What are the risk factors for acquired antibodies to Factor VIII?
ElderlyMalignancyCTDPostpartum or postsurgical
What are the findings in acquired antibodies to Factor VIII?
Soft-tissue ecchymoses, haematomas, mucosal bleeding (as opposed to haemoarthrosis in congenital haemophilia A)
What are the lab findings if you have acquired antibodies to factor VIII?
How do you treat it?
- prolonged APTT that does not correct on mixing- low factor VIII activity- Bethesda assay will give you titre
TreatmentLow titre - give high doses of factor VIIIHigh titre - prothromboninex or recombinant activated factor VII- plus steroids or cyclophosphamide
Refractory: IVIG, ritux or plasmapheresis
What is the red cell distribution width?
Measure of the variation of red blood cell (RBC) volume that is reported as part of a standard complete blood count. Usually red blood cells are a standard size of about 6-8 μm in diameter. Certain disorders, however, cause a significant variation in cell size. Higher RDW values indicate greater variation in size.
What is the diagnostic criteria for hereditary haemorrhagic telangectasia?
Four criteria, need 3/4 for definite, 2/4 for posible.
1.Spontaneous recurrent epistaxis2. Multiple telangiectasias in typical locations3. Proven visceral AVM (lung, liver, brain, spine)4. First-degree family member with HHT
What are the classical manifestations of hereditary haemorrhagic telangectasia?
Spontaneous, recurrent epistaxis - 90%Skin telangiectases - 75%Hepatic or pulmonary involvement (arteriovenous malformations [AVMs]) - 30%Gastrointestinal (GI) bleeding - 15%CNS lesions inc headache
What does GPIIb-IIIa do?
Expressed on activated plateletshelps platelets adhere to damaged endothelium and to stick to one another
Intrinsic - XII XI
What clinical phenotype and clotting study would you see in FXII (factor 12) deficiency? Prolonged APTT
but no clinical change on bleeding time
Has it normalised? (disclaimer: numbers don't correlate to actual reference ranges; I made it up in my head) NO! The mixed 1 : 1 is in the normal range
but it has not normalised. Need to get within 4-5 seconds of the control (in this example up to 28s) to have 'normalised'; 32 shows there's still some inhibitor at work
Name 2 causes of prolonged PT that correct with mixing studies PT = extrinsic pathway
ie Factor 7!
1-5% - minor trauma gives bleed
T/F? Getting haemophilia from a de novo mutation is rare - you nearly always inherit it False; 1/3rd of pts don't have a family history
ie haemophilia mutation came on spontaneously
Tranexamic acid is particularly useful for stabilising bleeding / clots in which area of the body? GI tract & mouth
good for dental procedures - use as mouthwasy or oral tablets
What is the Bethesda assay as it relates haemophilia? Both qualifies (presence / absence) and quantifies (the higher the titre
the stronger) inhibitors against (recombinant) factor
What's the most common bleeding disorder in the community? vWF
all pts with mild Type 1 vWD and pts with mild haemophilia A should receive what treatment as first-line therapy (prophylaxis/treatment) of low risk ops / slight bleeds? DDAVP
What causes HITs? Antibody-mediated platelet activation
antibodies bind to platelet factor 4 (PF4)
- thrombocytopenia or >50% fall in plts from baseline
- start anticoagulant - danaparoid cover (or direct thrombin inhibitors
eg lepirudin or argatroban or fondaparinux) and start warfarin for 3 months (as HITs is a procoagulant state)
What's the management of an INR 2.5 - 4.5 but no bleeding? Withhold or reduce next dose of warfarin
and restart when INR lower
What's your warfarin plan for someone with low risk of clots getting a low bleeding risk procedure (eg cataracts
dental work)? Keep on with the warfarin
What's the difference between forward grouping & reverse grouping for blood type sorting? Forward - mix pt RCs with anti-A
anti-B and anti-Rh D antibodies. Checks for antigens on pt's RCs. Agglutination = positive.
With regards to preparing blood products for transfusion
why do we do leucodepletion? Why do we do irradiation? Leucodepletion - to reduce febrile non-haemolytic transfusion reaction due to HLA sensitisation or release. "CMV safe".
Name 2 acquired thrombophilic conditions & two hereditary thrombophilias? Acquired: antiphospholipid syndrome
Why is 'lupus anticoagulant' a misnomer? Because it's not an anticoagulant
it's a prothrombotic agent
What is your management for a lady with APLS who is now pregnant
who has had prior clots but no pregnancy complications? Therapeutic anticoagulation
T/F? Rivaroxaban can be dialysed off False; highly protein bound
can't HDx off
T/F? Dabigatran inhibits free thrombin
but not thrombin that is bound to clots False; inhibits both free & clot-bound thrombin
T/F? Dabigatran primarily excreted by liver False
80% renally excreted