DVT and PE

Question 1

DVT epidemiology

Answer 1

• 1/1000 year
• 1-5% fatality
• M>F
• 60% in calf - distal DVT

Question 2

DVT aetiology

Answer 2

• Stagnation of blood flow
  
  • Hypercoagulability
  • Vascular injury
    Endothelial injury - thrombus

Question 3

DVT patient risk factors

Answer 3

• Age
  
  • Obesity
  • Varicose veins
  • Long haul flights >4hrs
  • Pregnancy

Question 4

DVT conditions risk factors

Answer 4

• Trauma
  
  • Malignancy
  • CCF
  • Infection
  • HRT

Question 5

DVT symptoms

Answer 5

• Asymptomatic
• Unilateral leg swelling
• Tenderness, warmth, redness
• Superficial veins
• Calf pain
• oedema

Question 6

DVT diagnosis

Answer 6

• 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

Question 7

what factors are taken into account when calculating a wells clinical score

Answer 7

○ Cancer
○ Immobilisation
○ Bedridden >3 days
○ Entire leg swelling
○ Tenderness along deep venous system
○ Calf swelling of >3cm
○ Pitting oedema
○ Previous DVT
Collateral superficial veins

Question 8

what is a d dimer assay

Answer 8

d dimers are a products of fibrin breakdown from thrombus formation - non specific to DVT - can be raised in pregnancy, sepsis, cancer

Question 9

differential diagnosis for DVT

Answer 9

• Trauma
  
  • Cellulitis
  • Ruptured bakers cyst
  • Oedema

Question 10

management of DVT

Answer 10

• Identify and treat underlying cause
• Prevent PE
• Immediate management with injectable anticoagulant
  
  • Heparin 1st line
• Compression stockings

Question 11

why are compression stockings used for DVT

Answer 11

• Assist calf muscle pump
  
  • Reduce venous hypertension, valvular reflux, oedema
  • Aids microcirculation
    Prevents venous ischaemia

Question 12

epidemiology of PE

Answer 12

• 1/1000 year
• High mortality (2nd biggest killer after ISD)

Question 13

aetiology of PE

Answer 13

• 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

Question 14

PE symptoms

Answer 14

• Acute onset chest pain
• Malaise
• Dyspnoea
• Haemoptysis
• Tachypnoea (>16 min)
• Abdominal pain
• Anxiety
• Arrythmias
• Syncope - fainting

Question 15

PE diagnosis

Answer 15

• 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

Question 16

what is a V/Q scan

Answer 16

• Inhalation of xenon-133 gas
  
  • Perfusion and ventilation

Question 17

what is a - Computed tomographic pulmonary angiography (CTPA)

Answer 17

allows you to see small clots

Question 18

what are the differential diagnosis for PE

Answer 18

• ACS
  
  • Pneumonia
  • CCF
  • AF
  • Acute anaemia
    COPD/asthma

Question 19

management of PE

Answer 19

• Supportive therapy
• Immediate anticoagulation - heparin
• thrombolytics - alteplase

Question 20

when is thrombolytics C/I for PE

Answer 20

recent surgery
active bleeding
renal/liver disease
stroke history

Question 21

how does unfractionated heparin work

Answer 21

○ Intrinsic pathway
§ Binds to Antithrombin III→ Inhibits factor Xa → thrombin

Question 22

unfractionated heparin side effects

Answer 22

§ Haemorrhage
§ Thrombocytopenia (monitor platelets > 5days)
§ Hyperkalaemia - aldosterone affect
§ Osteoporosis, alopecia

Question 23

monitoring for unfractionated heparin

Answer 23

Activated partial thromboplastin time (APTT), target of 80-100secs

Question 24

how does low molecular weight heparin work

Answer 24

inhibits factor Xa - no monitoring required

Question 25

how does warfarin work

Answer 25

inhibits metabolism of vitamin K and affects the activation of factors II, VII, IX and , can take 72 hours to work

Question 26

monitoring requirements for warfarin

Answer 26

® Baseline: Clotting screen, Hb, Plts, LFT’s
® INR and signs of bleeding (1.5 ideal INR)

Question 27

how do Rivaroxaban, apixaban, edoxaban
work

Answer 27

Direct inhibitors of activated factor X in
Treatment of VTE + Prophylaxis of VTE post- surgery

Question 28

how does dabigatran work

Answer 28

Direct thrombin inhibitor in Treatment of VTE + Prophylaxis of VTE post-surgery

Question 29

which surgeries have higher DVT/PE risk

Answer 29

○ Orthopaedic
○ Cardiac
○ Vascular
○ Urological
○ Thoracic
○ Gynaecological
○ Neuro

Question 30

what are the NICE guidelines for pharmacological prophylaxis of DVT/PE

Answer 30

LMWH (e.g. Dalteparin s/c 5000IU od , enoxaparin s/c 40mg od) /Fondaparinux