You're recovering from a major surgery, or maybe even a really long road trip or international flight, when you notice something unsettling: a spot on your leg feels unusually tight, warm and swollen. The pain escalates to a throbbing ache that doesn't go away when you stand up.
While you might compare the feeling to pulling a muscle, these symptoms could be the first sign of deep vein thrombosis (DVT), a life-threatening type of blood clot.
"If you suspect a DVT, call your doctor and go to the emergency room," says Dr. Linda Le, a vascular surgeon at Houston Methodist. "If left untreated, a DVT can become a medical emergency."
What is DVT, and what are the symptoms?
As the name suggests, a DVT is a type of blood clot that forms in a vein deep inside the body, most often in the lower leg, thigh or pelvis. A clot in one of these deep veins can potentially travel up to your lungs.
DVT can be tricky to detect because most people don't experience early, noticeable signs of the issue. Common symptoms include:
- Swelling in one leg
- Pain or tenderness, often starting in the calf
- A feeling of warmth in the affected area
- Skin discoloration (red or purple)
- Large veins that appear more prominent than usual
If you have any of these symptoms, especially after surgery, injury or a long period of inactivity, talk with your doctor right away.
(Related: Why Are My Feet & Ankles Swollen?)
Why is DVT considered a serious condition?
If a blood clot deep in a vein goes undetected or untreated, it can break off and travel into the lungs. When this happens, the clot can block a major artery inside a lung, a potentially fatal complication called pulmonary embolism (PE).
"You might feel a sudden shortness of breath, rapid heartbeat or chest pain," says Dr. Le. "That should be an immediate call to 911 or a trip to the emergency room. Pulmonary embolism is the third-leading cause of cardiovascular death and the number one cause of death in hospitalized patients."
In medical terminology, DVTs and PEs are grouped under the umbrella term venous thromboembolisms.
What causes DVT?
A DVT blood clot can happen when something keeps blood from flowing properly back to your heart. This can happen in three different ways: damage to the vein wall, slow blood flow (stasis) or blood that clots too easily (hypercoagulability).
The key risk factors include:
- Family history of DVT or PE
- Surgery
- Injury
- Prolonged bed rest
- Long-distance travel
- An underlying malignancy
"Even young and healthy people can be at risk," says Dr. Le. "Someone who's active but has to stay off their feet for a couple of weeks after an accident can develop a DVT." Anything that causes you to be sedentary or slows blood flow increases your risk.
A family history of blood clots might be linked to an inherited hypercoagulable disorder. People with certain genetic mutations have a higher risk of developing a blood clot, especially if it's passed down through both sides of the family.
(Related: How to Avoid Deep Vein Thrombosis While Traveling)
Do lifestyle factors increase the risk of DVT?
You might be surprised to learn that age and daily exercise are not associated with DVT. However, lifestyle habits are connected to another vascular condition called varicose veins.
"Unlike DVT, which happens in large veins deep inside the circulatory system, varicose veins occur in the superficial blood vessels just under the skin," Dr. Le explains. "Weight gain and lack of exercise can worsen symptoms of varicose veins."
(Related: When Should I Worry About Varicose Veins?)
How is DVT diagnosed?
The first-line test for confirming DVT is a duplex ultrasound. This non-invasive technology uses sound waves to create detailed images of the veins that allow your doctor to see how the blood is flowing.
Your doctor may also order a simple blood test called a D-dimer to check for a specific type of protein associated with blood clots. In complex cases, you may need additional imaging tests, such as venography, a CT scan or an MRI for a more detailed assessment.
What treatment options are available for DVT?
The primary goal of DVT treatment is to prevent the clot from growing larger, stop it from traveling to the lungs and reduce the risk of future clots.
The standard treatment is anticoagulation therapy, commonly known as blood thinners, which helps prevent the clot from growing and reduces the risk of new clots. Most patients take these medications for about three to six months, with follow-up ultrasounds to monitor progress.
For severe or extensive clots, especially those higher up in the leg or pelvis, you may need a minimally invasive procedure. A vascular surgeon can remove the clot with endovascular techniques.
"Very few patients need that kind of intervention," says Dr. Le. "Most do well with medication and follow-up. We want you to take your blood thinners, stay hydrated and be as active as you can."
To help support healthy blood flow, your doctor may also recommend wearing compression stockings. These knee-length socks are made of strong material that provide continuous pressure to the legs to improve blood flow and reduce swelling.
(Related: Should You Wear Compression Socks on a Plane?)
Are there any long-term complications of DVT?
About 20% to 50% of people who experience DVT will develop a condition called post-thrombotic syndrome (PTS). This happens when a blood clot or recurring clot damages the valves and lining inside the vein, causing the blood to flow backward and pool under the skin.
Symptoms of PTS include:
- Chronic pain and discomfort
- Persistent swelling
- Skin discoloration and thickening
- Skin sores or leg ulcers
DVT is a common but serious condition
While you can't change your genetics or family history, you can recover safely from a serious blood clot — and reduce the risk of it happening again.
"Early treatment is the best way to avoid an emergency situation like PE or a long-term issue like PTS," Dr. Le says. "Pay attention to what your body is telling you and talk with your doctor about anything unusual."
