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.
Blasts affected by the disease may come together and become swollen in the liver or in the lymph nodes causing pain and leading to nausea.If the leukemic cells invade the central nervous system, then neurological symptoms (notably headaches) can occur. Uncommon neurological symptoms like migraines, seizures, or coma can occur as a result of brain stem pressure. All symptoms associated with leukemia can be attributed to other diseases. Consequently, leukemia is always diagnosed through medical tests. The word leukemia, which means white blood, is derived from the characteristic high white blood cell count that presents in most affected people before treatment. The high number of white blood cells is apparent when a blood sample is viewed under a microscope, with the extra white blood cells frequently being immature or dysfunctional. The excessive number of cells can also interfere with the level of other cells, causing further harmful imbalance in the blood count.Some people diagnosed with leukemia do not have high white blood cell counts visible during a regular blood count. This less-common condition is called aleukemia. The bone marrow still contains cancerous white blood cells that disrupt the normal production of blood cells, but they remain in the marrow instead of entering the bloodstream, where they would be visible in a blood test. For a person with aleukemia, the white blood cell counts in the bloodstream can be normal or low. Aleukemia can occur in any of the four major types of leukemia, and is particularly common in hairy cell leukemia.