A deficiency of clotting Factor VIII (factor 8) is classified as Hemophilia A. It is a hereditary disorder in which the clotting ability of the blood is impaired and excessive bleeding results. Uncontrolled internal bleeding can result in pain, swelling, and permanent damage, especially to joints and muscles.
Hemophilia B (also called "Christmas disease") is a deficiency in clotting factor IX. Hemophilia A is 7 times more common than Hemophilia B. The incidence of Hemophilia B is 1 out of 34,500 men. The outcome is good with proper treatment and specialized management. Most people with Hemophilia B are able to lead successful and relatively normal lives. (see Hemophilia A information above to learn about how hemophilia affects)
Both Hemophilia A and B are treated by infusing a factor product that replaces the patient's missing clotting factor. The amount infused depends upon the severity of the bleeding episode, the site of the bleed, and the weight of the patient. Factor products are intended for home use and can be self-administered (self-infused), either on a regular basis to prevent bleeding or at the first sign of bleeding. Prophylaxis is the treatment method most commonly used. It involves infusing factor product on a regular schedule in order to prevent bleeding episodes from occurring. By treating before a bleed occurs, factor levels in the blood are more normalized which helps to prevent bleeding episodes and the pain and damage they cause. Both the dose and frequency of factor replacement depend on the severity of the bleeding problem. The dose is adjusted according to the results of periodic blood tests. During a bleeding episode, higher doses of factor product are often needed.
Von Willebrand Disease
Like hemophilia, von Willebrand Disease (vWD) is a hereditary deficiency or abnormality of clotting factor in the blood. In this case, it is the von Willebrand factor which is a protein that affects platelet function. It's the most common hereditary disorder of platelet function, affecting both women and men. The disease is estimated to occur in 1% to 2% of the population. The disease was first described by Erik von Willebrand, a Finnish physician, who reported a new type of bleeding disorder among island people in Sweden and Finland. In von Willebrand disease, blood platelets don't stick to holes in blood vessel walls. Platelets are tiny particles in the blood that clump together at the site of an injury to prepare for the formation of a blood clot. von Willebrand factor causes them to bind to areas of a blood vessel that are damaged. If there is too little von Willebrand factor, or the factor is defective, platelets do not gather properly when a blood vessel is injured. von Willebrand factor is found in plasma, platelets, and blood vessel walls. When the factor is missing or defective, the first step in plugging a blood vessel injury (platelets adhere to the vessel wall at the site of the injury) doesn't take place. As a result, bleeding doesn't stop as quickly as it should, although it usually stops eventually. There are no racial or ethnic associations with the disorder. A family history of a bleeding disorder is the primary risk factor.
During the late 1970's and early 1980's, factor products were manufactured using donations of human blood. These donations contained the HIV virus which causes AIDS. As a result, approximately 60% of hemophiliacs who were treated contracted the HIV virus.
The death of thousands of people with hemophilia drove the medical and scientific community to find to create safe factor products. Today, only a few products contain elements of donated blood but these products include safety steps in the manufacturing process such as heat treatment and filtration to guard against any virus ending up in the finished product. The good news is that most of the products are now manufactured synthetically.
Though these products are safer to use than they have ever been before, people who infuse any medication into their veins take a certain risk. There have been product recalls due to manufacturing errors, improper temperatures during shipping, and cracked vials. There have also been recalls of the devices used in the infusion process (needles, tubing, syringes) for improper manufacturing techniques or unsterile packaging.