INTRODUCTION

• A venous thrombus is the formation of a semi solid coagulum within flowing blood in the venous system.

• Venous thrombosis of deep veins of the leg is complicated by immediate risk of pulmonary embolus and sudden death.

• Risk of developing a post-thrombotic limb and venous ulceration.

AETIOLOGY

• Changes in the vessel wall(endothelial damage)

• Stasis ,diminished blood flow

• Coagulability of blood (thrombophilia)

Predisposing factors:

Injury ,esp fractures of the lower limb and pelvis pregnancy and the oral contraceptive pills.

PATHOLOGY

• A thrombus often develop in he soleal veins of the calf.

• Fibrin and red cells form a mesh until the lumen of the vein wall occludes.

• Thrombus extend as a propagated loose red clot.

• Extend up to the large venous branch ,break off and embolise to the lung.

• Embolus arising from the lower leg veins becomes detached passes through the large veins of the limb and venacava.

• Lodges in the pulmonary arteries

• Occlude the pefusion to all or part of one or both lungs.

• Sudden collapse and death.

DIAGNOSIS

• The most common presentation in DVT is pain and swelling esp in the calf.

• Many patients have no symptoms of thrombosis and present with pulmonary embolism.

• Sometimes leg appears cellulitic.

• Presenting with venous gangrene have underlying neoplasm.

• Mild pitting edemaof the ankle ,dialated veins,stiff calf and tenderness over the course of the deep veins.

• Low grade pyrexia in patients with pulmonary embolism.

• Signs-cyanosis, dyspnoea, raised neck veins, split second heart sound, pleural rub if there is right heart strain.

INVESTIGATION

• Patients with idiopathic thrombosis ususally have a D-dimer measurement.

• If d-dimer is raised ,a Duplex ultrasound examination of the deep veins should be performed.

• Ascending venography

• CTscan

DIFFERENTIAL DIAGNOSIS

• Ruptured baker’s cyst

• calf muscle haematoma

• Ruptured plantaris muscle

• Thrombosed popliteal aneurysm

• Arterial ischaemia

PROPHYLAXIS

Prophylactical methods include:

• Mechanical

• Pharmacological

Mechanical :graduated elastic compression stocking,external pneumatic compression.

These reduces the incidence of thrombosis.

Pharmacological:low molecular weight heparin given s\c .

TREATMENT

• Patients confirmed to have DVT on duplex imaging should be started on s\c low molecular weight heparin&rapidly anticagulated with warfarin.

Warfarin started at a dose of 10mgon day 1

10mg on day 2

5mg on day 3.

• Prothrombin time is taken on day 3.

• Thrombolysis :Tissue plasminogen activator in most patients is administered directly into the thrombus ,via the popliteal vein or by direct puncture in the groin.

• Thrombi can be compressed by stent grafting,this technique is very good in patients with ‘iliac vein compression syndrome’.