Hemophilia is a rare hereditary disorder that prevents blood from clotting. Internal or external bleeding that does not stop can damage organs and joints. Hemophilia is the result of a genetic problem that causes babies to have absent or low levels of a certain clotting factor. About 18,000 Americans have hemophilia, according to the U.S. Centers for Disease Control and Prevention (CDC). The majority of individuals affected by this condition are males.

Normally, a break in a blood vessel is followed by a complex set of reactions that cause the blood to form a plug known as a clot. The clot is able to reduce or stop bleeding until the wound heals. Proteins called clotting factors are an essential part of this process.

People with hemophilia have a deficient amount of some type of clotting factor. This can result in prolonged bleeding following an injury. Bleeding can also occur internally, and the loss of excessive amounts of blood can damage internal organs. Such bleeding into a vital organ, such as the heart or brain, can be fatal.

There are three types of inherited hemophilia:

• Hemophilia A. About 90 percent of people with hemophilia have this version of the disorder.
  
  
• Hemophilia B. About 10 percent of people with hemophilia have this version of the disorder.
  
  
• Hemophilia C. This type of hemophilia is rare in the United States.

Hemophilia A and B usually are passed from mother to son. A damaged gene on the X chromosome is responsible for these forms of hemophilia. All females inherit two X chromosomes, one from each parent. If only one X chromosome is affected, the other can provide the necessary clotting factor. Males inherit an X chromosome from their mothers and a Y chromosome from their fathers. If the X chromosome has the affected gene, the male will have hemophilia because the Y chromosome has no gene to compensate for the missing clotting factors. 

The process for developing the extremely rare hemophilia C is different, and both males and females can get this form of the disorder.

Patients with hemophilia are at risk of continual bleeding following an injury. In some cases, this bleeding is visible or is apparent from bruising of the skin. Bleeding that is internal may not be visible. Joints in the knees, ankles and elbows are particularly vulnerable to internal bleeding. Internal bleeding may create a tingly or bubbly sensation in the joint. The joint also may be warm to the touch.

In diagnosing hemophilia, a physician will perform a complete physical examination and compile a thorough medical history. A family history of hemophilia can significantly increase the chance that a patient may have this disorder. Blood tests may be ordered to measure levels of clotting factor and to monitor how long it takes blood to clot.

There is no cure for hemophilia. The main treatment is injections of the clotting factor that the patient is missing. Patients with hemophilia may need to make several lifestyle adjustments as a result of their condition. However, most patients are able to live full, active lives.

Hemophilia is a hereditary disorder that prevents a person’s blood from clotting properly.  It is rare and occurs almost exclusively in males. About 18,000 Americans have hemophilia, according to the U.S. Centers for Disease Control and Prevention (CDC).

Normally, a person who suffers an injury to a blood vessel experiences a chain of events that causes the blood to clot and seal off the wound. After an injury to a blood vessel, small blood cells called platelets stick to the vessel at the site of the injury. Proteins called clotting factors help the platelets to stick together with calcium and other tissue factors in a clump known as a clot. This helps plug breaks in blood vessels, causing bleeding to stop. Human blood has 20 clotting factors that contribute to this process. After the wound heals over time, the clot dissolves.

People with hemophilia lack one of two clotting factors essential to preventing excess bleeding. This makes them vulnerable to excess bleeding when they are injured. The loss of excessive amounts of blood due to an external wound can damage internal organs. Left untreated, internal bleeding caused by hemophilia can damage joints, which can limit mobility.  Internal bleeding into a vital organ such as the brain or heart can be fatal.

Hemophilia can be classified as mild, moderate or severe. The level of severity is determined by the amount of the specific clotting factors an individual has in their blood. For example, a person with severe hemophilia A has less than 1 percent activity of factor VIII. By comparison, people without hemophilia have 100 percent factor VIII activity.

The amount of bleeding that patients experience varies from individual to individual. For example, some patients with mild hemophilia may not bleed often, while some patients with severe hemophilia may bleed frequently.

In addition, some patients develop a rare, noninherited form of hemophilia when certain antibodies form and interfere with the functioning of clotting factor VIII or clotting factor IX. This is known as acquired hemophilia.

There are three types of inherited hemophilia:

• Hemophilia A (also known as classic hemophilia or factor VIII deficiency). Clotting factor VIII is low or missing in the patient. About 90 percent of people with hemophilia have this type. About 70 percent of the patients with this type of hemophilia have severe hemophilia.
  
