Thrombotic Disorders Flashcards
What causes venous vs arterial thrombi?
What are the general outcome of venous and arterial [3] thrombi and give examples of each
Arterial - Secondary to Atherosclerosis
- Result in ischemia and infarction - coronary thrombosis, stroke, peripheral embolism
Venous - Secondary to Stasis & Hypercoagulability
- Result in back pressure - DVT, PE, visceral venous thrombosis, intracranial venous thrombosis, superficial venous thrombophlebitis
Risk factors for an arterial thrombosis? [4]
- Age
- Smoking
- HTN, Hypercholesterolaemia
- DM, obesity, sedentary lifestyle
How do we manage an arterial thrombus? [3]
Primary prevention with lifestyle modification and treating the risk factors
Acutely: thrombolysis & Anti-platelets or Anti-coags
Secondary prevention
Risk factors for a DVT or PE? [5]
Age Surgery, Tissue Trauma Immobility, obesity Pregnancy, hormonal Therapy FH and systemic disease
What systemic diseases put you at risk of a DVT? [4]
Cancers
Myeloproliferative Neoplasm
Autoimmune diseases eg IBD, APS
CT disease eg SLE
How can we test for a DVT/PE (venous thrombus)? [4]
Clinical probability simplified score
* DVT likely: 2 points or more
* DVT unlikely: 1 point or less
If a DVT is ‘likely’ (2 points or more)
* leg vein ultrasound should be carried out within 4 hours
* if US result is negative > D-dimer
* if US cannot be done within 4 hours, start DOAC
* if US scan negative but the D-dimer is positive, repeat proximal leg vein ultrasound scan 6 to 8 days later
If a DVT is ‘unlikely’ (1 point or less)
* perform a D-dimer test within 4 hours.
* If not, interim therapeutic anticoagulation should be given until the result is available
* if D-dimer is positive then a proximal leg vein ultrasound scan should be carried out within 4 hours
*
How can we treat a DVT/PE? [2]
Anticoagulants e.g. LMWH, Warfarin & DOACs
Thrombolysis only if massive PE
What are the 2 commonest Inheritable thrombophilias?
What’s the major cause of microvascular Thrombus?
Components of microvascular thrombi [2]
Factor V Leiden and Prothrombin G20210A
Disseminated Intravascular Coagulation (DIC)
Microvascular thrombus made up of platelets and/or fibrin
What triggers DIC? [4]
Septicaemia
Malignancy
Eclampsia, placental abruption, amniotic fluid embolism
Microangiopathic haemolytic anaemia
What are the consequences of DIC? [2]
Diffuse Tissue ischaemia –> Gangrene & Organ Failure
Consumes platelets/clotting factors –> Bleeding
What investigation if pre-test probability score is high?
Skip lab test
Imaging modality - VQ or CTPA
Appearance of VTE on doppler ultrasound scan? [2]
In DVT, thrombosed vein enlarged, non-compressble
Factor V Leiden
Describe the mutation associated with this bleeding disorder
Describe inheritance pattern and penetrance of this genetic condition
Mutation of human Factor V leading to hyper coagulable state
- So inhibitor of Factor V can no longer inhibit it leading to unregulated coagulation
AD - incomplete penetrance
DIC symptoms and signs [4]
Investigations: FBC [3], Clotting [3], D-dimer
- Bleeding from at least unrelated sites
- confusion, fever
- ARDS
- petechiae, skin necrosis, acral cyanosis
- FBC and film: low platelets, schistocytes (microangiopathic haemolytic anaemia)
- Clotting profile: prolonged PT, prolonged APTT, prolonged bleeding time
- D-dimer: raised
DIC management
Treat underlying cause!!
When is platelet transfusion indicated?
What do you do for active bleeding and prolonged PT and APTT? [2]
What do you do if critically ill but not bleeding [1]
- High risk of bleeding and platelets <50x109/L: platelet transfusion
- Active bleeding and prolonged PT and APTT: FFP (if persists can give fibrinogen concentrate or cryoprecipitate)
- Critically ill BUT NOT BLEEDING: LMWH
