| What is hemophilia? Hemophilia is a bleeding problem. People with hemophilia do not bleed any faster than normal, but they can bleed for a longer time. Their blood does not have enough clotting factor. Clotting factor is a protein in blood that controls bleeding. Hemophilia is quite rare. About 1 in 10,000 people are born with it. Types of hemophilia The most common type of hemophilia is called hemophilia A. This means the person does not have enough clotting factor VIII (factor eight). Hemophilia B is less common. A person with hemophilia B does not have enough factor IX (factor nine). The result is the same for people with hemophilia A and B; that is, they bleed for a longer time than normal. How do you get hemophilia? People are born with hemophilia. They cannot catch it from someone like a cold. Hemophilia is usually inherited, meaning that it is passed on through a parent’s genes. Genes carry messages about the way the body’s cells will develop as a baby grows into an adult. They determine a person’s hair and eye colour, for example. Sometimes hemophilia can occur when there is no family history of it. This is called sporadic hemophilia. About 30% of people with hemophilia did not get it through their parent’s genes. It was caused by a change in the person’s own genes. How is hemophilia inherited? The hemophilia gene is passed down from parent to child. The genes for hemophilia A and B are on the X chromosome. For this reason, hemophilia is called an X-linked (or sex-linked) disorder. The figure below explains how the hemophilia gene is inherited. When the father has hemophilia but the mother does not, none of the sons will have hemophilia. All the daughters will carry the hemophilia gene. If a woman inherits a copy of the altered gene from either of her parents, she is said to “carry” the hemophilia gene and is therefore called a “carrier.” In other words, she has one normal and one altered copy of the gene. She can pass either gene onto her children. For each child, there is a 50% chance that a son will have hemophilia and a 50% chance that a daughter will carry the gene. On average, carriers of hemophilia will have about 50 per cent of the normal amount of clotting factor, but some carriers have far lower levels of clotting factor. Acquired hemophilia In rare cases, a person can develop hemophilia later in life. The majority of cases involve middle-aged or elderly people, or young women who have recently given birth or are in the later stages of pregnancy. This condition often resolves with appropriate treatment. Severity of hemophilia The severity describes how serious a problem is. The level of severity depends on the amount of clotting factor that is missing from a person’s blood. |
| Level | Percentage of normal factor activity in blood | Number of international units (IU) per millilitre (ml) of whole blood |
| Normal range | 50%–150% | 0.50–1.5 IU |
| Mild hemophilia | 5%–40% | 0.05–0.40 IU |
| Moderate hemophilia | 1%–5% | 0.01–0.05 IU |
| Severe hemophilia | Less than 1% | Less than 0.01 IU |
| People with severe hemophilia usually bleed frequently into their muscles or joints. They may bleed one to two times per week. Bleeding is often spontaneous, which means it happens for no obvious reason. People with moderate hemophilia bleed less frequently, about once a month. They may bleed for a long time after surgery, a bad injury, or dental work. A person with moderate hemophilia will rarely experience spontaneous bleeding. People with mild hemophilia usually bleed as a result of surgery or major injury. They do not bleed often and, in fact, some may never have a bleeding problem. Symptoms and diagnosis The signs of hemophilia A and B are the same: o Big bruises o Bleeding into muscles and joints o Spontaneous bleeding (sudden bleeding inside the body for no clear reason) o Prolonged bleeding after getting a cut, removing a tooth, or having surgery o Bleeding for a long time after an accident, especially after an injury to the head Bleeding into a joint or muscle causes: o An ache or “funny feeling” o Swelling o Pain and stiffness o Difficulty using a joint or muscle Where does bleeding occur? People with hemophilia can bleed inside or outside the body. Most bleeding in hemophilia occurs internally, into the muscles or joints. The most common muscle bleeds occur in the muscles of the upper arm and forearm, the iliopsoas muscle (the front of the groin area), the thigh, and the calf. The joints that are most often affected are the knee, ankle, and elbow. If bleeding occurs many times into the same joint, the joint can become damaged and painful. Repeated bleeding can cause other health problems like arthritis. This can make it difficult to walk or do simple activities. However, the joints of the hands are not usually affected in hemophilia (unlike some kinds of arthritis). How is hemophilia diagnosed? Hemophilia is diagnosed by taking a blood sample and measuring the level of factor activity in the blood. Hemophilia A is diagnosed by testing the level of factor VIII activity. Hemophilia B is diagnosed by measuring the level of factor IX activity. If the mother is a known carrier of hemophilia, testing can be done before a baby is born. Prenatal diagnosis can be done at 9 to 11 weeks by chorionic villus sampling (CVS) or by fetal blood sampling at a later stage (18 or more weeks). These tests can be done at a hemophilia treatment centre. Treatment Treatment for hemophilia today is very effective. The missing clotting factor is injected into the bloodstream using a needle. Bleeding stops when enough clotting factor reaches the spot that is bleeding. Bleeding should be treated as quickly as possible. Quick treatment will help reduce pain and damage to the joints, muscles, and organs. If bleeding is treated quickly, less blood product is needed to stop the bleeding. With an adequate quantity of treatment products and proper care, people with hemophilia can live perfectly healthy lives. Without treatment, most children with severe hemophilia will die young. An estimated 400,000 people worldwide are living with hemophilia and only 25% receive adequate treatment. The World Federation of Hemophilia is striving to close this gap. Treatment products Factor concentrates are the treatment of choice for hemophilia. They can be made from human blood (called plasma-derived products) or manufactured using genetically engineered cells that carry a human factor gene (called recombinant products). Factor concentrates are made in sophisticated manufacturing facilities. All commercially prepared factor concentrates are treated to remove or inactivate blood-borne viruses. Cryoprecipitate is derived from blood and contains a moderately high concentration of clotting factor VIII (but not IX). It is effective for joint and muscle bleeds, but is less safe from viral contamination than concentrates and is harder to store and administer. Cryoprecipitate can be made at local blood collection facilities. In fresh frozen plasma (FFP) the red cells have been removed, leaving the blood proteins including clotting factors VIII and IX. It is less effective than cryoprecipitate for the treatment of hemophilia A because the factor VIII is less concentrated. Large volumes of plasma must be transfused, which can lead to a complication called circulatory overload. FFP is still the only product available for treatment of hemophilia A and B in some countries. People with mild hemophilia A may sometimes use desmopressin (also called DDAVP) to treat minor bleeding. DDAVP is a synthetic hormone that stimulates the release of factor VIII. Source: https://elearning.wfh.org/elearning-centres/introduction-to-hemophilia/ |
