Bleeding disorders interfere with the body’s clotting ability, and lead to prolonged bleeding after an injury.
Under normal circumstances, when the body is injured, the platelets in blood gather around the wound. Proteins in the plasma (known as blood clotting factors) work with platelets and other substances to form a clot over the wound — the blood turns from liquid to solid.
In a person with a bleeding disorder, those clotting factors may be missing — or may not work they way they should.
The most common bleeding disorder is hemophilia A — also known as factor VIII deficiency or classic hemophilia. The majority of cases are inherited, though approximately thirty percent of cases appear in people with no family history of the disease.
In hemophilia A, one of the proteins needed to form blood clots (factor VIII) is missing or not present in high enough numbers. A person with hemophilia A will bleed longer than a person without the disease — but not harder or faster (there is a common myth that a person with hemophilia bleeds faster than a person without). Traumatic injuries have a high risk for complications.
The second most common type of bleeding disorder is hemophilia B — also known as factor IX deficiency or Christmas disease (named for the first person diagnosed with this disorder). The majority of cases are inherited, although approximately thirty percent of cases appear in people with no family history of the disease.
In hemophilia B, one of the proteins needed to form blood clots (factor IX) is missing or not present in high enough numbers. Hemophilia B is far less common than hemophilia A, but has many of the same symptoms and risks. The main difference is the clotting factor to blame for the problem.
- A person with mild hemophilia may only have problems with bleeding after serious injury or surgery. In many cases, the problem is discovered after an injury or surgery results in excessive bleeding.
- A person with moderate hemophilia (approximately fifteen percent of the hemophilia population) may have bleeding episodes after injuries and surgery and spontaneous bleeding episodes.
- A person with severe hemophilia (approximately sixty percent of the hemophilia population) may have bleeding episodes after injuries and surgery and frequent spontaneous bleeding episodes. There is a high risk of bleeding into the joints and muscles.
For people with severe hemophilia, missing clotting factors (VIII or IX) must be replaced in order for the blood to clot. Factor treatments — from human blood products or synthesized recombinant factors — can be injected or infused into the veins.
The third most common type of bleeding disorder is von Willenbrand Disease — it is estimated that between one and two percent of the population has this type of bleeding disorder.
The von Willenbrand factor is a protein used by the body in the initial stages of blood clotting. It is produced by the cells that line the walls of blood vessels, and works with platelets to form clots at injury sites. A person with von Willenbrand Disease either doesn’t have enough of this factor or the factor is abnormal.
- Type I: the most common and mildest form of the disease. Factor levels are lower than normal. Levels of factor VIII may also be low.
- Type II: the von Willenbrand factor itself is abnormal. This can interfere with the clumping ability of platelets.
- Type III: the most severe form of the disease. The von Willenbrand factor is absent. Levels of factor VIII are often low.
- Platelet type: defects are actually in the platelets themselves, not the von Willenbrand factor. This disorder resembles Type II.
For people with von Willenbrand disease, boosting factor VIII and von Willenbrand levels can help control bleeding.
For more information, visit the National Hemophilia Foundation.