Deep vein thrombosis is a serious but preventable medical condition in which blood clots occur, usually in veins in the lower leg, thigh, pelvis, and sometimes arms.
Deep vein thrombosis (DVT) is treatable, but it can have serious complications. For this reason, it is important to seek medical care if symptoms appear.
Pulmonary embolism (PE) is often associated with DVT. It usually happens when a part of a blood clot from a DVT breaks off from its original location in a vein and travels through the heart to the pulmonary arteries. This can result in damage to the lungs and other organs. It can be life-threatening.
DVT and PE can happen when the blood clot is in one of the deep veins, including those in the pelvis, thigh, or calf region.
Blood clots that form in veins closer to the skin’s surface, known as superficial venous thrombosis, typically do not result in a PE.
It is also possible to have a PE without DVT.
DVT happens when a blood clot forms, and PE can occur if part of it travels to the lungs and causes a blockage.
Anyone can develop DVT and PE. Many factors can contribute, but having multiple factors at once can increase the chance of having a blood clot.
The American Academy of Orthopaedic Surgeons (AAOS) note that the following common factors may increase the risk of DVT and PE:
cancer or undergoing radiotherapy or chemotherapy for cancer
injury to a vein from a fracture, muscle injury, or major surgery
slow blood flow, especially in the lower extremities
limited movement, due to bed rest, traveling, sitting for a long time, crossing the legs, paralysis, or other reasons
having varicose veins or another existing condition
high estrogen levels from birth control pills, hormone replacement therapy, or pregnancy
having a personal or family history of DVT and PE or clotting disorders
having a central venous catheter
having a broken hip or leg
having experienced major surgery on the hip, knee, or leg, especially in the first 2 to 10 days after surgery
What are the symptoms of a blood clot?
How do you recognize a blood clot? Find out more.
Symptoms of PE
Symptoms of a PE include difficulty breathing and chest pain.
A PE can occur with or without symptoms of DVT.
It can be serious. If a person experiences any of the following, they should see a doctor immediately:
irregular or quickened heartbeat
chest pain or discomfort, usually when breathing deeply
coughing up blood
low blood pressure, fainting, or feeling light-headed
increased anxiety or nervousness
A doctor will start by asking the person about their symptoms, and they will do a physical examination. They may then order some imaging tests.
These usually are not overly invasive or uncomfortable.
A duplex ultrasound examination can detect blood clots in veins or other reasons for the vascular problem.
A spiral chest CT scan can check for blood clots in the arteries of the lungs, commonly done with an intravenous injection of contrast to better see the pulmonary arteries.
A VQ scan of the lungs can identify how well blood and oxygen are moving in the lungs. It involves the administration of a small amount of a radioactive substance.
An MRI can evaluate the veins in the pelvis or both legs at the same time. This is less common than other tests for DVT and PE.
Venography involves injecting dye into a vein of an extremity and taking an x-ray to look for any blockages.
A D-dimer test is a blood test that can determine if there might be any excess blood clotting in the body. If it is negative and you have a low risk for blood clots, the chance of having a DVT or PE is very low.
However, a positive test does not necessarily indicate a serious problem. This could refer to something as simple as blood clotting in a healing skin wound or bruise.
Blood tests can also find out if a person has a clotting disorder, of which several types exist. However, these tests are very expensive, and the results can take several days.