Deep Vein Thrombosis Flashcards
1
Q
What is a DVT
A
When thrombus (blood clot) forms in deep veins - usually in leg
2
Q
How common is it
A
Affects 20-25% surgical pt
1 in 1000
3
Q
What are the causes/ risk factors in developing DVT
A
- Previous Hx of VTE – strongest risk factor
- Age >60
- Family Hx
- Immobilisation – after stroke, long-distance travel, surgery – esp ortho/pelvic
- Cancer
- Pregnancy
- BMI >30 (obese)
- Smoker
- Male
- Acquired or familial thrombophilia
- HF, varicose veins, antiphospholipid syndrome
- Trauma/ chronic low-grade injury (e.g. vasculitis, chemotherapy)
- COC pill / hormone replacement therapy
4
Q
What is the pathophysiology of DVT
A
- Solid mass formed in circulation from constituents of blood –> causes inflammation of vein wall
5
Q
What are the symptoms
A
- 65% asymptomatic (rarely embolise to lung)
- Calf pain
- Swelling
- Erythema –> if complete occlusion cyanotic
- Temp increase
- Engorged superficial veins
- Mild fever
6
Q
What are the signs of DVT
A
- Pitting / ankle oedema
- Homan’s sign - resistance/pain on forced foot dorsiflexion
- Palpable cord - hard thickened palpable vein
- Post-phlebitis syndrome - may be from chronic venous obstruction from DVT
7
Q
What are some differential Dx
A
- Cellulitis
- Ruptured Baker’s cyst
- trauma
- Superficial thrombophlebitis
- peripheral oedema, HF, vasculitis, septic arthritis, compartment syndrome
8
Q
What investigations do you perform
A
WELLS SCORE for clinical probability of DVT
- Active cancer
- Paralysis, paresis, recent plaster immbolisation
- Major surgery
- Local tenderness along distrib deep venous sys
- Entire leg swollen
- Calf swelling >3cm compared
- Pitting oedema
- Collateral superficial veins (non-varicose)
- Alt Dx more likely = -2
3 or more = high pretest prob - treat as DVT
1-2 = intermediated - treat as suspected DVT + perform compression US
0 = low - perform D-Dimer, if raised treat as DVT
- thrombophilia test before commencing anticoagulations
9
Q
What is a D-Dimer
A
- D-dimers = fibrin degradation product (FDP) = small protein fragment present in blood after clot has been degraded by fibrinolysis
- +ve test doesn’t rule out other causes need US or CT
- False +ve may be due to liver disease, high RF, inflammation or malignancy
10
Q
What prevention measure are the for DVT
A
- Stop pill 4 weeks pre-op, mobilise early, support stockings
- Heparin until mobile
- LMWH (enoxaparin) SC
11
Q
How do you treat DVT
A
- LMWH
- Start warfarin + stop heparin when INR = 2-3
- Treat ~3 months afterwards
- Anti-coagulants DO NOT lyse clot already present –> THROMBOLYTIC THERAPY
