Blood clots

What are they?

Blood clots are gel-like clumps of blood. They are beneficial when they form in response to an injury or a cut, plugging the injured blood vessel, which stops bleeding. Some blood clots form inside your veins without a good reason and don't dissolve naturally. These may require medical attention if found in your legs (thrombosis) or more critical locations, such as your lungs (embolism) and brain (stroke).


Deep vein thrombosis

Deep vein thrombosis (DVT) occurs when a blood clot forms in one of the deep veins of your body, usually in your legs, but sometimes in your arm. The signs and symptoms of a DVT include:

  • Swelling, usually in one leg (or arm).
  • Leg pain or tenderness often described as a cramp or Charley horse.
  • Reddish or bluish skin discoloration.
  • Leg (or arm) warm to touch.

Pulmonary embolism

Clots can break off from a DVT and travel to the lung, causing a pulmonary embolism (PE), which can be fatal. The signs and symptoms of a PE include:

  • Sudden shortness of breath.
  • Chest pain-sharp, stabbing; may get worse with deep breath.
  • Rapid heart rate.

Risk factors

Diagnosing blood clots

Complete medical history and physical examination.


  • Duplex ultrasound.
  • D-Dimer test.
  • Venography and MRI.


  • Chest x-ray.
  • Pulmonary angiogram.
  • CT chest scan.
  • Echocardiogram.
  • Ventilation-perfusion scan (VQ Scan).

Treating blood clots

When doctors detect a blood clot, particularly a DVT, the goal in treatment is to prevent the blood clot from getting larger or breaking loose. Treatment can reduce your chances of developing more blood clots in the future.

Treatment depends on where the blood clot is and how likely it is to harm you. 

  • Medications.
    • Anticoagulants, also called blood thinners, that help prevent blood clots from forming.
    • Thrombolytics can dissolve clots that are already formed.
  • Compression stockings.
  • Procedures.
    • Catheter-directed thrombolysis: To dissolve the clot with medication.
    • Thrombectomy: Special instruments are used to carefully remove the clot.
    • Stent placement:  To keep a blood vessel open.
    • Vena cava filter placement: A filter is put into the inferior vena cava (the body’s largest vein) to catch blood clots before they can travel to the lungs.