Bleeding and Clotting: A Delicate Balance
Hemostasis is the body’s system for controlling bleeding and clotting. Normally, a delicate balance exists. Too much clotting (thrombophilia) could cause dangerous blood clots to form, but not enough clotting could result in serious bleeding problems. The body has several mechanisms to maintain the right amount of bleeding and clotting. However, abnormalities in this control process can disrupt the balance and lead to excessive bleeding or clotting.
Throughout the course of a normal day, your blood vessels sustain many minor injuries of which you are not aware. When a blood vessel is damaged, your body triggers a cascade of clotting reactions that involve 3 major processes:
- Narrowing of the blood vessel – Injury to a blood vessel causes it to constrict, or narrow, slowing down the flow of blood through the damaged area.
- Platelet activity – Blood clotting cells, called platelets, are activated and drawn to the site of injury. They change shape from round to spiny and stick to the injured area.
- Blood clotting factors – The blood vessel wall produces von Willebrand factor, which acts like “glue” to hold the platelets to the injured area. Thrombin and Factor V convert fibrinogen, another blood clotting factor, into long strands of fibrin. The fibrin mesh traps more platelets and blood cells, which forms a blood clot and plugs the vessel wall.
Blood clot formation is balanced by reactions that stop the clotting process. When enough fibrin has formed, Factor V is inactivated by Activated Protein C (APC). This way the clot does not become larger than necessary. As enzymes repair the damaged blood vessel, the clot is slowly dissolved.
Although the activation of this clotting process occurs normally, a problem may arise in a person with thrombophilia. This is because he or she may possess blood clotting proteins in abnormal amounts or may have proteins that do not function normally, leading to a tendency to excessive blood clotting. Likewise, a person who does not possess adequate amounts of clotting proteins could be more susceptible to bleeding when blood vessels are injured.
Most clotting and bleeding disorders can be managed with the help of blood products and medications that can decrease the formation of blood clots or help accelerate the clotting of blood to stop bleeding. Many times these disorders require patients to remain under the care of a health care provider with expertise in the diagnosis and treatment of these bleeding and clotting disorders.
For information about specific bleeding and clotting diseases and conditions, visit the links below:
- Congenital Protein C or S Deficiency
- Factor II Deficiency
- Factor IX Hemophilia
- Factor V Deficiency
- Factor V Leiden (American Heart Association)
- Factor VII Deficiency
- Factor X Deficiency
- Factor XII (Hageman Factor) Deficiency
- Hemophilia and Inherited Bleeding Disorders
- Hypercoagulable States
- Prothrombin 20210 Mutation (Factor II Mutation) (American Heart Association)
- Pulmonary Embolism
- Specific Thrombophilias (NATT)
- Von Willebrand Disease
- What is Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE)? (NATT)
- Bleeding Disorders: Specific Conditions (Medline Plus)
- Thrombophlebitis: Specific Conditions (Medline Plus)
For more information:
Go to the Bleeding and Clotting Disorders health topic.