Bleeding, leukaemia and Denitstry Flashcards
(50 cards)
What is the process of haemostasis?
Injury and tissue damage Vascular response - VASOCONSTRICTION Platelet adhesion and aggregation -VWF/PLATELET/FIBRI Unstable platelet clot Coagulation factor cascade Fibrin - STABILITY TO THE CLOT Stable clot
Describe the intrinsic pathway?
Via factors 12, 11, 9 and 8 to get to factor 10 (activated partial thromboplastin time (APTT))
Describe the extrinsic pathway?
Via factor 7 to get to factor 5 (prothrombin time (PT))
What do the intrinsic and extrinsic pathway lead to?
Prothrombin - thrombin - fibrinogen to fibrin
What are the 2 types of coagulation defect?
GENETIC - haemophilia A, B, C, VWD
ACQUIRED - liver disease, kidney disease, anti platelet, anticoagulation - heparin, warfarin, enoxaparin, dabigatran, rivaroxiban, antiplatelet, liver disease, Vit K deficiency, blood transfusion
What is haemophilia A?
Genetic coagulation defect
Deficient in factor VIII
Can be mild, moderate or severe
Spontaneous bleeding which doesn’t stop.
A loose platelet plug will form but blood oozes around
Dental extractions and surgery are dangerous
How do we treat haemophilia A?
Give factor VIII and treat ASAP
What is haemophilia B?
Genetic coagulation defect
Deficient factor IX
How do we treat haemophilia B?
Give factor IX - can be given daily as factor IX has a long half life
What is haemophilia C?
Genetic coagulation defect
Deficient factor XI
Rapid fibrinolysis
How do we treat haemophilia C?
Give fresh frozen plasma (FFP), factor XI and transexamic acid (stops fibrin breakdown)
What is transexamic acid?
Transexamic acid is an antifibrinolytic drug so stops the break down of fibrin
What is von willebrands disease?
Deficiency of von willebrand factor (VWF) - required for platelet adhesion Type 1(mild), 2, 3 and pseudoVWD
How do we treat VWD?
Factor VII infusion for upper major procedures
DDAVP (desmopressin) and oral transexamic acid for minor procedures
Factor VIII supplements given if any chance of oral trauma (prior to procedure)
Regional blocks / injections in the floor of the mouth can cause haemhorrage and potential airway obstruction
Avoid intramuscular injections
Name 3 types of anticoagulants?
HEPARIN - usually given for immediate effects in acute thromboembolism
ENOXAPARIN - LMWH, Inhibits factor Xa
WARFARIN
Describe warfarin?
Warfarin impairs synthesis of Vit K dependant coagulation factors in the liver (2, 7, 9, 10)
Requires active and regular monitoring via INR value
Usually takes 2 - 4 days to become effective
What are the indications for warfarin?
SHORT TERM USE : prophylaxis to prevent DVT Established DVT PE MI CABG
LONG TERM USE:
Recurrent VTE
Rheumatic heart disease and atrial fibrillation
prosthetic value replacement
What is INR?
Prothrombin time - Dependant on weight, mass, diet
Must be check on day, prior to procedures
Normal = 1
4 = no extractions!
What interferes with warfarin?
Antiplatelet drugs
Antibiotics - affects INR
Miconazole oral gel
Aspirin and NSAIDs - increased bleeding, less platelet adhesion and increased gastric ulcers
Metronidazole - avoided
Erythromycin - unpredictable effects
Daktarin (antifungal) - fatal, affects INR
Name 4 antiplatelet medications?
Aspirin - thrombotic cardio or cerebrovascular disease
Clopidogrel -IHD
Ticlopidine - IHD
Dipyridamole - adjunct to oral anticoagulants with prosthetic heart valves
What is the action of aspirin, clopidogrel, and ticlopodine?
Inhibit platelet aggregation to the blood vessel walls
Lasts for the life of the platelets (7 - 10 days)
What is the action of dipyridamole?
Acts directly on the enzyme in platelets and vessel walls
Reversible
Name 2 non steroidal antiplatelet medications?
NSAIDs - not used clinically for antiplatelet function
Ibuprofen/ diclofenac - reversible effect once the drug is cleared, platelet function restored
What is the normal bleeding time?
2 - 10 minutes
