Deep Vein Thrombosis
Deep vein thrombosis is a serious condition where a blood clot forms in a deep vein, most commonly in the leg. While it can cause pain and swelling, sometimes there are no symptoms at all. The real danger lies in the clot breaking free and traveling to the lungs, which can be life-threatening.
Table of contents
- What Is Deep Vein Thrombosis?
- Signs and Symptoms
- Causes and Risk Factors
- Potential Complications
- How DVT Is Diagnosed
- Treatment Options
- Prevention and Lifestyle Tips
- Living With DVT
What Is Deep Vein Thrombosis?
Deep vein thrombosis, commonly called DVT, occurs when a blood clot (called a thrombus) forms in one or more of the deep veins in your body, usually in the legs[1]. These are veins located deep within your body’s muscles, not the ones you can see near the surface of your skin[2].
Most often, DVT affects the lower leg, thigh, or pelvis, but blood clots can also develop in other parts of your body, including your arms, brain, intestines, liver, or kidney[2][3]. The blood clots may partially or completely block blood flow through your vein[2].
DVT is a common and important medical problem. It represents the third most common cause of death from cardiovascular disease after heart attacks and stroke[3]. Each year, approximately 1 to 3 in every 1,000 adults develop a DVT or pulmonary embolism (a blood clot in the lungs) in the United States, and up to 300,000 people die each year as a result of these conditions[2].
DVT can occur at any age, but it is less common in children and adolescents and more common in those over the age of 60[2]. More than half of all DVTs happen as a result of being in the hospital from a medical illness or following surgery, mainly because people are lying in bed most of the time instead of moving around as they normally would[2].
Signs and Symptoms
One concerning aspect of DVT is that up to 30% of people with this condition don’t have any symptoms at all[2]. Sometimes there are no noticeable symptoms, or the symptoms may be very mild and not raise concern[1][2].
When symptoms do occur in the leg, they typically include[1][2][7]:
- Swelling in one leg (rarely both legs), which may happen suddenly
- Pain, cramping, or tenderness, usually in the calf or thigh, that often starts when walking or standing up
- Warm skin around the painful area
- Change in skin color on the leg, such as red, purple, or darkened skin (this may be harder to see on brown or black skin)
- Swollen veins that are hard or sore when you touch them
These symptoms can also happen in your arm or abdomen if that’s where the blood clot is located[7]. If blood clots affect the veins deep inside your abdomen, you may experience abdominal pain or flank pain. A severe headache, usually of sudden onset, may occur when clots affect veins in the brain[2].
When to Seek Medical Help
If you develop symptoms of DVT, contact your healthcare provider as soon as possible[1]. If a doctor thinks you have DVT, you should be referred to hospital within 24 hours for testing[7].
Call emergency services (such as 999 or 911) immediately if you have symptoms of DVT along with[1][7]:
- Sudden shortness of breath
- Chest pain or discomfort that worsens with deep breathing or coughing
- Coughing up blood
These symptoms may indicate a pulmonary embolism, which is a life-threatening complication that needs treatment straight away[1][7].
Causes and Risk Factors
DVT develops when a blood clot forms in the deep veins because your veins are injured or the blood flowing through them is too sluggish[2]. You can get DVT if you have certain medical conditions that affect how your blood clots[1].
Main Risk Factors
Several factors can increase your risk of developing DVT. These include[1][3][6][7]:
Reduced blood flow: Immobility from bed rest, general anesthesia, operations, stroke, or long flights can slow blood flow and make you more likely to get DVT[3]. A blood clot in the legs can develop if you don’t move for a long time, such as when traveling a long distance or when you’re on bed rest due to surgery, an illness, or an accident[1].
Age: People over 60 are at higher risk[7].
Body weight: Being overweight increases pressure on your veins, which can contribute to blood clots[7].
Smoking: Tobacco use increases your risk[7].
Previous DVT: Having had DVT before puts you at higher risk of another episode[7].
Hormones: Taking the contraceptive pill or hormone replacement therapy (HRT) can increase risk. Pregnancy or having had a baby in the previous 6 weeks also raises risk[7].
Medical conditions: Cancer, heart failure, varicose veins, increased blood viscosity from conditions like polycythemia or dehydration can all increase risk[3][7].
Mechanical injury to the vein: Trauma, surgery, peripherally inserted venous catheters, or intravenous drug abuse can damage veins[3].
