Haematology (DVT) Flashcards
What is a deep vein thrombosis?
a clot that develops in a deep vein, usually the leg
What are the signs and symptoms of a deep vein thrombosis?
asymptomatic, pain, oedema, erythema, discolouration, increased temperature in leg, engorgement of the surface veins, tenderness
What are the causes of deep vein thrombosis?
hypercoagulability - from malignancy, surgery, trauma, oral contraceptive pill, clotting abnormalities
venous stasis - immobility, pregnancy, heart failure
trauma - inflammation, previous thrombosis
DD of deep vein thrombosis?
musculoskeletal injury, bakers cyst rupture, cellulitis
Complications of deep vein thrombosis?
pulmonary emobolism, post thrombotic syndrome
What investigations should be done in deep vein thrombosis?
D dimer, B mode venous compression US, modified wells score, PT, APPT, blood films show evidence or myeloproliferative disorders
What does the modified wells score do?
calculates deep vein thrombosis probability
When is a B mode venous compression US used?
in deep vein thrombosis above the knee
What does it rule out it a d dimer is normal?
it excludes deep vein thrombosis
What can cause an abnormal d dimer?
deep vein thrombosis, pregnancy, surgery, infection
What is the treatment of deep vein thrombosis?
anticoagulation therapy with unfractional heparin e.g. telteparin vit k antagonist e.g. warfarin compression stockings treat cause hydration, early mobilisation
What classification is used for bleeding risk in DVT?
HAS-BLED hypertension 1 abnormal liver or renal function 1 or 2 stroke 1 bleeding 1 labile INR 1 elder >65 1 drugs or alcohols 1 or 2
what do LMWH and warfarin inhibit
L - inhibits Xa and IIa
W- inhibits vit K dependent factors
What should be kept between for LMWH and warfarin?
2-3INR
What clinical features are in the two level DVT Wells Score?
active cancer, paralysis, paresis, recent bedridden or major surgery, local tenderness in deep venous system, entire swollen leg, calf swelling, pitting oedema, colateral superficial veins, previously docuented DVT
What is PT?
a measure of how quickly the blood clots, standardized by the INR
What does a d dimer detect?
small protein fragments released following the breakdown of a clot
How does warfarin treat DVT and what is its risk?
inhibits vit k synthesis, but before of over coagulation
SE of LMWH?
bleeding, osteoporosis, heparin induced thrombocytopenia
When is LMWH contraindicated?
in bleeding disorders, low platelets and HTN
When is warfarin contraindicated?
pregnancy and peptic ulcer
examples of other anticoagulants?
apixaban, rivaroxaban (xa inhibitors), dabigatran (direct thrombin inhibitor)
What does TPA do?
generates plasmin and degrades fibrin
What is thrombolytic therapy?
streptokinase tissue plasminogen activator
What causes venous thrombosis?
antithrombin deficiency, protein c deficiency, protein s deficiency, PT20210A, Factor V Leiden, anti phospholipid syndrome, lupus anticoagulant, hyperhomocysteinaemia
What is the initial and after anticoagulant treatment for DVT?
LMW sc od initial and then oral warfarin 3-6 months after
How does heparin treat DVT?
glycoaminoglycan, binds to antithrombin and increases its activity
Does LMWH or warfarin have a longer half life?
warfarin
