Thrombotic disorders

Question 1

What are the three main veins where a DVT is likely to occur?

Answer 1

Femoral vein, popliteal vein, tibial vein

Question 2

Outline Virchows triad

Answer 2

Endothelial injury
Circulatory stress
Hyper-coagulable state

Virchow’s triad describes the three broad categories of factors that are thought to contribute to thrombosis.

Question 3

State 3 risk factors for thrombosis

Answer 3

Hospitalisation
Post-op
Pregnancy
OCP
Long haul flights
Cancer
Obesity
Drug use

Question 4

What are the clinical presentations of a thrombosis?

Answer 4

Asymptomatic
Unilateral calf swelling/heat/pain/redness/hardness
Differential diagnosis: cellulitus, Baker’s cyst, muscular pain
POTENTIALLY FATAL (approx. 1000 deaths/year)

Question 5

Why would a doppler ultrasound be aa good diagnostic tool for thrombosis?

Answer 5

Produces real-time 2D image of soft tissue stuctures
Colour duplex shows velocity and direction of blood flow
Veins non-compressible by U/S probe

Question 6

How is the d-dimer test used in diagnosis of thrombosis?

Answer 6

Likelihood of having a DVT can be assessed using the Wells risk score & D-dimers test
D-dimers indicate activation of clotting calscade
Low Wells score & negative d-dimer test have high negative predictive value (>99% NPV)

Question 7

What is the initial treatment for thrombosis?

Answer 7

Therapeutic LMW Heparin (Tinzaparin or enoxaparin)

If renal impairment anti-coag with IV unfractionated heparin

Question 8

What subsequent treatment for thrombosis would you give?

Answer 8

Load patient with oral warfarin for 3-5 days
Stop LMW Heparin once INR > 2 for 2 days
if 1st DVT in femoral or iliac- 6 months warfarin
if 2nd DVT/PE- lifelong warfarin
Maintain INR between 2-3

Question 9

What are the clinical signs of a PE?

Answer 9

Pleuritic pain (chest pain)
Dyspnoea
Haemoptysis

In massive PE: collapse, syncope, death
Micro-emboli: asymptomatic
On examination: Tachycardia, tachypnoe, hypotensive

Question 10

Which three investigations may be of interest when dealing with a suspected PE?

Answer 10

1. v/q scan
2. ECG
3. Chest X-ray ( although this is normal as it measure airation)

Question 11

What are the likely outcomes of PE?

Answer 11

5% mortality, 4% develop pulmonary hypertension
Death in 10-30% in-patients
Up to 60% of patients have a micro-emoboli at post mortem
Preventable death

Question 12

What treatment is given in the case of a massive PE?

Answer 12

Treat signs of shock

Thrombolysis and IV Heparin

Question 13

What treatment is given in the case of a standard PE?

Answer 13

LMW Heparin injections e.g. Tinzaparin (better if underlying cancer)
Warfarin 6 months
Consider DOAC

Question 14

Suggest an acquired and inherited condition that could increase risk of thrombosis

Answer 14

Acquired: Anti-phospholipid syndrome

Inherited: F-V Leiden, Pro-thrombin gene variant, anti-thrombin (protein C/S Deficiency)