Definition & Overview

Blood clotting plays an important role in the body’s healing process but can also create serious problems if it forms inside the veins and arteries that transport blood to and from the heart.

Also referred to as coagulation, the primary function of blood clots is to prevent blood from flowing freely from an open wound. To form blood clots, platelets and plasma attract each other and release chemicals that will eventually stop external bleeding. Once the ruptured vessel has healed, the body absorbs and dissolves the clot.

The ability of the body to dissolve the clot is important, but in some cases, this fails to happen. One of the most common blood clotting complications is caused by a condition called Deep Vein Thrombosis (DVT). This condition is characterized by the formation of blood clots in the veins, usually those located in the legs.

The arteries transport oxygen-rich blood from the heart to the various organs. Once the oxygen has been consumed, the blood is transported back to the heart via the veins. However, when a blood clot forms in the veins, blood begins to build-up at the back of the clot, unable to travel back to the heart.

This can result in the heart failing to receive enough nutrients. Furthermore, if the clot is somehow dislodged, it can travel to the heart causing a variety of problems. Meanwhile, if the clot finds its way to the arteries that supply blood to the brain, it can cause a stroke.

Cause of Condition

When blood clots form to seal a ruptured vessel caused by a skin lesion, it’s considered as a normal condition that rarely causes any complications. However, when blood clots form in the veins and arteries, medical problems can arise. They can be caused by the damage to the inner lining of a vein, an abnormal or sluggish flow of blood, or if blood is thicker than normal and is more prone to clotting.

The risk of developing abnormal blood clots and DVT is also increased by:

  • Smoking
  • Obesity
  • Pregnancy
  • Injury
  • History of abnormal blood clots or DVT
  • Age
  • Hormone replacement therapy
  • Cancer
  • Birth control pills
  • Sitting or remaining still for long periods
  • Heart failure

Diseases and medical conditions, such as antiphospholipid syndrome, arteriosclerosis, and atherosclerosis are also known to cause the condition.

Blood clots can also form when cholesterol plaques build up in the arteries. Such plaques contain thrombogenic substances that are usually found in the skin and play an important role in the formation of clots. If the plaque breaks open, the substances come in contact with the blood, which will then start the clotting process. This can result in a heart attack or a stroke.

Since blood clots can cause serious complications, it’s important to be able to recognize the symptoms and signs that you require medical attention so you can receive appropriate treatment right away.

Key Symptoms

If you’re at risk of developing blood clots in the veins and/or arteries, you should be aware of the symptoms so that you can seek medical assistance immediately. Call your doctor or seek medical consultation if you experience:

  • Chest heaviness
  • Chest pains
  • Light-headedness
  • Shortness or breath
  • Unusual sweating
  • Weakness of the facial muscles
  • Weakness in the arms and legs
  • Speaking difficulties
  • Vision problems
  • Dizziness
  • Severe headaches
  • Swelling in the extremities
  • Coughing blood
  • Severe abdominal pain
  • Diarrhea

Who to See & Types of Treatment Available

If you experience any of the symptoms, you should seek medical assistance. In most cases, patients consult their primary care physicians. If the symptoms are severe and affect your ability to function, it’s best to proceed directly to the nearest hospital’s emergency department or call emergency medical services for assistance.

In non-emergency cases, the doctor will assess your condition by asking about your symptoms and reviewing your medical history. A physical examination will also be performed and this will include listening to your heart for any signs of abnormal heartbeat, taking your blood pressure, and checking your weight. Your doctor will also inspect your arms and legs for any signs of swelling.

If the doctor determines that the symptoms are caused by a formation of blood clots, treatment will be immediately provided and will depend on the location of the blood clot and your health condition.

Treatment can include medications, such as anticoagulants that prevent blood from clotting, and thrombolytics that dissolve blood clots. If these techniques fail to improve your condition, or if your condition is life threatening, the doctor may opt to remove the blood clot through a surgical procedure called thrombectomy.

Since blood clots affect different body parts, it’s normal for different specialists to work on your condition. These will usually include a hematologist (specialist in blood diseases), a cardiologist (heart specialists), and possibly a neurologist (brain specialist).


  • Schafer AI. Thrombotic disorders: hypercoagulable states. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 179.
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