DVT and PE Flashcards
DVT epidemiology
- 1/1000 year
- 1-5% fatality
- M>F
- 60% in calf - distal DVT
DVT aetiology
- Stagnation of blood flow
- Hypercoagulability
- Vascular injury
Endothelial injury - thrombus
DVT patient risk factors
- Age
- Obesity
- Varicose veins
- Long haul flights >4hrs
- Pregnancy
DVT conditions risk factors
- Trauma
- Malignancy
- CCF
- Infection
- HRT
DVT symptoms
- Asymptomatic
- Unilateral leg swelling
- Tenderness, warmth, redness
- Superficial veins
- Calf pain
- oedema
DVT diagnosis
- Wells clinical score - assessment of how likely it is to be DVT/other diagnosis
- High >3
- Low <0
D dimer assay
venography - invasive
duplex ultrasonography
what factors are taken into account when calculating a wells clinical score
○ Cancer
○ Immobilisation
○ Bedridden >3 days
○ Entire leg swelling
○ Tenderness along deep venous system
○ Calf swelling of >3cm
○ Pitting oedema
○ Previous DVT
Collateral superficial veins
what is a d dimer assay
d dimers are a products of fibrin breakdown from thrombus formation - non specific to DVT - can be raised in pregnancy, sepsis, cancer
differential diagnosis for DVT
- Trauma
- Cellulitis
- Ruptured bakers cyst
- Oedema
management of DVT
- Identify and treat underlying cause
- Prevent PE
- Immediate management with injectable anticoagulant
- Heparin 1st line
- Compression stockings
why are compression stockings used for DVT
- Assist calf muscle pump
- Reduce venous hypertension, valvular reflux, oedema
- Aids microcirculation
Prevents venous ischaemia
epidemiology of PE
- 1/1000 year
- High mortality (2nd biggest killer after ISD)
aetiology of PE
- Blood clots or thrombi formed in the venous system break free and embolise to lung
- Obstruct pulmonary artery system
- Increases pulmonary artery pressure
- Right heart failure
- Infarction of lung tissue
PE symptoms
- Acute onset chest pain
- Malaise
- Dyspnoea
- Haemoptysis
- Tachypnoea (>16 min)
- Abdominal pain
- Anxiety
- Arrythmias
- Syncope - fainting
PE diagnosis
- Chest xray - Westermark sign - collapse of pulmonary vessels
- V/Q scan
- d-dimer
- White cell count, arterial oxygen sats
- Computed tomographic pulmonary angiography (CTPA)
- pulmonary angiography
what is a V/Q scan
- Inhalation of xenon-133 gas
- Perfusion and ventilation
what is a - Computed tomographic pulmonary angiography (CTPA)
allows you to see small clots
what are the differential diagnosis for PE
- ACS
- Pneumonia
- CCF
- AF
- Acute anaemia
COPD/asthma
management of PE
- Supportive therapy
- Immediate anticoagulation - heparin
- thrombolytics - alteplase
when is thrombolytics C/I for PE
recent surgery
active bleeding
renal/liver disease
stroke history
how does unfractionated heparin work
○ Intrinsic pathway
§ Binds to Antithrombin III→ Inhibits factor Xa → thrombin
unfractionated heparin side effects
§ Haemorrhage
§ Thrombocytopenia (monitor platelets > 5days)
§ Hyperkalaemia - aldosterone affect
§ Osteoporosis, alopecia
monitoring for unfractionated heparin
Activated partial thromboplastin time (APTT), target of 80-100secs
how does low molecular weight heparin work
inhibits factor Xa - no monitoring required
how does warfarin work
inhibits metabolism of vitamin K and affects the activation of factors II, VII, IX and , can take 72 hours to work
monitoring requirements for warfarin
® Baseline: Clotting screen, Hb, Plts, LFT’s
® INR and signs of bleeding (1.5 ideal INR)
how do Rivaroxaban, apixaban, edoxaban
work
Direct inhibitors of activated factor X in
Treatment of VTE + Prophylaxis of VTE post- surgery
how does dabigatran work
Direct thrombin inhibitor in Treatment of VTE + Prophylaxis of VTE post-surgery
which surgeries have higher DVT/PE risk
○ Orthopaedic
○ Cardiac
○ Vascular
○ Urological
○ Thoracic
○ Gynaecological
○ Neuro
what are the NICE guidelines for pharmacological prophylaxis of DVT/PE
LMWH (e.g. Dalteparin s/c 5000IU od , enoxaparin s/c 40mg od) /Fondaparinux
