What is hemophilia?
Hemophilia is a rare, inherited bleeding disorder in which blood cannot clot (form a mass) normally at the site of a wound or injury. The disorder occurs because certain blood clotting factors are missing or do not work properly. Because a clot does not form, extensive bleeding can be caused from a cut or wound. Spontaneous internal bleeding can occur as well, especially in the joints and muscles.
Hemophilia affects males only, but there are rare circumstances when a female can be affected with the disorder.
There are two types of inherited hemophilia:
- Type A, the most common type, is caused by a deficiency of factor VIII, one of the proteins that helps blood to form clots.
- Type B hemophilia is caused by a deficiency of factor IX.
Although hemophilia is usually diagnosed at birth, the disorder can also be acquired later in life if the body begins to produce antibodies that attack and destroy clotting factors. However, this acquired type of hemophilia is very rare.
What causes hemophilia?
The genes that regulate the production of factors VIII and IX are found on the X chromosome only. Hemophilia is caused by mutations in either the factor VIII or factor IX gene on the X chromosome.
If a woman carries the abnormal gene on one of her chromosomes (females have a pair of X chromosomes), she will not have hemophilia herself, but she will be a carrier of the disorder. That means that she can pass the gene for hemophilia on to her children. There is a 50% chance that any of her sons will inherit the gene and will be born with hemophilia. There is also a 50% chance that any of her daughters will be carriers of the gene, without having hemophilia themselves.
It is very rare for a girl to be born with hemophilia, but it can happen if the father has hemophilia and the mother carries the gene for hemophilia.
In about 20% of all cases of hemophilia, the disorder is caused by a spontaneous gene mutation. In such cases there is no family history of abnormal bleeding.
How common is hemophilia?
Hemophilia is an extremely rare disorder. Hemophilia A affects 1 in 5,000 to 10,000 males. Hemophilia B is less common, affecting 1 in 25,000 to 30,000 males. Around 60% to 70% of people with hemophilia A have the severe form of the disorder, about 15% have the moderate form, and the rest have mild hemophilia. Hemophilia can occur in all races and ethnic groups.
What are the symptoms of hemophilia?
Prolonged external bleeding after trauma and bruising that occurs easily or for no apparent reason, are two major symptoms of hemophilia. Symptoms vary depending on whether the patient has the mild, moderate, or severe form of the disorder:
- In severe hemophilia, bleeding episodes occur often and with little or no provocation.
- In moderate hemophilia, prolonged bleeding tends to occur after a more significant injury.
- In mild hemophilia, a patient might have unusual bleeding only after a major injury, surgery, or trauma.
People with hemophilia may have any type of internal bleeding, but most often it is in the muscles and joints, such as the elbows, knees, hips, shoulders, and ankles. Often there is no pain at first, but if it continues, the joint may become hot to the touch, swollen, and painful to move.
Repeated bleeding into the joints and muscles eventually causes permanent damage, such as joint deformity and reduced mobility.
Bleeding in the brain is a very serious problem for those with severe hemophilia, and may be life-threatening. Signs of bleeding in the brain may include changes in behavior, excessive sleepiness, persistent headaches and neck pain, double vision, vomiting, and convulsions or seizures.
How is hemophilia diagnosed?
A doctor will perform a physical examination to rule out other conditions. If you have symptoms of hemophilia, the doctor will ask about your family’s medical history, since this disorder tends to run in families. In children with severe hemophilia, the diagnosis is usually made in infancy, either at circumcision, or when the toddler starts to walk and sustains minor injuries when falling.
Blood tests are then performed to determine how much factor VIII or factor IX is present. These tests will show which type of hemophilia you have and whether it is mild, moderate, or severe, depending on the level of clotting factors in the blood:
- People who have 5%-30% of the normal amount of clotting factors in their blood have mild hemophilia.
- People with 1%-5% of the normal level of clotting factors have moderate hemophilia.
- People with less than 1% of the normal clotting factors have severe hemophilia.
How is hemophilia treated?
Treatment depends on the type and severity of the disorder. It consists of replacement therapy, in which human plasma concentrates or recombinant (produced from DNA) forms of the clotting factors VIII or IX are given to replace the blood clotting factors that are missing or deficient.
- Blood factor concentrates are made from donated human blood that has been treated and screened to reduce the risk of transmitting infectious diseases, such as hepatitis and HIV.
- Recombinant clotting factors, which are made in the laboratory and not from human blood, are commonly used today. Newer recombinant products are now available which survive longer in the circulation, which means fewer doses are needed for treatment.
During replacement therapy, the clotting factors are injected or infused (dripped) into a patient’s vein. Usually, people with mild or moderate hemophilia do not need replacement therapy unless they are going to have surgery.
- In cases of severe hemophilia, treatment may be given to stop bleeding when it occurs. Patients who have frequent bleeding episodes may be candidates for prophylactic factor infusions. These are given two or three times per week to prevent bleeding from occurring.
Some people with the mild or moderate form of hemophilia type A can be treated with desmopressin (DDAVP), a synthetic (man-made) hormone that helps to stimulate the release of factor VIII and another blood factor that carries and binds to it. Sometimes DDAVP is given as a preventive measure before a person with hemophilia has dental work or some other minor surgical procedure.
DDAVP is not effective for people with type B hemophilia or severe hemophilia type A. Aminocaproic acid or tranexamic acid are agents which prevent breakdown of clots (“antifibrinolytic”), and are often used as adjunctive therapy to treat nosebleeds or bleeding from the mouth (such as after a tooth extraction).
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 10/25/2016...#14083