deep vein thrombosis
Post on 15-Jul-2015
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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’.
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