Bleeding disorders Flashcards
What is the coagulation cascade?
A series of reactions catalysed by protein enzymes known as coagulation ‘factors’.
What does the coagulation cascade result in?
Secondary haemostasis and stabilisation of activated platelets due to fibrin strands.
Name the three pathways of the coagulation cascade.
- Intrinsic pathway
- Extrinsic pathway
- Common pathway
What is tranexamic acid?
An antifibrinolytic that prevents or reduces bleeding by impairing fibrin dissolution (the process by which blood clots break down).
How does tranexamic acid work?
It is a potent competitive inhibitor of the activation of plasminogen to plasmin which prevents bleeding by stopping the breakdown of blood clots. It binds to plasminogen, which prevents it from becoming plasmin, an enzyme that breaks down clots.
What is the elimination half-life of tranexamic acid?
About 3 hours.
What percentage of the administered dose of tranexamic acid is excreted by the kidney in the first twelve hours?
90%.
List indications for tranexamic acid.
- Local fibrinolysis
- Menorrhagia
- Hereditary angioedema
- Epistaxis (nosebleeds)
- General fibrinolysis (process that breaks down blood clots)
- Prevention and treatment of significant haemorrhage following trauma
What is emicizumab?
A monoclonal antibody that bridges activated factor IX and factor X.
What is the indication for emicizumab?
Prophylaxis of haemorrhage in haemophilia A.
How are coagulation factors designated?
By a number in Roman numerals with a letter ‘a’ for the active form.
What is the function of protein C?
It prevents blood clotting by inactivating proteins that encourage blood clotting.
What disorder is associated with a deficiency of von Willebrand factor?
Von Willebrand Disease (VWD) - an inherited condition where your blood does not clot properly.
What are common symptoms of a subarachnoid haemorrhage?
- Sudden severe headache
- Stiff neck
- Nausea
- Sensitivity to light
- Blurred or double vision
- Stroke-like symptoms
- Loss of consciousness or convulsions
What is a main complication of a subarachnoid haemorrhage?
Secondary cerebral ischaemia.
What medication is commonly used to reduce the risk of secondary cerebral ischaemia?
Nimodipine.
Name two common pain-relieving medicines used for subarachnoid haemorrhage.
- Morphine
- Codeine and paracetamol combination
What types of medicines can be used to prevent seizures in subarachnoid haemorrhage?
Anticonvulsants, such as phenytoin.
What is coiling in the context of treating a brain aneurysm?
A procedure where a catheter is used to insert platinum coils into the aneurysm to seal it off.
What is clipping in the context of treating a brain aneurysm?
A surgical procedure where a metal clip is fitted around the base of the aneurysm to seal it shut.
