PATHOPHYS: Pulmonary Embolism and DVT Flashcards

1
Q

True or false: 90% of emboli in pulmonary thromboembolism arise from the lower extremities.

A

TRUE

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2
Q

True or false: bronchospasm and wheezing are seldom a part of the physical findings in pulmonary thromboembolism.

A

FALSE

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3
Q

True or false: the reason for hypoxia in pulmonary thromboembolism is usually alveolar ventialtions.

A

FALSE: it is due to V/Q mismatch

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4
Q

True or false: anticoagulation therapy should not be initiated until the diagnose is proven.

A

FALSE

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5
Q

True or false: the pathogologic EKG finding of S1Q3T3 is seen only in a minority of patients.

A

TRUE! it is only seen in LARGE PEs (shows right ventricle strain)

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6
Q

True or false: PE is usually diagnosed during routine CXR.

A

FALSE: 67% are diagnosed after death at autopsy

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7
Q

True or false: most people with a PE die from it.

A

False, 11% die suddenly but most people do not even realize they have them

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8
Q

If an elderly patient has mental status change, thrombocytopenia, and petechiae after a long bone break, what should be on the differential?

A

Fat embolus

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9
Q

What are the factors of Virchow’s Triad?

A
  • Venous stasis
  • Hypercoagulability
  • Endothelial injury
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10
Q

What are some causes of venous stasis that can lead to a PE?

A

immobility
bed rest
anesthesia
CHF

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11
Q

What are some congenital causes of hypercoagulability that can lead to a PE?

A

Factor V Leiden mutation (V cannot be broken down by protein C)

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12
Q

What are some acquired causes of hypercoagulability that can lead to a PE?

A
Estrogen use
Hormonal changes during pregnancy
malignancy (via TF activation)
HIT
Nephrotic syndrome
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13
Q

What is the most common cause of thrombocytopenia int he ICU?

A

DIC (due to sepsis/cancer)

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14
Q

True or false: HIT is a bleeding disorder.

A

FALSE: though it does cause thrombocytopenia it causes tons of clots!

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15
Q

How do risk factors and DVT incidence coorelate?

A

4 or more met risk factors coorelates with 100% confirmation of DVT

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16
Q

What are the determinants of the physiologic consequences of PE?

A
  • Size of embolus
  • Cardiopulmonary reserve status
  • neurohormal substances
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17
Q

True or false: PE will decrease pulmonary vascular resistance.

A

FALSE: increases it due to vascular obstruction and neurohormonal agents like serotonin and endothelin causing vasoconstriction

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18
Q

True or false: PE impairs gas exchange.

A

TRUE! increased alveolar dead space from vascular obstruction (ventilated but NOT perfused–leads to V/Q mismatch)

19
Q

What finding on a PFT is very suggestive of PE?

A

low DLCO (but PFTs are rarely done on PE patients)

20
Q

How can PE lead to a right to left shunt?

A

if a PE is large enough, it will “shut off” circulation to one lung. All of right heart blood will have to go to a single lung (and some of this blood will not be oxygenated because not enough alveoli are left to be recruited!)

21
Q

Why are infarcts NOT common in the lung?

A

lung has dual circulation

22
Q

What is the most common abnormality on a CXR of a patient with PE?

A

atelectasis

23
Q

True or false: patients with PE will be hypercapnic.

A

FALSE: hypocapnic, because they will increase their respirations to fight hypoxia

24
Q

True or false: PEs always have a negative effect on a person’s oxygenation?

A

FALSE: vasodilation of uninvolved vasculature (part of lung that is not blocked) helps to increase the pulmonary vascular resistance and improves V/Q relationship in uninvolved areas (ex. involves apex more)

25
Q

What are some fates of clots in the lung?

A

1) Fibrinolysis
2) Organization
3) Partial resolution/ compensation

26
Q

What is the gold standard diagnostic test for PE?

A

(pulmonary angiography)

but now a helical CT is more commonly done

27
Q

What are D-dimers?

A

by-products of fibrinolysis (increase after trauma)

28
Q

What is the most common finding of a CXR of a PE patient?

A

normal CXR

29
Q

What is PITCHED?

A
Way to clinically predict PE
Previous DVT/PE (1.5)
Immobilizaiton/Surgery past 4 weeks (1.5)
Tacycardia (HR> 100) (1.5)
Cancer(1) 
Hemoptysis (1)
Edema/Symptoms of DVT (3)
Diagnosis other than PE less likely (3)

If ? 6 points–high risk

30
Q

What is Hampton’s Hump?

A

triangular area of infarcted lung

31
Q

What is “Westermark’s Sign”?

A

When you do not see any vasculature on one side

32
Q

Why might you get an elevated hemidiaphragm with PE?

A

decreased surfactant may lead to atelectasis (so lung not able to deep diaphragm down

33
Q

True or false: you can confirm PE with a high clinical suspicion and a high probability V/Q scan.

A

TRUE: and you can rule one out with a low clinical suspicion and low probability V/Q scan

34
Q

What are pitfalls to V/Q scanning?

A
  • 15 second breath hold
  • Better results in patients without structural disease
  • 30% observer variability
  • Majority of scans are indeterminate
35
Q

What will a PE look like on a pulmonary angiography?

A
  • filling defect

- cutoff sign

36
Q

True or false: a normal perfusion scan excludes PE.

A

TRUE

37
Q

In low clinical probability settings, when is the possibility of PE very low (after what tests)?

A

Normal perfusion scan

d-dimer <500

38
Q

What are some clinical manifestations of DVT?

A
swelling of leg
duskiness
Homan's sign
palpable deep thrombi
tender cord in femoral triangle
39
Q

What is the gold standard for testing DVT?

A

ascending contrast venography

but not practical

40
Q

What is the most practical test for diagnosis of DVT?

A

Real-time (B-mode) ultrasonogrpahy

41
Q

How do you prevent DVTs?

A
  • Early mobilization
  • compression stockings
  • Heparin 5000 units SQ every 8 hours
  • Enoxaparin (low molecular weight heparin)
42
Q

How do you test for efficacy of low molecular weight heparin?

A

Factor Xa

enoXaparin

43
Q

How do you test for efficacy of heparin?

A

aPTT (activated partial thromboplastin time)

44
Q

What are some treatment options for DVT?

A
  • Thrombolysis (ex. t-PA)
  • Radiological intervention (clot disruption catheters)
  • Surgical (pulmonary embolectomy)