Inherited deficiencies of blood clotting factors, causing excessive bleeding
- Affect males only
- Due to abnormal genes, which in some cases are inherited
- Age and lifestyle are not significant factors
Normally, a cut or internal injury stops bleeding within a few minutes, unless it is very serious. In haemophilia, even a small cut may bleed for hours or days, and there are sometimes episodes of spontaneous bleeding. The much rarer Christmas disease has similar features and is named after the person in whom the disease was first diagnosed. Both conditions affect only males.
What are the causes?
Haemophilia and Christmas disease are both due to a deficiency of a protein involved in blood clotting. In haemophilia, the deficient protein is Factor VIII; in Christmas disease, the protein is Factor IX. In both these conditions, the deficiency is the result of a faulty gene. The particular gene involved is different in the two disorders.
In both disorders, the abnormal gene is inherited in a recessive manner and is located on the X chromosome (see Gene disorders). The disorders affect males only; females are unaffected, although women can pass on the faulty gene to their children. Each son of a woman who carries the abnormal gene has a 1 in 2 chance of being affected.
In a third of all cases of haemophilia and Christmas disease, the cause is a spontaneous gene abnormality and there is no family history of the disorders.
What are the symptoms?
The symptoms are highly variable, and their severity depends on how much Factor VIII or IX is produced. They usually develop in infancy and may include:
Easy bruising even after minor injury.
Sudden, painful swelling of muscles and joints due to internal bleeding.
Prolonged bleeding after an injury or a minor surgical operation.
Blood in the urine.
Without treatment, prolonged episodes of bleeding into the joints may result in long-term damage and, eventually, may lead to deformity of the joints.
What might be done?
Your doctor will arrange for tests to see how long your blood takes to clot and to measure the level of Factor VIII or IX.
The aim of treatment is to maintain the clotting factors at a high enough level to prevent bleeding. If you have a severe form of either condition, you will probably need regular intravenous injections of Factor VIII or IX to boost the levels of these factors in the blood. If you have a mild form of either condition, you may need injections only after an injury or before surgery. You may also be prescribed desmopressin, which contains a pituitary hormone, to boost the level of Factor VIII in your blood (see Pituitary drugs).
Some people develop antibodies to Factor VIII supplements, which makes treatment difficult. These people may need to take an immunosuppressant drug to destroy the antibodies.
What is the prognosis?
If you have haemophilia or Christmas disease, you can lead an active life but need to avoid sustaining any injuries. Activities such as swimming, running, and walking are beneficial, but contact sports, such as wrestling and football, should be avoided. Regular dental care is necessary to avoid the risk of bleeding from inflamed gums.
If you have a family history of either disorder, you should obtain medical advice when planning a pregnancy (see Genetic counselling). In the past, some people with haemophilia contracted acute or chronic hepatitis or HIV (see HIV infection and AIDS) after receiving clotting factors contaminated with hepatitis B or C viruses or HIV. Synthetic Factor VIII and Factor IX clotting factors are now available and these eliminate the risk of infection with these viruses.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.