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A hereditary blood coagulation disorder caused by a deficient activity of plasma protein factor VIII, which affects the clotting property of blood. Hemophilia A is the most common of the hemophilia group. The disorder is caused by an inherited sex-linked recessive trait with the defective gene located on the X chromosome. Females are carriers of this trait. Fifty percent of the male offspring of female carriers have the disease and 50% of their female offspring are carriers. All female children of a male hemophiliac are carriers of the trait.
The severity of symptoms can vary with this disease, and the severe forms become apparent early on. Bleeding is the hallmark of the disease and typically occurs if an infant is circumcised. Additional bleeding manifestations make their appearance when the infant becomes mobile. Mild cases may go unnoticed until later in life when try occur in response to surgery or trauma. Internal bleeding may happen anywhere, and bleeding into joints is common. Risk factors are a family history of bleeding and being male.
Bleeding into joints and associated pain and swelling
Gastrointestinal tract and urinary tract hemorrhage
Blood in the urine or stool
Prolonged bleeding from cuts, tooth extraction, and surgery
Standard treatment is infusion of factor VIII concentrates to replace the defective clotting factor. The amount infused depends upon the severity of bleeding, the site of the bleeding, and the size of the patient. Mild hemophilia may be treated with infusion of cryoprecipitate or desmopressin (DDAVP), which causes release of factor VIII that is stored within the body on the lining of blood vessels.
To prevent a bleeding crisis, people with hemophilia and their families can be taught to administer factor VIII concentrates at home at the first signs of bleeding. People with severe forms of the disease may need regular prophylactic infusions.
With treatment, the outcome is good; most people with hemophilia are able to lead relatively normal lives. A small percentage of people with hemophilia will develop inhibitors of factor VIII and may die from loss of blood.