Sometimes DVT can happen for no obvious reason[7]. These are called “unprovoked” or idiopathic (unexplained) blood clots[10].
Potential Complications
Deep vein thrombosis can be dangerous and lead to serious complications. Even though DVT itself is not life-threatening, the blood clots have the potential to break free and travel through your bloodstream[2].
Pulmonary Embolism
The most serious complication of DVT happens when a part of the blood clot breaks off and travels through the bloodstream to the lungs, causing a blockage called pulmonary embolism (PE)[1][2][6]. When DVT and pulmonary embolism occur together, it’s called venous thromboembolism (VTE)[1].
A pulmonary embolism can be life-threatening and needs immediate medical attention[1]. If the clot is small and with appropriate treatment, people can recover from PE. However, there could be some damage to the lungs. Chronic thromboembolic pulmonary hypertension is a complication that can happen after a PE with a large clot, which can stop blood from reaching the lungs and can be fatal[6].
Post-Thrombotic Syndrome
As many as half of those who get a DVT in their legs develop symptoms of intermittent leg pain and swelling that may last months to years. These symptoms are called post-thrombotic syndrome (PTS)[2][6].
PTS can happen because of damage to the valves and inner lining of your veins, leading to blood “pooling” more than it should. This increases the pressure inside your veins and causes pain and swelling[2]. Characteristics of this condition include pooling of blood, chronic leg swelling, increased pressure within your veins, increased pigmentation or discoloration of your skin, and leg ulcers known as venous stasis ulcers[2].
How DVT Is Diagnosed
To diagnose DVT, your healthcare provider will do a physical exam and ask questions about your symptoms. The provider will check your legs for swelling, tenderness, or changes in skin color[8].
If a doctor thinks you have DVT, you should be referred to hospital within 24 hours for an ultrasound scan[7]. The tests you have depend on whether your provider thinks you are at a low or a high risk of DVT[8].
Diagnostic Tests
Tests used to diagnose or rule out DVT include[8]:
D-dimer blood test: D-dimer is a type of protein produced by blood clots. Almost all people with severe DVT have increased blood levels of D-dimer. This test often can help rule out pulmonary embolism[8].
Duplex ultrasound: This noninvasive test uses sound waves to create pictures of how blood flows through the veins. It’s the standard test for diagnosing DVT. The scan shows whether blood is flowing normally through the vein[7][8]. For the test, a healthcare provider gently moves a small hand-held device over the skin of the body area being studied. Additional ultrasounds may be done over several days to check for new blood clots or to see if an existing one is growing[8].
Venography: You may also have an X-ray of the vein, called a venogram. For this, you’ll be injected with a dye to show where the blood clot is[7]. This test uses X-rays and dye to create a picture of the veins in the legs and feet. The test is invasive, so it’s rarely done, and other tests such as ultrasound are often done first[8].
Magnetic resonance imaging (MRI) scan: This test may be done to diagnose DVT in veins of the belly (abdomen)[8].
You may have an injection of a blood-thinning medicine called heparin while you’re waiting for an ultrasound scan to see if you have DVT[7].
Treatment Options
There are three main goals to deep vein thrombosis treatment: prevent the clot from getting bigger, prevent the clot from breaking loose and traveling to the lungs, and reduce the chances of another DVT[8]. Get treatment right away so you can prevent serious complications[2].
Blood-Thinning Medications
A medication called an anticoagulant, also known as a blood thinner, is the main treatment for DVT[8]. These medicines help prevent blood clots from getting bigger and reduce the risk of developing more clots[8]. Blood thinners don’t dissolve a blood clot that is already formed; however, the body will absorb the clot over time[15].
At first, your treatment may include two anticoagulants at the same time (one administered intravenously or injected into the skin and one taken by mouth). After the oral medication becomes effective by itself, you may not need the second medication[15]. You’ll probably need to take blood-thinning medicines for at least 3 months[7].
Depending on the type of anticoagulant, a blood test called the International Normalized Ratio (INR) may be needed to make sure you’re taking the right dose of medicine[15]. Your primary physician will determine how often you need to have your INR checked, if necessary, and how long you will take this medication[15].
Anticoagulants can cause side effects; bleeding is the most common side effect. It is important to discuss these side effects with your physician or pharmacist[15]. If you are taking a blood thinner, be sure you get instructions about how to take your medicine safely[21].
