Deep Vein thrombosis and Pulmonary embolism

DVT and PE

Evans OmondiMunyaga Byanjo

CONTENT

DefinitionEpidemiologyAetiology Risk factorsPathophysiology Clinical PresentationInvestigationsTreatmentComplicationsPrevention

Defn:

Deep vein thrombosis(DVT)• Is the formation of blood clots in the deep

veins. Most commonly involves calf, femoral or iliac veins.Is less common in the upper limbs but the axillary vein may be involved as a complication of trauma, long venous infusion catheters, neoplasm or radiotherapy.

Epidemiology

• Common in older women >40 years• Incidence is at 0.2% in ante-natal period and

0.6% in postpartum. The incidence rises to 1-2% post caesarian section.

• Left leg>80%• Ileofemoral more common than calf vein (72%

versus 9%)• Unfortunately only 5-10% are symptomatic.

Aetiology

This is based on the Virchow’s triad: • Stasis• Endothelial injury• Hypercoagulability stateVenous stasis-immobility (prolonged bed rest, limb paralysis) low cardiac output(heart failure) varicose veins.

• Venous injury- Trauma, i.v cannulation.• Increase coagulability-malignant diseases,

drugs(oestrgen,oral contraceptives)dehydration,polycythaemia

• Inherited coagullation effect- Antithrombin III, protein C, protein S.

Risk factors

• Abdominal or pelvic surgery• Old age• Prolonged surgery and general anaesthesia• Obesity• Malignancy• Prior DVT• Increase coagulation diseases-protein C or S

• Oestrogen• Oral contraceptive pills• Smocking• Prolonged bed rest• Pregnancy

Pathophysiology

• The thrombus occur in the deep veins of the leg. Usually originate around the valves. The calf vein is the usual site.

• It may also originate in the iliac or femoral vein.

• There is progressive obstruction following thrombosis in the deep veins.

Clinical presentation

Symptoms:»Asymptomatic »Pain» Swelling » Increase in temperature» Engorgement of superficial veins» Erythema

Signs:» Fever, calf warmth, tenderness, pitting

oedema, cyanotic limb.» Homan’s sign (increased resistance/ pain on

forced foot dorsiflexion)- may dislodge the thrombus.

Well’s Score

Each of following scores a point» Active cancer(Rx within last 6mths or palliative)» Paralysis, paresis or recent plaster immobilisation» Major surgery in last 4wks or recently bedridden > 3days.» Local tenderness along distribution of deep venous system» Entire leg swollen» Calf swelling > 3cm compared to asymptomatic leg measured 10cm below the tibial tuberosity» Pitting oedema> in the symptomatic leg» Collateral superficial vein

» Alternative diagnosis is more likely than DVT minus 2 pts.

» Score ≥ 3pts, DVT is likely» Score 1-2, treat as suspected DVT and perform

compression US» Score ≤ 0 perform D- dimer test.

Investigations

• Ascending venograpthy; invasive but more sensitive than duplex

• Doppler U/S• Blood • CBC• INR• Duplex U/S• Venography

Treatment

• Aim of Rx is to prevent further thrombosis and pulmonary embolisation,

• Bed rest, elevate the limb, good hydration.• Calf vein thrombosis may be treated by

compression stockings. • LMWH e.g. Enoxaparin preferred to

unfractionated heparin because:» It has a higher bioavailability.» Less risk of bleeding

Oral anticoagulants:» Warfarin- it inhibits synthesis of vitamin k dependent

clotting factors (II, VII, IX, X), proteins C and S.» LMWH is given first for 3-5 days then Warfarin» The duration for Warfarin is still debatable

However if the risk is reversible its given for 6wks-6months

» Before starting and during treatment, the patient’s INR is monitored.

DDx

• Ruptured Baker’s cyst• Cellulitis• Calf hematoma• Lymphoedema

Complication

• PE-most feared• Venous Gangrene• Recurrent DVT• Varicose veins• Chronic venous insufficiency• Post phlebitic syndrome (pain, oedema,

ulceration)

Prevention

• Avoid the risk factors-obesity,smoking• Prevent blood stasis in susceptible patients

through ambulation, use of elastic stockings, exercise or elevation of legs

• Prophylaxis of susceptible patients with low dose Aspirin

Thank you