Haematostasis and Thrombosis in Practice: Clinical Cases Haemostasis and Thrombosis Flashcards
Case 1:
- A 20 month old boy attends accident and emergency with his father
- The child has refused to walk for the past 2 days having been walking unsupported for 4 months
- The right knee is slightly swollen and feels warm to touch
- Blood is aspirated from the knee
Which of the following is the most likely diagnosis?
A. Acute lymphoblastic leukaemia
B. Osteomyelitis
C. Von Willebrand Disease
D. Haemophilia A
•Diagnosis is most likely haemophilia
Case 1:
•How do you differentiate between haemophilia A and haemophilia B?
A. Measure the APTT
B. Measure the PT
C. Measure factor VIII and IX levels
D. Do a platelet count
•Measure the factor VIII or IX level
Clinical presentation of A and B is the same and depends on residual levels of factor 8 and 9 in the circulation
Platelet count will most likely be normal so doesn’t tell you anything
Top 2 tests are screening tests of coagulation – measure deficiencies in coagulation factors – both of these are very non-specific measures
Many thing prolong APTT including both haemophilia A and B. Many thing prolong PT time
Answer is C – can tell clearly between them
Comes down to what has highest frequencies in population – haemophilia A (factor 8 deficiency) is 5 times more common than haemophilia B
Case 1:
- Diagnosis is most likely severe haemophilia A
- Patients factor VIII level was 0%
- Patients factor IX level was 73%
- How is haemophilia A inherited?
A. Autosomal Recessive
B. X-linked
C. Y-linked
D. Autosomal Dominant
B
No affected women - X-linked
In a carrier a Women has a normal X to balance the abnormal one so they have normal coagulation factors but a male doesn’t have a normal X to balance it out
what pattern of inheritance is shown here?
This may be the pattern of vWF disease in a family
Equal numbers of men and women affected and unaffected
No skipping of generation (you may see skipping in X-linked conditions)
Autosomal dominant
Case 1:
•The mother tells you that her father also has haemophilia A and wants to know the chances of haemophilia in any further children born to her
Daughters of affected man with haemophilia have to have the affected genes on one of their chromosomes so obligate carriers
She has one normal and one abnormal X and partner has normal X and normal Y
•What is the chance of any further child having haemophilia A?
A. 1 in 2
B. Can’t say because it depends on the mothers status
C. 1 in 4
D. Random chance – not quantifiable
•The chance is 1 in 4 as the mother is an obligate carrier of haemophilia
1 in 4 chance of affected boy
1 in 4 chance of unaffected boy
1 in 4 of carrier girl
1 in 4 of girl who is not a carrier
Case 1:
•Having established the diagnosis of severe haemophilia A with a joint bleed, what optimal treatment should you give?
A. Fresh frozen plasma
B. Plasma derived Factor VIII
C. DDAVP and tranexamic acid
D. Recombinant factor VIII
D. Recombinant factor VIII
DDAVP – natural analogue of vasopressin, not used for all haemophilic bleeding – can raise factor 8 levels but only for people with mild haemophilia
3 options contain some factor 8
A – contains small amount of factor 8 but also every other factor – would need a large volume
B – concentrate of factor 8 and its plasma derived and this is the issue. Plasma is from thousands of donors so infection is more likely
Where there is a recombinant product this should be used over a plasma derived one
When possible avoid the blood donor as be aware of risk you are putting the patient at in regards to transfusion (not just factor 8 or 9, blood cells and other things aswell)
Case 1:
- The father is concerned about the boy receiving factor VIII because of infections in his father –in-law related to factor VIII treatment
- Which of these is not a complication of plasma derived factor VIII treatment?
A. Hepatitis B
B. HIV
C. Hepatitis C
D. Hepatitis A
Hepatitis A is very rare as not a chronic virus
•Hepatitis A is not transmitted by concentrate
Case 1:
•What is the other main complication of treatment of severe haemophilia A with factor VIII concentrates?
One is blood borne infection the other is what?
