DVT Flashcards
Where do most DVTs occur?
DVTs are formations of a blood clot in a deep vein, most commonly in the lower extremities.
90% are proximal (femoral and iliac veins), 10% are distal (posterior tibial vein).
What is Virchow’s Triad?
The three major risk factors for thrombosis: endothelial injury, venous stasis, and hypercoagulability.
What are common risk factors for DVT?
Cancer, surgery, obesity, smoking, oral contraceptives, pregnancy, immobility, and hereditary thrombophilia.
What genetic disorders increase the risk of DVT?
Factor V Leiden mutation, prothrombin gene mutation, protein C or S deficiency, and antithrombin III deficiency.
What autoimmune disorder increases the risk of DVT?
Antiphospholipid syndrome (associated with recurrent miscarriages and arterial/venous thrombosis).
What is the most common cause of upper extremity DVT?
Effort-induced thrombosis (Paget-Schroetter syndrome), often in young athletes who perform repetitive arm movements (e.g., baseball pitchers).
What are the common symptoms of DVT?
Calf pain (Homan sign, pain with dorsiflexion), tenderness, erythema, swelling, and superficial vein dilation.
What is Homan’s sign?
Calf pain upon dorsiflexion of the foot, which is a nonspecific finding for DVT.
What are complications of untreated DVT?
Pulmonary embolism (PE), post-thrombotic syndrome (chronic venous insufficiency), and phlegmasia cerulea dolens (severe pain and edema with blue discoloration due to ischemia from excessive proximal DVT; indication for thrombolytic surgical thrombectomy).
What is the first-line diagnostic test for DVT?
Lower extremity ultrasound with Doppler.
What is the Well’s score used for?
Risk stratification of suspected DVT based on clinical probability.
<1 = low
1-2 = moderate
>3 = high
What are the criteria in the Well’s score?
Previous DVT, active cancer, immobilization, localized tenderness, leg swelling, asymmetric calf swelling, pitting edema, collateral superficial veins, hemoptysis, malignancy.
How is DVT risk stratified using the Well’s score?
Low (<1), moderate (1-2), high (≥3).
How do you manage low-risk patients (Well’s score <1)?
Order a D-dimer; if elevated, perform an ultrasound.
How do you manage high-risk patients (Well’s score ≥3)?
Proceed directly to ultrasound imaging.
What is the treatment for proximal DVT?
Anticoagulation with heparin, warfarin, low molecular weight heparin (LMWH), or direct oral anticoagulants (DOACs).
What is the duration of anticoagulation for DVT?
At least 3 months; longer if unprovoked or persistent risk factors.
When should an IVC filter be considered for DVT?
When anticoagulation is contraindicated (e.g., active bleeding).
What is the management of massive proximal DVT?
Thrombolytics (tPA) or surgical thrombectomy if severe swelling or ischemia is present.
What is the treatment for distal DVT?
Anticoagulation or close observation with serial ultrasound if asymptomatic.
What is the recommended anticoagulation for pregnancy-associated DVT?
Low molecular weight heparin (LMWH), as warfarin is teratogenic.
What is phlegmasia cerulea dolens?
A severe DVT complication causing ischemia, massive swelling, and blue discoloration.
What is post-thrombotic syndrome?
Chronic venous insufficiency due to prior DVT, presenting with pain, edema, and skin changes.
Who should receive DVT prophylaxis in the hospital?
Patients with ICU admission, cancer, stroke, CHF, MI, age >75, prior DVT, renal failure, obesity, or prolonged immobility.
What are pharmacologic options for inpatient DVT prophylaxis?
LMWH, unfractionated heparin, or fondaparinux (unless contraindicated due to bleeding risk).
What are non-pharmacologic options for DVT prophylaxis?
Mechanical compression devices (e.g., graduated compression stockings, intermittent pneumatic compression).
What is the most common inherited thrombophilia leading to DVT?
Factor V Leiden mutation.
Which cancers are commonly associated with DVTs?
Pancreatic cancer, lung cancer, and gastrointestinal malignancies (Trousseau syndrome).
What is Trousseau syndrome?
Migratory superficial thrombophlebitis associated with malignancy.
What is the gold standard test for DVT diagnosis?
Contrast venography, but it is rarely used clinically due to invasiveness.
