Blood clotsBy Mayo Clinic staff
Original Article: http://www.mayoclinic.com/health/blood-clots/MY00109
Blood clots can occur under many different circumstances and in many different locations. Blood clots that form in response to an injury or a cut are beneficial, stopping potentially dangerous bleeding. However, a number of conditions can cause you to develop blood clots in critical locations, such as your lungs and brain, and they require medical attention.
Blood clots may form inside small veins near the surface of your skin (superficial phlebitis), resulting in localized redness, pain and swelling. Superficial phlebitis rarely causes complications and requires minimal treatment. Blood clots that form inside larger, deeper veins (deep vein thrombosis) may cause more widespread symptoms in the affected area, usually your leg, and can cause more-serious problems.
Blood clots may also break away from their original source and cause damage elsewhere in your body. Blood clots that break away from a deep vein thrombosis and travel to your lungs may cause a potentially life-threatening blood clot in the lungs (pulmonary embolism).
Blood clots that arise in one of the chambers of your heart, usually due to an irregular heart rhythm such as atrial fibrillation, may travel to your brain and cause a stroke. Blood clots that arise in the arteries of the heart itself may block the flow of blood through that artery and cause a heart attack.
Blood clots that arise from within the carotid arteries in your neck may travel to the brain and cause a stroke.
Factors and conditions that can cause blood clots, as well as serious conditions that are associated with blood clots once they form and travel to other parts of your body, include:
- Antiphospholipid syndrome
- Arteriosclerosis / atherosclerosis
- Buerger's disease
- Deep vein thrombosis (DVT)
- Essential thrombocythemia
- Factor V Leiden
- Family history of blood clots
- Heart arrhythmias, including atrial fibrillation
- Heart attack
- Heart failure
- Medications, such as oral contraceptives, hormone therapy drugs, tamoxifen
- Peripheral artery disease (PAD)
- Polycythemia vera
- Prolonged sitting or bed rest
- Pulmonary embolism
When to see a doctor
Seek emergency care if you experience:
- Shortness of breath
- Pressure, fullness or a squeezing pain in the center of your chest lasting more than a few minutes
- Pain extending to your shoulder, arm, back, teeth or jaw
- Sudden weakness or numbness of your face, arm or leg
- Sudden difficulty speaking or understanding speech (aphasia)
- Sudden blurred, double or decreased vision
Consult your doctor if you develop:
- Swelling, redness, numbness or pain in a leg or arm
- Intense burning or throbbing on your palms or soles
- Chronic headache or dizziness
To reduce your risk of developing blood clots, try these tips:
- Avoid sitting for long periods. If you travel by airplane, walk the aisle periodically. For car trips, stop and walk around frequently.
- Move. After you've had surgery or been on bed rest, the sooner you move, the better.
- Change your lifestyle. Lose weight, lower high blood pressure, stop smoking and exercise regularly.
- Majerus PW, et al. Blood coagulation and anticoagulation, thrombolytic, and antiplatelet drugs. In: Brunton LL, et al. Goodman & Gilman's The Pharmacological Basis of Therapeutics. 11th ed. New York, N.Y.: McGraw Hill; 2006. http://www.accessmedicine.com/resourceTOC.aspx?resourceID=28. Accessed Sept. 27, 2010.
- Coagulation disorders. The Merck Manuals. The Merck Manual for Healthcare Professionals. http://www.merck.com/mmpe/sec11/ch136/ch136a.html. Accessed Sept. 27, 2010.
- Your guide to preventing and treating blood clots. Agency for Healthcare Research and Quality. http://www.ahrq.gov/consumer/bloodclots.htm. Accessed Sept. 27, 2010.
- Wilkinson JM (expert opinion). Mayo Clinic, Rochester, Minn. Sept. 29, 2010.