What are blood clots? What is a thrombus?

A thrombus is a blood clot that occurs in one of your veins. A thrombus does not move and partially or entirely stops the flow of blood through that vein.
Your arteries allow oxygen within your blood to flow from your heart to your body. Arteries deliver oxygen via blood to all of your tissues and organs.
Your veins do the opposite. They carry blood back to your lungs to trade carbon dioxide for more oxygen. Every cell in your body requires this steady supply of oxygen-rich blood to stay alive.
Clotting is an important process in which blood thickens and creates a scab. This stops the bleeding from an injury. When this coagulation happens inside of your circulatory system, it can cause problems.
If a clot forms within your artery or vein, or breaks off and travels to the heart or lungs, you will have a medical emergency. This is because the clot blocks the flow of blood to or from your heart. Your brain and body do not receive enough oxygen when this happens.
Symptoms of blood clots and a thrombus
When a clot forms in one of your veins and does not move, it is called a thrombus. A thrombus is more likely to form in your veins than in your arteries. This is because the overall pressure of the blood flow through your veins is lower.
Arteries are more likely to develop hardening, also known as atherosclerosis. The higher pressure and speed of blood flow in your arteries makes a thrombus or blood clot less likely to form there.
Symptoms of a thrombus include:
- Pain or discomfort
- Heaviness or tenderness in the affected area
- Swelling, itchiness, or warmth near the clot
- Skin changes such as discoloration or thickening
Causes of blood clots and a thrombus
A thrombus is most likely to form in your legs or arms. They can occasionally occur in your pelvis or core.
A thrombus can be caused by a variety of factors, including:
- Disease or injury to leg veins
- Immobility or not being able to move around
- A broken bone
- Certain medications
- Obesity
- Autoimmune disorders
Other risk factors for developing a thrombus include:
- A hospital stay
- Surgery
- Injury or trauma
- Infection
- Active cancer or chemotherapy
- Estrogen-containing birth control pills
- Pregnancy
- History of heart attack or stroke
- Prior blood clots
- Family history of blood clots
- Genetic or acquired clotting disorders
Diagnosis for a thrombus
Only a licensed healthcare professional can diagnose a thrombus. There are a few ways that your doctor will determine whether you are experiencing a thrombus.
First, you will likely undergo duplex ultrasonography, which is an imaging test that uses sound waves to look at the flow of blood in your veins. Your doctor will look for any blockages that may be caused by a thrombus.
An alternative to duplex ultrasonography is a procedure called contrast venography.
In this procedure, your doctor injects your vein with a special highly-visible liquid and then takes an X-ray to locate any blockages. This is the most effective way to locate a thrombus. Since it is invasive and has more risks for infection, most doctors prefer to rely on duplex ultrasonography exams.
Finally, your doctor may perform a blood test called a D-dimer that looks for the enzymes present after a blood clot starts to break up. If your test is negative, you probably do not have a thrombus or blood clot.
Treatments for a thrombus
The treatment for this blood clot that is stationary in one of your veins is a type of medication known as a blood-thinner.
The blood-thinners that are most often administered to treat a thrombus are heparin and warfarin.
Blood clots can also be prevented by:
Possible complications and side effects
The possible complications from a thrombus or blood clot are very serious.
If the clot breaks away and travels to your lungs, it can cause a pulmonary embolism.
If the clot reaches your heart, it can cause a heart attack.
If it travels to your brain, it can cause a stroke.
In order to avoid these serious and potentially lethal complications, it is important to seek medical care immediately if you think you have a blood clot or thrombus.
Quick intervention can make all the difference and be life-saving in this situation.

SLIDESHOW
Spider & Varicose Veins: Causes, Before and After Treatment Images See SlideshowHealth Solutions From Our Sponsors
American Association for Clinical Chemistry: "D-dimer."
American Society of Hematology: "Blood Clots."
Centers for Disease Control and Prevention: "Diagnosis and Treatment of Venous Thromboembolism."
Harvard Health Publishing: "How to Prevent Clots in the Legs and Lungs."
Johns Hopkins Medicine: "Thrombosis."
National Blood Clot Alliance: "SIGNS AND SYMPTOMS OF BLOOD CLOTS."
National Blood Clot Alliance: "TREATMENT OF THROMBOSIS."
North American Thrombosis Forum: "What is Thrombosis?"
St. Luke's Hospital: "Complications of Deep Vein Thrombosis."
UNC Hemophilia and Thrombosis Center: "What is a blood clot?"
Top Difference Between a Thrombus and a Blood Clot Related Articles
alteplase (TPA, Activase, Cathflo Activase)
Alteplase is a drug prescribed to treat conditions caused by arterial blood clots such as heart attacks, strokes, chest pain from unstable angina, and pulmonary embolism. The most common and serious side effect of alteplase is bleeding. Minor bleeding is more common, but significant bleeding such as into the brain (intracranial hemorrhage) or fatal bleeding also occurs. Other important side effects include nausea and vomiting.Anticoagulants
Anticoagulants are drugs that inhibit blood clots from forming in the veins and arteries of the body. There are a variety of uses for these drugs, which include the treatment or prevention of deep vein thrombosis (DVT), blood clots in the lung (pulmonary embolism), stroke, blood clots during AFib, and heart attacks.Eliquis (apixaban)
Apixaban is a medication prescribed to prevent blood clots in the heart and strokes in patients with atrial fibrillation, and to prevent and treat deep vein thrombosis and pulmonary embolism. The most common side effects of apixaban involves bleeding in the stomach, intestines, brain, and eyes. Bleeding due to apixaban may be fatal.Are Blood Clots Normal in Early Pregnancy?
