Both venous and arterial thrombosis are caused by a number of factors that can either increase the risk of thrombosis, or create a clotting cascade that leads to a blood clot.
The most common risk factors for thrombosis include immobility, age, obesity, a history of blood clots, a family history of blood clots, cancer, certain medications, and certain medical conditions.
Immobility, such as being bedridden or sitting for long periods, can impair blood flow which increases the risk of a clot forming. Age is also a risk factor, as the older a person is, the more likely they are to develop a clot. Obesity increases the risk of thrombosis by increasing the likelihood of immobility, as well as increasing the risk of developing conditions that increase the risk of clotting.
A history of blood clots increases the risk of developing another clot, as does having a family history of blood clots. Cancer can also increase the risk of thrombosis, as can certain medications such as oral contraceptives and estrogen. Certain medical conditions, such as diabetes, heart failure, and stroke, can also increase the risk of thrombosis.
In addition, a clotting cascade can lead to thrombosis. In this process, small pieces of a clot form and travel through the bloodstream, eventually collecting enough pieces of the clot to form a large clot. This is why it is important to seek medical attention if you have any signs or symptoms of a clot, as early treatment can help prevent the formation of a larger clot.