Hypercoagulation disorders
Hypercoagulation disorders (or hypercoagulable states or disorders) have theopposite effect of the more common coagulation disorders. In hypercoagulation, there is an increased tendency for clotting of the blood, which may put a patient at risk for obstruction of veins and arteries (phlebitis or pulmonaryembolism).
In normal hemostasis, or the stoppage of bleeding, clots form at the site ofthe blood vessel's injury. However, in hypercoagulation, clots develop in circulating blood. This disorder can cause clots throughout the body's blood vessels, sometimes creating a condition known as thrombosis. Thrombosis can leadto infarction, or death of tissue, as a result of blocked blood supply to the tissue. However, hypercoagulability does not always lead to thrombosis. Inpregnancy, and other hypercoagulable states, the incidence of thrombosis is higher than that of the general population, but is still under 10%. However, in association with certain genetic disorders, hypercoagulation disorders may be more likely to lead to thrombosis.
Hypercoagulation disorders may be acquired or hereditary. Some of the geneticdisorders that lead to hypercoagulation are abnormal clotting factor V, variations in fibrinogen, and deficiencies in proteins C and S. Other body systemdiseases may also lead to these disorders, including diabetes, sicklecell anemia, congenital heart disease, lupus, and others. Antithrombin III deficiency is a hereditary hypercoagulation disorder that affects both sexes.Symptoms include obstruction of a blood vessel by a clot (thromboembolic disease), vein inflammation (phlebitis), and ulcers of the lower parts of the legs. The role of proteins C and S is a complex one. In order for coagulation tooccur, platelets (small, round fragments in the blood) help contract blood vessels to lessen blood loss and also to help plug damaged blood vessels. However, the conversion of platelets into actual clots is a complicated web involving proteins that are identified clotting factors. The factors are carried in the plasma, or liquid portion of the blood. Proteins C and S are two of theclotting factors that are present in the plasma to help regulate or activateparts of the clotting process. Protein C is considered an anticoagulant. Mutation defects in the proteins may decrease their concentrations in the blood,and may or may not affect their resulting anticoagulant activity. Factor V is an unstable clotting factor also present in plasma. Abnormal factor V resists the changes that normally occur through the influence of protein C, whichcan also lead to hypercoagulability. Prothrombin, a glycoprotein which converts to thrombin in the early stage of the clotting process, is affected by thepresence of these proteins, as well as other clotting factors.
The diagnosis of hypercoagulation disorders is completed with a combination of physical examination, medical history, and blood tests. An accurate medicalhistory is important to determine possible symptoms and causes of hypercoagulation disorders. There are a number of blood tests that can determine the presence or absence of proteins, clotting factors, and platelet counts in the blood. Among the tests used to detect hypercoagulation is the Antithrombin IIIassay. Protein C and protein S concentrations can be diagnosed with immunoassay or plasma antigen level tests.
Coumadin and heparin anticoagulants may be administered to reduce theclotting effects and maintain fluidity in the blood. Heparin is an anticoagulant that prevents thrombus formation and is used primarily for liver and lungclots.
The prognosis for patients with hypercoagulation disorders varies depending on the severity of the clotting and thrombosis. If undetected and untreated, thrombosis could lead to recurrent thrombosis and pulmonary embolism, apotentially fatal problem.
Hereditary hypercoagulation disorders may not be prevented. Genetic and bloodtesting may help determine a person's tendency to develop these disorders.
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