  
• Hemophilia B (also known as Christmas disease or factor IX deficiency). Clotting factor IX is low or missing in the patient. About 10 percent of people with hemophilia have this version of the disorder. Christmas disease refers to the first patient with hemophilia B who was studied in detail, Stephen Christmas.
  
  
• Hemophilia C. Clotting factor XI is low or missing in the patient. This type of hemophilia is extremely rare in the United States and symptoms are typically mild.

The manner in which the medical community deals with hemophilia has experienced several radical changes during medical developments of the 20^th century. For most of history, people who had it frequently died or were disabled by joint- or organ-damaging bleeding. Today, the prognosis for people with hemophilia has vastly improved. The identification of the clotting factors in the 1960s and the ability to treat people with clotting factors drawn from donated blood led to longer, healthier lives.

However, in the late 1970s and early 1980s, many people with hemophilia were infected with viruses that were transmitted through blood donations, including hepatitis and HIV, the virus that causes AIDS. In the early 1980s, about half of the people with hemophilia contracted HIV through blood products and many of them died, according to the National Hemophilia Foundation. Blood screening for these viruses began in 1985, which has essentially stopped this form of transmission. In addition, a newer kind of clotting factor became available in 1992, when researchers were able to synthesize the product in laboratory proteins, without the need of human blood. The resulting recombinant products cannot transmit viruses, although it is still uncertain whether other disease-causing pathogens can be transmitted through these products.

Hemophilia occurs when there is a problem with the amount or functioning of proteins in the body that affect the ability of the blood to coagulate (clump together to form blood clots). Because of their function, these proteins are called clotting factors.

Most cases are the result of a genetic defect and are present from birth. Hemophilia A and B are usually passed from mother to son. The gene that produces clotting factors is located on X chromosomes. Females have two X chromosomes, while males have an X chromosome and a Y chromosome. Females inherit an X chromosome from each parent, while males inherit an X chromosome from their mothers and a Y chromosome from their fathers.

A woman is a carrier for hemophilia if she has a defective gene for either of two clotting factors on one of her X chromosomes. This means that she can pass this defective chromosome on to her children, with the odds of such a transmission being about 50 percent. A female child who receives the defective X chromosome from her mother will be a carrier for hemophilia, but will not develop the disease because she has another functioning X chromosome from her father. A male child who receives a defective X chromosome from his mother will have hemophilia.

Males who have hemophilia cannot pass it on to their sons, but can pass on the defective gene that causes these disorders to their daughters, who will then become carriers of the disorder. A female can inherit hemophilia only if her father has hemophilia and her mother is a carrier. This is extremely rare.

This genetic origin of hemophilia makes the risk factors clearly identifiable: having a family history of the condition, especially a mother who is a carrier, and being male.

About 30 percent of hemophilia cases occur where there is no traceable family history of the disease. In these cases, a genetic mutation occurs in the male child or in the mother to make her a carrier, who passes it on to her children. In addition, some patients have acquired hemophilia, a disease that does not have a genetic component that occurs when certain antibodies form and interfere with the functioning of clotting factor VIII or clotting factor IX.

Hemophilia C can occur in both boys and girls and can be passed on by either parent. However, this disease is rare and usually mild.

Patients with hemophilia are at risk of continued bleeding following an injury. In some cases, this bleeding is visible or apparent from bruising of the skin. The first signs of hemophilia often appear when a newborn experiences significant bleeding following circumcision. In milder cases, or when there is no circumcision, bruising or bleeding may appear on the gums when the infant’s teeth appear. Another sign of hemophilia is frequent bumps and bruises that a child accumulates while learning to walk.

Hemophilia may not be as evident in children who have a mild form of the disorder. The condition may go undetected for years until the child’s first dental procedure or surgery, or until an accident occurs.  

Bleeding that is internal may not be visible. Joints in the knees, ankles and elbows are particularly vulnerable to internal bleeding. When not treated promptly, internal bleeding can cause damage to joints, muscles or other body tissues. Internal bleeding may create a tingly or bubbly sensation in the joint. The joint also may be warm to the touch.

Severe hemophilia is most evident in bleeding in the joints, a condition known as hemarthrosis. In most cases, this bleeding is not the result of an injury, though it can continue for days if left untreated. Patients are urged to learn to recognize the signs of internal bleeding so that it can be treated before it damages the joints (e.g., causes arthritis) or other tissues.