Around 15-20% of pregnant women experience bleeding during the first trimester. Light bleeding can be normal, but heavy bleeding or clots can indicate something more serious. Always let your doctor or midwife know if you're experiencing any bleeding.Blood Clot Picture
Blood that has been converted from a liquid to a solid state. See a picture of Blood Clot and learn more about the health topic.Blood Clots (in the Leg)
Blood clots can form in the heart, legs, arteries, veins, bladder, urinary tract, and uterus. Risk factors include high blood pressure and cholesterol, diabetes, smoking, and family history. Symptoms and treatment depend on the location of the clot.Blood Clots: 4 Signs You Could Have One
Blood clots can be deadly medical emergencies that can form in different parts of your body. Learn the warning signs that you might have one.clopidogrel bisulfate (Plavix)
Plavix (clopidogrel bisulfate) is an antiplatelet drug prescribed for the prevention of heart attacks and strokes in high risk individuals. Review side effects, drug interactions, warnings and precautions, and pregnancy information prior to taking this or any medication.Deep Vein Thrombosis (DVT, Blood Clot in the Legs)
Deep vein thrombosis (DVT) is a blood clot in the deep veins, and can be caused by broken bones, trauma to a limb, immobility, medications, smoking, cancer, genetic predisposition, and cancer. Symptoms and signs of a deep vein thrombosis in a leg are swelling, tenderness, redness, warmth, and pain. Treatments for DVT include medications and surgery.fresh frozen plasma
Fresh frozen plasma is administered as an intravenous transfusion based on ABO blood group compatibility. The uses of fresh frozen plasma include managing and preventing bleeding, replacement of coagulation factors, and plasma exchange in adults with thrombotic thrombocytopenic purpura (TTP). Common side effects of fresh frozen plasma include transfusion-transmitted infections and septic reactions, hemolytic transfusion reactions that destroy red blood cells, feverish (febrile) non-hemolytic reactions, transfusion related acute lung injury (TRALI), transfusion-associated graft-versus-host disease (TA-GVHD), transfusion-associated circulatory overload (TACO), and allergic reactions.heparin
Heparin is a natural anticoagulant compound in the body that prevents the formation of blood clots (thrombosis). Heparin is used to treat venous thromboembolism, pulmonary embolism, atrial fibrillation with embolization and other conditions. Common side effects of heparin include hemorrhage (gastrointestinal tract, urinary tract, adrenal bleeding with resultant adrenal insufficiency, ovarian hemorrhage, retroperitoneal hemorrhage, heparin-induced thrombocytopenia, heparin-induced thrombocytopenia and thrombosis, thrombocytopenia, bruising, blood vessel spasm (vasospasm), and heparin resistance. Heparin overdose may result in severe bleeding. Consult your doctor if pregnant and do not use if breastfeeding.How Serious Is a Blood Clot in the Lungs?
A blood clot is a solid or semisolid clump of blood. When the tissues of our body are injured, excessive blood loss is prevented by the clotting of blood. When a blood clot occurs inside the blood vessels it may lead to serious medical conditions. When a blood clot occurs inside the arteries to the lungs, the condition is called pulmonary embolism (PE).How Do You Know If You Have a Blood Clot in Your Leg?
Blood clots are clumps of blood formed when the blood changes from a fluid to a semisolid form. When a blood clot is formed in one of the large veins in the legs or arms, the condition is called deep vein thrombosis (DVT). A blot clot in your leg can hamper the flow of oxygen and nutrients to the affected area. An untreated DVT may cause the clot to grow bigger and break in small pieces that can travel to other organs, such as the heart and lungs, causing serious consequences.prasugrel
Prasugrel is a medication used during the treatment of patients with acute coronary syndrome (ACS) and unstable angina. Prasugrel can cause significant, sometimes fatal, bleeding. Common side effects of prasugrel include high blood pressure (hypertension), high level of cholesterol/lipids in blood (hypercholesterolemia/hyperlipidemia), headache, back pain, shortness of breath (dyspnea), nausea, diarrhea, dizziness, cough, low blood pressure (hypotension), fatigue, noncardiac chest pain, rapid and irregular rhythm in the atria (atrial fibrillation), slow heart rate (bradycardia), and others. Consult your doctor if pregnant or breastfeeding.Pulmonary Embolism (Blood Clot in the Lung)
A pulmonary embolism (PE) occurs when a piece of a blood clot from deep vein thrombosis (DVT) breaks off and travels to an artery in the lung where it blocks the artery and damages the lung. The most common symptoms of a pulmonary embolism are shortness of breath, chest pain, and a rapid heart rate. Causes of pulmonary embolism include prolonged immobilization, certain medications, smoking, cancer, pregnancy, and surgery. Pulmonary embolism can cause death if not treated promptly.rivaroxaban
Rivaroxaban is a blood thinner prescribed to reduce the risk of blood clots in patients with atrial fibrillation (not due to a heart problem), treat and reduce the risk of blood clots in the legs (deep vein thrombosis or DVT) and blood clots in the lung (pulmonary embolism), and to reduce the risk of blood clots in the legs and lungs of patients who have just had hip or knee replacement. You should review the side effects, drug interactions, dosage, storage, and pregnancy safety information prior to taking this medication.What Does a Blood Clot Feel Like?
Blood clots are semi-solid masses of blood that may be immobile (thrombosis) and impede blood flow or dislodge to other parts of the body (embolism). Deep vein clots, if dislodged, can travel through veins through the lungs to the arteries in the lungs. This is referred to as a pulmonary embolism and can be deadly. Blood clots can also lead to a heart attack or stroke.