Heparin Flashcards
What syndrome is associated with Heparin Induced Thrombocytopaenia?
HIT (Heparin Induced Thrombocytopaenia Syndrome)
HIT is a serious immune-mediated adverse reaction to heparin.
What factors increase the risk of HIT?
- Increased age
- Increased BMI
- Being old and fat
These factors contribute to a higher likelihood of developing HIT.
When does HIT typically occur after therapy initiation?
After 1 week of therapy
This timing is crucial for diagnosis and management.
What type of HIT is characterized by IgG mediation?
Type 2
Type 2 HIT is more severe and has a worse outcome.
What is the primary mechanism causing thrombosis in HIT?
Prothrombotic and resolves slower
HIT leads to a higher incidence of venous thrombosis compared to arterial thrombosis.
What is the diagnostic criterion for HIT?
- 50% reduction in platelets
- Detection of anti-PF4 antibodies
These criteria are essential for confirming a diagnosis of HIT.
What is the first step in managing HIT?
Stop heparin
Immediate cessation of heparin is critical to prevent further complications.
What should be avoided in the management of HIT?
Platelet transfusion
Platelet transfusions can exacerbate the condition.
Name an alternative to heparin in HIT management.
- Indirect thrombin inhibitor (Fondaparinux)
- Direct thrombin inhibitors (e.g. Bivalirudin)
These alternatives are safer options for anticoagulation in patients with HIT.
When should warfarin be avoided in HIT?
Until the platelet count has recovered
Warfarin can increase the risk of thrombosis if started too early.
What does VITT stand for?
Vaccine Induced Immune Thrombotic Thrombocytopaenia
VITT is a rare side effect associated with certain vaccines.
What causes VITT?
Autoantibodies against PF4
These autoantibodies lead to thrombocytopenia and thrombosis.
What are the platelet criteria for diagnosing VITT?
Platelets <150x10^9/L or falling AND either
* D-dimers elevated (>5x ULN)
* Fibrinogen reduced
These laboratory findings are essential for diagnosis.
What is the recommended treatment for VITT?
- Non-heparin anticoagulation (e.g. fondaparinux)
- IVIG 2g/kg
These treatments are similar to those used in HIT management.
What is the reversal agent for Heparin?
Protamine
Protamine is used to reverse the effects of heparin.
What is the dosing of Protamine for UFH?
1 mg IV for each 100 Units of UFH administered in the preceding 4 hrs
This dosing is crucial for effective reversal.
What is the dosing of Protamine for LMWH?
1 mg IV for every 1 mg enoxaparin in last 8 hrs
Proper dosing ensures a safe reversal process.
