Deep vein thrombosis | |
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DVT in the right leg with swelling and redness | |
Classification and external resources | |
Specialty | Hematology |
ICD-10 | I80.2 |
ICD-9-CM | 453.40 |
DiseasesDB | 3498 |
MedlinePlus | 000156 |
eMedicine | med/2785 |
Patient UK | Deep vein thrombosis |
MeSH | D020246 |
Deep vein thrombosis, or deep venous thrombosis (DVT), is the formation of a blood clot (thrombus) within a deep vein, most commonly the legs. Nonspecific signs may include pain, swelling, redness, warmness, and engorged superficial veins. Pulmonary embolism, a potentially life-threatening complication, is caused by the detachment (embolization) of a clot that travels to the lungs. Together, DVT and pulmonary embolism constitute a single disease process known as venous thromboembolism. Post-thrombotic syndrome, another complication, significantly contributes to the health-care cost of DVT.
In 1856, German pathologist Rudolf Virchow postulated the interplay of three processes resulting in venous thrombosis, now known as Virchow's triad: a decreased blood flow rate (venous stasis), increased tendency to clot (hypercoagulability), and changes to the blood vessel wall. DVT formation typically begins inside the valves of the calf veins, where the blood is relatively oxygen deprived, which activates certain biochemical pathways. Several medical conditions increase the risk for DVT, including cancer, trauma, and antiphospholipid syndrome. Other risk factors include older age, surgery, immobilization (as with bed rest, orthopedic casts, and sitting on long flights), combined oral contraceptives, pregnancy, the postnatal period, and genetic factors. Those genetic factors include deficiencies with antithrombin, protein C, and protein S, the mutation of factor V Leiden, and the property of having a non-O blood type.