Haemostasis and Bleeding Flashcards
What are the 3 necessary qualities required for normal haemostasis?
- Speed and efficiency
- localised damage / repair
- careful regulation
What is haemostasis?
The process that causes bleeding to stop (clot formation at the site of injury)
What does epistaxis mean?
Nose bleed
If a patient comes in complaining of nose bleeds that take ages to stop (which her sister and father also suffer with) is known to be iron deficient and has lesions on lips and tongue with dilated bloods vessels in those regions too what is the likely diagnosis?
Hereditary Haemorrhagic Talengectasia
What type of genetic disorder is Hereditary Haemorrhagic Talengectasia? (Note the girls father and sister suffer from it)
Autosomal Dominant
Want is thrombocytopenia?
Low platelet count
What is the most common form of thrombocytopenia?
Immune Thrombocytopenia (autoimmune condition)
How should you treat thrombocytopenia?
Autoimmune: With steroids as giving platelet infusion would only result in the immune system attacking the new platelets
Bone marrow failure: platelet transfusion
If a baby presents with a hot swollen knee which he cannot bend, with no history of trauma and a low Factor VIII test result what is he likely to have?
Haemophilia A
What type if genetic inheritance are Haemophilia A and B?
X-linked recessive (therefore far more men than women suffer with them)
What clotting factor is deficient in Haemophilia B?
Factor IX
If a 74 year old lady presents with dark tarry stools, a BP of 90/60, looking pale, with a pulse if 124bpm and a PMH of atrial fibrillation for which she is taking Warfarin what should you check?
Her INR (coagulation speed) If it is slow it is likely she has a GI bleed due to warfarin
What processes does Primary Haemostasis involve?
1) Vasoconstriction
2) Platelet aggregation (plug)
What processes does Secondary Haemostasis involve?
Clot forming with fibrin mesh
What converts fibrinogen (FI) to fibrin (FIa)?
Thrombin (FIIa = activated factor II)
What is the precursor for thrombin?
Prothrombin (FII)
What is the final common pathway in the coagulation cascade?
Prothrombin (FII) to thrombin (FIIa) which initiates Fibrinogen (I) to convert into Fibrin (FIa)
When would secondary haemostasis not be necessary?
With a very small injury e.g. Paper cut or pin prick (platelet plug enough)
What is fibrinolysis and how does it occur?
It is the breakdown process of a clot (necessary in normal haemostasis )
It occurs by plasmin lysing fibrin into it’s degradation products
What is D-Dimer test and what is it used to help diagnose?
It tests the level of fibrin degradation products
Helps diagnose: Thrombosis e.g. DVT
What is Haemophilia B also known as?
Christmas disease
What clotting factors do not exist?
FIII, FIV and FVI
What part of the coagulation cascade is known as the “extrinsic pathway”?
Tissue Factor and FVIIa activating FXa with the aid of FVa