A clot within a blood vessel is called a thrombus and the process by which it forms is known as thrombosis. It can be damaging as it might block the flow of blood.
| | | Venous Thromboembolism (VTE) | |
| | Also, part of the clot might break away and block a blood vessel further along, cutting off the blood supply to important organs. |
Deep vein thrombosis (DVT) is the formation of a blood clot in one of the deep veins within the body, such as in the leg or pelvis. This kind of thrombosis can occur after surgery and may cause redness, pain and swelling.
Pulmonary embolism (PE) is a serious condition in which the arteries leading from the heart to the lungs becomes blocked. It can occur when a blood clot breaks away from its original location and travels to the lungs. Symptoms may include sharp chest pain, shortness of breath and coughing up blood.
The process by which blood clots occur and travel through the veins is known as venous thromboembolism (VTE), the collective term for DVT and PE.
How do you get thrombosis?
There are three main factors that are important in maintaining the correct thickness and flow of blood within the vessels and disruption to any of these may trigger the formation of a blood clot: - The flow of blood – If blood is moving within a vessel it is less likely to clot. When blood flow within the veins is slowed or blocked, this allows more time for the blood to clot, prevents small clots known as microthrombi from being washed away, and increases the thickness of the blood.
- The vessel wall – The lining of the vessel wall needs to be intact. Damage to the wall (e.g. caused by surgery or injury) hinders the flow of blood and leads to the formation of a blood clot.
- Blood composition – There are a number of substances present in the blood that can affect clotting. The body maintains an effective balance between processes that dissolve and form blood clots. If this balance is disturbed and there are too many blood-clotting factors present, this increases the tendency of the blood to clot.
A number of conditions and risk factors that cause poor blood circulation or thickening of the blood, increase the risk of developing VTE. Blood clots that form in the veins near the surface of the skin are common and may cause reddening and soreness of the skin (thrombophlebitis). These blood clots are rarely serious.
Most deep vein clots occur in veins of the leg or pelvis. Swelling, discomfort, redness, or warmth in your legs may be the first sign of a clot forming, although in many cases there are no initial symptoms. DVT itself is not life threatening.
If part of a clot dislodges and blocks the flow of blood to the lungs (pulmonary embolism or PE) this may cause chest pain, shortness of breath and possibly haemoptysis (coughing up of blood). A large clot in the lungs may obstruct blood circulation, causing breathlessness, dizziness or shock and may be life threatening.
There are a number of medicines, mechanical therapies and surgical procedures that can be used in both the prevention and treatment of deep vein thrombosis and pulmonary embolism:
Anticoagulant (anti-clotting) medicines: these medicines make the blood less able to clot and are sometimes called ‘blood thinners’. They can block the formation of new clots and stop existing clots getting bigger.
Compression stockings or intermittent pneumatic compression (IPC) boots: these improve circulation and help to prevent DVT by increasing the speed at which blood flows through the veins in the legs.
Surgery: in extreme situations, the blood clot may need to be trapped (to prevent it reaching the lungs) or removed.
It is important to continue taking any medicines you have been given, whether for prevention or treatment, even if you feel normal. Your doctor may also give you lifestyle advice in order to avoid any risk factors, like trying to give up smoking, reducing your weight and doing more exercise. |