Formation of blood clot inside the blood vessels is called thrombosis and the blood clots that are formed inside the veins situated deep within the body are called deep vein thrombosis or DVT. Lower legs and thighs are the most common body parts that are affected by deep vein thrombosis. The blood clot at times can detach from its location and travel through the blood stream to other parts of the vascular system. Such a floating blood clot is called embolus. It may even travel to the lungs and block the blood supply to the lungs resulting in a condition called pulmonary embolism. There are two types of deep vein thrombosis distinguished. They are,
Non occlusive thrombosis – that do not completely obstruct the blood flow through the vein.
Occlusive thrombosis – that completely obstruct the blood flow through the vein.
Common Causes of Deep Vein Thrombosis
Centuries ago, the occurrence of deep vein thrombosis associated with pregnancy was clearly understood. However, they believed that the symptoms are due to milk deposits in the thigh muscles and called it ‘milk leg.’ It resulted in one of the earliest public health notifications asking mothers to breast feed their children to avoid the complications of ‘milk leg’.
In United States, an estimated 300,000 fresh cases of DVT is reported every year. Certain factors greatly increase the risk of deep vein thrombosis. Young people are less likely than older people to develop thrombosis. Conditions such as cancer, surgery, being confined to bed, etc. can provoke DVT. There are also some speculated factors such as inheritance or congenital onset in people who develop DVT spontaneously. Hormonal drugs such as oral contraceptives also cause deep vein thrombosis. Technically, changes in the vessel wall, changes in the blood flow, and changes in the blood composition are the major causes of deep vein thrombosis.
Symptoms and signs of deep vein thrombosis
At onset, common symptoms of inflammation such as redness, warmth, tenderness, and swelling of the vein and nearby tissues are observed. Some people start to experience DVT as night let pains. Visible dilation of the surface veins is also observed. Most people notice it when their leg swells and become painful. Discoloration of the surrounding skin may follow. Tingling in the leg veins and tiredness are other symptoms. In cases of immediate onset DVT, some people experience fever, dizziness, extreme swelling, purple-reddish coloration, and of course, strong pains.
James, A. H., Ortel, T. L., & Tapson, V. F. (2008). 100 Questions & Answers About Deep Vein Thrombosis and Pulmonary Embolism. London: Jones and Bartlett Publishers.