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Coagulation Product Line
Areas of Therapy
Hereditary Coagulation Disorders
Most inherited coagulation disorders involve a deficiency of a single clotting factor, with deficiencies of factor VIII (FVIII) (haemophilia A) , von Willebrand factor (VWF) and factor IX (haemophilia B) being the most common.
Haemophilia is an inherited disorder of blood clotting.
The body depends on clotting of blood to stop bleeding after injury and to help healing. Normal blood clotting restricts bruising after injury and stops bleeding into muscles and joints which can follow minor injuries associated with activities of everyday life. Normal blood clotting depends on the interaction of many substances within the blood. Some of these are called clotting factors.
If one of these clotting factors is not present in sufficient amounts prolonged bleeding may occur. A person with haemophilia has less clotting factor than usual.
Haemophilia A is the most common form of the disorder and is due to a deficiency of a factor called factor VIll (FVIII).
Haemophilia B is due to a deficiency of factor IX (FIX). It is about five times less common than haemophilia A.
A person with haemophilia does not bleed any faster than a normal person but the bleeding carries on for much longer.
Haemophilia affects males almost exclusively and is found in all populations. It is passed on by female carriers who usually have no bleeding problems themselves. In about one third of people with haemophilia there is no family history of the disorder.
Haemophilia occurs in about 1:5,000 male births.
Severity of Haemophilia
Haemophilia varies in severity and this variability is related to the amount of clotting factor present in the blood. All affected members in a particular family tend to have the same amount of clotting factor.
The normal range of FVIII and FIX is 50%-200% where 100% is the average value for the unaffected population.
Severe haemophilia: Factor VIIl or IX levels less than 1 %.
Bleeding into joints, muscles and other tissues occurs with minimal or no obvious injury (spontaneous haemorrhage) as well as with surgery or tooth extraction. Severe haemophilia A affects about 1:16,000 males.
Moderate haemophilia: Factor VIIl or IX levels between 1-5%.
Bleeding follows known minor injury as well as operations and tooth extractions.
Mild haemophilia: Factor VIll or IX levels between 6%-50%.
Bleeding is usually associated only with major injuries, surgical operations or tooth extractions. Diagnosis may not be made until adulthood when unexplained excessive bleeding may follow one of these events.
Inheritance of Haemophilia
The genes that control the production of clotting factors VIll and lX. are carried on the X chromosome.
In each pregnancy involving a female carrying the haemophilia gene there is a 1 in 2 chance that the haemophilia gene will be passed on, and when this happens a male child will have haemophilia, and a female will be a carrier of the haemophilia gene.
- Each son has a 50% chance of having haemophilia
- Each daughter has a 50% chance of being a carrier
If the father has haemophilia then all of his daughters will be carriers. None of his sons will have haemophilia.
- All the sons will be unaffected
- All the daughters will be carriers
If a man with haemophilia marries a woman who is a carrier, there is the possibility of having a daughter with haemophilia...
Management of Haemophilia
Haemophilia is a lifelong condition for which, at present, there is no cure. However, with the development of comprehensive care and the provision of preparations containing the missing clotting factors, it is possible for people with even severe haemophilia to control bleeding and live near normal lives.
Treatment is required for bleeding into joints and muscles and for all forms of surgery including circumcision and tooth extraction. It may also be needed for bleeds into other tissues, and after accidents and injuries.
Factor Replacement
Haemophilia is treated by replacing the deficient blood clotting factor using a product which is prepared either from human donor plasma or synthetically by genetic engineering.
Treatment
Treatment should be given as soon as possible after the onset of the haemorrhage. Pain is often relieved within minutes. Repeat doses of blood products may be needed in some situations, for example if pain and swelling of a joint or muscle are persisting, in mouth lesions where bleeding often stops for a few hours then starts up again, when there are stitches, or after a head injury.
Home transfusion programmes are widely used in many countries. These are supervised by hospital based specialists and nurses. The parents or patients are taught to administer the blood products themselves. This ensures early treatment and gives independence to the patient and family. It also reduces trips to hospital and the consequent financial, emotional and social burden to the person with haemophilia, his family, and the community.
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