[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Conditions](https://durgical.com/en/conditions/) › Deep vein thrombosis [Conditions](https://durgical.com/en/conditions/) · [Lower limb](https://durgical.com/en/anatomy/region/lower-limb/) # Deep vein thrombosis Deep vein thrombosis is a blood clot in a deep vein, usually of the leg; it can cause a swollen, painful leg and can travel to the lungs. Updated 2026-10-30 ## Structures involved Tap one to see what it is and open it in 3D. - [Femoral vein](https://durgical.com/en/anatomy/femoral-vein/) - [Popliteal vein](https://durgical.com/en/anatomy/popliteal-vein/) - [Leg veins](https://durgical.com/en/anatomy/anterior-tibial-veins/) - [Deep femoral vein](https://durgical.com/en/anatomy/deep-femoral-vein/) - [External iliac vein](https://durgical.com/en/anatomy/external-iliac-vein/) - [Great saphenous vein](https://durgical.com/en/anatomy/great-saphenous-vein/) - [Small saphenous vein](https://durgical.com/en/anatomy/small-saphenous-vein/) - [Soleus](https://durgical.com/en/anatomy/soleus-muscle/) - [Gastrocnemius (inner head)](https://durgical.com/en/anatomy/medial-head-of-gastrocnemius/) ## In biochemistry - [Homocysteine](https://durgical.com/en/biochemistry/molecules/homocysteine/) - [Vitamin K epoxide reductase (VKORC1)](https://durgical.com/en/biochemistry/enzymes/vitamin-k-epoxide-reductase/) - [Vitamin K (phylloquinone)](https://durgical.com/en/biochemistry/molecules/vitamin-k/) ## In histology - [Blood vessels: artery, vein and capillary layers](https://durgical.com/en/histology/blood-vessels-artery-vein-and-capillary-layers/) ## In embryology - [Warfarin embryopathy](https://durgical.com/en/embryology/warfarin-embryopathy/) ## In the clinical exam - [Signs of deep vein thrombosis: Homans and the Wells score](https://durgical.com/en/clinical-exam/signs-of-deep-vein-thrombosis-homans-and-the-wells-score/) - [Varicose veins: the Trendelenburg (Brodie–Trendelenburg) test](https://durgical.com/en/clinical-exam/varicose-veins-the-trendelenburg-test/) - [Edema: pitting, grading and distribution](https://durgical.com/en/clinical-exam/edema-pitting-grading-and-distribution/) ## In physiology - [The coagulation cascade](https://durgical.com/en/physiology/the-coagulation-cascade/) - [Fibrinolysis and natural anticoagulants](https://durgical.com/en/physiology/fibrinolysis-and-natural-anticoagulants/) - [Thrombosis and bleeding: Virchow's triad and hemostatic defects](https://durgical.com/en/physiology/thrombosis-and-bleeding-virchow-s-triad-and-hemostatic-defects/) ## Why it happens - [Hypercoagulable states: inherited and acquired](https://durgical.com/en/general-pathology/hypercoagulable-states-inherited-and-acquired/) - [Thrombosis and Virchow's triad](https://durgical.com/en/general-pathology/thrombosis-and-virchow-s-triad/) - [Arterial vs venous thrombi; mural thrombi and lines of Zahn](https://durgical.com/en/general-pathology/arterial-vs-venous-thrombi-mural-thrombi-and-lines-of-zahn/) - [What happens to a thrombus: propagation, embolism, dissolution, organization](https://durgical.com/en/general-pathology/what-happens-to-a-thrombus-propagation-embolism-dissolution-organization/) - [Pulmonary thromboembolism: where it comes from and what it does](https://durgical.com/en/general-pathology/pulmonary-thromboembolism-where-it-comes-from-and-what-it-does/) ## What it is A blood clot (thrombus) in a deep vein, most often of the leg or [pelvis](https://durgical.com/en/anatomy/region/pelvis/). Together with pulmonary embolism it forms venous thromboembolism. ## Who gets it Common in hospitalised, post-surgical, trauma and cancer patients, and more frequent with age. Latin American data are scarce: a 2016 review cites an Argentine estimate, extrapolated from one hospital, of 0.48 DVT cases per 1,000 person-years, and about half of hospitalised patients in Mexico and Brazil were at risk. Thromboprophylaxis is standard hospital care. ## Causes - Virchow's triad: slow or stagnant flow, vein-wall injury and a hypercoagulable state - Immobility after surgery, trauma, plaster casts or long journeys - Inherited or acquired clotting disorders ## Risk factors - Recent major surgery, especially hip or knee surgery, or hip fracture - Active cancer - Previous venous thromboembolism - Pregnancy, the postpartum period, and oestrogen-containing contraception or hormone therapy - Older age, obesity and prolonged bed rest - Central venous catheters ## Pathophysiology Clots usually start in the valve pockets of calf veins where flow is slow. They can grow upward into the popliteal, femoral and iliac veins (proximal DVT). Pieces of a proximal clot can break off and lodge in the [pulmonary arteries](https://durgical.com/en/anatomy/right-pulmonary-artery/). Damage to the valves can leave lasting venous hypertension. ## Classification - Distal (calf veins only) - Proximal ([popliteal vein](https://durgical.com/en/anatomy/popliteal-vein/) and above) - Provoked (clear transient trigger) or unprovoked ## Symptoms and signs - Swelling of one leg, often with a calf circumference difference - Pain or tenderness along the deep veins - Warmth and redness of the leg - Prominent superficial veins (non-varicose) - May be silent: many clots cause few or no signs ## Red flags - Sudden breathlessness, [chest](https://durgical.com/en/anatomy/region/chest/) pain