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Blood clots

Clot; Emboli; Thrombi; Hypercoagulable state

 

Blood 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 .

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
  • Crossing your legs for long periods when sitting, or 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.

A buildup of cholesterol that narrows an artery may change or slow the flow of blood, making it easier for a blood clot or thrombus to form.

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 thrombophilia
  • Prothrombin G20210A mutation
  • Other rare conditions, such as protein C, protein S , and antithrombin III deficiencies

A blood clot may block an artery or vein in the heart, affecting the:

  • Heart (angina or a heart attack)
  • Intestines ( mesenteric ischemia  or mesenteric venous thrombosis )
  • Kidneys ( renal vein thrombosis )
  • Leg or arm arteries
  • Legs ( deep vein thrombosis )
  • Lungs ( pulmonary embolism )
  • Neck or brain (stroke)

 

 

Open References

References

Schafer AI. Thrombotic disorders: hypercoagulable states. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 176.

 
  • Thrombus

    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

  • Janeway lesion on the finger

    Janeway lesion on the finger - illustration

    Janeway lesions appear as flat, painless, red or reddish-blue patches on the hands and soles of people with acute bacterial endocarditis.

    Janeway lesion on the finger

    illustration

  • Deep venous thrombosis, ileofemoral

    Deep venous thrombosis, ileofemoral - 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, ileofemoral

    illustration

    • Thrombus

      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

    • Janeway lesion on the finger

      Janeway lesion on the finger - illustration

      Janeway lesions appear as flat, painless, red or reddish-blue patches on the hands and soles of people with acute bacterial endocarditis.

      Janeway lesion on the finger

      illustration

    • Deep venous thrombosis, ileofemoral

      Deep venous thrombosis, ileofemoral - 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, ileofemoral

      illustration

    A Closer Look

     

    Talking to your MD

     

      Self Care

       

      Tests for Blood clots

       
       

      Review Date: 5/20/2016

      Reviewed By: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

      The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

       
       
       

       

       

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