PBL 8 - DVT + Pulmonary Embolism

Question 1

Name two deep veins in the calf muscles (2 marks).

Answer 1

Any two from: anterior tibial, posterior tibial, peroneal

Question 2

Explain the role of plasmin (1 mark) and prostacyclin (1 mark) in the regulation of blood coagulation.

Answer 2

Plasmin breaks down fibrin in blood clots (1 mark)

Prostacyclin acts on platelets to prevent the release of platelet granules (1 mark)

Question 3

How is heparin normally administered and why is this route chosen? (1 mark)

Answer 3

Heparin is given parenterally (that is, administered other than through the digestive tract). (1/2 mark) because it is not absorbed from the gut (1/2 mark)

Question 4

List the three classic signs of a deep vein thrombosis (11/2 marks)

Answer 4

swelling (1 mark) , pain (1 mark) and redness (1 mark)

Question 5

List the three main risk factors for DVT (Virchow’s triad) (11/2 marks)

Answer 5

Increased or hypercoagulability of the blood (1 mark)
Damage to the endothelial wall (1 mark)
Slow or stagnant blood flow (1 mark)

Question 6

Name two further tests Patricia would probably have in hospital (2 marks)

Answer 6

The further tests would have been an ultrasound scan and measurement of plasma D-dimer levels

Question 7

List two classic symptoms of acute pulmonary embolism (2 marks).

Answer 7

Abrupt onset of pleuritic chest pain, shortness of breath, dyspnea.
(any two 1 mark each)

Question 8

Patients with pulmonary embolism may present with atypical symptoms. Other than the symptoms described by Ms Aledambo, list two other common atypical symptoms (2 marks)

Answer 8

Seizures 
Syncope 
Abdominal pain 
Fever 
Confusion/Decreasing level of consciousness 
Delirium (in elderly patients)

Question 9

Explain why sickle cell disease is a risk factor for pulmonary embolism

Answer 9

Sickle cell erythrocytes are more fragile than normal erythrocytes and tend to break up in capillaries (1 mark) leading to infarction. When this happens in bone marrow fat emboli are released (1 mark)which can lodge in the lungs

Question 10

What is D-dimer (1 mark) , how is it produced (1 mark)?

Answer 10

D-Dimer is a breakdown product of cross-linked (1/2 mark) fibrin (1/2 mark). It is produced by plasmin (1 mark) and related proteases.

Question 11

List four components in a Wells Test for PE (2

Answer 11

history of DVT or PE
tachycardia (heart rate > 100)
immobilization (≥ 3d)/surgery in previous four weeks
haemopytis
malignancy (with treatment within six months) or palliative
alternative diagnosis is less likely than PE
(any four points ½ mark each)

Question 12

Define DVT, PE and venous TE (3)

Answer 12

DVT - deep vein blocked or partially blocked, usually in the deep venous sinuses in the calf muscles

PE - clot present in the pulmonary artery or arteries,

VTE - a PE from dislodgement of a DVT or part of a DVT with passage up the venous system through the right side of the heart and into the pulmonary arteries

Question 13

What are common risk factors for DVT? (2)

Answer 13

long-haul flight, family history (possible heritable

predisposition), pregnancy, obesity, smoking history.

Question 14

Name 4 components of the wells test for DVT (2)

Answer 14

• Active cancer
• Previous documented DVT
• Swelling of entire lef
• Pitting oedema (syptomatic leg)
• Paralysis, paresis, or recent cast immobilization of lower extremities
• 8. Recently bedridden > 3 days, or major surgery requiring regional or general
     anaesthetic in past 4 week

Question 15

What further tests can be given to a patient to diagnose DVT? (2)

Answer 15

• INR (blood coagulability)
• Plasma D-dimer
• ECG
• CT pulmonary angiogram
• Chest CT
• FBC

Question 16

What is the D-dimer test? (1)

Answer 16

fibrin degradation product

Question 17

What is the difference between UFH *unfractionated heparin and LWMH? (2)

Answer 17

LMWH - quick, subcutaneous injection, better bioavailability, does not need appt monitoring and fixed dosage

UFH - administered via IV

Question 18

What is the treatment for DVT ? (1) Why is it given? (1)

Answer 18

o Anti-coagulant therapy
o Heparin
Warfarin
prevent clot extension + break down the clot

Question 19

Explain why warfarin cannot be given to Patricia? (2)

Answer 19

She is pregnant

it is teratogenic as it can cross the placental barrier and cause fetal malformations

Question 20

What is thrombolytic therapy and when would you give it? (2)

Answer 20

drugs called lytics to dissolve blood clots

Question 21

Function of antithrombin

Answer 21

Antithrombin anticoagulant that inhibits the activated thrombin (factor IIa), factor Xa, and, to a lesser extent, factor XIa and factor IXa.

Question 22

What would you give to a patient with renal failure and DVT

Answer 22

IV UFH

Question 23

Why can sickle cell disease make it difficult to diagnose PE

Answer 23

Hypoxemia, dehydration, and fever lead to intravascular sludging within
pulmonary vasculature. This promotes a vicious cycle, further exacerbating local
hypoxemia, ultimately leading to local tissue infarction.

Question 24

What is a thrombus

Answer 24

Blood clot in the arterial or venous system

Question 25

Why are thrombi more common in veins

Answer 25

More sluggish

Question 26

Common heritable thrombophilia

Answer 26

factor V Leiden followed by the prothrombin G20210A variant. Less common
causes are deficiencies of the naturally-occurring anti-coagulants, anti-thrombin, protein C
and protein S

Question 27

What coagulation factors does warfarin act upon?

Answer 27

II,VII,IX,X, Protein C + S

Question 28

MoA dabigatran,

Answer 28

Thrombin inhibitors

Question 29

MoA Fondaparinux Apixaban, , rivaroxaban

Answer 29

Factor 10a inhibitor

Question 30

Thrombolytics

Answer 30

streptokinase, urokinase

Question 31

PE symptoms

Answer 31

o Abrupt pleuritic chest pain, SOB, Hypoxia
o Wheezing, fever, productive cough
- Signs – Fever, tachycardia, tachypnea, diaphoresis

Question 32

o Post thrombotic syndrome

Answer 32

Long term discomfort/swelling, leg ulcers –> wear compression stockings for at least 2 years