or coughing blood (possible pulmonary embolism) - Fainting, low blood pressure or fast heart rate - A very swollen, bluish, painful leg (phlegmasia), which threatens the limb ## Diagnosis **Clinical** Pre-test probability with the Wells score for DVT guides the work-up; signs alone are unreliable. **Tests** D-dimer: a normal result helps exclude DVT when probability is low; it is non-specific (raised after surgery, in pregnancy, cancer, infection). Baseline blood count, clotting tests and [kidney](https://durgical.com/en/anatomy/kidney/) function before treatment. **Imaging** Compression ultrasound (a vein that does not collapse under the probe holds a clot) is the test of choice. CT or MR venography for pelvic veins. ## Differential diagnosis - Baker's cyst rupture - Cellulitis - Calf muscle strain or tear - Superficial thrombophlebitis - Lymphoedema or heart, [liver](https://durgical.com/en/anatomy/liver/) or kidney oedema ## Goal of treatment Stop the clot from growing, prevent pulmonary embolism and recurrence, and limit post-thrombotic syndrome, while keeping bleeding risk low. ## Treatment **Medical** Anticoagulation is the mainstay: low-molecular-weight heparin, unfractionated heparin, direct oral anticoagulants or vitamin K antagonists, chosen by the patient's profile; length depends on provoked or unprovoked cause. **Procedure** Thrombolysis or catheter-directed clot removal for selected cases (e.g. limb-threatening DVT); an [inferior vena cava](https://durgical.com/en/anatomy/inferior-vena-cava/) filter when anticoagulation cannot be given. **Conservative** Early walking once anticoagulated; compression stockings may help symptoms, though their role in prevention is debated. **Follow-up** Follow-up for bleeding, recurrence and post-thrombotic symptoms; cancer screening is considered in some unprovoked cases. ## Drugs for this condition - [Warfarin](https://durgical.com/en/pharmacology/warfarin/) - [Heparin](https://durgical.com/en/pharmacology/heparin/) - [Rivaroxaban](https://durgical.com/en/pharmacology/rivaroxaban/) - [Dabigatran](https://durgical.com/en/pharmacology/dabigatran/) - [Apixaban](https://durgical.com/en/pharmacology/apixaban/) - [Enoxaparin](https://durgical.com/en/pharmacology/enoxaparin/) - [Fondaparinux](https://durgical.com/en/pharmacology/fondaparinux/) - [Edoxaban](https://durgical.com/en/pharmacology/edoxaban/) - [Dalteparin](https://durgical.com/en/pharmacology/dalteparin/) ## Complications - Pulmonary embolism, which can be fatal - Post-thrombotic syndrome (chronic swelling, pain, [skin](https://durgical.com/en/anatomy/skin/) changes, ulcers) - Recurrent venous thromboembolism - Bleeding from anticoagulation - Chronic thromboembolic pulmonary hypertension (after PE) ## Prognosis With prompt anticoagulation most patients recover well. Recurrence is more likely after unprovoked clots, and a proportion develop post-thrombotic syndrome. ## Prevention - Risk assessment and thromboprophylaxis (drug or mechanical) for hospitalised and surgical patients - Early mobilisation after surgery - Moving the legs and staying hydrated on long journeys ## Test yourself Think of the answer, then tap the question to see it. ## Which three elements make up Virchow's triad? Venous stasis, endothelial (vein-wall) injury and hypercoagulability. ## What is the first-line imaging test for suspected leg DVT? Compression ultrasound: a deep vein that cannot be compressed contains a thrombus. ## When is a normal D-dimer most useful? When clinical probability (e.g. Wells score) is low: a normal D-dimer then helps rule out DVT. A raised D-dimer is non-specific. ## What is the most feared acute complication of proximal DVT? Pulmonary embolism, when part of the clot travels to the pulmonary arteries. ## What chronic complication causes leg swelling, skin changes and ulcers after DVT? Post-thrombotic syndrome, from valve damage and persistent venous hypertension. [Add to my cards (5)](https://durgical.app/estudiar/?add=/en/conditions/deep-vein-thrombosis/) ## Related conditions - [Intertrochanteric hip fracture](https://durgical.com/en/conditions/intertrochanteric-hip-fracture/) - [Femoral Neck Fracture](https://durgical.com/en/conditions/femoral-neck-fracture/) - [Varicose veins](https://durgical.com/en/conditions/varicose-veins/) - [Baker's (Popliteal) Cyst](https://durgical.com/en/conditions/baker-s-cyst/) - [Lymphoedema](https://durgical.com/en/conditions/lymphoedema/) - [Patellar fracture](https://durgical.com/en/conditions/patellar-fracture/) - [Ankle fracture](https://durgical.com/en/conditions/ankle-fracture/) - [Achilles tendon rupture](https://durgical.com/en/conditions/achilles-tendon-rupture/) Educational information, not medical advice. For any symptom, see a health professional. Sources: [Deep Venous Thrombosis](https://www.ncbi.nlm.nih.gov/books/NBK507708/) (StatPearls (NCBI Bookshelf), 2023); [Venous thromboembolism in Latin America: a review and guide to diagnosis and treatment for primary care](https://europepmc.org/article/PMC/PMC4732387) (Clinics (Sao Paulo, Brazil), 2016) · adapted, [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/). [← All conditions](https://durgical.com/en/conditions/) ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/conditions/deep-vein-thrombosis/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/deep-vein-thrombosis/