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Hemophilia
What is it?
Hemophilia is a disorder of the blood clotting system. Normally, an injury to a blood vessel activates certain proteins in the blood known as ?clotting factors?. A series of 12 natural clotting factors helps to change ordinary blood components into sticky clumps. Platelets, tiny cell particles that circulate in blood, begin attaching to each other and to protein fibers that are also in the blood. Ordinarily, a soft mass of platelets and fibers (a blood clot) forms quickly, bleeding stops, and the wound begins to heal. This process is known as coagulation (pronounced: ?co-ag-u-lay-shun?). Hemophilia results when one or more clotting factors are absent or insufficient. As a result, either blood clots break apart because they are too fragile to withstand blood flow or clots just do not form.
Although a deficiency of any of the 12 clotting factors is possible, the two that appear to be most essential to forming blood clots are factor 8 (designated by the Roman numeral VIII) and factor 9 (IX). A deficiency of factor VIII is also called hemophilia A or classic hemophilia. Approximately 80% of individuals with hemophilia have hemophilia A. Abnormal production of factor IX is called hemophilia B or Christmas Disease (because the first person diagnosed with it was named Stephen Christmas). About 10% to 15% of individuals with hemophilia have hemophilia B. Other inherited bleeding disorders that are results of deficiencies in other clotting factors, such as von Willebrand's disease, are very rare.
von Willebrand?s disease is a bleeding disorder in which an individual?s body has a deficiency of the von Willebrand factor or the factor is not working as it should be. von Willebrand is a protein that aids in the clotting process. It not only helps transport factor VIII, but it acts like a glue to help keep all platelets together when the blood is trying to clot.
Both hemophilia A and hemophilia B are classified by the estimated percentage of factor XIII/IX that are produced by the individual.
- Mild hemophilia is considered to be 5-30% of normal production
- Moderate hemophilia is 1% to 5% of normal production
- Severe hemophilia is 1% or less of normal production
About two-thirds of individuals with hemophilia A and about half with hemophilia B have severe cases. The severity of an individual?s condition often corresponds to the likelihood of physical problems. It may also predict how serious those problems might be and suggest which treatments may be most effective.
Although most bleeding episodes in mild to moderate hemophilia usually result from an injury, individuals with severe hemophilia may experience bleeding with no apparent cause. In severe hemophilia, most bleeding is internal. Bleeding may occur inside joints and muscles, or more seriously, in organs such as the stomach or brain. However, if the appropriate clotting factor is given as quickly as possible following injury, individuals with hemophilia may not have either visible evidence of bleeding or interference with everyday life.
The physical damage that can result from untreated serious bleeding depends on where the bleeding occurs.
- Serious bleeding into muscle tissue: Areas of muscle cells around the bleeding may die. The resulting scar tissue contracts as it is formed, potentially leading to decreased ability to bend joints. The scar tissue may also squeeze nerves, causing numbness and tingling.
- Serious bleeding into joints: knees, elbows, ankles, shoulders, hips, and wrists, are usually affected in that order. Joint bleeding may cause multilayered damage that may result in sever, painful arthritis. This arthritis can eventually led to muscle wasting and if the bones are weakened enough, there could be an increased risk of fractures.
- Bleeding into the skull or brain: Because bleeding can press on the brain, drowsiness, extreme headaches, nausea, vomiting, and sensitivity to light may result. Scar tissue, which can also be caused by bleeding into the brain, occasionally leads to epilepsy (or seizure disorder).
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What is it?
