What is blood clots?

A blood clot is a clump of blood that forms in a blood vessel, such as a vein or an artery. If a clot gets stuck in a blood vessel, it can cause serious problems like a deep vein thrombosis (DVT) or a pulmonary embolism.

A DVT is a blood clot in certain veins of the legs, pelvis, or arms. It most often occurs in the legs. Blood clots in these veins need to be treated, because they can get bigger, break loose, and travel through the bloodstream to the heart and then to the lungs. This causes a pulmonary embolism.

A pulmonary embolism is a sudden blockage of an artery in the lung. Blood clots in the deep veins of the leg are the most common cause of a pulmonary embolism. In many cases, the clots are small. They may damage the lung. But if the clot is large and stops blood flow to the lung, it can be life-threatening.

Call 911 anytime you think you may need emergency care. For example, call if:

• You have symptoms of a blood clot in your lung (called a pulmonary embolism). These may include:
  • Sudden chest pain.
  • Trouble breathing.
  • Coughing up blood.

Call your doctor now or seek immediate medical care if:

• You have symptoms of a blood clot in your arm or leg (called a deep vein thrombosis). These may include:
  • Pain in the arm, calf, back of the knee, thigh, or groin.
  • Redness and swelling in the arm, leg, or groin.