Deep vein thrombosis

Question 1

Name risk factors for venous thromboembolism

Answer 1

Advanced age
Previous DVT
Cancer
Chemotherapy
Tamoxifen
Surgery
Obesity
Immobilization
Fractures
Oral contraceptives
Pregnancy
HRT
Varicose veins
Hypercoagulable states

Question 2

What 3 factors is venous outflow dependent on?

Answer 2

Muscle pump
Venous valves
Cardiac output

Question 3

Name the 3 groups of paired veins in the calf

Answer 3

Anterior tibial
Posterior tibial
Peroneal

Question 4

When does the common femoral v become the external iliac v?

Answer 4

At the inguinal ligament

Question 5

Which natural factors are responsible for thrombolysis?

Answer 5

Monocytes
Endothelial derived
- tissue-type plasminogen activator
- urokinase-type plasminogen activator

Question 6

Name the clinical features of DVT

Answer 6

Swollen limb
Pain
Muscle tenderness

Question 7

Give a differential DVT diagnosis for unilateral symptoms

Answer 7

Cellulitis
Ruptured Baker's cyst
Ruptured popliteal aneurysm
Arterial occlusion
Lymphedema

Question 8

Give a differential DVT diagnosis for bilateral symptoms

Answer 8

Congestive cardiac failure
Liver failure
Nephrotic syndrome
Fluid overload

Question 9

Give the Wells score for DVT

Answer 9

Active cancer
Bedridden >3d
Major surgery within 12w
Calf swelling>3cm
Collateral superficial veins
Entire leg swollen
Pitting edema
Immobilization
Localised tenderness along the venous system
Previous DVT
Alternative diagnosis more likely 

Score>2 = likely

Question 10

Name other conditions that elevate D-dimers

Answer 10

Infections
Trauma
Surgery
Malignancy

Question 11

What is D-dimer a byproduct of?

Answer 11

Fibrin degradation

Question 12

Is D-dimer sensitive or specific?

Answer 12

High sensitivity (97%)
Low specificity (35%)

Question 13

What is the most objective criterion of venous duplex ultrasound?

Answer 13

Venous compressibility

Question 14

Name imaging studies for DVT

Answer 14

Venous duplex ultrasound
Venogram
CTV/MRV

Question 15

What do you do if the duplex ultrasound is negative?

Answer 15

Repeat after 5-7d

Question 16

Name complications of DVT

Answer 16

PE
Venous gangrene
Post-thrombotic syndrome

Question 17

Name treatment options for DVT

Answer 17

1. Mechanical therapy
2. Anticoagulation therapy
3. Thrombolytic therapy
4. Caval filters
5. Surgical thrombectomy

Question 18

When is heparin discontinued?

Answer 18

INR between 2-3 for 2 consecutive days

Question 19

How does UFH function?

Answer 19

Via antithrombin III -> inhibits thrombin and factor Xa

Question 20

How do you monitor UFH?

Answer 20

aPTT 1.5x

Question 21

Name complications of UFH

Answer 21

Bleeding
Thrombocytopenia
Osteoporosis

Question 22

Discuss the benefits of LMWH

Answer 22

1. Predictable coagulation response
2. Long-half life and predictable clearance
3. Good bioavailability
4. Fewer complications

Question 23

How does warfarin function?

Answer 23

Inhibits vitamin K dependent factors 2, 7, 9, 10

Question 24

How long should long-term anticoagulation be given?

Answer 24

Reversible cause - 3 months
First episode - 6 months
Thrombophilia - 12 months
Recurrent - indefinite

Question 25

Which factors increase bleeding risk on warfarin?

Answer 25

``` History of bleeding Hypertension Renal failure Diabetes Decreased Hct High INR ```

Question 26

Name features of PE on ECG

Answer 26

Right bundle branch block T wave inversion V1-4 and lead 3 S wave in lead I Q wave in lead III

Question 27

Name imaging studies for PE

Answer 27

V/Q scan | Spiral CT scan