What is Deep Vein Thrombosis (DVT)?
Deep vein thrombosis (DVT) occurs when a blood clot (thrombus) forms in one or more of the deep veins in your body, usually in your legs. Deep vein thrombosis can cause leg pain or swelling, but also can occur with no symptoms.
Deep vein thrombosis can develop if you have certain medical conditions that affect how your blood clots. It can also happen if you don't move for a long time, such as after surgery or an accident, or when you're confined to bed.
Deep vein thrombosis can be very serious because blood clots in your veins can break loose, travel through your bloodstream and lodge in your lungs, blocking blood flow (pulmonary embolism).
Deep vein thrombosis signs and symptoms can include:
Swelling in the affected leg. Rarely, there's swelling in both legs.
Pain in your leg. The pain often starts in your calf and can feel like cramping or soreness.
Red or discolored skin on the leg.
A feeling of warmth in the affected leg.
Deep vein thrombosis can occur without noticeable symptoms.
When to see a doctor
If you develop signs or symptoms of deep vein thrombosis, contact your doctor.
If you develop signs or symptoms of a pulmonary embolism — a life-threatening complication of deep vein thrombosis — seek immediate medical attention.
The warning signs and symptoms of a pulmonary embolism include:
Sudden shortness of breath
Chest pain or discomfort that worsens when you take a deep breath or when you cough
Feeling lightheaded or dizzy, or fainting
Coughing up blood
To diagnose deep vein thrombosis, your doctor will ask you about your symptoms. You'll also have a physical exam so that your doctor can check for areas of swelling, tenderness or discoloration on your skin. Depending on how likely you are to have a blood clot, your doctor might suggest tests, including:
Ultrasound. A wandlike device (transducer) placed over the part of your body where there's a clot sends sound waves into the area. As the sound waves travel through your tissue and reflect back, a computer transforms the waves into a moving image on a video screen. A clot might be visible in the image.
Sometimes a series of ultrasounds are done over several days to determine whether a blood clot is growing or to check for a new one.
Blood test. Almost all people who develop severe deep vein thrombosis have an elevated blood level of a substance called D dimer.
Venography. A dye is injected into a large vein in your foot or ankle. An X-ray creates an image of the veins in your legs and feet, to look for clots. However, less invasive methods of diagnosis, such as ultrasound, can usually confirm the diagnosis.
CT or MRI scans. Either can provide visual images of your veins and might show if you have a clot. Sometimes these scans performed for other reasons reveal a clot.