Coagulation Disorders Health Article

Definition

Coagulation disorders (coagulopathies) are disruptions in the body's ability to control blood clotting, an essential function of the body designed to prevent blood loss. The most commonly known coagulation disorder is hemophilia, a condition in which a critical component of blood coagulation is missing, causing individuals to bleed for long periods of time before clotting occurs. There are numerous other coagulation disorders stemming from a variety of causes.

Description

Coagulation, or clotting, is a complex process (called the coagulation cascade) that involves 12 coagulation factors (designated by Roman numerals as factors I through XII) found in blood plasma and several other blood components. The factors include prothrombin, thrombin, and fibrin. Each has a precise role in coagulation. Besides the factors, which are all proteins, plasma (the fluid component of the blood) carries a number of other proteins that regulate bleeding. Platelets, tiny colorless cells in the blood, initiate contraction of damaged blood vessels so that less blood is lost. They also help plug damaged blood vessels and work with other constituents in plasma to accelerate blood clotting. A deficiency in clotting factors or a disorder that affects platelet production or one of the many steps in the entire process can disrupt clotting and severely complicate blood loss from injury, childbirth, surgery, and specific diseases or conditions in which bleeding can occur.

Coagulation disorders arise from different causes and involve different complications. Some common coagulation disorders are:

• Hemophilia or hemophilia A (factor VIII deficiency) is an inherited coagulation disorder, affecting about 20,000 Americans. This genetic disorder is carried by females but most often affects male offspring. It is characterized by spontaneous musculoskeletal bleeding. Christmas disease or hemophilia B (factor IX deficiency) is less common than hemophilia A with similar symptoms. Factor IX is produced in the liver and is dependent on interaction with vitamin K in order to function properly. Deficiency in the vitamin can affect the clotting factor's performance as well as deficiency in the factor itself.
• Disseminated intravascular coagulation, also known as consumption coagulopathy, is not a disease in itself but a clinical emergency that occurs as a result of other diseases and conditions. This condition accelerates clotting, which ironically can result in hemorrhage when the clotting factors are exhausted.
• Thrombocytopenia, the most common cause of coagulation disorder, is characterized by reduced numbers of circulating platelets in the blood. This disease also includes idiopathic thrombocytopenia.
• Von Willebrand's disease, a hereditary disorder with prolonged bleeding time, is due to a clotting factor deficiency and impaired platelet function. It is the most common inherited coagulation disorder.
• Hypoprothrombinemia is a congenital deficiency of clotting factors that can lead to hemorrhage.
• Other coagulation disorders include factor XI deficiency (hemophilia C), and factor VII deficiency. Hemophilia C afflicts one in 100,000 people and is the second most common bleeding disorder among women. Factor VII is also called serum prothrombin conversion accelerator (SPCA) deficiency. One in 500,000 people may be afflicted with this disorder that is often diagnosed in newborns because of bleeding into the brain as a result of traumatic delivery.