Deep vein thrombosis (DVT) occurs when a blood clot develops in a vein deep in the body. Deep veins are found within groups of muscles. The veins close to the skin are called superficial veins.
While these clots most often develop in the lower legs or thighs, they may appear in the upper body, such as the arms or other locations in the body. Deep vein thrombosis is a risk after any major surgery, but patients who have surgery of the legs or hips are at higher risk.
Deep vein thrombosis can pose a serious threat to health. Pieces of a clot can break off and travel through the bloodstream to the lungs. This is called a pulmonary embolism and can be fatal soon after it occurs. Deep vein thrombosis can also block blood flow in the veins, causing the blood to pool. This can cause swelling, pain, and permanent damage to the leg called post-thrombotic syndrome.
When a clot forms in a vein, inflammation of the vein may occur at the affected site. This is referred to as thrombophlebitis. Inflammation may be minimal, or may be more pronounced, causing swelling, redness, warmth, and tenderness at the site. When thrombophlebitis occurs, the body's response to inflammation may promote the formation of more clots.
Although these risk factors increase a person's risk, they don't necessarily cause the disease. Some people with 1 or more risk factors never develop the disease, while others develop the disease and have no known risk factors. Knowing your risk factors for any disease can help to guide you into the appropriate actions, including changing behaviors and being clinically monitored for the disease.
Risk factors related to or that may contribute to deep vein thrombosis and thrombophlebitis include, but are not limited to:
An inherited tendency that increases risk for blood clots
Age (older than 60)
Surgery, particularly surgery of the hip or leg, or abdominal surgery
A long period of bed rest or sitting for a long time (for example, on an airplane or in a car)
Birth control pills or hormones taken for symptoms of menopause
Certain diseases and conditions, such as:
Chronic atrial fibrillation
Inflammatory bowel disease
Lupus erythematosus, a disease of the immune system
Spinal cord injury and resulting paralysis
Previous blood clot (thrombosis)
Intensive care treatment involving placement of a central venous catheter
People with cancer receiving chemotherapy
Deep vein thrombosis occurs without symptoms about 50% of the time. When symptoms do occur, they may include:
Swelling in the leg
Red, discolored, or white skin
Rapid heart beat (tachycardia)
More visible surface veins
Dull ache, tightness, tenderness or pain in the leg (these symptoms may only occur while walking or standing)
The symptoms of deep vein thrombosis may resemble other medical conditions or problems. Always consult your doctor for a diagnosis.
In addition to a complete medical history and physical examination, diagnostic procedures for deep vein thrombosis may include:
Duplex ultrasound. This involves using high frequency sound waves to look at the speed of blood flow, and the veins. A blood clot may be visualized by ultrasound. This procedure is noninvasive (the skin is not broken) and involves placing ultrasound gel on the affected area and then moving a handheld device across it. A picture of the blood flow is displayed on a monitor. Duplex ultrasound is the most commonly performed diagnostic test for DVT.
Magnetic resonance imaging (MRI). This diagnostic procedure uses a combination of large magnets, radio frequencies, and a computer to produce detailed images of organs and structures within the body, and is particularly effective in diagnosing deep vein thrombosis in the pelvis.
Venogram. This uses X-rays and intravenous (IV) contrast dye to visualize the veins. Contrast dye causes the blood vessels to appear opaque on the X-ray image, allowing the doctor to visualize the blood vessels being evaluated.
Specific treatment will be determined by your doctor based on:
Your age, overall health and medical history
Extent of the disease
Your signs and symptoms
Your tolerance for specific medications, procedures, or therapies
Expectations for the course of the disease
Your opinion or preference
The goal of treatment is to prevent the clot from growing, to ensure that it doesn't break off and travel through the veins to the lungs, and to help reduce the possibility of another blood clot forming.
Treatment may include:
Medications. Various types of medications may be used in the treatment of DVT. Although anticoagulants (blood thinners) don't destroy the clots, they may keep the clot from growing and other clots from forming. Warfarin (Coumadin) may be taken orally or a heparin injection may be given either intravenously (IV) or under the skin (subcutaneously). Treatment with blood thinners may last 6 months or more. If a blood clot develops after surgery, treatment may be shorter. If there have been previous clots or treatment for another illness is underway, the treatment may last as long as risk factors are present.
The most common side effect of blood-thinning medication is bleeding. Bruising or bleeding should be reported to the doctor right away.
Another type of medication called fibrinolytics or thrombolytics ("clot busters") can dissolve a clot quickly, over a period of a few days. Fibrinolytics are used in certain situations as determined by a doctor.
Thrombin inhibitors are medications that can disrupt the formation of a clot. Patients who can't take heparin may be given one of these medications.
Vena cava filter. In some cases, a vena cava filter may be inserted into the vena cava (the large vein which returns blood from the body to the heart) of patients who can't take medication or if blood thinners aren't working. The filter is a kind of "clot catcher."
Preventing deep vein thrombosis is important to prevent pulmonary embolism, which can lead to serious complications.
Anticoagulant medications, such as heparin or fondaparinux, may be given to certain surgical patients to prevent deep vein thrombosis after the risk of surgical bleeding has subsided. Those patients who have had a previous clot should follow the instructions of their doctor.
Preventing deep vein thrombosis caused by long periods of sitting or reclining involves moving the lower leg. Flexing (bending) the knees may be helpful.
When you travel and must sit for longer than 4 hours, the National Heart, Lung and Blood Institute suggests you:
Walk up and down the aisles (if traveling by plane or bus)
Stop about every hour and walk a little (if traveling by car)
While sitting, stretch your feet and move your legs
Wear loose clothing
Drink plenty of fluids
Other preventive measures may include:
Getting up and moving as soon as possible after surgery or illness, as movement can help to prevent clots from forming by stimulating blood circulation
A pneumatic compression device, which looks like a special fitted sleeve, placed on the legs to help keep blood moving during some types of surgery
Elastic stockings to reduce swelling and promote circulation
Consult your doctor for diagnosis and treatment.