If you get a DVT when you’re pregnant, you’ll have injections for the rest of the pregnancy and until your baby is 6 weeks old[7].
Other Treatment Approaches
Thrombolytic therapy: In certain situations, a thrombolytic medication may be used to dissolve the blood clot. This medication is injected through a catheter into the veins[15]. These procedures are sometimes used together for very large clots or in people who are at high risk of developing a pulmonary embolism[13].
Surgery: In some cases, surgery may be needed to remove blood clots or stop them from forming[7].
Inferior vena cava (IVC) filters: These can be placed in a major vein called the inferior vena cava to catch blood clots, usually temporarily, for patients when medications aren’t working or can’t be taken[13].
Compression Therapy
Wear compression stockings if your doctor recommends them. These stockings are tighter at the feet than on the legs. They may reduce pain and swelling in your legs[21]. There are different types of stockings, and they need to fit right, so your doctor will recommend what you need[21]. Treatments include compression stockings, and you may need to wear them for two years[2].
Prevention and Lifestyle Tips
There are things you can do to lower your chance of getting DVT. With the right knowledge and simple lifestyle changes, you can significantly reduce your risk for developing DVT[20].
Stay Active
Regular physical activity is one of the best ways to improve blood flow and reduce your risk of DVT. Stay active by taking regular walks[7]. Aim for at least 30 minutes of moderate exercise daily[20]. Try to walk several times a day[21].
Do not sit still for long periods of time. Get up and move around every hour or so[7]. If you have a sedentary job, make sure to take breaks and move around every hour to prevent blood pooling and clot formation[20].
If you’re in the hospital and have to stay in bed, move your toes (up and down) and ankles (in circles). Your healthcare team may give you some exercises to do[7].
Healthy Weight and Hydration
Stay a healthy weight. Being overweight increases pressure on your veins[7]. Adopting a balanced diet and maintaining a healthy weight can reduce your DVT risk. Focus on eating plenty of fruits, vegetables, whole grains, and lean proteins[20].
Drink plenty of fluids to avoid dehydration. DVT is more likely if you’re dehydrated[7].
Other Prevention Tips
Do not cross your legs while you’re sitting[7]. Do not smoke, and do not drink lots of alcohol[7].
During Long Journeys
If you’re travelling for 3 hours or more by plane, train, or car, there are things you can do during the journey to lower your chances of getting DVT. These include[7]:
- Wearing loose clothing
- Drinking plenty of water
- Avoiding alcohol
- Walking around when possible
If you are taking a long car or plane trip, take a break, walk or stretch your legs and drink plenty of liquids[1].
Hospital Prevention
If you go into hospital, your healthcare team should check if there’s a higher chance you’ll get DVT. If they think you’re more likely to get DVT, you may be given treatment to prevent it, such as medicine or compression stockings (knee-high elastic socks that help your blood circulation), while you’re in hospital. You may continue treatment after you leave hospital because a blood clot can happen weeks later[7].
You can also help protect yourself against DVT while you’re in hospital by staying active and walking around if you can[7].
Living With DVT
After you leave hospital, you’ll be encouraged to take steps to help you recover from DVT[7][21]:
- Walk regularly
- Keep your affected leg raised when you’re sitting. When you sit, use a pillow to raise the arm or leg that has the blood clot. Try to keep it above the level of your heart[21]
- Delay any flights or long journeys until at least 2 weeks after you start taking blood-thinning medicine
Be patient. You may need to take medicine for a few months and wear compression stockings for two years[2].
Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It’s also a good idea to know your test results and keep a list of the medicines you take[21].
When to Contact Your Doctor
Watch closely for changes in your health, and be sure to contact your doctor if you do not get better as expected[21].
Call emergency services immediately if you have symptoms of a blood clot in your lung (pulmonary embolism), such as sudden chest pain, trouble breathing, or coughing up blood. Also call if you passed out (lost consciousness), have new or worse trouble breathing, are dizzy or light-headed, or feel like you may faint[21].
Contact your doctor or seek immediate medical care if you have symptoms of a blood clot in your arm or leg, including pain, redness and swelling[21].
After a blood clot, it’s important to follow your doctor’s advice and treatment plan to keep you healthy and help prevent future blood clots[16].
