The blood in our body is in a liquid state so that it can circulate through arteries and veins; it only coagulates when it is necessary to cut off blood flow.
For this to happen, there is a series of anticoagulative and procoagulative elements dissolved in the blood, which are in balance. However, this mechanism does not always work correctly and sometimes the blood coagulates during circulation, forming a thrombus that prevents blood circulation, and that is when venous thrombosis occurs.
The symptoms of venous thrombosis depend on whether the thrombus has occurred in a superficial vein or a deep vein. In addition, its importance and severity vary greatly in one case or another.
Thrombi can occur in both arteries and veins, but it is much more common for them to occur in venous vessels, especially in the veins of the legs.
Within the veins of the legs we can differentiate two types: deep veins and superficial veins. Superficial veins are the veins that are just under the skin and can be seen with the naked eye as bluish lines.
The most important superficial veins of the legs are the internal saphenous and the external saphenous. There are several reasons why the blood balance can be decompensated and cause coagulation within the veins and venous thrombosis. The most important ones are:
Venous stasis: or what is the same, stagnation of blood in the veins of the legs. This often happens when varicose veins appear in the legs.
Traumatism: Broken bones or ligaments of the lower extremities make their mobility very limited.
Cancer: Some types of cancer by themselves are capable of increasing the amount of procoagulant substances in the blood, thus making venous thrombosis in the legs frequent.
Infection: In a local infection, the bacteria are capable of activating the procoagulant substances in the blood, gradually forming thrombi that end up interrupting the blood flow and perpetuating the infection (these cases occur more frequently in the arms).
Dehydration: The loss of body water causes the blood to be denser than usual, hindering continuous flow in small vessels and favoring coagulation.
Congenital hypercoagulability: Refers to people who, by genetic inheritance, have blood that is easier to coagulate than usual.
Tobacco: Smoking is a widespread cause of venous thrombosis in our society.
Drugs: Some drugs have a tendency to facilitate blood clotting. Some examples are diuretics (because they can increase body water loss) and also oral contraceptives. Heart failure: This malfunction of the heart causes venous blood to not be easily collected by it and to pool in different body organs (lungs, liver and legs).
Pregnancy: The pregnant woman already has a state of natural hypercoagulability that develops throughout the pregnancy, with the aim of stopping the foreseeable bleeding during childbirth.
Obesity: The usual thing is that obesity is associated with a greater sedentary lifestyle and, therefore, with venous stasis.
Prevention of venous thrombosis: The ideal is to stop smoking, perform moderate physical exercise frequently and maintain an adequate weight. Second, extraordinary measures must be taken in special situations. An example of this is preventing economy class syndrome, a disorder in which venous stasis occurs in the leg during a long-term trip (transatlantic flight).
