Thrombotic disorders Flashcards
DVT
Deep vein thrombosis-
Thrombosis (blood clot), in a deep vein in the leg.
Causes:
Hypercoagulability
Haemodynamic changes
Endothelial injury/ dysfunctions
Thrombosis risk factors
Post-operative injury- especially orthopaedic.
Prolonged hospitalisation
Pregnancy
OCP- oral contraceptive pill
Long-haul flights
Cancer
Obesity
IV drug abuse- veins.
Hypercoagulability causes for DVT
Late pregnancy
Hyperviscosity
Contraceptives
Haemodynamic causes for DVT
Varicose veins
Long immobility
Venous stasis
Endothelial injury/dysfunction causes for DVT
Piercings
Bacteria/ foreign materials
Chronic inflammation
Medical implants
Clinical presentation of DVT
A lot of the times it is asymptomatic.
Unilateral calf swelling
Heat, pain, redness and hardness in leg.
Diagnosis of DVT
Doppler ultrasound:
Shows blood velocity and flow through the colour duplex.
Non-compressible veins indicate a thrombosis.
Wells risk score:
Low score indicates increase predictive value for having a DVT.
D-dimers:
Presence indicates the activation of the clotting cascade.
Low wells score and negative D-dimers test indicate high negative predictive value >99%.
Initial treatment of DVT
Low molecular weight heparin is given- Tinzaparin or enoxaparin.
Dosing is calculated according the weight- with no monitoring required.
IF patient has renal failure/ impairment- IV unfractionated heparin is used to maintain APTT 1.5-2.0
Later treatment of DVT
- Oral warfarin is loaded into patients for 3-5 days.
- Stop LMW heparin when the INR (international normalised ratio) is >2.0, for 2 days.
- If it is the first DVT- warfarin is administered for 6 months post. If it is the second DVT then warfarin given for lifetime.
Pulmonary embolism
Thrombosis in the pulmonary artery- resulting from the mobilisation of a DVT.
Micro-emboli- asymptomatic.
Massive emboli- syncope, death
Symptoms of PE
- Pleuritic pain
- Dyspnoea
- Haemoptysis
Could also be:
Tachycardiac
Tachypnoeic
Hypotensive
Investigations into PE
CTPA- CT pulmonary angiogram- shows clot in BV.
V/Q scan- radio-isotope that shows underperfusion due to V/Q mismatch. BUT it is affected by underlying lung problems.
ECG: Sinus tachycardia AF Right heart strain SI, QIII, TIII
CXR: usually normal but there may be linear atelectasis or small effusions
Effects of PE
Development of pulmonary HT- 4%
5% mortality with treatment
Massive PE treatment
Thrombolysis and IV heparin
Standard treatment of PE
LMW heparin injections- Tinzaparin
Better for underlying cancer
Warfarin administered to trager INR 2.5 for 6 months
IVC filteres
DOAC
