Venous Thromboembolism - DVT

Question 1

Definition

Answer 1

Caused when a blood clot forms in deep leg vein
- if below/around calf = minor veins (e.g. ant. + post tibial) = less concerning = (MC)
- if above calf (in thigh) = fewer major veins (e.g superficial femoral), occlusion here may impede distal flow life threatening (LC)
Common post-operatively due to immobilisation
Assosciated with contraceptive pill, long haul flights, leg fractures + malignancy
Commonly seen in calf

Question 2

Risk factors

Answer 2

Increase age
Pregnancy
Synthetic oestrogen
Trauma
Surgery
Past DVT
Cancer
Obesity
Immobility
Thrombophillia

Question 3

Pathophysiology

Answer 3

Venous thromboembolism (VTE) = common potentially fatal condition involving blood clots (thrombi) developing in the circulation. Usually secondary to stagnant blood + hyper-coagulable states.
When a thrombus develops in the venous circulation = deep vein thrombosis

Question 4

Budd-chiari syndrome

Answer 4

Blood clot in hepatic vein blocking outflow of blood
- hyper-coagulable started
- causes acute hepatitis
- presents as:
Abdo pain
Hepatomegaly
Ascites
- treat with LMWH or warfarin

Question 5

Aetiology

Answer 5

Contraceptive pill
Long haul flights
Leg fractures
Malignancy
Surgery
Genetic factors
Rare =
- Antithrombin deficiency
- Protein C or Proteins deficiency

Question 6

Signs

Answer 6

Unilateral swollen calf w/ engorged leg veins. Typically warm + oedematous
Calf warmth
Tenderness
Dilated superficial changes
Colour changes
Swelling
Erythema
Mild fever
Pitting oedema
NB = complete occlusion of a large vein; phlegmasca cerulea dolens -> severe ischaemic leg, turns blue

Question 7

Most common types of DVT

Answer 7

Almost always unilateral.
Bilateral DVT is rare + bilateral symptoms more likely due to an alternative diagnosis such as chromic venous insufficiency or heart failure

Question 8

How to examine for leg swelling

Answer 8

Measure the circumference of the calf 10cm below the tibial tuberosity. More than 3cm difference in the calf is significant
- Always ask questions + examine in suspicion of a potential PE
* SOB
* Palpitations
* Pleuritic chest pain

Question 9

Diagnosis

Answer 9

FIRST LINE = Wells score = predicts risk of a patient presenting with symptoms having a DVT or PE. Includes risk factors + clinical findings (calf swelling)
1 or less points = d-dimer -not raised = not PE
2 or more = D-dimer + duplex USS (GS) - DIAGNOSTIC
D-dimer - positive test not diagnostic
* sensitive BUT NOT specific
- negative D-dimmer exclude DVT
- can be positive in cancer, pregnancy + post operative, pneumonia, heart failure
Doppler USS
- Repeat -ve USS 6-8 days if +ve D-dime and wells score

Question 10

Treatment

Answer 10

DOAC ANTICOAGULATION
- APIXABAN/ ROVAROXIBAN
- LMWH if above CI (renal impairment)
+ mobilisation, compression stockings

Question 11

Differential diagnosis

Answer 11

CELLULITIS (skin infection typically staph aureus + strep pyogenes)
- tender, inflamed swollen calf with pronounced demarcation
- will show LEUKOCYTOSIS (indicative of infection) on blood test FBC, while DVT will have normal levels
- DVT will have normal levels. D-dimmer + DUSS also can confirm DVT