Diagnosis Flashcards
Risk factors for DVT
HX of thromboembolism DVT/PE
VIRCHOW’S TRIAD
Age > 40
Malignancy
Surgery > 45 min for laparotomy
Obesity
Postop inactivity >3 days
Meds: OCPs, oral estrogen, SERMS
Cardiac, COPD, IBD
List of inherited thrombophilias
Factor V Leiden
Prothrombin mutation
Protein C and/or S deficiency
Antithrombin deficiency
Antiphospholipid antibody syndrome
Multiple mutation carriers
Leiden V Mutation
- prevalence
- MOA
- Test
- ?x fold increased risk in Hz vs Homozygote
Prevalence 5-10% of caucasians
MOA: Activated protein C resistance
Test: genetic or functional assay of protein C
Hz: 3-8x risk
Homo: 50-80x risk
Prothrombin G20210A mutation
- prevalence
- MOA
- Test
- ?x fold increased risk in Hz vs Homozygote
Prevalence 2-5%
MOA: increases PROthrombin levels
Test: genetic
Hz: 3x risk
Homo: 8x risk
Protein C/S deficiency
- prevalence
- MOA
- Test
- ?x fold increased risk in Hz vs Homozygote
Prevalence <1% (uncommon cause of DVT)
Test: Protein C functional assay, checking for quality and quantity measures of function
Protein S - free antigen assay
Hz: 10x risk
Homo: so rare, we don’t know
Antithrombin deficiency
- prevalence
- Test
- ?x fold increased risk in Hz vs Homozygote
Prevalence 0.02% RARE BUT DEADLY
85% of carriers have a DVT by age 50 yo
Test: Test antithrombin III cofactor activity assay
2 types
Type I: true deficiency
Type II: functional deficiency - abnormal protein structure
50-100x risk of clot
Antiphospholipid antibody syndrome
- prevalence
- MOA
- Test
- ?x fold increased risk in Hz vs Homozygote
1/2000 have antiphospholipid SYNDROME (vs just having the antibodies which is 1-5%)
Clotting risk is variable
Test: 12w apart (two values elevated over 12 weeks)
– Lupus anticoagulant (dRVTT is a functional APL assay that tests lupus anticoagulant activity)
– Beta2 glycoprotein (IgM, IgG)
– Anticardiolipin Ab assay (IgM, IgG)
Multiple mutation carriers
- name most common multiple mutations
Factor V Leiden, Protein C and Protein S
you should test for all thrombophilia during workup
Who needs thrombophilia workup?
Patient has VTE …AND…
- Strong FMH
- Recurrent clots
- Clot in a weird place - portal vein, hepatic vein, cerebral vein, mesenteric vein
- Warfarin induced skin necrosis - suspect protein C deficiency
- ARTERY thrombus - suspect APLS
Diagnosis of DVT: CLINICAL SIGNS?
May be asymptomatic
May have LE signs that are unilateral
- swollen >3 cm vs other, warm, locally tender, venous cords (HOMAN’S IS NOT USEFUL)
Use Wells score to assess probability of DVT
How to use Wells score for DVT workup
to get a D dimer or US
Wells score is…
0 - get D dimer – if >500 ng/ml, get US
1-2 - get D dimer or US
3+ - get US
D dimer is not useful for patients with recent surgery or pregnant
Wells Scoring
A point for each:
- active cancer
- immobilization of lower extremities
- recently bedridden for > 3 days or major surgery within 4 WEEKs
- Localized tenderness along deep venous system
- entire leg swollen
- calf swelling >3 cm vs other leg (below tibial tuberosity)
- pitting edema greater in symptomatic leg
- collatoeral superficial veins?
Minus 2 points if there is another cause for symptoms
Diagnosis of DVT: IMAGING
Compression Doppler Ultrasound
- first choice test for femoral veins, popliteal veins
CT venography or MRI-venography - only for iliac vein or IVC thrombosis
Diagnosis of PE: IMAGING
Remember s/s of PE
- Dyspnea
- Pleuritic chest pain
- Cough
- Increased RR, HR, rales, calf or thigh swelling
- May have EKG changes
Get a CT PE
Modified Wells for PE, list and name points
Clinical symptoms of DVT: 3
Other dx r/o: 3
HR > 100 BPM: 1.5
Hx of immobilization/surgery past 4wks: 1.5
Previous DVT/PE: 1.5
Hemoptysis: 1
Malignancy: 1
