What are the symptoms of DVT?

DVT most commonly occurs in just one leg or one arm. Not everyone with DVT will experience symptoms, although when present, they may include:

  • Swelling of the leg or arm (sometimes it occurs suddenly)
  • Pain or tenderness in the leg that may only be present when standing or walking
  • Feeling of increased warmth in the area of the leg or arm that is swollen or that hurts
  • Redness or discoloration of the skin
  • Enlargement of the superficial veins in the affected leg or arm

Symptoms of a pulmonary embolism include:

  • (Sudden) shortness of breath
  • Sharp chest pain, often aggravated by coughing or movement
  • Pain in the back
  • Cough with or without bloody sputum
  • Excessive sweating
  • Rapid pulse or breathing
  • Lightheadedness or passing out

Some people only find out they have DVT after the clot has moved from the leg or arm and traveled to the lung.

It is important to notify your doctor immediately or go to the emergency room if you have symptoms of a pulmonary embolism or DVT. Do not wait to see if the symptoms will "go away." Get treatment right away to prevent serious complications.

What are the potential risk factors?

The following conditions may increase your risk of developing DVT:

  • An inherited (family) condition that increases the risk of blood clotting
  • Cancer and some of its treatments (chemotherapy)
  • Limited blood flow in a deep vein, due to injury, surgery, or immobilization
  • Long periods of inactivity that decrease blood flow, such as:
    • Sitting for a long period of time on long trips in a car, truck, bus, train, or an airplane
    • Immobility after surgery or a serious injury
  • Pregnancy, and the first 6 weeks after giving birth
  • Being over age 40 (although deep vein thrombosis can occur in any age group)
  • Being overweight
  • Taking birth control pills or hormone therapy, including for postmenopausal symptoms
  • Placement of a central venous catheter or pacemaker

How is DVT diagnosed?

Your doctor will ask you questions about your medical history and perform a physical exam as part of your diagnostic evaluation. Several tests will also be performed.

A duplex venous ultrasound is the most common test used to diagnose deep vein clots. It is used to evaluate the blood flow in the veins and to detect the presence and specific location of blood clots. During a venous ultrasound, the technologist applies pressure when scanning your arm or leg. If the vein does not compress with pressure, it may indicate a blood clot is present.

Venography is an X-ray procedure used to examine the deep veins. During the procedure, a contrast material (dye) is injected into the veins before the X-rays are taken. Venography may be performed if the Duplex ultrasound does not provide a clear diagnosis. The dye makes the vein and the blood clot visible on the x-ray. If the blood flow in the vein is blocked, it may also show on the x-ray.

Other tests that may be performed to detect a blood clot include:

  • Magnetic Resonance Imaging (MRI) or Magnetic Resonance Venography (MRV): MRI shows pictures of organs and structures inside the body, while MRV shows pictures of the blood vessels in the body. Radio waves are used in MRI and MRV to create the images. In many cases, MRI and MRV can provide information that may not show up on an x-ray. However, MRV is a more expensive technology and not always readily available.
  • Computed tomography (CT) scan is a type of x-ray that can provide pictures of structures inside the body. A CT scan may be used to diagnose deep vein thrombosis in the abdomen or pelvis, as well as blood clots in the lung to diagnose pulmonary embolism.

If your doctor suspects that an inherited disorder could be causing the clots, he or she may conduct a series of blood tests. This may be important if:

  • You have repeated blood clots that cannot be linked to any other cause
  • You have a blood clot in a vein at an unusual location, such as in a vein from the intestines, liver, kidney or brain
  • You have a strong family history of blood clots