When blood clots, it changes from a liquid to a solid. This is part of your body’s normal response to an injury. Normal clotting occurs within seconds after an injury and seals damaged blood vessels so that you donâ€™t lose too much blood. As your body heals, the clots dissolve and are absorbed by the body without causing problems.
Sometimes blood clots form inside the blood vessels without an injury, usually in leg veins. Clots can break into pieces and float in the bloodstream until they block a smaller blood vessel. The result can be a heart attack, stroke, loss of vision, or other problems.
What is the cause?
Your risk of blood clots is higher if:
You have an injury to a vein such as from an IV, surgery, a broken bone, or a severe bruise.
You have slow blood flow from not being able to move for long periods, such as during a car or airplane ride, or if you are on bedrest after surgery or because of an injury
You have a health problem that affects blood flow, such as being very overweight, or having varicose veins, kidney disease, cancer, HIV, or an immune system disorder such as lupus or rheumatoid arthritis. The immune system is your bodyâ€™s defense against infection.
You have increased hormone levels from using birth control pills, hormone replacement therapy, or during pregnancy.
You have inherited genes that cause your blood to clot too much.
Your risk for blood blots may be higher if you smoke, or if you have health problems such as diabetes or high cholesterol levels.
You may also be at a higher risk for another blood clot if you have had blood clots before, or if you have had a stroke or a heart attack.
What are the symptoms?
About half of people with blood clots have no symptoms until a clot blocks a blood vessel. When clots block blood flow, symptoms may include:
Pain, swelling, redness, or warmth in the area of the clot
Bluish color of the skin near the clot
Severe abdominal pain with vomiting or diarrhea
Shortness of breath
How are they diagnosed?
Your healthcare provider will ask about your symptoms and medical history and examine you. Tests may include:
IPG (impedance plethysmogram), which uses a pressure cuff on your arm or leg to measure blood flow in the veins of the arm or leg
A Doppler exam, which uses sound waves (ultrasound) to look at the blood flow in your blood vessels
A contrast venogram, which uses X-rays and a dye injected into a vein to show any blockages in your veins
Angiogram, which is a series of X-rays taken after your healthcare provider injects a special dye into your blood vessels to check for problems
MRI, which uses a strong magnetic field and radio waves to show detailed pictures of the blood vessels.
CT scan, which uses X-rays and a computer to show detailed pictures of the blood vessels
How are they treated?
If you have a heart attack or stroke caused by a blood clot, you may be given medicine to dissolve the clot.
You may need to take a blood thinner. If you have a condition that puts you at high risk for blood clots you may need to take medicine for the rest of your life.
A catheter (small tube) inserted into your blood vessel may be used to remove a blood clot.
You may need surgery to remove the clot. If you keep having problems, you may have surgery to put a small plastic filter in the large vein in your belly that returns blood to the heart. The filter can trap blood clots and keep them from reaching your lungs.
How can I take care of myself?
Follow the full course of treatment prescribed by your healthcare provider. In addition:
If you are taking a blood thinner:
Make sure you understand how to take your medicines and follow the instructions exactly.
Depending on the type of blood thinner you take, you may need blood tests often. Make sure you have all the blood tests recommended by your provider. The tests check how well the blood thinner is working.
Avoid pain medicines such as aspirin, ibuprofen (Motrin, Advil), and naproxen (Naprosyn, Aleve). Nonsteroidal anti-inflammatory medicines (NSAIDs), such as ibuprofen, naproxen, and aspirin, may cause stomach bleeding and other problems. These risks increase with age.
Be sure that you tell all healthcare providers who treat you about all of the products (prescription, nonprescription, supplements, natural remedies, and vitamins) that you are taking.
Blood thinners will make you bleed more than usual. To help prevent cuts, consider wearing rubber gloves or garden gloves for household and outdoor work. Don’t walk barefoot.
Take care of your health. Try to get at least 7 to 9 hours of sleep each night. If you smoke, try to quit. If you want to drink alcohol, ask your healthcare provider how much is safe for you to drink. Learn ways to manage stress. Exercise according to your healthcare provider’s instructions.
Keep your legs raised when you are in bed or sitting down. Wear special elastic stockings if prescribed by your healthcare provider.
Ask your provider:
How and when you will hear your test results
How long it will take to recover
If there are activities you should avoid and when you can return to your normal activities
How to take care of yourself at home
What symptoms or problems you should watch for and what to do if you have them
Make sure you know when you should come back for a checkup.
How can I help prevent blood clots?
Exercise as recommended by your healthcare provider.
Avoid sitting or standing for long periods of time. When you are traveling, move your feet and legs often. Go for short walks if possible. Avoid crossing your legs and ankles when you sit.
If you are planning surgery, ask your provider what can be done to prevent blood clots.
Keep a healthy weight. If you are overweight, try to lose some weight.
Stop smoking. Smoking increases the risk for blood clots.
Avoid wearing control-top pantyhose, leg garters, and other tight-fitting garments.
Developed by RelayHealth.
Adult Advisor 2015.1 published by RelayHealth. Last modified: 2014-12-08 Last reviewed: 2014-12-08
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
Blood Clots: References
Kearon C, Akl EA, Comerota AJ, et al. (2012). Antithrombotic therapy for VTE disease: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest; 141:e419S.
Lijfering WM, Rosendaal FR, Cannegieter SC. (2010). Risk factors for venous thrombosis – current understanding from an epidemiological point of view. Br J Haematol; 149:824.
Antithrombotic Therapy and the Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-based GuidelinesÂ (February 2012)Â Included are over 600 recommendations for the prevention, diagnosis, and treatment of thrombosis, addressing a comprehensive list of clinical conditions, including medical, surgery, orthopedic surgery, atrial fibrillation, stroke, cardiovascular disease, pregnancy, neonates and children, among others. Resources related to these guidelines can be found on theÂ ACCP Antithrombotic Guidelines 9th EdÂ page. These Guidelines replace theÂ Antithrombotic and Thrombolytic Therapy, 8th ed: ACCP Guidelines.Â (June 2008).
Dickson, BC. Venous thrombosis: on the history of Virchow’s triad. Univ Toronto Med J 2004; 81:166.
Goldhaber, SZ. Risk factors for venous thromboembolism. J Am Coll Cardiol 2010; 56:1.
Lijfering, WM, Rosendaal, FR, Cannegieter, SC. Risk factors for venous thrombosis – current understanding from an epidemiological point of view. Br J Haematol 2010; 149:824.