Causes and Risk Factors

Deep vein thrombosis usually and most commonly occurs after an individual reaches the age of 60, but it can occur at any age. There are many factors that contribute to deep vein thrombosis including:

• Damage to the inner vein, usually from previous blood clot or due to injury during accident, surgery, immune response, or inflammation

   

• Family history of blood clots in the veins

   

• Slow or sluggish blood flow, occurring due to lack of motion or regular exercise; a fracture in the pelvis or leg; post surgery or prolonged illness; extensive bed rest; or after travelling for a long time (this last factor usually is only an issue if other factors are already present)

   

• Thrombophilia, an inherited factor that causes blood to become thicker and clot more than normal, thrombophilia can also develop from using estrogen (in the case of menopause) or birth control pills

The large veins in the lower leg and thigh are most susceptible to deep vein thrombosis. Blood clots may form when something slows or changes the flow of blood in the veins. Risk factors include the following:

• Thrombophilia

   

• After a pacemaker catheter has been passed through the vein in the groin

   

• Heart failure

   

• Cancer and cancer treatment

   

• Obesity

   

• Smoking

   

• Recent surgery, especially in the hip or knee replacement surgery

Deep vein thrombosis usually and most commonly occurs after an individual reaches the age of 60, but it can occur at any age. There are many factors that contribute to deep vein thrombosis including:

• Damage to the inner vein, usually from previous blood clot or due to injury during accident, surgery, immune response, and/or inflammation

• Family history of blood clots in the veins

• Slow or sluggish blood flow, occurring due to lack of motion or regular exercise; a fracture in the pelvis or leg; post surgery or prolonged illness; extensive bed rest; or after travelling for a long time (this last factor usually is only an issue if other factors are already present)

• Thrombophilia, an inherited factor that causes blood to become thicker and clot more than normal, thrombophilia can also develop from using estrogen (in the case of menopause) or birth-control pills

• The large veins in the lower leg and thigh are most susceptible to deep vein thrombosis. Blood clots may form when something slows or changes the flow of blood in the veins. Risk factors include the following:

• Thrombophilia

• After a pacemaker catheter has been passed through the vein in the groin

• Heart failure

• Cancer and cancer treatment

• Obesity

• Smoking

• Recent surgery, especially in the hip or knee replacement surgery

Less than half of the people with deep vein thrombosis experience symptoms. If symptoms do occur someone may experience pain and swelling in the leg or along one single vein in the leg. The pain and swelling may increase while walking or standing. The swollen area may feel warm, and the color of skin may become red or discolored.

Most of the people who suffer from deep vein thrombosis do not know it until an embolus reaches the lungs. Symptoms of a pulmonary embolism include sudden unexplained shortness of breath, pain while breathing deep, spitting blood while coughing, and rapid heartbeat.

If someone is experiencing any of these symptoms, they should see a doctor immediately to determine if the symptoms are being caused by deep vein thrombosis or pulmonary embolism. Left untreated, pulmonary embolism can result in fatal complications.

Diagnosis

Deep vein thrombosis poses great challenges for diagnosis because in eighty percent of cases, there are no symptoms present. Despite this hurdle, deep vein thrombosis is diagnosed primarily by the doctor taking a thorough medical history, performing a physical examination, and administering a few laboratory tests.

A detailed medical history is required to discern whether or not the person has been or is still taking any medicines, undergone any recent surgeries, suffered any injury or recently underwent any cancer treatment. The physical examination includes the doctor looking at the legs for signs of deep vein thrombosis or checking the leg presenting symptoms, in the case that symptoms are present. The doctor will usually check blood pressure, and investigate the condition of the heart and lungs as well.

Ultrasound, the most common diagnostic technique for deep vein thrombosis, is used to detect the flow of blood through arteries and veins. If the ultrasound does not give a sufficiently detailed picture of the blood flow, then a venography will be done. A venography is a procedure that starts by injecting a dye into the vein and then taking an X-ray of the affected leg. The X-ray then is used in order to identify the blood clot in the vein.

A D-dimer test measures the amount of a substance that is released when a blood clot is dissolved. If the substance is at a high level within the blood, then the risk of deep vein thrombosis is more likely. Sometimes, a blood test will be done to check whether the person has inherited a clotting disorder that may cause deep vein thrombosis.

Sometimes a magnetic resonance imaging (MRI) and computer tomography (CT) scan will be performed to examine the existing structure and organs.

Treatment for deep vein thrombosis is aimed at stopping the growth of the blood clot, preventing the blood clot from breaking off and potentially travelling to the lungs, and decreasing the chance of future blood clots. Treatment for deep vein thrombosis includes both medicines and therapies.

Medicines for treatment include the following:

• Anticoagulants – blood thinners that change chemicals in the blood to stop clots from forming so easily. Anticoagulants reduce the chance of another blood clot but they do not dissolve an already-existing blood clot. They can stop the already-present blood clot from growing bigger. Most common anticoagulants used are heparin (given intravenously and usually requiring a hospital stay) and warfarin (taken orally). Warfarin usually takes two to three days to start working; therefore heparin is often prescribed first until the warfarin takes effect. Warfarin is dangerous during pregnancy and in the case of pregnancy; only heparin should be taken for treatment.

• Thrombin inhibitors – hinder the clotting process and are usually prescribed to patients who cannot take heparin.

• Thrombolytics – used only under life-threatening situations, thrombolytics can cause sudden bleeding and they are only given in severe cases in order to dissolve a blood clot more quickly.

Therapies include the following:

• Compression stockings reduce pain, swelling, and provide support to counteract post-thrombotic symptoms

• Vena cava filter is a surgical procedure. If the person cannot take anticoagulants or is taking anticoagulants but blood clots are still developing, then a filter is inserted in the vena cava vein. This filter prevents the entry of bloods clot into the heart and into the lungs

Side Effects

Anticoagulants are drugs that act against coagulation or clotting process; therefore, taking them may result in easy bleeding and longer clotting time and the person may bruise easily. Sometimes, the bleeding is internal, or inside the body. People treated with blood thinners usually have regular blood tests to measure their blood's ability to clot.

Any excess prolonged bleeding should be treated as emergency. Taking other over-the-counter medicines, vitamins, and foods that are rich in vitamin K can interfere with anticoagulants. Therefore, before taking any drugs or making any changes in the diet, consulting the doctor is imperative.

If a person knows that they are at risk for deep vein thrombosis, the following tips can aid in prevention:

• Go in for regular doctor check-ups

• Follow all instructions and take medicines as prescribed by the doctor

• Try not to be in bed for a long time after illness and surgery

• Exercise or move the lower legs during long journeys

• Wear loose and comfortable clothes while traveling

• Control blood pressure

• Reduce weight

• Avoid alcohol and drink lots of fluids

• Quit smoking

Outlook

Elderly people are at greater risk for deep vein thrombosis because, as a population, they typically have a more sedentary lifestyle and the risk factors increase with age.

People diagnosed with deep vein thrombosis should remember to follow doctor’s instructions carefully and return for regular check-ups. The diagnosis of one clot increases a person’s risks for another.