Thrombosis and risk factors of thrombosis Flashcards
what is virchows triad
blood flow, composition of blood and vascular endothelial.
what is the primary cause of a arterial thrombosis
atherosclerosis.
what is the pathogenesis of a arterial thrombosis
rupture of a atheromatous plaque
endothelial injury
platelet aggregation and platelet thrombi.
risk factors for arterial thrombi formation
smoking, hypertension, hypercholesterolaemia, diabetes, family history, obesity, physical inactivity, male and sex.
what is the main component of a venous thrombus
fibrin
what is the pathogenesis of venous thrombosis
venous stasis
hypercoagubale states.
symptoms of DVT
swollen, red, hot to touch, painful, unilateral leg
what secondary condition is DVT above the leg likely to present with
Pulmonary embolism
symptoms of PE
chest pain, breathlessness and haemotypysis.
how can hospital acquired VTE be prevented
risk assessment
prophyalaxis- “Low dose” low molecular weight heparin, fondaparinux
Newer anticoagulants- direct inhibitors of Factor Xa: rivaroxaban, direct thrombin inhibitors : dabigatran
how is hospital acquired VTE treated
care pathway- anticoagulant drugs.
If patient is at increased risk of bleeding provide stocking to improve circulation to the legs
what are the risk factors of VTE
- Active cancer or cancer treatment
- Age over 60 years
- Critical care admission
- Dehydration
- Known thrombophilias
- One or more significant medical comorbidities
- Surgery
- Major Trauma
- Personal history of VTE
- Use of hormone replacement therapy
- Use of oestrogen-containing contraceptive therapy
- Varicose veins with phlebitis
- Obesity (BMI over 30 kg/m2 )
- Pregnancy and postnatal period
- Immobility
- First degree relative with VTE
what molecules does unfractionated heparin work on.
anti thrombin (2 sites) and anti Xa
what molecule does LMW heparin bind
anti Xa, and anti thrombin
Factor Xa inhibitor
what molecule does Fondaparinux find to
anti Xa
what molecule do direct thrombin inhibitors act on
thrombin
What does a d-dimer test show
D-dimer breakdown product form fibrin clot.
Indicates that a clot was previously present although it has now been broken down
how can a ultrasound help diagnose a thrombus
Look for loss of flow signal, intravascular defects or non collapsing vessels in the venous system.
Vessels with clot will not compress if you apply pressure with the ultrasound probe.
what is a spiral/multi sliced CT used for
detect PE
what is a VQ scan
radio isotope scan.
Compare radioisotope pattern of a inhaled isotope (ventilation scan), injected isotope (perfusion scan)- this is diagnostic of DVT.
treatment plan for a uncomplicated patient with dot
Suspected DVT- single dose LMWH
confirm diagnosis-LMWH for 5 days.
Start warfarin
Start patient-held anti-coagulant book + inpatient warfarin chart
which anticoagulants are used as both treatment and prevention of DVT
- Rivaroxaban, Apixaban- direct factor Xa inhibitor
- Dabigatran- diresct thrombin inhibitor.-oral.
- Fondaparinux, LMWH- paraenteral
how long is DVT/VTE treated for upon first episode and what medication is typically used
3-6 months.
warfarin
what are recurrent episodes Recurrent episodes of VTE.
Treat with long term anticoagulation.
Recurrent episodes of VTE.
define thrombophillia
familial or acquired disorders of the haemostatic mechanism which are likely to predispose to thrombosis.
common inherited thrombophillias
- Antithrombin deficiciency
- Protein C deficiency
- Protein S deficiency
- Activated Protein C resistance/FV Leiden
- Dysfibrinogenaemia- give rise to bleeding, thrombosis or both.
- Prothrombin 20210A
acquired thrombophillia
antiphospholipid syndrome
clinical features of thrombophillaas
DVT, PE, superficial thrombophlebitis, thrombosis of the cerebral axillary, portal mesenteric veins, arterial thrombosis- unusual to be inherited.
arterial thrombosis- anti phospholipid syndrome
Coumarin induced skin necrosis (Protein C deficiency).
Obstetric complications : fetal wastage (Anti Phospholipid Syndrome)- due to thrombosis in the placental circulation.
where is the point mutation in factor V leiden
mutation in factor V gene were activated protein C cleaves factor V.
does protein C circulate in a activates or inactive form
inactive
what complex activates factor
protein C
thrombin and thrombomodulin
where is the point mutation in Prothrombin 20210A
untranslated region of prothrombin gene
increases pro thrombin levels
what are common clinical manifestations of antiphospholipid syndrome
- Venous thrombosis or
- Arterial thrombosis or
- Recurrent fetal loss (>2)
what is antiphospholipid syndrome seen in connection with
connective tissue disorders.
pathogenesis of Antiphospholipid syndrome
immune system produces abnormal antibodies called antiphospholipid antibodies. These target proteins attached to fat molecules (phospholipids), which makes the blood more likely to clot
if several miscarriages which thrombophilla is tested for
antiphospholipid antibody
