haematology Flashcards
What is haemophilia?
Haem A- factor VIII deficiency
Haem B- factor XI deficiency
X linked recessive
Affects secondary haemostasis
Associated w nose bleeds, bleeding gums, prolonged bleeding from wounds, joint bleeding
What are signs and symptoms?
Nosebleeds
Easy bruising
Spontaneous gingival bleeding
GI bleeding
Difficult clotting after cuts
Bleeding into joints
Cranial bleeds
What is the tx for haemophilia?
Antifibrinolytic agents (transexamic acid)
DDAVP (desmopressin)
Direct factor replacement
Emicizumab
Novosen/FEIBA
Mild- no tx unless surgery/trauma, or on demand tx for epistaxis, menorrhagia etc
Moderate- prophylaxis, tx at S/T
Severe- regular prophylaxis, tx at S/T
What is tranexamic acid?
Antifibrinolytic agent
Blocks binding of plasminogen and plasmin to fibrin
Mouthwash/tablets
Use QDS, 5-10 mins post x
Rinse w 5ml of 5% solution, hold for 2 mins then spit
5 days
What is desmopressin?
Synthetic replacement of vasopressin (reduces urine)
Stimulates release of FVIII and VWF from stores in pts w mild Haem A and VWD
What are signs and symptoms of VWD?
VWF promotes platelet aggregation and is a carrier for factor VIII
What is the tx for VWD?
Desmopressin
Direct factor replacement
How would you manage an exam in a haem pt?
No BPE
Manage soft tissues carefully
Place IO films carefully
Thorough med history
How do you manage a bleed?
1. Pts know how to manage
2. Local measures, apply pressure
3. Contact haem centre and ask advice
What are drugs that can affect bleeding?
Cytotoxic drugs (eg hydrochloroquine, infliximab)
NSAID (eg ibuprofen, naproxen)
SSRI anti depressants (eg citalopram)
Immunosuppressants (eg methotrexate)
Drugs affecting nervous system (eg gabapentin, carbamazepine)
What is low molecular weight heparin?
Delivered subcutaneous- anticoagulant
VTE, post valve replacement, cancer, spinal injury
Short onset of action, short half life
Renally excreted
Last tx 24hrs prior procedure, post tx 4 hrs
No interruption in prophylactic tx
Eg. Enoxaparin (Clexane)
What are antiplatelet drugs?
Impairs primary haemostasis
Reduce platelet aggregation 
Increases bleeding time, dual increases even more
Prevents arterial thrombosis
Often used in combination after cardiac stents
Eg. Clopidogrel, aspirin, ticagrelor
Don’t need to be stopping before primary care- may lead to prolonged bleeding however
What is warfarin anticoagulant?
Vit K antagonist
For DVT, AF, stroke, valve replacement
Multiple interactions
Inhibits factor II, VII, IX, X and protein C and S
Metabolised by liver- cytochrome P450
Slow on and off action
What is International Normalised
Ratio?
Time taken for clot to form in blood sample relative to standard of 1
Stable INR hx- 72 hrs prior procedure
Unstable within 24hrs of procedure
>4- refer to med practitioner for advice, don’t stop med yourself
Warfarin interacts w many antibiotics and anti fungal which increase bleeding risk (erythromycin, fluconazole, metronidazole)
What are DOACs?
Dabigatran- direct thrombin inhibitor- prevents fibrinogen turning into fibrin
Rivaroxaban and apixaban- inhibit factor Xa
Fast onset, fixed doses, less interactions, lower risk of major bleeds, increased risk of GI bleeding, no antidote
When do you do tx for a pt on DOACs?
If pt started meds or had PE/DVT within 3 months- discuss w haematologist before omitting
Tx 12 hrs post BD dose or 18-24hrs post OD dose
Restart- 6hrs post w no bleeding present