Acquired bleeding disorders Flashcards
Common causes of acquired bleeding disorders?
Antithrombotic drugs
Thrombocytopenia
Liver disease
Some uncommon causes of acquired bleeding disorders?
Vitamin K deficiency
Severe renal failure
Coagulation inhibitors : acquired Haemophelia
Scurvy
Cause of thrombocytopenia?
Medications
Infections
Bone marrow disorders
These cause: reduced survival or reduced production
Thrombocytopenia?
a condition that occurs when the platelet count in your blood is too low
An aunt immune disease
Antibody-induced platelet destruction
May be triggered by medications or infection
Anticoagulants drugs?
Warfarin
Heparins
Dabigatran - Direct thrombin inhibitor
Direct FXa inhibitors - rivaroxaban, apixaban, edoxaban
Platelet inhibitors?
Aspirin
Dipyridamole
Clopidogrel/ prasugrel
Ticagrelor
INR?
A standardised prothrombin time
Use of warfarin?
AF
Prosthetic heart valve
Arterial thromboembolism
Venous thromboembolsims
Drawbacks of warfarin?
High indices fo drug interactions
Dietary interaction (dark green veg)
Serious/fatal bleeding in around 1% of users per year
Target enzyemof warfarin?
Vitamin K epoxied reductive
Metabolism of warfarin?
Cytochrome p-450 dependent
What is the bleeding die to warfarin dependent on?
INR
When to INR due to warfarin before dental procedure?
Under INR=4, go ahead
Over INR=4
No more than 24 values
Up to 73 hours for a stable anti-coagulated pt
Advise for warfarin and dental surgery?
Check INR
Suture and packing
Consider tranexamic acid mw
Avoid nsaids
Single use antibiotic prophylaxis unlikely to affect inr
Heparin?
Inhibits thrombin and fXa indirectly
Polysaccharide
When to use LMWH?
Used in the prophylaxis of venous thrombi’s and tx of arterial and venous thrombi’s
What to do if pt is on LMWH?
Need to interrupt at least 24 hours pre procedure
DOACs anti-Xa?
Rivaroxaban
Apixaban
Edoxaban
DOACs antithrombn?
Dabigatran
Movement of DOACs
Metabolism in liver
Excretion kidneys
How to proceed with pt on DOACs with a low bleeding ris procedure?
Treat pt without interruption of anticoagulatin
How to proceed with pt on DOACs witha. High bleeding risk procedure?
Advise to omit dose of DOAC on morning of procedure.
Possibly omit for linger (48-72 hours) of creatinine clearance diminished
How does aspirin work?
Arreversible inhbir of platelet clycooxygenase
Reduces platelet aggregability
Impairs primary haemostasis
How does clopidogrel work?
Blocks platelet ADP receptor (P2Y12 receptor)
How does dipyridamole work?
Blocks platelet phosphodieterase and adenosine deaminase
Why is aspirin widely used?
Secondary prophylaxis of arterial thrombosis
When is aspirin used with dipyridamole?
Stroke
When is aspirin used with clopidogrel?
After coronary intervention
When is aspirin used with rivaroxaban?
In peripheral area disease and coronary artery disease
How long do the effects of aspirin last?
7 days due to irreversibleacetylation of platelet cyclyoxygenase
How long do the effects of clopidogrel last?
Over 5 days due to irreversible blockade of ADP receptor
Do you interrupt pt medication: within 12 months of placement of. A drug - eluding coroary stent taking clopidogrel?
No, do not interrupt
When do ou to interrupt clopidogrel?
Why may a pt have reduced survival of platelets?
Immune thrombocytopenic purpura [ITP]
Drug induced
Why may a pt have reduced platelet production?
After chemo
Bone marrow malignancy/ failure
Megaloblastic anaemia
Drug induced
Alcohol excess
Tx for ITP?
Responsive to immunosuppressive therapy/splenectomy
How does liver failure affect clotting?
All clotting factors and fibrinogen are synthesised by hepatocytes and almost all are reduced in plasma in liver failure
Effect of liver disease on spleen?
Enlarged
Why does the spleen engage in liver disease?
Due to portal hypertension
- leads to thrombocytopenia
Common manifestation of hyperspleenism?
Thrombocytopenia
Caused by liver disease
Coagulopathy?
a condition that affects how your blood clots, resulting in more bleeding during surgery, injury, delivery of a baby and/or menstruation
How does coagulopathy from liver disease result in bleeding?
Reduced clotting factors and thrombocytopenia
How does coagulopathy of liver disease cause thrombosis?
Reduced natural anticoagulants
Why is the management of pre ad post op for coagulopathy of liver disease complex?
Striking balance between preventing bleeding and thrombosis
Often avoid replacement of clotting factors unless haemorrhagic
Rare causes of acquired bleeding - acquired Haemophelia
What are the signs?
New onset bruising/ subcutaneous leading/ internal haemorrhage
Rare causes of acquired bleeding - acquired Haemophelia
Causes of AH?
Isolated prolonged APTT and low levels FVIII
Antibody to FVIII
Management of acquired Haemophelia?
Bypassing agent e.g. vovoseven to control bleeding
Immunosuppressive with high dose steroid +/- cyclophosphamide
Refractory cases may require B cell depletion with rituximab
Rare causes of acquired bleeding - vitamin C deficiency
What is vitamin C needed for with regard to bleeding?
A co-factor in collagen synthesis
Rare causes of acquired bleeding - vitamin C deficiency
Daily dose?
Requir at least 40 mg daily
Rare causes of acquired bleeding - vitamin C deficiency
What demographic need more vit C?
Smokers need more
Rare causes of acquired bleeding - vitamin C deficiency
Deficiency causes what?
Scurvy after a few months
Normocytic anaemia
Bleeding with normal platelet and coagulation
Skin and gum changes
High risk groups for scurvy?
Alcohol excess
Malignancy
Rare causes of acquired bleeding - myoproliferative neoplasm
Arises due to what?
Somatic mutation in haematopoietic stem cell disorder
Types of myeloproliferative neoplasm?
Polycythaemia
Essential thrombocythaemia
Myelofibrosis - mixed picture
myeloproliferative neoplasm
What is essential thrombocythaemia?
Increased platelet count
myeloproliferative neoplasm
What is polycythaemia?
Excess red cells leading to high Hb and Hct
Myeloproliferative neoplasm
What is Myelofibrosis?
Myelofibrosis is an uncommon type of bone marrow cancer that disrupts your body’s normal production of blood cells. Myelofibrosis causes extensive scarring in your bone marrow, leading to severe anemia that can cause weakness and fatigue
What to do if pt has myeloproliferative neoplasm, what should you do?
Discuss with haematology department
Hct?
Percentages RBC in pt blood
What can raised Hb/hct and thrombocytosis paradoxically lead to?
Acquired bleeding phenotype
You would think it would do the opposite