Bleeding into a joint typically follows a sequence that begins with tightness in the joint that initially occurs without pain. As bleeding continues, pain may accompany this tightness, followed by a swelling of the joint, which becomes hot to the touch. At this point, patients often cannot bend or extend the joint without pain due to the swelling, which presses on the nerves.

As bleeding continues, swelling of the joint may continue until there is complete loss of motion in the joint. Pain may become severe at this point. Eventually, bleeding will stop as the joint becomes filled with blood. 

Other common signs or symptoms of hemophilia include:

• Excessive bleeding or bruising in soft tissue and muscle
  
• Excessive bleeding in the mouth after a cut, bite or tooth loss
  
• Blood in the urine or stool
  
• Regular nosebleeds that occur for no apparent reason

Some young children with hemophilia may try to hide or deny that they are bleeding to avoid treatment. Parents should be sure to learn the signs and symptoms of hemophilia so they can identify a potential bleeding incident in their child.

In some cases, a bump on the head or other head injury may cause bleeding in the brain in a hemophilia patient. This is a very dangerous condition that demands emergency medical treatment. Symptoms of bleeding in the brain may include:

• Convulsions or seizures
• Double vision
• Extended, painful headaches
• Repeated vomiting
• Sleepiness
• Stiffness or pain in the neck
• Sudden weakness or awkwardness in an arm or leg
• Walking difficulties

In diagnosing hemophilia, a physician will perform a complete physical examination and compile a thorough medical history. A family history of hemophilia can be a strong indicator that a patient may have this disorder.

Coagulation tests also may be ordered to measure levels of clotting factor and to monitor how long it takes blood to clot. From these results, a physician can tell not only whether or not a patient has hemophilia, but also the type of hemophilia (type A or B) that is present and its level of severity. Hemophilia is diagnosed in one of the following three severities:

Severe hemophilia is more likely to be diagnosed very early in a child’s life. It is often recognized during the child's first year because it tends to cause severe bleeding in babies. Children with other forms of hemophilia may not be diagnosed until they are older.

Pregnant women can have their fetus tested for the presence of hemophilia. This is usually done through chorionic villus sampling (CVS) or amniocentesis. CVS is usually performed nine to 10 weeks into the pregnancy and involves the analysis of a sample of chorionic villi taken from the placenta. Amniocentesis is usually done 16 weeks into the pregnancy and involves an analysis of fetal cells taken from a sample of the amniotic fluid in the uterus. Because very little can be done based on the results of these tests, they are rarely recommended.

If a patient has experienced serious internal bleeding from hemophilia, imaging tests such as ultrasounds or MRIs may be used to view the joints and any damage that may have occurred.

Patients can learn more about their treatment options by consulting with their physician and by visiting any of the hemophilia treatment centers funded by the federal government and established nationwide. Patients are urged to contact their physician to learn more about these centers. Parents of children with hemophilia can learn about the disease and how to monitor and treat their child’s condition.

There is no cure for hemophilia. The main treatment for hemophilia is replacement of the clotting factor that the patient is missing. For example, patients with hemophilia A will have factor VIII injected into the bloodstream, while patients with hemophilia B will have factor IX injected. This replacement clotting factor comes from human donors or from a synthetic variety of clotting factor called recombinant factor that is created in a laboratory.

Injections of factor VIII or factor IX can be used to prevent bleeding or to stop it after it has begun. Patients with moderate hemophilia will likely need injections only when problems arise, such as after an injury or before participating in an activity that could potentially cause cuts or other injury.

Patients with severe hemophilia often undergo preventive injections either long-term (two to three times a week, continually) or short-term (several times over the course of a few months). The purpose of these injections is to keep the amount of clotting factors high at all times so that bleeding will not get a chance to start. However, not all people with severe hemophilia receive preventive injections.

Clotting factor replacement therapy is often given in the patient’s home. In many cases, patients or their parents learn to administer the treatments. In addition, patients who undergo clotting factor replacement on a long-term basis may have a vein access device surgically implanted to make it easier to tap into a vein during treatments. There is a risk of infection with these devices.

Injections of clotting factors can stop bleeding very quickly. Patients with any type of hemophilia are urged to seek prompt treatment anytime they have bleeding problems. This will help prevent complications that can cause long-term damage.

