Oncology Encyclopedia:
Hypercoagulation Disorders
Key Terms: Antithrombin, Congenital, Hemostasis, Heparin, Phlebitis, Polycythemia, Thrombophlebitis.
Description
Hypercoagulation disorders (or hypercoagulable states or disorders) cause an increased tendency for clotting of the blood. In normal hemostasis (the stoppage of bleeding) clots form at the site of the blood vessel's injury. However, in hypercoagulation disorders the clots can develop in circulating blood. This may put a patient at risk for obstruction of veins and arteries (phlebitis, thrombosis, or thrombophlebitis). The hypercoagulable state and thrombophlebitis is common cases of cancer involving solid tumors such as pancreatic, breast, ovarian, and prostate cancer.
Hypercoagulation disorders can cause clots throughout the body's blood vessels, a condition known as thromboembolic disease. Thromboembolic disease can lead to infarction (death of tissue as a result of blocked blood supply to the tissue). Other serious results of hypercoagulation make this a dangerous condition. Clotting (thrombosis) in the veins and arteries leading to the lungs can prevent blood flow, causing sudden and severe loss of breath and chest pain. These clots, called pulmonary embolisms, are potentially fatal. Clots in the blood vessels of the brain can result in a stroke, and clots in the heart's blood vessels can result in a heart attack.
Symptoms of hypercoagulation disorders include swelling or discoloration of the limbs, pain or tenderness of the skin, visible obstructions in the surface veins, and ulcers of the lower parts of the legs.
The diagnosis of hypercoagulation disorders is completed with a combination of physical examination, imaging studies, and blood tests. The presence of deep clots can be determined using Doppler ultrasound examination—special x-ray techniques called venography or arteriography (in which a solution is injected into the blood vessel to aid in imaging), or a specific type of blood pressure test called plethysmography. 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 III assay. Protein C and Protein S concentrations can be diagnosed with immunoassay or plasma antigen level tests.
Causes
Hypercoagulation disorders are associated with cancer of the pancreas. About half of patients with pancreatic cancer experience incidence of thrombosis. Approximately 10% of patients with pancreatic cancer develop a specific type of hypercoagulation disorder known as migratory thrombophlebitis, or Trousseau's syndrome. In Trousseau's syndrome the blood vessels become inflamed and clots in the blood vessels spontaneously appear and disappear. Other types of cancer may also result in hypercoagulation disorders.
In order for blood coagulation to occur, platelets (small, round fragments in the blood) help contract blood vessels to lessen blood loss and also to help plug damaged blood vessels. The conversion of platelets into actual clots is a complicated process 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 the clotting factors that are present in the plasma to help regulate or activate parts of the clotting process. It is believed that pancreatic tumors produce chemicals that promote clotting, or coagulation, of the blood (procoagulants), or that they activate platelet function. It is also possible that tumors interfere with the functions of proteins C and S.
Treatments
The treatment for patients with hypercoagulation disorders varies depending upon the severity of the clotting and the other conditions it may have caused. Medications may include blood thinners (anticoagulants) such as heparin and warfarin, which prevent the formation of new blood clots; antiplatelet drugs such as aspirin; or thrombolytic drugs to dissolve existing clots. Pain medications and nonsteroidal anti-inflammatory medications may be given to reduce pain and swelling. Antibiotics will be prescribed if infection has occurred.
Resources
Books
Deloughery, Thomas G. Hemostasis and Thrombosis. Georgetown, TX: Landes Bioscience, 1999.
Goodnight, Scott H., and William E. Goodnight. Disorders of Hemostasis and Thrombosis. 2nd ed. New York: McGraw-Hill, 2000.
Organizations
National Heart, Lung and Blood Institute. Building 31, Room 4A21, Bethesda, MD 20892. (301) 496-4236. .
National Hemophilia Foundation. 116 West 32nd St., 11th Floor, New York, NY 10001. 800-42-HANDI. .
Other
American Academy of Family Physicians. Hypercoagulation: Excessive Blood Clotting. (15 April 2001). [cited July 5, 2005]. .
—Paul A. Johnson, Ed.M.
