Blood Disorders

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Hemophilia

Hemophilia is a bleeding disorder caused by a deficiency in one of two blood clotting factors: factor VIII (Hemophilia A) or factor IX (Hemophilia B). Symptoms can range from very mild, which may go undiagnosed, to severe. People with mild hemophilia may bleed more than expected after surgery, dental extractions, or a major injury. They have few unprovoked bleeding episodes, but surgery or injury may cause uncontrolled and fatal bleeding. When the clotting activity is less than 1 percent of normal, hemophilia is severe. Serious episodes of bleeding occur and recur for no apparent reason.

In severe hemophilia, the first bleeding episode often occurs during or immediately after delivery. The infant may develop a collection of blood under the scalp (cephalhematoma) or may bleed excessively during circumcision. A bleeding episode generally occurs before 18 months of age and may follow a minor injury. A child who has hemophilia bruises easily. Even an injection into a muscle can cause bleeding that results in a large bruise and hematoma. Recurring bleeding into the joints and muscles can lead to crippling deformities. Bleeding can swell the base of the tongue until it blocks the airway, making breathing difficult. A slight bump on the head can trigger substantial bleeding in the brain or between the brain and the skull, causing brain damage and death.

Diagnosis

Severe forms of hemophilia usually present with bleeding early after delivery, mild forms may not present until bleeding with a surgical procedure or during bleeding risk screening. The blood test called the PTT is useful for moderate to severe hemophilia. Specific blood tests for the factor VII or IX levels are then performed. Sometimes the disorder von Willebrand disease can resemble hemophilia and tests for the von Willebrand protein are also checked. Finally, once established, tests may be done for inhibitors to these proteins and sequencing tests may be performed to identify the specific genetic effect. The doctors at Seattle Cancer Care Alliance work closely with the doctors at Seattle Children's and the Puget Sound Blood Center Hemophilia Clinic in diagnosing and managing treatments.

Treatment

People who have hemophilia should avoid situations that might provoke bleeding and should avoid drugs that interfere with the function of platelets, like aspirin. They should take special care of their teeth to avoid extractions. If people who have milder forms of hemophilia need to have dental or other surgery, drugs may be given to improve temporarily the body's ability to control bleeding so that transfusions can be avoided.

Treatment for hemophilia often involves transfusions to replace the deficient clotting factor. These factors are normally in the liquid component of blood (plasma). Clotting factors may be obtained from donated blood by concentrating or purifying them from plasma products, or they may be produced using special technological procedures. Clotting factors may also be used to prevent bleeding before surgery or at the first sign of bleeding.

Some people with hemophilia develop antibodies to transfused clotting factors, which destroy the factors. As a result, factor replacement therapy becomes less effective. If antibodies are detected in the blood of a person with hemophilia, the dosage may be increased, or different types of clotting factors or drugs may be needed to reduce the antibody levels.