OnlineMedEd: Pulmonology - "Pulmonary Embolism"

Question 1

Review Virchow’s triad.

Answer 1

• Stasis
• Endothelial injury (e.g., surgery, catheter insertion, smoking)
• Hypercoagulable state (e.g., estrogen use)

Question 2

What is Hamand’s sign?

Answer 2

Calf tenderness

This has been demonstrated to be a poor predictor of DVT.

Question 3

Why does pulmonary embolism cause pleuritic chest pain?

Answer 3

The clot induces a wedge-shaped infarction of the lung which causes necrosis of the visceral pleura. Breathing rubs the infarcted pleura.

Question 4

____________ is diffusion limited.

____________ is perfusion limited.

Answer 4

Oxygen

CO2

Question 5

How do pulmonary embolisms cause diffusion defects?

Answer 5

Platelet-derived factors cause inflammation around the pulmonary vessels that leads to an increased distance from the alveoli to the blood.

Question 6

The ____________ criteria are used to calculate the probability of a PE.

Answer 6

Well’s

Question 7

Why should you only get a D-dimer when the pre-test probability is high (greater than 4 on the Well’s criteria)?

Answer 7

D-dimers can be elevated due to many other things –inflammatory states, illness, etc.

Question 8

The best scan for evaluating pulmonary embolisms is _________________.

Answer 8

CT scan with contrast

Note: pulmonary angiogram is actually better technically, but because it is invasive and takes longer you don’t actually do it in practice.

Question 9

In the acute treatment of pulmonary embolisms, ______________ should be given.

Answer 9

heparin (or enoxeparin) and then warfarin

Question 10

_________ should only be given in life-threatening PEs (indicated by hypotension).

Answer 10

tPA