Hemophilia and Inherited Bleeding Disorders Overview
Inherited Bleeding Disorders
The blood clotting system in the human body is made up of over a dozen different proteins, which work together with special blood cells called platelets to form a blood clot.
If one of these clotting proteins is missing or not working properly, abnormal bleeding may occur. Abnormal bleeding can also happen if there are not enough platelets present, or if the platelets do not work normally. Arteries, veins, and capillaries are the blood vessels, or tubes, which carry our blood throughout our bodies. When we are hurt a hole can form in any of these blood vessels causing bleeding to happen.
Sometimes you can see bleeding outside your body, for example from a cut or scrape.
Bleeding which happens under the skin or in a muscle might show up as a bruise, or hematoma.
You can also bleed inside your body, and it can’t be seen from the outside at all–not even as a bruise. An example might be bleeding from an ulcer in your stomach, or bleeding from another internal injury to an organ in your body resulting from a car accident.
Your body does two things to stop bleeding.
- Platelets travel to the hole in the blood vessel and start sticking to the wall of the damaged blood vessel to form a “plug”, which helps fill the hole and slow the bleeding. More platelets stick to them until the hole is loosely filled.
- In the second step, fiber-like strands form a network around the platelets, making a more stable clot to seal the hole and stop bleeding.
- Both steps are needed for bleeding to stop. A clot will not form unless the platelet plug forms first.
Directions for making clotting proteins are found in genes located in certain cells of the body.
- Changes in these genes can cause too little of the clotting factor to be made.
- These genes can also cause production of clotting factor proteins or platelets that do not work the way they should.
- Abnormal clotting factor genes can be inherited, or passed from parent to child. Sometimes the abnormal gene is inherited–less often a new mutation occurs.
- It is estimated that at least 1% of the population (1 in 100 people) has some form of inherited bleeding disorder.
- The two most common inherited bleeding disorders are von Willebrand’s Disease and Hemophilia.
Inherited bleeding disorders can be mild, moderate, or severe, depending on the amount of normal clotting factors present in the blood. People with severe bleeding disorders make little or none of the affected clotting factor, or the factor they make does not work. These people can have prolonged bleeding with very minor injuries. They sometimes bleed without having any known injury at all. People with mild or moderate bleeding disorders usually have problems with bleeding only after an injury or an invasive procedure such as surgery or having a tooth pulled. Common symptoms seen in people with inherited bleeding disorders include:
- Easy Bruising
- Frequent nosebleeds that are hard to stop
- Bleeding longer than expected following circumcision, surgery, or having a tooth pulled
- Bleeding into joints and soft tissues
- Women often have heavy bleeding with menstrual periods (menorrhagia)
Diagnosis of Bleeding Disorders
If your primary care provider suspects that you might have a bleeding disorder s/he will usually refer you to a hematologist, a doctor who specializes in treating various kinds of bleeding disorders. Along with a history and physical, a number of blood tests will be needed to make the diagnosis of a bleeding disorder. Some of the tests that may be done are listed below:
- Platelet count – measures the number of platelets present.
- Bleeding time – measures how long it takes you to stop bleeding. This test is one way to tell whether or not your platelets are working normally.
- PT (prothrombin time) – measures the clotting activity of factors I, II, V, VII, and X
- aPTT (activated partial thromboplastin time) – measures clotting activity of factors I, II, V, VIII, IX, X, XI, and XII
- Factor assays – measure the amount of specific clotting factors
Results of blood tests, along with the results of the history and physical exam will help the hematologist determine whether you have a bleeding disorder, and if so which one you have. In order to decide what treatment you may need and what precautions you should take it is important to know what clotting factors are low, and exactly how low the levels are.
von Willebrand Disease (vWD)
There are three types of von Willebrand Disease. No matter what type you have, it will not change to another type at a later time.
- The most common is Type I. In this form, the von Willebrand factor (vWF) in your blood works properly, you just don’t have enough of it.
- Those with Type II vWD have enough factor, but it doesn’t work properly. Type II can be further divided into Type IIA or Type IIB, which may require different treatment.
- People who have almost no vWF in their Blood have Type III von Willebrand’s disease. This is the most severe form of this bleeding disorder.
In the two-step process of controlling bleeding, the platelet plug can’t be made without von Willebrand factor being present. Without the platelet plug, clotting won’t take place.
Besides making the platelets stick to form a “plug,” von Willebrand factor also carries factor VIII in the blood. Therefore, people with von Willebrand’s disease may also have low amounts of clotting factor eight (Factor VIII). Both men and women have an equal chance to inherit von Willebrand’s Disease.
There are two types of hemophilia. As with von Willebrand Disease, no matter which type you have, it will not change to another type at a later time.
- The most common type is called hemophilia A, or classic hemophilia. People with hemophilia A don’t have enough factor VIII, or the factor VIII they have doesn’t work right. About 70% of people (7 out of 10) with hemophilia have hemophilia A.
- Hemophilia B, also called “Christmas disease”, is less common than hemophilia A. About 30% of people with hemophilia have hemophilia B. In this form there is either not enough clotting factor nine (factor IX), or the factor IX that is present doesn’t work right.
Both factor VIII and factor IX are needed for the second step of the clotting process. They help form the fiber-like strands that make a network around the platelets to make the clot more stable. Although most people with hemophilia are men, women can sometimes have low levels of factor VIII or factor IX as well.
Treatment of Bleeding Disorders
People with mild bleeding disorders usually don’t need any treatment for bleeding problems unless they have surgery or a severe injury. Those with severe bleeding disorders often require frequent treatments. Treatments include the following:
- Concentrated forms of factor VIII, factor IX, and von Willebrand factor can be given by IV to temporarily increase levels of the missing factor.
- Products are available that can be put directly on a wound to help a blood clot form.
- Medications called antifibrinolytics can be given to prevent or slow the breakdown of clots that form on mucous membranes such as the lining of the mouth.
- DDAVP (desmopressin) is a synthetic hormone that causes factor VIII and von Willebrand factor to be released from storage sites in the body. It can be used to treat mild hemophilia A and some forms of vWD
Many people with inherited bleeding disorders get their care at special hemophilia treatment centers. These centers provide comprehensive care for persons with all kinds of bleeding disorders. Benefits of comprehensive care given at hemophilia treatment centers include lower treatment costs, fewer complications, less time lost from work or school, and a significantly lower death rate.
For more information:
Go to the Hemophilia and Inherited Bleeding Disorders health topic.