Deep vein thrombosis (DVT) is a serious condition that occurs when a blood clot forms in a vein located deep inside your body. A blood clot is a clump of blood that is in a gelatinous, solid state. Deep vein blood clots typically form in your thigh or lower leg, but they can also develop in other areas of your body. Other names for this condition include thromboembolism, post-thrombotic syndrome, and post-phlebitic syndrome.
DVT occurs most commonly in people who are over 50 years in age. Certain conditions that alter how your blood moves through your veins can raise your risk of developing clots. These include:
- having an injury that damages your veins
- being overweight, which puts more pressure on the veins in your legs and pelvis
- having a family history of DVT
- having a catheter placed in a vein
- taking birth control pills or undergoing hormone therapy
- smoking (especially heavy usage)
- staying seated for a long time while you’re in a car or on a plane, especially if you already have at least one other risk factor
Some diseases and disorders can increase your risk of having blood clots. These include hereditary blood clotting disorders, especially when you have at least one other risk factor. Cancer and inflammatory bowel disease can also increase the risk of developing a blood clot. Heart failure, a condition that makes it more difficult for your heart to pump blood, also occurs with an increased risk of clots.
DVT is a major risk associated with surgery. This is especially true if you’re having a surgery in the lower extremities, such as joint replacement surgery. Your doctor will discuss the risk of DVT if you need joint replacement surgery.
Being pregnant increases your risk of DVT. Increased hormone levels, and a slower blood flow as your uterus expands and restricts blood flowing back from your lower extremities, contribute to this risk. This elevated risk continues until about six weeks after giving birth. Being on bed rest or having a C-section also increases your risk of having DVT.
According to the National Heart, Lung, and Blood Institute, symptoms of DVT only occur in about half of the people who have this condition. Common symptoms include:
- swelling in your foot, ankle, or leg, usually on one side
- cramping pain in your affected leg that usually begins in your calf
- severe, unexplained pain in your foot and ankle
- an area of skin that feels warmer than the skin on the surrounding areas
- skin over the affected area turning pale or a reddish or bluish color
People may not find out that they have deep vein thrombosis until they’ve gone through emergency treatment for a pulmonary embolism. A pulmonary embolism is a life-threatening complication of DVT in which an artery in the lung becomes blocked.
DVT treatments focus on keeping the clot from growing. In addition, treatment will attempt to prevent a pulmonary embolism and lower your risk of having more clots.
Your doctor might prescribe medications that thin your blood, such as heparin and warfarin. This makes it harder for your blood to clot. It also keeps existing clots as small as possible and decreases the chance that you’ll develop more clots.
If blood thinners don’t work or if you have a severe case of DVT, your doctor might use thrombolytic drugs. Thrombolytic drugs work by breaking up clots. You’ll receive these intravenously.
Wearing compression stockings can prevent swelling and lower your chance of developing clots. They reach just below your knee or right above it. You’ll most likely wear these every day.
You might need to have a filter put inside the large abdominal vein called the vena cava if you aren’t able to take blood thinners. This form of treatment helps prevent pulmonary embolisms by stopping clots from entering your lungs.
A major complication of DVT is a pulmonary embolism. You can develop a pulmonary embolism if a blood clot moves to your lungs and blocks a blood vessel. This can cause serious damage to your lungs and other parts of your body. You should get immediate medical help if you have signs of a pulmonary embolism. These signs include:
- chest pain that gets worse with coughing or inhaling deeply
- rapid breathing
- coughing up blood
- rapid heart rate
You can lower your risk of having DVT by making a few lifestyle changes. These include keeping your blood pressure under control, giving up smoking, and losing weight if you’re overweight. Moving your legs around when you’ve been sitting for a while also helps keep your blood flowing. Walking around after being on bed rest can prevent clots from forming. Take any blood thinners your doctor prescribes if you’re having surgery, as this can lower your chance of developing clots afterward.
Your risk of developing DVT during travel is low, but it becomes higher if you’re sitting for more than four hours at a time while driving or flying. You can lower risk by moving around every so often — get out of your car and move around at intervals during long drives. Walk in the aisles if you’re flying, taking a train, or riding a bus. Stretch your legs and feet while you’re sitting; this keeps your blood moving steadily in your calves. Don’t wear tight clothes that can restrict blood flow.
You asked, we answered
- How will my doctor diagnose deep vein thrombosis?
There are two major phases when it comes to your doctor diagnosing DVT. The first (and most important) is that she has to SUSPECT that you have a DVT — based on your presenting symptoms. Such symptoms generally include calf pain (or tenderness), calf swelling with redness, and warmth, in the area of the clot. Once your doctor has a strong suspicion for a DVT, then she will order the requisite diagnostic tests, which usually include: a 2-phase duplex ultrasound study, blood tests (D-dimer), and possibly either a venogram or MRI scan.- Steve Kim, MD