Blood Clots
Definition
Blood clots are semi-solid clumps of coagulated blood. Blood clots that form in an uninjured blood vessel are not normal.
Description
Clotting of blood is a natural process in which liquid blood thickens to a jelly-like consistency. Normally, a blood clot stops the flow of blood after an injury to a blood vessel, to prevent blood loss and to allow healing to occur. As healing takes place, the blood clot gradually dissolves and is absorbed by the body. However, blood clots can occur in an abnormal way when an injury has not occurred.
A blood clot that forms in an artery is called an arterial thrombus or thrombosis. A blood clot that forms and blocks a major artery is potentially life-threatening or limb-threatening because blood flow through the artery is compromised and damage to vital organs can occur. A blood clot in a vein is called a venous thrombus or thrombosis. Blood clots are also dangerous because they may travel through the circulation and block distant blood vessels. A blood clot that leaves the site where it formed and travels through the bloodstream is called an embolus. A blood clot anywhere may or may not be life-threatening, and may cause anything from virtually no symptoms to sudden death.
Demographics
A history of mitral valve prolapse, an enlarged heart, atrial fibrillation (an irregular heartbeat), or heart failure increase risk of developing an arterial blood clot. Obesity, varicose veins, heart failure, or a sedentary lifestyle is risk factors for development of a venous blood clot. People who smoke are at an increased risk for blood clots, as are people with a family history of blood clots or blood clotting disorders.
Causes and symptoms
The clotting of blood is a complicated process that may be affected by many factors. Some factors are unknown, but blood clots are often the result of an underlying condition or lifestyle element. The following list is a sample of known causes for an increased risk of blood clots:
· Current diagnosis of cancer: Cancer interferes with normal blood circulation.
· Elevated levels of homocysteine: Homocysteine is an amino acid (building block of protein). Excess levels in the body are associated with an increased risk of arterial blood clots.
· Family or personal history of a blood clot or blood clotting disorder.
· Hormone replacement therapy.
· Long distance travel, immobility, or a sedentary lifestyle.
· Smoking.
· Advancing age.
· Obesity.
· Heart problems such as a history of stroke, heart attack, and heart disease including coronary artery disease.
· Elevated cholesterol levels.
· Hypothyroidism.
· Infection, inflammation, serious trauma, or surgery l High blood pressure.
· Autoimmune disorders such as lupus and rheumatoid arthritis.
The symptoms of a blood clot are dependent upon where the clot is located in the body. A blood clot in the lungs may cause chest pain, an accelerated heart rate, shortness of breath, dizziness or fainting, coughing up blood-tinged mucus, or a low-grade fever. In the artery of an arm or leg, a blood clot may cause pain, especially with moving the limb; difficulty moving the limb; numbness or tingling; and a pale discoloration to the affected extremity. In the vein of an arm or leg a blood clot may cause swelling, redness, tenderness, and discomfort to the affected arm or leg. Chest pain and a heart attack may ensue if a blood clot forms or travels to the heart. A blood clot in the abdomen may cause abdominal pain, vomiting, and/or diarrhea.
Diagnosis
When a blood clot is suspected, certain tests are ordered to confirm the diagnosis. These tests include ultrasound, computerized axial tomography (CAT scan), and magnetic resonance imaging (MRI). An angiogram (also known as an arteriogram) may be done if a blood clot is suspected in an artery.
Ultrasound produces images of the blood vessels and organs in the body to help assess blood flow. CAT scans and MRI provide high quality imaging of blood vessels and blood flow through the arteries. An arteriogram involves injection of a dye to evaluate the condition of the arteries and to determine if there is any blood flow obstruction.
Treatment
Treatment depends on whether the blood clot is an arterial or venous embolus or thrombus, the size of the blood clot, and the patient's general medical condition. If a blood clot has resulted in a heart attack or stroke, intravenous (IV) medication may be used to break up the clot. This treatment is followed by anticoagulant (blood-thinning) medication. Medication that interferes with the blood's ability to clot, called anti-platelets, may also be used. Aspirin is an example of an anti-platelet medication.
If anticoagulant medication is not effective, a special device called a vena cava filter may be used.
The filter is placed by a physician into the vena cava (the large vessel that transports blood from the lower extremities to the heart and lungs) to trap blood clots in the lower extremities before they reach the heart and lungs. Surgical intervention may be attempted to aspirate or remove the blood clot. Surgery may involve bypassing the area of obstruction caused by the clot in an attempt to improve blood flow or dilatation (with or without a balloon catheter called a stent) of the obstructed blood vessel.
Nutrition/Dietetic concerns
A diet low in fats and cholesterol can help reduce the risk for blot clot development. Individuals who are overweight or obese should take measures to lose weight through improved nutrition and exercise. Ginseng, a nutritional supplement, may interfere with the effects of blood-thinning medication. Use of ginseng and other supplements or medications should be discussed with a physician. Individuals who smoke are encouraged to quit as smoking significantly increases risk for blood clots.
Therapy
Special support hose called compression stockings can be used to help improve blood circulation. Blood-thinning medication may be prescribed for individuals with a history of a blood clot.
Prognosis
The location of the blood clot and how much the clot has obstructed blood flow determines the prognosis. The death rate for arterial embolism is 25-30%.
Approximately 25% of arterial embolism cases require amputation.
Prevention
Regular exercise enhances blood circulation and helps to prevent blood clots. Performing frequent leg exercises when immobile for extended periods of time, such as long distance travel, can maintain adequate blood flow. Not crossing the legs and not wearing tight-fitting clothes below the waist are also beneficial. Individuals should take measures to prevent the development of coronary artery disease, which increases the risk of blood clot formation. These measures include losing weight if overweight, decreasing stress, maintaining physical fitness, and not smoking.
QUESTIONS TO ASK YOUR DOCTOR
· What steps can I take to reduce my risk of serious complications from a blood clot?
· Am I at increased risk for a heart attack, stroke, or pulmonary (lung) embolism?
· What lifestyle changes can I make to decrease my risk of a blood clot?
· Will I always be at risk for development of a blood clot?
· Will I need to take medication to reduce my risk of developing a blood clot?
Caregiver concerns
Knowing the warning signs and symptoms of a blood clot may enable rapid diagnosis and treatment and thus avoid serious complications. It is important to know the side effects of anticoagulant and antiplatelet medications. Unusual bruising , bleeding that does not stop, headache, dizziness, trouble breathing, chest pain, nosebleed, bleeding gums, red or dark urine, or red or black color in the stool should be reported to a physician immediately.
Anticoagulant medication therapy requires regular blood testing. Activities that can result in serious injury should be avoided if anticoagulation or anti-platelet medication is being used. Vitamin K is involved in the blood clotting process so intake of Vitamin K foods in the diet should be closely monitored. Some over-the-counter (OTC) and prescription medications interfere with certain anticoagulant medicines; a physician should be consulted before starting any medication. An identification card listing the medication being taken should be carried by patients on either of these two types of medication.
Resources
OTHER
“Are You at Risk for Blood Clots?” DNADirect. December 6, 2007 [cited April 5, 2008].http://www.dnadirect.com/patients/tests/blood_clotting/more_about/GH_Thr_Risk.jsp.
“Blood Clot Prevention: Battling a Dangerous Condition.” LifeExtension January 19, 2006 [cited April 5, 2008]. http://www.lef.org/protocols/heart_circulatory/blood_clot_01.htm
Matsui, William. “Blood Clots.” MedlinePlus. November 2, 2006 [cited April 5, 2008].http://www.nlm.nih.gov/medlineplus/ency/article/001124.htm.
June G. Borazjani RN, MSN, CPHQ
