Deep Vein Thrombosis

Not everyone with deep vein thrombosis will experience noticeable signs and symptoms. The National Heart, Lung, and Blood Institute estimates that symptoms occur in only half of all cases. When they are present, they usually include:

• Swelling in the affected leg, including swelling in your ankle and foot
• Pain or tenderness in your leg, that often starts in your calf and may only be present when standing or walking
• Feeling of increased warmth over the affected area
• Changes in your skin colour, such as turning pale, red or blue
• Enlargement of the superficial veins in the affected area.

Warning signs of a pulmonary embolism

If a blood clot breaks free and travels to your lungs, it causes a life-threatening complication called a pulmonary embolism. The warning signs of pulmonary embolism include:

• Unexplained sudden onset of shortness of breath
• Sharp chest pain that worsens when you take a deep breath or when you cough
• Feeling severely lightheaded or dizzy, or fainting
• Rapid breathing and fast heart rate
• Sweating
• Coughing up blood
• A sense of anxiety or nervousness
• Excessive sweating.

If you develop signs or symptoms of deep vein thrombosis, contact your doctor for guidance. If you develop any of the warning signs of a pulmonary embolism, seek medical attention or go to the emergency room immediately. Do not wait for the symptoms to pass, as immediate treatment reduces the risk of serious complications.

Deep vein thrombosis is a blood clot that develops in a vein deep in the body. The clot may partially or completely block blood flow through the vein. Deep vein thrombosis mostly occurs in the lower leg, thighs or pelvis, although it is possible for it to occur in other parts of the body, such as the arm.

Even though deep vein thrombosis itself is not life-threatening, a blood clot in a deep vein is a serious problem because a piece of the clot can break off and travel through the deep veins back to the heart, and eventually be pumped by the heart into the arteries of the lung. When this happens, the condition is called pulmonary embolism. Pulmonary embolism can damage the lungs and other organs of the body and cause death.

Blood clots in the thighs are more likely to break off and cause pulmonary embolism than blood clots in the lower legs or other parts of the body. Blood clots also can form in veins closer to the skin's surface. However, these clots won't break off and cause pulmonary embolism.

Causes of deep vein thrombosis

Blood clots in your body’s deep veins can be caused by many different things, namely anything that causes your blood not to circulate normally or clot properly. The most common causes of deep vein thrombosis are:

• Physical inactivity: Ordinarily, as you walk around, your leg muscles squeeze your veins and keep blood flowing back to the heart. But if you are inactive for many hours, blood flow in the veins of your legs may become sluggish and slow so much that clots form. Deep vein thrombosis can occur during long periods of inactivity, such as on a long airplane flight or while recovering from an illness or injury.
• Injury: Injuries caused by physical, chemical, or biological factors can damage the inner lining of veins. Such factors include surgery, serious injuries, inflammation, and immune responses.
• Medical conditions: Certain medical conditions such as factor V Leiden, in which your blood is thicker or more likely to clot than normal, can increase the risk of deep vein thrombosis. Hormone therapy or birth control pills also can increase the risk of clotting.

To diagnose deep vein thrombosis, your doctor will ask you questions about your symptoms and medical history. He or she will also perform a physical exam to examine your limbs for swelling, tenderness or discolouration. Depending on how likely you are to have a blood clot, your doctor may suggest further testing, including:

• Ultrasound: The most common test for diagnosing deep vein blood clots is ultrasound, according to Cleveland Clinic . This test uses sound waves to create pictures of blood flowing through the arteries and veins in the affected area. This test is painless and noninvasive, however less sensitive in finding blood clots that are very deep inside the body, such as in the pelvis.
• Venography: During this procedure, a dye is injected into a large vein in the affected area, which makes the vein visible in an x-ray image. The x-ray will show whether blood flow is slow in the vein, which may suggest a blood clot. This test is used less frequently because less invasive methods can usually be used to confirm the diagnosis.
• Computed tomography (CT) or magnetic resonance imaging (MRI) scans: Both CT and MRI can provide visual images of your veins and may show if you have a clot. CT is a type of x-ray that can provide pictures of structures inside the body. A CT scan may be used to diagnose deep vein thrombosis in the abdomen or pelvis, as well as blood clots in the lung to diagnose pulmonary embolism. In an MRI, radio waves are used to shows pictures of organs and structures inside the body. MRIs can provide information that may not show up on an x-ray.
• Blood test: Almost all people who develop severe deep vein thrombosis have an elevated blood level of a clot-dissolving chemical called D dimer. Your doctor may order a D dimer test, which is most useful for ruling out deep vein thrombosis or for identifying people at risk of recurrence.

Deep vein thrombosis treatment options include:

• Medicines: Your doctor may prescribe medicines to prevent or treat deep vein thrombosis. Some common options are:
  • Anticoagulants: Anticoagulants, also called blood thinners, are used often to treat deep vein thrombosis. These medicines decrease your blood's ability to clot, and also stop existing blood clots from getting bigger. However, blood thinners can't break up blood clots that have already formed. Blood thinners can be taken as a pill, an injection under the skin, or through a needle or tube inserted into a vein. Warfarin and heparin are 2 anticoagulants used to treat deep vein thrombosis. If you're prescribed warfarin or heparin by your doctor, it is important to take your medication exactly as instructed. Both medications can have serious side effects, such as an increased risk of bleeding, if you take too much.
  • Thrombolytics: Doctors prescribe these medicines to quickly dissolve large blood clots that cause severe symptoms. As thrombolytics can cause sudden bleeding, they're typically used only in life-threatening situations.
• Vena cava filters: If you can't take blood thinners, your doctor may recommend a vena cava filter. The filter catches blood clots before they travel to the lungs, which prevents pulmonary embolism. However, vena cava filters don’t prevent new blood clots from forming.
• Compression stockings: Compression stockings help to reduce leg swelling caused by a blood clot. These stockings are worn on the legs from the arch of the foot to just above the knee. These stockings are tight at the ankle and become looser as they go up the leg. This creates gentle pressure up the leg to keep blood from pooling and clotting. Stockings are often worn for a recommended duration of one year.

Most cases of deep vein thrombosis develop in people who are inactive because of injury or surgery. If you have had deep vein thrombosis before, or you have a family history of blood-clotting problems, you can take steps to prevent blood clots. These steps are:

• Follow-up with your doctor as often as recommended to both evaluate your risk and follow strategies for reducing your risk of further clots.
• Avoid all medications that may cause blood clots. These include birth control pills and other medications that contain estrogen.
• Avoid prolonged periods of bed rest. Get out of bed and move around as soon as possible after surgery or illness. The sooner you move around, the lower your chance of developing a blood clot.
• With your doctor’s direction, Cleveland Clinic recommends to take medications or use intermittent compression garments to prevent clots after some types of surgery.
• During long trips, exercise your lower leg muscles, stay hydrated and avoid alcohol. This helps to prevent blood clots from forming. Stand up and walk at least every half hour if you are on a long flight. Or get out of the car every hour if you are on a long road trip.
• Discuss your medical or family history of deep vein thrombosis with your doctor before considering any surgical procedures.