Blood clots
Clot; Emboli; Thrombi; Thromboembolus; Hypercoagulable stateBlood clots are clumps that occur when blood hardens from a liquid to a solid.
- A blood clot that forms inside one of your veins or arteries is called a thrombus. A thrombus may also form in your heart.
- A thrombus that breaks loose and travels from one location in the body to another is called an embolus.
Embolus
Arterial embolism refers to a clot (embolus) that has come from another part of the body and causes a sudden interruption of blood flow to an organ o...
ImageRead Article Now Book Mark Article
A thrombus or embolus can partly or completely block the flow of blood in a blood vessel.
- A blockage in an artery may prevent oxygen from reaching the tissues in that area. This is called ischemia. If ischemia is not treated promptly, it can lead to tissue damage or death.
- A blockage in the vein will often cause fluid buildup and swelling.
Causes
Situations in which a blood clot is more likely to form in veins include:
- Being on long-term bed rest
- Sitting for long periods, such as in a plane or car
- During and after pregnancy
- Taking birth control pills or estrogen hormones (especially in women who smoke)
- Long-term use of an intravenous catheter
- After surgery
Blood clots are also more likely to form after an injury. People with cancer, obesity, and liver or kidney disease are also prone to blood clots.
Smoking also increases the risk of forming blood clots.
Conditions that are passed down through families (inherited) may make you more likely to form abnormal blood clots. Inherited conditions that affect clotting are:
- Factor V Leiden mutation
- Prothrombin G20210A mutation
Other rare conditions, such as protein C, protein S, and antithrombin III deficiencies.
Protein C, protein S
Congenital protein C or S deficiency is a lack of proteins C or S in the fluid part of the blood. The proteins are natural substances that help prev...
Antithrombin III deficiencies
Congenital antithrombin III deficiency is a genetic disorder that causes the blood to clot more than normal.
A blood clot may block an artery or vein in an organ, affecting the:
- Heart (angina or a heart attack)
- Intestines (mesenteric ischemia or mesenteric venous thrombosis)
Mesenteric ischemia
Mesenteric artery ischemia occurs when there is a narrowing or blockage of one or more of the three major arteries that supply the small and large in...
ImageRead Article Now Book Mark ArticleMesenteric venous thrombosis
Mesenteric venous thrombosis (MVT) is a blood clot in one or more of the major veins that drain blood from the intestine. The superior mesenteric ve...
Read Article Now Book Mark Article - Kidneys (renal vein thrombosis)
Renal vein thrombosis
Renal vein thrombosis is a blood clot that develops in the vein that drains blood from the kidney.
ImageRead Article Now Book Mark Article -
Leg or arm arteries
Leg or arm arteries
Peripheral artery disease (PAD) is a condition of the blood vessels that supply the legs and feet. It occurs due to narrowing of the arteries in the...
ImageRead Article Now Book Mark Article - Legs (deep vein thrombosis)
Deep vein thrombosis
Deep vein thrombosis (DVT) is a condition that occurs when a blood clot forms in a vein deep inside a part of the body. DVT mainly affects the large...
ImageRead Article Now Book Mark Article - Lungs (pulmonary embolism)
Pulmonary embolism
A pulmonary embolus is a blockage of an artery in the lungs. The most common cause of the blockage is a blood clot.
ImageRead Article Now Book Mark Article - Neck or brain (stroke)
References
Anderson JA, Hogg KE, Weitz JI. Hypercoagulable states. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 7th ed. Philadelphia, PA: Elsevier; 2018:chap 140.
Cross SS. Ischaemia, infarction and shock . In: Cross SS, ed. Underwood's Pathology. 7th ed. Philadelphia, PA: Elsevier; 2019:chap 7.
Schafer AI. Approach to the patient with bleeding and thrombosis: hypercoagulable states. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 162.
-
Thrombus - illustration
A thrombus is a blood clot that forms in a vessel and remains there. An embolism is a clot that travels from the site where it formed to another location in the body. Thrombi or emboli can lodge in a blood vessel and block the flow of blood in that location depriving tissues of normal blood flow and oxygen. This can result in damage, destruction (infarction), or even death of the tissues (necrosis) in that area.
Thrombus
illustration
-
Deep venous thrombosis - iliofemoral - illustration
This picture shows a red and swollen thigh and leg caused by a blood clot (thrombus) in the deep veins in the groin (iliofemoral veins) which prevents normal return of blood from the leg to the heart.
Deep venous thrombosis - iliofemoral
illustration
-
Thrombus - illustration
A thrombus is a blood clot that forms in a vessel and remains there. An embolism is a clot that travels from the site where it formed to another location in the body. Thrombi or emboli can lodge in a blood vessel and block the flow of blood in that location depriving tissues of normal blood flow and oxygen. This can result in damage, destruction (infarction), or even death of the tissues (necrosis) in that area.
Thrombus
illustration
-
Deep venous thrombosis - iliofemoral - illustration
This picture shows a red and swollen thigh and leg caused by a blood clot (thrombus) in the deep veins in the groin (iliofemoral veins) which prevents normal return of blood from the leg to the heart.
Deep venous thrombosis - iliofemoral
illustration
Review Date: 4/29/2022
Reviewed By: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
All rights reserved.