PE/DVT

Question 1

Aetiology of DVT (Virchow Triad)

Answer 1

Virchow Triad

1. Slowed blood flow (stasis)
   a. Turbulent flow so blood is slow or static blood
   b. Inactivity of skeletal muscle pump e.g. long flights
2. Hypercoagulations
   a. Altered amount of clotting factors
   b. This can be due to genetics, surgery or medication like birth control
3. Damage to blood vessels
   a. Infections, chronic inflammation, toxins

Question 2

RF of DVT

Answer 2

• Age
• Surgery
• Immobility e.g. Long haul flight, leg fracture/POP
• Oral contraceptive pill
• Pregnancy
• Trauma
• Inherited thrombophilia (genetic predisposition)
• Spontaneous/unprovoked DVT (cause is unknown - look for malignancy)

Question 3

Signs and Sx of DVT and PE

Answer 3

DVT

• commonly below knew
• Inflamed - pain, swelling, redness, warm
• Tenderness
• Discolouration

PE-related
- SoB, pleuritic chest pain (sharp), Tachycardia, Tachypnoea, Pleural rub

Question 4

Investigations of DVT

Answer 4

(1. ) Wells Score
- Assesses likelihood of DVT/PE
- <1 = DVT unlikely, perform D-dimer
- >2 = DVT is likely, perform D-dimer and USS

(2. ) D-dimer blood test
- D-dimers are fibrin breaks down products. This is high when there is a clot.
- Not DVT specific, can also inc in pregnancy, infection, malignancy, post-op

(3. ) Duplex US
- Sensitive + specific, can see how blood flows through veins
- not reliable in early thrombosis

(4. ) Venogram
- vein is visualised using dye - see if there is a blood clot or another kind of blockage.

Question 5

Complication of DVT

Answer 5

PE

1. Thromboembolism of DVT moving to lungs can be life-threatening.
2. PE is a massive clot will cause hemodynamical disturbance: Hypotension, cyanosis, severe dyspnoeas, right heart failure, near death experiences. medical emergency

Question 6

Investigations for PE

Answer 6

1. CXR - to rule out other things like HF, pneumonia
2. ECG sinus tachy (Q3, S1, T3 on ECG)
3. Arterial blood gases in pt’s with Type 1 resp failure
4. D-dimers - high in PE
5. CTPA spiral CT with contrast - visualise major segmental thrombi, this reliable and investigation of choice usually

Question 7

Treatment of PE

Answer 7

(1. ) Anticoagulant
- LMW heparin for 5d or fondaparinux
- Oral warfarin for 6m or DOAC (e.g. apixaban) are commonly used, instead of warfarin as it doesn’t require monitoring

(2. ) Treat underlying causes: malignancy, thrombophilia
(3. ) IVC filter - If anticoagulants fail

Question 8

Three ways for prevention of PE

Answer 8

1. Mechanical
   - hydration and early mobilisation
   - compression stockings
   - foot pumps, calf exercises –> to keep blood moving
2. Chemical
   - LMW heparin
   - Use Wells Score system to identify if individual is high risk thus prescribe LMW heparin
3. Stop oral contraception before pre-op

Question 9

When would you give a Thromboprophylaxis

Answer 9

Low risk of thrombosis

• <40years, short surgical procedural
• Early mobilisation and hydration, no chemical, stockings if surgical

High risk

• hip and knee, pelvis, malignancy, immobility
• Should be prescribed LMW heparin (dalteparin)