Hemophilia (bleeding disorder)

Hemophilia is an inherited disorder of blood clotting. In case of injuries, the blood of the affected person does not clot or clots too slowly. In addition, so-called spontaneous bleeding often occurs without a wound or other cause for the bleeding being identified. Affected people do not bleed more heavily than healthy people when they are injured, but they usually bleed for much longer, which can lead to severe blood loss.

The most common blood coagulation disorders are haemophilia A and haemophilia B, in which the activity of a certain blood coagulation factor is disturbed.

In most cases, only men are affected by haemophilia. On average, about one in 5000 male newborns suffers from haemophilia. Colloquially, a person with haemophilia is referred to as a haemophiliac.

In haemophilia, patients suffer from a congenital disorder of certain blood clotting factors. These are substances dissolved in the blood which cause the formation of thrombi (blood clots) in the event of injury, thereby sealing the vascular injury and stopping blood loss. The human blood clotting system consists of 13 blood clotting factors, which are designated by the Roman numerals I to XIII. In haemophilia A, the activity of blood clotting factor VIII is reduced, and in haemophilia B, the activity of factor IX is reduced.

Haemophilia A and B are the best-known forms of haemophilia. In addition, there are other clinical pictures that are sometimes grouped together under the term "haemophilia":

• Hemophilia A: This form is caused by reduced activity of blood clotting factor VIII (antihemophilic globulin). The disease is inherited in an X-linked recessive manner, which means that almost without exception only men are affected, as they, in contrast to women, only have one X sex chromosome.
• Haemophilia B: This is caused by a deficiency of the blood clotting factor IX (Christmas factor). This disease is also inherited in an X-linked recessive manner, which means that it primarily affects men.
• Stuart-Prower factor deficiency: The cause of this blood clotting disorder is a deficiency of factor X (Stuart-Prower factor). The disorder is inherited in an autosomal recessive manner, which means that men and women are affected with equal frequency. However, this blood clotting disorder is very rare.
• Parahaemophilia (Owren's syndrome, hypoproaccelererinemia): This is a deficiency of clotting factor V, which is inherited in an autosomal recessive manner.
• Angiohaemophilia (Willebrand-Jürgens syndrome): This blood clotting disorder is caused by a deficiency of the von Willebrand factor. This is a carrier protein of factor VIII. Angiohaemophilia is the most common autosomal-dominant inherited coagulation disorder.
• Haemophilia C (Rosenthal syndrome): The cause of this disease is a deficiency of factor XI. As a result, joint haemorrhages or bleeding from minimal injuries occur easily, especially in children.

A disease with haemophilia is noticeable in that patients bleed longer when injured than healthy people. In addition, in severe forms of haemophilia, so-called spontaneous haemorrhages can occur, in which bleeding occurs without a specific cause (for example, a previous injury) being identified. Healthy people also suffer from spontaneous haemorrhages, but these normally heal quickly and unnoticed. In principle, spontaneous haemorrhages can occur anywhere, but there are typical localisations in haemophilia, such as bleeding into the joints.

The severity of the symptoms depends on the extent to which the activity of the blood clotting factors is reduced. If the activity is less than one percent of the normal activity of the clotting factors, it is a severe hemophilia. Up to five percent activity around moderate hemophilia and five to 40 percent is a mild form of hemophilia. The symptoms of hemophilia A do not differ from those of hemophilia B.

The first indication of the presence of haemophilia is the occurrence of unusual bleeding. Spontaneous, painful bleeding into large joints (e.g. the knee joint) or muscles is characteristic of haemophilia. In addition, extensive bleeding under the skin and, in the case of minor injuries, a greatly prolonged period of time until the bleeding stops can be indications of the disease. If abnormal bleeding occurs, a simple coagulation test can be used to make a rough assessment of the clotting factors.

However, the final diagnosis of haemophilia can only be made by analysing the blood clotting factors VIII and IX. With the help of certain examination procedures in the laboratory, the exact concentration of these factors in the blood can be determined. In addition, the genetic changes underlying haemophilia are usually determined. By determining the exact extent of the disease, a therapy can then be started that is precisely tailored to the individual patient.

If cases of haemophilia have already occurred in a family, a blood test is normally carried out on male offspring immediately after birth so that haemophilia can be ruled out or confirmed.

A cure for haemophilia cannot yet be achieved today. The current therapy consists of substituting the missing blood clotting factors prophylactically or in case of injury. For this purpose, haemophilia patients are administered certain factor concentrates several times a week - normally they can inject the preparations into their veins themselves. With the help of factor substitution, haemophilia patients can usually lead a largely normal life.

If major bleeding occurs despite prophylactic therapy, an additional dose of factor concentrates must be administered. In the case of minor wounds (for example, abrasions), no further administration of factor concentrates is usually necessary - the bleeding can also be stopped by covering and applying light pressure.

If there is a risk of internal bleeding (for example after a serious injury), hospital must be sought as soon as possible.

The prognosis of a haemophilia disease depends primarily on whether patients receive therapy with clotting factor preparations at an early stage. With sufficient medical care, the life expectancy as well as the quality of life of people with haemophilia hardly differs from healthy people. However, those affected must refrain from extreme physical stress and from sports such as boxing, winter sports or athletics.

Without adequate therapy (for example in countries with inadequate medical care), many patients with a more severe form of haemophilia do not reach adulthood. According to WHO estimates, only about 25 percent of all hemophilia patients worldwide receive adequate treatment with the very expensive blood clotting factor preparations.

Since hemophilia is a genetically inherited disease, prevention is not possible.