In people with bleeding disorders, the blood clotting process does not work properly. People might bleed for longer than normal and may have bleeding into joints, muscles or other parts of the body.
In haemophilia A, haemophilia B and von Willebrand disease (VWD), specific proteins required for the blood clotting process are missing or do not work as they should.
Signs of haemophilia include large bruises, bleeding into muscles and joints, sudden bleeding inside the body for no clear reason, or bleeding for a long time after a cut or wound.
People with haemophilia A do not have enough clotting factor VIII (factor eight or FVIII). Haemophilia A is a rare bleeding disorder, affecting approximately one in 5,000 male births and one in 10,000 across the population. It is usually inherited from the parents (called congenital haemophilia A), although it can also develop without being inherited during fetal development (sporadic haemophilia A) and in people who develop an autoimmune condition causing a deficiency of factor VIII (acquired haemophilia). Haemophilia A is diagnosed by taking a blood sample and measuring the level of FVIII activity.
Haemophilia A varies in severity and is classified as mild, moderate or severe, depending on the amount of FVIII the person has. People with severe haemophilia A have less than 1% of the normal amount of FVIII.
Haemophilia B is caused by a deficiency in clotting factor IX (factor nine or FIX) and is diagnosed by measuring the level of FIX activity in a blood sample. The signs and consequences of haemophilia B are very similar to those of haemophilia A.
People with von Willebrand disease (VWD) have a problem with a protein called von Willebrand factor (VWF). When a blood vessel is injured and bleeding occurs, VWF helps cells in the blood (called platelets) to form a clot to stop the bleeding. People with VWD have reduced levels of VWF, or their VWF does not work normally, so it takes longer for blood to clot and for bleeding to stop.
VWD is the most common bleeding disorder and is generally less severe than other bleeding disorders. It is estimated that up to 1% of the world’s population suffers from VWD but, because many people have mild symptoms, only a small number of them know they have VWD. For most people with VWD, the disorder causes little or no disruption to their lives except when they bleed heavily (e.g. during surgery or dental procedures, because of a serious injury, during childbirth, or due to heavy periods). However, with all forms of VWD, there can be bleeding problems.
There are three main types of VWD, based on the specific problem with the VWF protein. Bleeding symptoms can differ within each type. It is important to know which type of VWD a person has so that the right treatment is given.
Factor replacement therapy can be used to provide patients with the missing clotting factor:
On-demand treatment is used to stop bleeds when they occur.
Prophylactic therapy is used to prevent bleeding episodes.