Deep vein thrombosis

Deep vein thrombosis (DVT) is the development of a blood clot within a vein deep to the muscular tissue planes.

Patients who develop DVT commonly have risk factors, such as active cancer, trauma, major surgery, hospitalisation, immobilisation, pregnancy, or oral contraceptive use. DVT may also be unprovoked (idiopathic) and occur in the absence of any identifiable extrinsic risk factors.

DVTs commonly cause asymmetrical leg swelling, unilateral leg pain, dilation or distension of superficial veins, and red or discolored skin, but can also be asymptomatic.

Assessment of pre-test probability (using a validated score such as Wells) is key if DVT is suspected, and should be used in combination with an algorithmic diagnostic approach to avoid unnecessary imaging when the likelihood of DVT is low.

Diagnosis requires confirmation of a blood clot in a deep vein in the leg, pelvis, or vena cava by venous ultrasound imaging (or other imaging techniques such as computed tomography scan).

DVT is usually treated with anticoagulants such as unfractionated heparin, low molecular weight heparin, fondaparinux, rivaroxaban, apixaban, edoxaban, dabigatran, and/or warfarin. Interventional therapies, including thrombolysis, are rarely indicated.

Generally, anticoagulant therapy for at least 3 months is required for patients with DVT. Thereafter, continued anticoagulant therapy for secondary prevention is indicated in selected patients to reduce the risk of recurrent events.

Post-thrombotic syndrome may occur with symptoms of chronic pain, swelling, skin discoloration, or venous ulcers following chronic obstruction of venous outflow and/or incompetence of venous valves.

DVT is the development of a blood clot in a major deep vein in the leg, thigh, pelvis, or abdomen. It may also occur in less common locations such as the arm veins; the portal, mesenteric, ovarian, or retinal veins; or the veins and venous sinuses of the brain. DVT can result in impaired venous blood flow. DVT is rarely life-threatening on its own, but has the potential to cause pulmonary embolism (PE), which can be fatal. Venous thromboembolism is the broad term that includes DVT and PE. Superficial vein thrombophlebitis (also known as superficial vein thrombosis), a common related condition, affects veins superficial to the musculature. This topic focuses on the diagnosis and management of lower-extremity DVT.