Deep vein thrombosis

David Hughes

Pathophysiology

• normal deep pelvic/leg veins• thrombus (red cells, fibrin) around valves• propagation• Virchow’s triad (endothelium, coagulability,

stasis)

Symptoms

• asymptomatic• warm, red, swollen leg• unilateral pain, improved by elevation• gradual onset• superficial venous distension• pitting oedema• mild fever• tachycardia

Wells criteria

• active Ca (Rx last 6/12 or palliative) +1• calf swelling >3cm compared to other calf +1• distended non-varicose superficial veins +1• pitting oedema +1• previous DVT +1• swelling of entire leg +1• localised pain along deep venous system +1• paralysis/paresis/recent cast immobilisation lower limbs +1• recently bedridden > 3/7 or major surgery in past 4/52 +1

• alternative diagnosis at least as likely -2

Wells interpretation

• ≥2 - DVT likely, consider imaging leg veins• <2 - DVT unlikely, consider D-dimer to further

rule out DVT

Other predisposing factors

• age (>40)• smoking• obesity• pregnancy• oral contraceptive• HRT• thrombophilia• long-distance flight• cardiac failure• dehydration

Prophylaxis

• early mobilisation• elevation of legs• compression stockings• LMW heparin• weight loss

Differential diagnosis

• cellulitis• ruptured Baker’s cyst

Investigation

• calf circumference (calf >3cm than other 10cm below tibial tuberosity)

• D-dimer (not diagnostic, suggestive but not conclusive)

• Homan’s sign ill-advised• Doppler ultrasonography (iliofemoral)• venography (definitive, calf)

Treatment

• bed rest initially• elevate leg• analgesia• compression stocking (post-thrombotic)• anticoagulation• Rx-dose heparin (1.5mg/kg/24h SC)• warfarin for 3-6/12 (INR 2-3)• thrombolysis/surgery (extensive, limb-

threatening)

Complications

• PE (~10%)• post-thrombotic syndrome• recurrence DVT (~20%)