DVT & PE Flashcards
Components of virchows triad
Vessel wall damage
Hypercoagulability
Altered blood flow (stasis)
Hereditary deficiencies that lead to hypercoagulable state capable of producing DVT
Antithrombin deficiency Protein C and S deficiency Factor V Leiden mutation Prothrombin 20210 gene mutation Methylene tetrahydrofolate reductase deficiency (hyperhomocyteinemia) Factor XII deficiency Dysfibrogenemia
Acquired disorders associated with recurrent venous or arterial thromboembolism
Protein C and S deficiency
Dysfibrogenemias
Antiphospholipid syndrome
[note: DSA puts C and S deficiency and dysfibrogenemias in “inherited” category; DSA lists acquired risk factors as cancer, pregnancy, OCPs, HRT, PRV, smoking, antiphospholipid syndrome, and chemotherapy]
What is Homans sign
Pain in calf or popliteal area on dorsiflexion of the foot
What is Moses sign (bancroft’s sign)
Pain caused by compression of the calf against the tibia bt not when squeezing the calf itself
Lisker’s sign
Pain with percussion of the anteromedial tibia
Lowenberg’s sign
BP cuff applied to mid calf and pain elicited with inflation to 80 mm Hg
What sign might you see on visual inspection with someone with a lower extremity DVT?
Unilateral superficial venous distention — veins of affected leg distended in comparison to non-affected leg
Wells criteria for DVT
Active cancer = +1
Bedridden recently >3 days or major surgery w/i 4 weeks = +1
Calf swelling >3cm compared to other leg = +1
Collateral (nonvaricose) superficial vv. present = +1
Entire leg swollen = +1
Localized tenderness along deep venous system = +1
Pitting edema confined to symptomatic leg = +1
Paralysis, paresis, or recent plaster immobilization of LE = +1
Previously documented DVT = +1
Alternative dx to DVT as likely or more likely = -2
Scoring the wells criteria for DVT
0 = DVT unlikely
1-2 = moderate risk of DVT (proceed with high-sensitivity d-dimer testing)
3+ = DVT is likely
List 5 major diagnostic tests that may be utilized for diagnosing DVT/PE
Contrast venography Doppler venography Ventilation/perfusion scan CT pulmonary arteriography D-dimer
Pros/cons of the following for evaluation of DVT or PE:
Contrast venography
Pros:
Anatomic and luminal evaluation
Flow physiology (collaterals)
Cons:
Requires contrast (allergies, AKI)
Painful
Invasive
Pros/cons of the following for evaluation of DVT or PE:
Doppler venography
Pros: Inexpensive Easy No radiation Flow physiology
Cons:
Tech dependent
Increased false positives/negatives
Pros/cons of the following for evaluation of DVT or PE:
Ventilation/perfusion scan
Pros:
High sensitivity
Inexpensive
Cons:
Low specificity
May not demonstrate small sub-segmental defects
Pros/cons of the following for evaluation of DVT or PE:
CT pulmonary angiography
Pros:
High sensitivity and specificity
Accurate anatomy assessment certainty
Often considered “gold standard” in intermediate risk cases
Cons: Requires contrast Expensive Radiation exposure May miss small peripheral clots
Pros/cons of the following for evaluation of DVT or PE:
d-dimer
Pros:
Negative test makes DVT unlikely
Simple to perform
Cons:
Positive test is not diagnostic of DVT
Other conditions can elevate d-dimer
Explain utility of D-dimer in dx of thromboembolic dz
Pts with low clinical likelihood of DVT should undergo testing with d-dimer as combination of a low clinical probability, and negative D-dimer rules out DVT
If a D-dimer is positive, or if clinical likelihood is high, then duplex ultrasonography should be performed