Superficial vein thrombosis (SVT) is a blood clot formed in a superficial vein, a vein near the surface of the body. Usually there is thrombophlebitis, which is an inflammatory reaction around a thrombosed vein, presenting as a painful induration (thickening of the skin) with redness. SVT itself has limited significance (in terms of direct morbidity and mortality) when compared to a deep vein thrombosis (DVT), which occurs deeper in the body at the deep venous system level. However, SVT can lead to serious complications (as well as signal other serious problems, such as genetic mutations that increase ones risk for clotting), and is therefore no longer regarded as a benign condition. If the blood clot is too near the saphenofemoral junction there is a higher risk of pulmonary embolism, a potentially life-threatening complication. SVT has risk factors similar to those for other thrombotic conditions and can arise from a variety of causes. Diagnosis is often based on symptoms. There are multiple possible treatments, with the goal of providing symptomatic relief and preventing complications. Signs and symptoms
SVT is recognized by the presence of pain, warmth, redness, and tenderness over a superficial vein. The SVT may present as a "cord-like" structure upon palpation. The affected vein may be hard along its entire length. SVTs tend to involve the legs, though they can affect any superficial vein (e.g. those in the arms). Complications
SVT in the lower extremities can lead to a dangerous complication in which the clot travels to the lungs, called pulmonary embolism (PE).
This is because lower limb SVTs can migrate from superficial veins into deeper veins. In a French population, the percent of people with SVTs that also suffered from PEs was 4.7%. In the same population, deep vein thrombosis (DVT) was found in 24.6% of people with SVTs. However, because superficial veins lack muscular support, any clots that form are far less likely to be squeezed by muscle contraction, dislodged, and induce a PE.SVTs can recur after they resolve, which is termed "migratory thrombophlebitis." Migratory thrombophlebitis is a complication that may be due to more serious disorders, such as cancer and other hypercoagulable states. Causes
SVTs of the legs are often due to varicose veins, though most people with varicose veins do not develop SVTs. SVTs of the arms are often due to the placement of intravenous catheters.Many of the risk factors that are associated with SVT are also associated with other thrombotic conditions (e.g. DVT). These risk factors include age, cancer, history of thromboembolism, pregnancy, use of oral contraceptive medications (containing estrogen), hormone replacement therapy, recent surgery, and certain autoimmune diseases (especially Behçets and Buergers diseases). Other risk factors include immobilization (stasis) and laparoscopy.Hypercoagulable states due to genetic conditions that increase the risk of clotting may contribute to the development of SVT, such as factor V Leiden, prothrombin 20210A mutation, and protein C, S, and antithrombin III and factor XII deficiency. Mechanism
The mechanism for the development of an SVT depends upon the specific etiology of the SVT.