While clotting factor replacement is usually effective, it can be very expensive. Patients should consult with their physician and their insurance company to make sure they will not exhaust their coverage limits for this treatment. In addition, clotting factor replacement does come with some risks. Patients may develop antibodies to the replacement factors. These are proteins that prevent clotting factors from doing their job. About one in five people with severe hemophilia A and one in 100 people with hemophilia B will develop these antibodies during treatments, according to the National Heart, Lung and Blood Institute. When this happens, a physician often will inject larger doses of the clotting factor or try clotting factors from different sources.

Viruses such as HIV and hepatitis can be transmitted through clotting factor injections. However, careful donor screening and testing and preparation of blood products have resulted in no documented cases of such transmission since the mid-1980s. Recombinant factor, which is not drawn from human blood, cannot transmit such viruses. It is theoretically possible that other disease-producing pathogens could be transmitted in clotting factors, although no known cases of other transmissions have been identified.

Finally, patients may benefit from other treatment approaches. A synthetic hormone called desmopressin is sometimes used to treat patients with mild to moderate hemophilia A. This drug is given by injection or nasal spray and promotes release of both clotting factor VIII and von Willebrand factor (which helps to bind platelets) in blood vessels.

Medications known as antifibrinolytic drugs help keep blood clots from breaking down. They are used in pill form and are often given to people with hemophilia before dental work, and to treat mild bleeding in the intestines and bleeding from the mouth or nose. For mild bleeding (e.g., tooth extractions) these drugs are often effective alone, although they are frequently used with other clotting factors when heavy blood loss is a possibility (e.g., invasive surgery).

Infusions of blood plasma usually are sufficient to stop bleeding in patients with hemophilia C, because they restore the missing blood factor XI. Blood infusions are used for this type of hemophilia because there is currently no commercially available synthetic factor XI available in the United States.

In some cases, hemophilia causes damage to the joints of patients. Physical therapy can help restore functioning to these joints. However, severe damage may require surgery to replace the damaged joint with an artificial joint.

Hemophilia prevention involves genetic counseling. Women can find out if they are carriers or, if they know they are, they can receive prenatal testing to see if their child has hemophilia. However, the disease itself cannot be prevented.

Patients with hemophilia may need to make several lifestyle adjustments as a result of their condition. For example, they cannot have intramuscular injections when they receive immunizations, because these injections have the potential to cause internal bleeding. They should also avoid medications that may interfere with blood clotting, including aspirin, ibuprofen and other nonsteroidal anti-inflammatory drugs. Patients who are having dental work may need to take medications in advance of their appointment to prevent bleeding.

In the past, blood transfusions were a source of danger for patients with hemophilia because of possible contamination of donated blood products. However, in recent years, improved donor screening techniques and the use of recombinant clotting factors have substantially reduced or even eliminated the risk of transmission of viruses such as HIV or hepatitis during transfusions. Nonetheless, patients with hemophilia may want to consider receiving immunization against hepatitis A and B.

Patients with mild hemophilia often can participate in a full range of activities. Exercise can help build muscle, which provides extra protection for the joints. However, those with severe hemophilia may need to avoid contact sports and other activities that have a higher probability of causing injury to the participant (e.g., football, hockey, wrestling).

People with hemophilia and parents of children with hemophilia may want to order medical identification bracelets or necklaces that explain their condition. Parents also are urged to tell babysitters, school officials, coaches and others of the child’s condition. It is also advisable to explain the circumstances under which it may be necessary to call emergency medical services.

Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients and parents may wish to ask their doctor the following questions about hemophilia:

1. Does my family history place me at higher risk for having a child with hemophilia?
   
   
2. If I have hemophilia, what are the chances my child will be born with it?
   
   
3. What type of tests can I have in utero to determine if my child wil have hemophilia?
   
   
4. What signs should I look for that might indicate hemophilia in my child?
   
   
5. How will I know if bleeding is normal or more severe?
   
   
6. What tests can diagnose hemophilia in my child and how soon should they be done?
   
   
7. How should I monitor my child for potential internal bleeding?
   
   
8. What are my/my child’s treatment options?
   
   
9. What are the risks or side effects of such treatments?
   
   
10. Are there methods of delivering these treatments that do not involve injections?
    
    
11. What activities should I/my child avoid?
    
    
12. What first aid steps should be taken if I/my child is cut or injured? What signs indicated a medical emergency?
    
    
13. What lifestyle changes are necessary for me or my child?
    
    
14. Can you recommend a hemophilia support group?