Venous thrombo embolic disease (VTE)

Question 1

Where are the common anatomical locations of deep vein thromboses?

Answer 1

Ant and post tibial veins
Perineal vein
Superficial femoral vein
Popliteal vein

Question 2

What are the risk factors for DVT?

Answer 2

Virchows Triad: Stasis, hypercoagulabilty of blood, endothelial damage.

Unmodifiable factors:
Increased age. (greater than 60)
Pregnancy.

Modifiable factors:
Extra oestrogen (coc)
Obesity.
Immobility.
Dehydration.

Medical factors:
Surgery.
Previous DVT/FH.
Malignancy .
Thrombophilia.
Serious co-morbidity (reanl/heart failure/copd etc)

Question 3

What is the scoring system used to assess risk of DVTs?

Answer 3

Wells Score

Question 4

Describe the clinical features of a DVT?

Answer 4

Calf Pain.
Red swollen leg with engorged superficial veins.
Tight shiny skin.
Ankle oedema.

Question 5

What does the d-dimer test show and how is it useful in triage of patients with a suspected DVT?

Answer 5

A d-dimer tests for a small protein fragment present after a clot is broken down by fibrinolysis.

As any clotting can cause the D-dmier test to be raised as a diagnostic tool for diagnosing VT’s it has poor specificity e.g it only has a true negative rate of ~50% as lots of things will cause it to be raised.

But it is has good sensitivity e.g true positives >90%.

It is therefore useful in ruling out DVT as it almost always raised if someone has any clot. Therefore if it is negative it is very unlikely that they have VT.

Question 6

What are the differential diagnoses of patients with painful swelling of the lower leg?

Answer 6

DVT

Thrombophelbitis: Superficial vein thrombosis similar presentation to DVT, treat with compression stockings

Chronic Venous Insufficiency: Ineffective venous valves aka varicose veins

Cellulitis: Infection of the skin, tender, hot and maybe systemic illness

Acute arterial ischaemia: 6 p’s. Pain, Pallor, Pulseless, Parasthesia, Paralysis, Poikilothermia (variable temperature) (perishingly cold)

Hypoproteinaemia: Legs swelling not painful

Question 7

What are the different investigations which can be used to investigate suspected DVT’s?

Answer 7

D-dimer

Compression US: vein does not collapse on compression indicates DVT

Venography

Thrombophilia testing?

Question 8

Define PE and describe the the main pathological consequences?

Answer 8

PE is a thromboembolism usually follwing a DVT which blocks the pulmonary artery.

2 main consequences:
Increased pulmonary arterial pressure putting a strain on the right side of the heart.

Ischaemia of the lung with a lack of perfusion of ventilated areas.

Question 9

Describe the range of clincal presentations and pathology depending on clot size?

Answer 9

Massive PE: 60% or more of the pulmonary circulation is blocked, the heart cannot pump blood to the lungs. There is a cardiovascular collapse therefore therefore there is no cardiac output resulting in rapid death. Clinically the patient will be haemodynamically unstable. Occurs in 5% of cases.

Major PE: Blockage of a middle-sized pulmonary aa. Patients experience SOB, haemoptysis and pleuritic chest pain. Occurs in 10% of cases.

Minor PE: blockage of small peripheral vessels. May be assymptomatic or may present with SOB and pleuritic pain. Occurs in 85% of cases.

Each category can develop into a more severe PE.

Question 10

What is the treatment for VTE?

Answer 10

LMWH treatment dose.

For enoxoparin 1.5mg/kg OD
Halve dose if eGFR is less than 30
Very obese patients are dosed differently.

If unprovoked treat with Warfarin/DOAC for 6 months
If provoked treat for 3 months

Question 11

How are PE’s classified in terms of cause and how are they investigated?

Answer 11

Provoked or unprovoked.

Provoked have a clear precipitating cause aka: COCP, period of immobility etc.

Unprovoked do not have a clear precipitate most commonly caused by an undiagnosed Ca or rarely may be caused by a thrombophilia.

Question 12

How are unprovoked PE’s investigated?

Answer 12

Ca Screen: CT chest/abdo/pelvis + mammogram in females, PSA in males.

Thrombophilia screen.

Question 13

Outline the indications for primary thrombo-prophylaxis?

Answer 13

Every patient coming into hospital should have a VTE risk assessment: this includes risk factors for VTE and bleeding.

High risk admissions are commonly:

• Critical illness admissions
• Any major surgery particularly orthopaedic

Patients with RF.

Question 14

What are the methods used for primary thrombo-prophylaxis?

Answer 14

Avoid dehydration.

Mechanical: Compression stockings

Pharmacological: LMWH

Question 15

What is venous chronic insufficiency?

Answer 15

It is where there is venous valvular dysfunction allowing blood to flow back into the legs.

Potentially causing:

• Varicose veins (can become infected thrombophlebitis)
• Venous eczema
• Venous ulceration
• Oedema
• Venous hyperpigmentation

Question 16

What is post thrombotic syndrome?

Answer 16

It is chronic venous insufficiency which occurs post DVT.

It is caused by a combination of reflux due to valvular incompetence, and venous hypertension due to thrombotic obstruction.