DVT / PE

Question 1

Define venous thrombosis

Answer 1

the formation of a blood clot (thrombus) within a vein, which can lead to a blockage of blood flow

Question 2

Types of venous thrombosis

Answer 2

• Deep vein thrombosis
• Superficial venous thrombosis

Question 3

what triad is used to describe the poathophysiology of the formation of a thrombus?

Answer 3

Virchow’s triad

Question 4

SHE

Virchow’s Triad

Answer 4

1. Stasis of blood flow
2. Hypercoagulability
3. Endothelial damage

Question 5

Stasis of blood flow factors for VT

Answer 5

• immobility - long haul flight, post-op bed rest, bed-bound in hospital (most common)

Question 6

Endothelial damage factors for VT

Answer 6

• atheroma formation
• inflammatory response
• direct trauma

Question 7

Hypercoagulability factors for VT

Answer 7

• smoking
• blood disorders (Factor V Leiden, Anti-phospholipid syndrome)
• malignancy
• sepsis
• pregnancy

Question 8

Define superficial veins

Answer 8

Veins located just beneath the skin (subcutaneous), drain into deep veins

Question 9

GPS

Superficial veins of the LL/Pelvis

Answer 9

1. Great saphenous vein - medially up to femoral vein
2. Small Saphenous vein - back of calf –> popliteal
3. Perforator vein - connects all superficial veins to deep veins

Question 10

Deep veins of the LL/Pelvis

Answer 10

1. Iliac –> common iliac –> inferior vena cava
2. Femoral
3. Popliteal
4. Tibial –> popliteal

Question 11

Venous thrombosis risk factors

Answer 11

• Increasing age
• Previous VTE
• Smoking
• Pregnancy or recently post-partum
• Recent surgery (especially abdominal surgery, pelvic surgery, or hip or knee replacements) or prolonged immobility (approx. > 3 days)
• HRT / COCP
• Current active malignancy
• Obesity
• thrombophilia disorder (e.g. antiphospholipid syndrome or Factor V Leidin)

Question 12

Define DVT

Answer 12

refers to the formation of a blood clot in the deep veins of a limb, most commonly affecting those of the legs or pelvis.

Question 13

DVT clinical presentation

Answer 13

• unilateral leg pain / swelling

Question 14

how to measure calf size in DVT

Answer 14

• 10cm below the tibial tuberosity
• measure the circumference
• compare both calves
• > 3cm = significant

Question 15

What score is used to calculate risk of DVT

Answer 15

DVT Well’s score

Question 16

what does DVT Well’s score < or = 1 mean

Answer 16

• DVT unlikely
• D-dimer within 4hrs OR interim therapeutic anticoag
• -ve (consider other Dx)
• +ve (Doppler USS within 4hrs)

Question 17

what does DVT Well’s score > 1 mean

Answer 17

• DVT likely
• Doppler USS within 4hrs
• Doppler USS +ve (confirm + treat)
• Doppler USS -ve (stop interim antocoag and perform d-dimer, repeat USS in 6-8 days)

Question 18

what other conditions cause a raise in d-dimer

Answer 18

• malignancy
• HF
• Pregnancy
• Infection
• Surgery

Question 19

what is the 1st line Tx for antiphospholipid syndrome (APS) to prevent DVT

Answer 19

Warfarin

VKA

Question 20

what is the 1st line Tx for a DVT

Answer 20

DOACs

Question 21

what is the INR target range DVT / PE

Answer 21

2-3

Question 22

what is the 1st line Tx for DVT in pregnancy

Answer 22

LMWH - Enoxaparin

Question 23

what is the duration of the Tx in unprovoked DVT

Answer 23

6 months

Question 24

what is the duration of the Tx in provoked DVT

Answer 24

3 months

Question 25

what is an **inferior vena cava filter**

Answer 25

Devices inserted into the **inferior vena cava** to filter out any blood clots that are travelling from the **venous system** towards the heart / lungs | Acting as a sieve

Question 26

what should be considered in a **first, unprovoked VTE** (no clear risk factors)

Answer 26

Cancer

Question 27

Indications for an **inferior vena cava filter**

Answer 27

- Reccurent PEs - Unsuitable for anticoag

Question 28

what further Ix should be carried out in a **first, unprovoked VTE** (no clear risk factors)

Answer 28

1.**Consider cancer** - thorough med Hx - Examination - Baseline bloods (FBC, UEs, LFTs, Clotting screen) 2. **Antiphosphlipid Abs (APS)** 3. **Hereditary thrombophilia** (FMHx, 1st degree relative)

Question 29

Main complication of DVT

Answer 29

PE

Question 30

what type of shock does PE cause

Answer 30

**Obstructive shock** - **Pulmonary occlusion** from an embolus prevents blood from returning to the heart

Question 31

Define Pulmonary Embolism

Answer 31

to a **blockage of the pulmonary artery** by a substance that has travelled there in the bloodstream

Question 32

PE Sx

Answer 32

- sudden onset **dyspnoea** (SOB) - **pleuritic CP** - cough - haemoptysis (rare)

Question 33

PE signs

Answer 33

- Tachycardic - Tachypnoea - Low O2 sat. (hypoxia) - Pyrexia - raised JVP (rare) - pleural rub on auscultation - hypotension

Question 34

what does PE Well's score < or = 4 mean

Answer 34

- PE unlikely - D-dimer within 4hrs - D-dimer **-ve** --> NAD - D-dimer **+ve** CTPA OR interim anticoag

Question 35

what does d-dimer blood test detects

Answer 35

**fibrin degradation products**, indicating recent clot formation.

Question 36

what is the **gold standard** Ix for DVT

Answer 36

Contrast venography (**contrast dye** into a vein and **using X-rays** to visualize **venous blood flow and clots**) | invasive, contrast/radiation risks

Question 37

what is the 1st line imaging for DVT

Answer 37

Doppler USS

Question 38

How is **doppler USS** used in diagnosing / managing DVT

Answer 38

- Detects **thrombus presence**, **size, and location** in deep veins. - Evaluates **venous valve function** and **risk of post-thrombotic syndrome**. - Can be used for **follow-up** to **monitor clot resolution**

Question 39

when is contrast venography indicated

Answer 39

- inconclusive doppler USS - complex DVT - **ilian vein** or **recurrent DVT**

Question 40

Most common ECG findings for PE

Answer 40

1. Sinus Tachy 2. unremarkable

Question 41

PE Well's score > 4

Answer 41

- PE likely - CTPA OR interim anticoag - CTPA **+ve** --> Tx - CTPA **-ve** --> susp. DVT --> Doppler USS

Question 42

when is VQ scan indicated over CTPA in PE

Answer 42

- CrCl < 30 - Allergy to contrast

Question 43

what is the Mx for **massive** **haemodynamically unstable** PEs

Answer 43

Thrombolysis

Question 44

PE CXR findings

Answer 44

Normal

Question 45

PE ABG findings

Answer 45

**Resp alkalosis**: hypoxia --> hyperventilation --> loss of CO2 --> low CO2 --> more alkalotic

Question 46

PE VQ scan findings

Answer 46

- High V/Q ratio - ventilation-perfusion mismatch

Question 47

# HHR What are the clinical consequences of a PE

Answer 47

**Hypoxemia** due to impaired gas exchange. **Hyperventilation** as compensation, leading to respiratory alkalosis (low PaCO₂). **Right heart strain** due to increased pulmonary vascular resistance.