A. Allergic reactions
B. Increased risk of thrombosis
C. Development of inhibitory antibodies
D. Addiction to factor VIII
C
•Biggest complication is development of inhibitory antibodies (About 20% of cases)
In 25% of boys with haemophilia have never seen factor 8 so when they see it for the first time when they are treated, 25-30% will go on to develop an inhibitory antibody so antibody binds to infused factor 8 and stops it working and this is not a good outcome and then you continue to bleed
Case 1:
- The boy should be treated with recombinant factor VIII
- What is the best treatment regimen for these patients?
A. Treat the patient as soon as possible only after he has a bleed
B. Give factor VIII regularly once weekly
C. Give factor VIII at least 3 times weekly
D. Give factor VIII every day
E. Consider bone marrow transplantation
Want to convert severe patient into mild patients
Give factor 8 regularly enough, what to keep level at 3,4, 5%
Once a week is not frequently enough, 3 times a week will just about cover it but small dose ever day is better
Pegalyted factor 8 or 9 and this extends half life
With these new molecules you can get away with giving it once every week or once every 2 weeks
Case 2:
- A 24 year old female student presents with a 4 day history of easy bruising and small red spots on her ankles
- She has no previous history of abnormal bleeding
- Previous tonsillectomy with no bleeding
- Recently been off colour with flu like symptoms
- Only medication COCP
If you push this it doesn’t blanch - petechiae
•What are these non-blanching spots on her arms?
A. Spider naevi
B. Bruises
C. Petechiae
D. Telangectasia
C
•They are petechiae
A and D both blanch, small blood vessels you force the blood out of and the blood flows back in after
Case 2:
•Which of these symptoms is she unlikely to have
A. Menorrhagia
B. Swollen, hot painful leg
C. Epistaxis
D. Buccal bleeding
- She has petechiae, menorrhagia, epistaxis easy bruising, and blood blisters in her mouth
- She is least likely to have a swollen leg
A yes
C yes
D blood blusters in mouth – yes
Unlikely to have painful swollen legs – don’t get bleeding into muscles of joints in thrombocytopenia
Case 2:
•What is the likely cause of her symptoms?
A. Thrombocytopenia
B. Scurvy
C. Vitamin K deficiency
D. Liver failure
A - Post infection thrombocytopenia
•She has thrombocytopenia as a cause of the symptoms
These could all the associated with it
B - Scurvy – unlikely – deficient in vitamin C – loss vascular integrity and patient bleed
C – usually find this in green veg but this is a fat soluble vitamin so to absorb you need to emulsify it and this is done by bile from the gallbladder and then you can absorb vitamin K
If someone has biliary tree disease – stones, cancer – then you may get vitamin K deficiency
Case 2:
•Which of the following is not a cause of thrombocytopenia
A. Acute myeloid leukaemia
B. Vitamin K deficiency
C. Aplastic anaemia
D. ITP
•AML, Aplastic Anaemia, ITP, may all cause thrombocytopenia. Vit K deficiency does not
Either due to underproduction or increased destruction of platelets
If bone marrow fails like in A
Aplastic anaemia – bone marrow replaced with fat – bone marrow failure
Don’t get it in B so that’s the answer
Case 2:
•This patient has spontaneous bruising and petechiae formation which platelet count is most likely?
A. 30
B. 10
C. 50
D. 100
•Answer is 10
Spontaneous bleedings and stuff happens when count is down around 10
Case 2:
•Which underlying illness is not associated with ITP?
A. HIV infection
B. Vitamin C deficiency
C. SLE
D. Glandular fever
•Vitamin C deficiency is not associated with thrombocytopenia. SLE, EBV and HIV infection are
Propensity to having other autoimmune diseases
Can see in acute viral infection like D but can also see it in A
Cross reactivity to virus and hitting platelets at the same time
Case 4:
•Which of these drugs does not inhibit platelet function?
A. Clopidogrel
B. Dabigatran
C. Abciximab
D. Ticagrelor
A - P2Y12
D – newer on and off inhibitor of same pathway as Clopidogrel
