DVT

Question 1

What is Deep Vein Thrombosis (DVT)?

Answer 1

• Formation of a blood clot in a deep vein
• Most common in lower limb (calf, popliteal, femoral veins)

Question 2

Why are leg veins prone to DVT?

Answer 2

• Low pressure system
• Blood must move against gravity
• Relies on calf muscle pump

Question 3

What happens during immobility?

Answer 3

• Muscles don’t contract
• Blood pools in veins
• Clot formation risk increases

Question 4

Why do clots form near venous valves?

Answer 4

• Pockets of slow flow behind valve leaflets
• Low oxygen
• Accumulation of clotting factors

Question 5

Main danger of DVT

Answer 5

• Clot may detach and travel to lungs → Pulmonary Embolism (PE)

Question 6

Pathway of a clot causing PE

Answer 6

• Leg vein → Inferior vena cava → Right heart → Pulmonary artery

Question 7

Complications of DVT

Answer 7

• Pulmonary embolism
• Post‑thrombotic syndrome (chronic swelling, pain, skin changes)

Question 8

Virchow’s Triad

Answer 8

• Stasis
• Hypercoagulability
• Endothelial injury

Question 9

Examples of stasis risk factors

Answer 9

• Immobility, long flights, bed rest
• Heart failure
• Venous obstruction

Question 10

Examples of hypercoagulability

Answer 10

• Cancer
• Pregnancy
• Oestrogen therapy (COC, HRT)
• Protein C/S or antithrombin deficiency

Question 11

Examples of endothelial injury

Answer 11

• Surgery
• Trauma
• Inflammation
• Atherosclerosis

Question 12

How oestrogen increases DVT risk

Answer 12

• Increases clotting factors
• Decreases natural anticoagulants

Question 13

Typical symptoms of DVT

Answer 13

• Calf swelling
• Pain/tenderness
• Warmth
• Redness

Question 14

Why superficial veins become visible

Answer 14

• Deep vein blocked
• Blood diverted to superficial circulation

Question 15

Key patient risk factors

Answer 15

• Age
• Obesity
• Pregnancy
• Previous DVT

Question 16

Situational risk factors

Answer 16

• Surgery
• Hospitalisation
• Dehydration
• Long travel

Question 17

Why previous DVT increases recurrence risk

Answer 17

• Valve damage
• Persistent abnormal venous flow

Question 18

What is the Wells Score?

Answer 18

• Clinical probability assessment tool for DVT

Question 19

Interpretation of Wells Score

Answer 19

• ≥2: DVT likely
• <2: DVT unlikely

Question 20

What is D‑dimer?

Answer 20

• Breakdown product of fibrin clot

Question 21

How to interpret D‑dimer

Answer 21

• Negative: rules out DVT
• Positive: non‑specific

Question 22

Conditions causing false positive D‑dimer

Answer 22

• Infection
• Cancer
• Pregnancy
• Surgery
• Inflammation

Question 23

First‑line imaging test

Answer 23

• Compression ultrasound

Question 24

Blood tests before treatment

Answer 24

• FBC
• Platelets
• PT
• aPTT

Question 25

NICE scenario: Wells ≥2 + negative D‑dimer + negative ultrasound

Answer 25

- Stop anticoagulation - Repeat ultrasound in 6–8 days

Question 26

Why repeat ultrasound?

Answer 26

- Early calf clots may initially be too small to detect

Question 27

Main treatment of DVT

Answer 27

- Anticoagulation

Question 28

Purpose of anticoagulants

Answer 28

- Prevent clot extension - Prevent PE - Allow natural fibrinolysis

Question 29

Do anticoagulants dissolve clots immediately?

Answer 29

- No — they stabilise clot while body breaks it down

Question 30

Why early treatment is urgent

Answer 30

- Fresh clots unstable - Highest PE risk in first days

Question 31

Oral vs transdermal oestrogen DVT risk

Answer 31

- Oral: higher risk (liver first‑pass ↑ clotting factors) - Transdermal: lower risk

Question 32

Lifestyle prevention

Answer 32

- Movement during travel - Hydration - Weight control - Smoking cessation