Understanding Deep Vein Thrombosis

image of muscle contracting, and vein  valve opening

 image of blood clot in vein

A deep vein thrombosis (DVT) is a blood clot that forms in a deep vein. If not treated, a part of the clot (embolus) can travel to the lungs and cause a life-threatening complication called pulmonary embolism (PE). Most DVTs develop in the lower leg or thigh, although they can develop in other areas in the body. Over time, a DVT can also permanently damage veins. To protect your health, a DVT must be treated right away.

How DVT Develops

The leg muscles have deep veins. These help carry blood from the legs to the heart. When leg muscles contract and relax, blood is squeezed up the veins toward the heart. One-way valves located along the walls of the veins help keep blood moving upward. When blood moves too slowly or not at all, it can pool in the veins. This makes a clot more likely to form. 

Risk Factors

Anyone can develop a deep vein thrombosis. However, the following risk factors make the condition more likely to occur:

  • Being inactive for a long period (such as when you’re bedridden due to illness)

  • immobility due to plane rides or long car rides

  • Injury to a vein caused by a trauma, a broken bone, inflammation, or surgery

  • Family history of blood clots

  • Recent surgery

  • Cancer and certain cancer treatments

  • Smoking

Other factors such as older age, pregnancy, taking birth control or hormone replacement, having another vein problem, smoking while using oral contraceptives, or being overweight can also put you at higher risk for DVT.

Use of pacemakers or central venous catheters or injecting drugs use can be risk factors for DVTs, specifically in the upper extremities.

Common Symptoms

DVT does not always cause obvious symptoms. If you do have symptoms, they usually occur suddenly. Symptoms can include:

  • Pain, especially deep in the muscle

  • Swelling

  • Aching or tenderness

  • Red or warm skin

Symptoms of pulmonary embolism may include:

  • Unexpected shortness of breath

  • Rapid breathing and fast heart rate

  • Chest pain

  • Coughing up blood

  • Pain with deep breathing

Diagnosing DVT

Your doctor will evaluate your veins to see if you have a blood clot. This includes taking a health history and performing a physical exam. During the health history, tell your doctor if your family has a history of vein problems and if you’ve had a history of blood clots, leg injuries, recent surgical procedures, or pregnancies. An imaging test called a duplex ultrasound will also be done. This test uses sound waves to create pictures of vein structures and blood flow. It helps the doctor pinpoint the size and location of a blood clot, if you have one. your doctor may also order some lab work. If your doctor suspects pulmonary embolism, additional testing will be recommended. After the evaluation, your doctor will discuss treatment options with you. Treatment typically includes certain types of blood thinners. Under certain circumstances, your doctor may recommend a vena cava filter placed in a large vein to prevent blood clots from traveling to the lungs.