DVT

1. DVT Atiya Khalid GPST1 A & E;AGH

2. Defination: • DVT is the formation of a thrombus (blood clot) in a deep vein, usually in the legs, which partially or completely obstructs blood flow. Epidemiology: • 1 in 1000 /yr • Male: female = 1.2:1 • Two thirds of proven PE have no symptoms of DVT • 5-15% with untreated DVT may die from PE • Autopsy studies demonstrate that approximately 80% of all cases of DVT and PE remain undiagnosed, (even when they are the immediate cause of death)

3. Risk factors: • Intrinsic Risk Factors: • Cancer (known or undiagnosed). • Increasing age, being overweight or obese, and male sex. • Heart failure. • Acquired or familial thrombophilia. • Chronic low-grade injury to the vascular wall (vasculitis, hypoxia from venous stasis, or chemotherapy)

4. Risk Factors: (contd) • Risk factors that temporarily raise the likelihood of DVT • Immobility ( following stroke, operation, plaster cast, hospitalization, or long-distance travel). • Significant trauma or direct trauma to a vein (intravenous catheter). • Hormone treatment (oestrogen-containing contraception or HRT ). • Pregnancy and the postpartum period. • Dehydration.

5. Clinical features • Limb pain and tenderness along the line of the deep veins. • Swelling of calf or thigh (usually unilateral). Can be bilateral ( iliac bifurcation,pelvicvein,venacavalinvolvemnet) • Distension of superficial veins. • Increase in skin temperature. • Skin discolouration (erythema or purple or cyanosed). • A palpable cord (hard, thickened palpable vein). • Low-grade fever ( rare). • There may be pain upon dorsiflexion of the foot (Homans' sign is not helpful in diagnosis as it is very non-specific_

6. DVT difficult to diagnose clinically • Many DVTs progress to PE without DVT being clinically apparent. • In those with classic clinical signs, only about 50% have DVT. • History, examination and the presence of risk factors can be unreliable in making the diagnosis, and ambulatory patients (as in primary care) may be rather different from hospital inpatients, who are the group most studied.

7. Cellulitis adds to problem Severe signs of DVT can resemble cellulitis Secondary cellulitis may develop with primary DVT Primary cellulitis may be followed by a secondary DVT Superficial thrombophlebitis may hide an underlying DVT

8. Differential Dx Physical trauma • Calf muscle tear or strain. • Haematoma • Sprain or rupture of a leg tendon. • Fracture. Cardiovascular dis • Superficial thrombophlebitis • Post-thrombotic syndrome • Venous obstruction or insufficiency, or external compression of major veins (by fetus, cancer). • Arteriovenous fistula and congenital vascular abnormalities. • Vasculitis. • Heart failure.

9. D/D Contd • Other conditions include: • Ruptured Baker's cyst • Cellulitis (commonly mistaken as DVT). • Dependent (stasis) oedema. • Lymphatic obstruction. • Septic arthritis. • Cirrhosis. • Nephrotic syndrome

10. Management: • Refer immediately for same-day assessment and management: If DVT is suspected in a pregnant woman 6/52 post-partum IVDU D-dimer testing not available or practical • If D-dimer testing is available, use the Wells Clinical Prediction Rule to assess the probability of a DVT.

11. Management: Risk assessment Score one point for each of the following: • Active cancer (treatment ongoing or within the last 6 months) • Paralysis, paresis or recent plaster immobilisation of the legs • Recently bedridden for more than 3 days or major surgery within the last 12 weeks • Localised tenderness along the distribution of the deep venous system (such as the back of the calf) • Entire leg is swollen • Calf swelling by more than 3 cm compared with the asymptomatic leg (measured 10 cm below the tibialtuberosity) • Pitting oedema (greater than on the asymptomatic leg) • Collateral superficial veins (non-varicose) • Previously documented DVT

12. Mx Contd • Subtract two points if an alternative cause is considered The risk of DVT is likely if the score is two or more, and unlikely if the score is one or less. • Refer people who are likely to have DVT for same-day assessment and management. • For people who are unlikely to have DVT: • D-dimer testing if available, and it is reasonably practical and safe to do so ( results will be reported that day). • If the D-dimer test is positive, refer immediately for further assessment and management. • If the D-dimer test is negative, reassure the person, and tell them to seek urgent medical advice if they develop difficulty breathing, increased breathing rate, or chest pain (since these symptoms may indicate pulmonary embolism).

13. Mx: Definitive Investigations: • USS • Venography • MRI

14. Mx A Practical Approach in GP setting: • Patients likely to have a DVT on the grounds of clinical suspicion or risk factors should be referred immediately to hospital. • For people who are unlikely to have DVT, perform a D-dimer test if available. • If the test is positive, refer immediately for further assessment and management. • If the test is negative, reassure the person, and tell them to seek urgent medical advice if they develop difficulty breathing, increased breathing rate, or chest pain (since these symptoms may indicate pulmonary embolism). • If D-dimer testing is not available or practical, refer for same-day assessment. • Treat the suspicion of DVT with subcutaneous LMWH if no contra-indications.1

15. Target Ranges • Patients with confirmed DVT are usually commenced on warfarin • A loading dose of warfarin is needed usually • First episode of a proximal vein thrombosis should receive anticoagulants for 6 months, with a target INR of 2.5 (±0.5 is acceptable), duration-debatable • INR 3.5 if recurrence or mechanical valves BTSconcluded that if VTE arises after surgery, 4 weeks of anticoagulation should be adequate. • In other settings, patients with new DVT, PE, or both, who do not have a persisting underlying cause or risk factor, should receive anticoagulants for 3/12

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