DVT

Question 1

What does venous thromboembolism mean?

Answer 1

Blood clot that originates in the vein and includes deep vein thrombosis and pulmonary embolism

Question 2

Pathogenesis of VTE

Answer 2

Virchow’s triad
1. Venous stasis
2. Endothelial injury
3. Hypercoagulability (hereditary or acquired)

Question 3

Clinical features of DVT

Answer 3

• Unilateral leg swelling, pain or warmth
• Dilated superficial collateral veins
• Tenderness of deep venous system
• Homan’s sign (pain in the posterior calf or knee with forced dorsiflexion of the foot)
• Phlegmasia cerulea dolens

Question 4

Types of DVT

Answer 4

1. Proximal DVT (iliac, femoral, popliteal) (80%)
2. Distal DVT (ant + post tibial, peroneal) (20%)

Question 5

Differential diagnosis for DVT (unilateral leg swelling)

Answer 5

1. Cellulitis
2. Ruptured baker’s cyst
3. Superficial thrombophlebitis
4. Muscle tear/hematoma/sprain/fracture
5. Lymphedema
6. Chronic venous insufficiency

Question 6

What score to use for DVT?

Answer 6

Well’s score

Question 7

Clinical features of well’s score

Answer 7

+1:
Active cancer
Bedridden recently for >3 days or major surgery within 12 weeks
Calf swelling >3 cm compared to other leg
Collateral superficial veins present
Entire leg swollen
Localised tenderness along the deep venous system
Pitting edema, confined to symptomatic leg
Paralysis, paresis or recent plaster immobilisation of the lower extremity
Previous DVT

-2:
Alternative diagnosis to DT as likely or more likely

Question 8

How to interpret findings from well’s score and how does it guide next steps?

Answer 8

<2: low/moderate probability of DVT
- proceed to do D-dimer test
2 or more: high probability of DVT
- proceed to do venous compression ultrasound

Question 9

If D-dimer < 500ng/ml means

Answer 9

DVT is excluded

Question 10

If D-dimer > 500ng/ml, what is the next step

Answer 10

Venous compression ultrasound

Question 11

Ultrasound features of DVT

Answer 11

Non-compressible deep vein
Direct visualisation of the thrombus

Question 12

Positive findings in venous compression ultrasound suggests

Answer 12

DVT confirm, start therapy

Question 13

Indications to start anticoagulation

Answer 13

Anticoagulation is indicated when the clots are:
- Acute proximal DVT (popliteal, femoral, iliac vein)
- Distal and symptomatic
- Upper extremities and symptomatic

Question 14

Options of anticoagulants to start

Answer 14

1. LMWH (SC clexane) bridged to oral warfarin
2. LMWH (SC clexane) for 5 days first followed by direct thrombin inhibitor (dabigatran) - not preferred choice
3. DOAC (factor 10a inhibitor - rivaroxaban)

Question 15

Duration for anticoagulation lasts for

Answer 15

At least 3 months
*choice and duration of anticoagulants depend on doctor and patient factors

Question 16

Disposition of DVT patients

Answer 16

Admission
Outpatient home treatment for patients with uncomplicated DVT, hemodynamically stable, low bleeding risks

Question 17

When to treat patients with thrombolytic therapy?

Answer 17

Adjunct to anticoagulation in:
1. Severe or limb threatening DVT
2. Acute proximal DVT with high thrombus burden in young patients with few medical comorbidities and long expected life expectancy

Question 18

What thrombolytic treatment modalities can be considered?

Answer 18

Catheter directed thrombolysis
Percutaneous mechanical thrombectomy

Question 19

For patients who are contraindicated to anticoagulation, what treatment option is available?

Answer 19

IVC filter
*also indicated for recurrent DVT/PE despite therapeutic anticoagulation

Question 20

Complications of untreated DVT

Answer 20

Acute:
- Pulmonary embolism
- Phlegmasia alba dolens
- Phlegmasia cerulea dolens

Chronic:
- Post thrombotic syndrome
- Chronic venous insufficiency

Question 21

Superior vena cava syndrome

Answer 21

Obstruction of blood flow in superior vena cava either from invasion or external compression of SVC

Question 22

Causes of SVC syndrome

Answer 22

1. Malignancy (lung cancer, lymphoma) - most common
2. Thoracic aortic aneurysms
3. Iatrogenic causing thrombosis
   - Indwelling central venous device
   - Dialysis access
   - Pacemaker leads

Question 23

Clinical symptoms of SVC syndrome

Answer 23

• Dyspnea
• Facial swelling, especially when bending forward or in supine
• Upper limb swelling
• Neurological sx (headache, giddiness)
• Chest pain

Question 24

Clinical signs of SVC syndrome

Answer 24

• Facial edema or plethora
• Venous distension of neck, chest wall and upper limbs especially when patient raises upper limbs
  = Pemberton’s manoeuvre (exacerbates obstructive symptoms by decreasing thoracic inlet area)
• Cyanosis
• Horner’s syndrome

Question 25

Immediate investigation in the ED

Answer 25

CXR
- look for external compression
- Mediastinal widening
- Pleural effusion

Question 26

Management of SVC syndrome

Answer 26

1. Manage in P1
2. High flow oxygen in upright position
3. ETT + mechanical ventilation if patient develops airway compromise
4. Consider IV dexamethasone
5. Escalate to vascular surgeons for endovenous intervention
6. Treat underlying cause (usually secondary to malignancy)