?
IV heparin
Oral warfarin
When could a fat embolism occur?
After a long bone fractures as the bone marrow can get into the circulation
Damage to endothelium releases …
vWF
Describe a paradoxical embolism
If the patient has a septal defect in the heart and they are straining/coughing then an embolism may move through the defect (right to left) and travel to the brain.
Haemophilia A is a deficiency in …
Factor VIII
Haemophilia B is a deficiency in …
Factor IX
What is the inheritance pattern of haemophilia A and B?
X linked recessive
What is a saddle embolism?
The embolism gets impacted across the bifurcation of the pulmonary artery.
When is an air embolism most likely to occur?
Dissolved nitrogen comes out of solution in divers during rapid decompression
Thrombocytopenia is a deficiency of …
Platelets
What is thrombophilia?
Hereditary defect leading to a lifelong tendency to thrombosis
Define stricture
An abnormal narrowing of a body passage
May be due to scar tissue or a tumour
Which cells are platelets fragments of?
Megakaryocytes
