Venous thromboembolism

Deep Vein Trombosis

Low risk if distal to knee, high risk if proximal to knee.

Clinical features

• mild fever
• pitting oedema
• calf tenderness
• warmth
• distended veins
• Homans' sign DANGEROUS

Pulmonary embolus

Signs

• dyspnoea
• pleuritic pain
• signs of DVT

ECG

• sinus tachycardia/AF
• P pulmonale
• R axis deviation
• RBBB
• S_IQ_IIIT_III

Diagnosis

PIOPED study (Prospective Investigation of Pulmonary Embolism Diagnosis) Worsley, Alavi. J Nucl Med, December 1995; 36(12):2380-2387.

Risk factors

1. immobility (56%)
2. surgery (54%)
3. malignancy
4. high oestrogen state (oral contraceptive pill, pregnancy)
5. previous PE/DVT
6. cardiac disease

Consider thrombophilia (Factor V Leiden mutation, Protein C, Protein S). Factor V Leiden mutation (=Activated Protein C resistance) is present in 5% of caucasians, but 20% of patients presenting with venous thromboembolic disease.

CXR

1. atelectasis (51%)
2. pleural effusion
3. pulmonary oedema
4. Hampton's Hump (wedge infarct) (23%)
5. Westermark's sign (regional oligaemia) (11%)
6. Fleischner's sign (prominent pulmonary artery)

Blood

Other imaging

• ventilation/perfusion scan (V/Q scan)
• pulmonary angiography

Treatment

• below knee DVT: watchful waiting.
• proximal DVT: heparin IV. Warfarin for 6/12; for life if recurrent.
• PE: O₂, analgesia, heparin IV. Warfarin for 6/12; for life if recurrent.
• Thrombolysis if PE >50% of pulmonary bed or pre-existing heart/lung disease.

Mortality in treated PE is 2.5%