Table of Contents
- Blood clot definition and facts
- What are blood clots?
- What causes blood clots (blood clots in veins or arteries)?
- What causes blood clots (blood clots in the heart and medical problems)?
- What are the signs and symptoms of blood clots?
- What are the risk factors for forming blood clots?
- What happens when a blood clot forms in the leg travels to the lung?
- What happens when blood clots form and travel to the heart?
- How are blood clots found or diagnosed?
- What tests are used to diagnose blood clots?
- What is the treatment for blood clots?
- What kind of doctors treat blood clots?
- What are the complications of blood clots?
- How can blood clots be prevented?
Quick GuideDVT in Pictures: Symptoms of Deep Vein Thrombosis, Beyond Leg Pain and More
What are the signs and symptoms of blood clots?
Signs and symptoms of blood clots in the veins
Blood clots in the veins do not allow blood to return to the heart, and symptoms occur because of this "damming effect." These clots often occur in the legs or the arms, symptoms include:
- redness, and
Most often, only one leg or arm is affected and the swelling occurs over the course of many hours. Because the leg or arm becomes red, warm and swollen, it is sometimes difficult to decide whether the cause is a DVT (deep vein thrombosis) or an infection.
On occasion, the whole leg may become very swollen, painful and turn bluish due to a blood clot located in the femoral vein in the upper leg or the iliac vein in the pelvis. This is called phlegmasia cerulia dolens. A similar situation may occur in the arm if the blood clot affects the subclavian vein located in the chest.
Signs and symptoms of blood clots in the arteries
Blood clots in the arteries do not allow blood to pump to an affected area. Body tissue that is deprived of blood and oxygen begins to die and becomes ischemic. Symptoms of blood clots in the arteries depend upon the location of the clot. Arterial blood clots cause diseases and illnesses that are medical emergencies, and it is appropriate to activate the emergency medical system or call 911.
Heart attack: Blood clots in the coronary arteries of the heart cause a heart attack. Symptoms of a heart attack may include:
The pain also may radiate to the arm, jaw or back.
Stroke or transient ischemic attack (TIA or "mini-stroke"): Blood clots to arteries in the brain may cause a stroke or transient ischemic attack (TIA). Symptoms may include:
FAST is the memory tool to remember regarding the symptoms for stroke:
- Facial drooping
- Arm weakness
- Speech difficulties
- Time (time is of the essence to try to reverse the stroke process. Call emergency services and get to a hospital.)
What are the risk factors for forming blood clots?
The risk factors for arterial clots are those that are common to all diseases that cause narrowing of blood vessels, cholesterol plaque formation, and plaque rupture.
- High blood pressure
- High cholesterol levels
- Family history of early heart attack or stroke
Blood clots in the veins are formed due to one of two main reasons: 1) immobility, and 2) genetic errors in the clotting mechanism. There are other associated risk factors including smoking and the use of birth control pills.
- Immobility: Commonly, when the body stops moving, the risk of blood clots increases since muscle movement is required to pump blood toward the heart. Stagnant blood in a vein is prone to clot. Examples of how blood clots may occur from immobility include:
- Being hospitalized or bedridden after illness or surgery
- Taking long trips (such as in a car, train, or plane), when hours may pass without standing to move, walk, or stretch, and blood pools in the leg veins and may potentially clot
- Orthopedic injuries and/or has casts placed over broken bones or limbs
- Undergoing knee or hip replacement
- Pregnancy is a risk factor for forming blood clots in the legs and pelvis, due to insufficient blood flow back to the heart.
- Immobility due to paralysis from a stroke or spinal cord injury.
- Genetic errors in the clotting mechanism: There may be a genetic or inborn error in the clotting mechanism, making a person hypercoagulable (hyper=more + coagulation= clotting) and at greater risk for forming clots.
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Dzsheka MS, et al. Stroke and bleeding risk in atrial fibrillation. Clin Cardiol.2014, Oct, 37(10)
Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.
Kearon, C., et al. "Antithrombotic Therapy for VTE Disease: Chest Guideline and Expert Panel Report." Chest. 2016;149(2):315-352. IMAGES:
1.Universal Images Group / Getty Images
8.Brand X Pictures / Getty Images