#21 - Pulmonary Embolism

Question 1

T/F: Physical exam and history can reliably diagnose PE.

Answer 1

false. diagnosis off Physical exam/history is no better than chance. Get a pulmonary angiogram or CT!

Question 2

gold standard diagnostic test for PE.

Answer 2

pulmonary angiogram

Question 3

Most commonly used diagnostic test for PE.

Answer 3

CT scan. (pulmonary angiogram= gold standard, but hard to get.)

Question 4

Uses/limitations for D-dimer test ( how helpful?)

Answer 4

• very sensitive
• not very specific
• high false positive rate due to post-surgery increase
• can rule out, but not confirm, PE.

Question 5

pros and cons of CT testing for pulmonary embolism

Answer 5

technology and image are excellent, but they are expensive, not portable, need expertise to interpret, and may identify a clinically insignificant PE.

Question 6

T/F: if there is no pulmonary embolism on a CT scan, it is safe to rule out PE.

Answer 6

True.

Question 7

When is it safe to withhold anti-coagulants when you are unsure if there is a pulmonary embolism?

Answer 7

• low/mild Wells score
• normal or low V/Q scan (it is high in PE)
• low D-dimer (can rule out PE)

Question 8

If you are administering unfractionated heparin, what should you monitor?

Answer 8

Monitor PTT, aim for 1.5-2x normal value.

Question 9

advantage of Low molecular weight heparin

Answer 9

• don’t need lab monitoring as frequently (reliable dosing)

- decreased heparin-induced thrombocytopenia

Question 10

Warfarin interferes with the production / maturation of which clotting factors?

Answer 10

factors 2,7,9,10,

protein C and S

Question 11

T/F -

Warfarin can cause a hypercoagulable state

Answer 11

True - due to blocking protein C/S before other clotting factors.

This is why you should overlap with heparin for at least 5 days.

Question 12

When is thrombolytic therapy indicated?

Answer 12

-for a massive PE when systolic BP

Question 13

Where do most pulmonary emboli come from?

Answer 13

The proximal ileo-femoral veins. Thrombi in these veins can grow/extend asymptomatically and recurrently embolize when not treated.

Question 14

Recommendations for preventing pulmonary embolism in low bleed risk patients

Answer 14

heparin (either form)

Question 15

Recommendations for preventing pulmonary embolism in high bleed risk patients

Answer 15

pneumatic stocking (prevent pooling / thrombosis)

Question 16

Major risk factors for PE

Answer 16

• immobilization
• surgery w/in three months
• stroke
• history of VTE
• malignancy (cancer)

Question 17

T/F if chest wall pain is reproducible with pressure, this makes PE a more likely diagnosis

Answer 17

FALSE. worthless.

Also of note: pulse ox may be normal in 20% of cases of PE

Question 18

what is hampton

s hump?

Answer 18

pleural-based, wedge shaped density.(infiltrate) on CXR. This is pathognomonic for PE, but rarely seen

Question 19

T/F Most EKG’s are abnormal in PE patients

Answer 19

TRUE.
But they are not abnormal in a characteristic pattern - so it is not very helpful in diagnosis (insensitive and nonspecific).

Question 20

Value of V/Q scan in diagnosing PE

Answer 20

if you have high pretest clinical probability, and it is positive, you can rule in PE. If you have low pretest probability and it is low, you can rule out. However, it isn’t of much use for patients in between (which is a lot of patients). Today it has been supplanted by CT angiography.

Question 21

D - dimer is described a “unidirectional test” what does that mean?

Answer 21

-it is much more helpful when it is negative ,b/c you can rule PE out, but not helpful if +.

(it is sensitive, but not very specific)

Question 22

positive value for D-dimer

Answer 22

traditionally >500

New - pt age x 10 (eg 69 year old, positive value would be >690)
-this new method is validated and better, fewer false +

Question 23

role of lower extremity doppler ultrasound in diagnosis of PE

Answer 23

it is specific - if you see a deep vein thrombus on ultrasound, stop testing and treat (same treatment for DVT and PE).

However, low sensitivity (30-40% of patients with PE have negative ultrasound).
-if it’s negative and you can’t do CT angio….
-do serial testing (higher probability)
or do pulmonary angiography

Question 24

Indications for getting a Chest CT angiogram

Answer 24

Wells >4
OR..
positive D-dimer

Question 25

What should you do if Wells score is

Answer 25

get a d-dimer. if positive, get CT. If it is negative, rule out PE.

Question 26

Treatment of new, confirmed pulmonary embolism

Answer 26

anticoagulation for 3 -6 months. After discontinuing, do a d-dimer after a month and resume treatment if +.

Question 27

treatment of recurrent pulmonary embolism

Answer 27

anticoagulate for a year, maybe indefinitely, depending on risk/benefit.

Question 28

Ideal INR in a patient on warfarin

Answer 28

in between 2.0 and 3.0

Question 29

Certain medications are now replacing warfarin. What is their mechanism? - 2 mechanism

Answer 29

they inhibit factor 10a directly, or inhibit thrombin directly.

Question 30

What is the downside of direct factor 10 inhibitors and direct thrombin inhibitors?

Answer 30

• cannot use in renal failure patients
• expensive
• no reversal agents.

Question 31

utility of IVC filters for preventing PE.

Answer 31

not much value - poor data