What is hemophilia?

By Peter Crosta 

Reviewed by Nancy Choi, MD

Hemophilia is a rare condition in which the blood does not clot properly. It mostly affects men.

People with hemophilia lack a protein called a clotting factor, which works with platelets to stop bleeding at the site of an injury. This means the person tends to bleed for a longer time after an injury, and they are more susceptible to internal bleeding.

This bleeding can be fatal if it occurs within a vital organ such as the brain.

There are currently about 20,000 people living with hemophilia in the United States.

Causes

In hemophilia, the blood does not clot as it should. Hemophilia is normally an inherited disorder. A person is born with it.

It happens because of a defect in one of the clotting factor genes on the X chromosome.

Hemophilia tends to occur in males, since the gene can be passed from mother to son.

Males typically lack a second X chromosome so they are unable to make up for the defective gene. Most females have XX sex chromosomes while most males have XY sex chromosomes.

Females may be carriers of hemophilia, but they are unlikely to have the disorder. For a girl to have hemophilia, she must have the abnormal gene on both of her X chromosomes, and this is very rare.

Sometimes, hemophilia is acquired because of a spontaneous genetic mutation.

The disorder can also develop if the body forms antibodies to clotting factors in the blood that then stop the clotting factors from working.

von Willebrand disease

von Willebrand disease (vWD) is another genetic bleeding disorder in which patients are prone to frequent bleeding such as nosebleeds, bleeding gums, and excessive menstrual periods.

It affects around 1 percent of the American population.

Unlike hemophilia, vWD affects men and women equally.Like hemophilia, the severity of vWD depends upon the level of the blood protein. The lower the level of protein in the blood, the more severe is the bleeding.

Types

There are two major types of hemophilia, type A and type B.

In hemophilia A, there is a lack of clotting factor VIII. This accounts for about 80 percent of hemophilia cases. About 70 percent of people with hemophilia A have the severe form.

In hemophilia B, also known as "Christmas disease," the person lacks clotting factor IX. Hemophilia occurs in around 1 in every 20,000 males born worldwide.

Both A and B can be mild, moderate, or severe, depending on the amount of clotting factor that is in the blood. From 5 to 40 percent of normal clotting factor is considered mild, 1 to 5 percent is moderate, and less than 1 percent is severe.

Symptoms

Hemophilia symptoms include excessive bleeding and easy bruising. The severity of symptoms depends on how low the level of clotting factors is in the blood.

Bleeding can occur externally or internally.

Any wound, cut, bite, or dental injury can lead to excessive external bleeding.

Spontaneous nosebleeds are common.

There may be prolonged or continued bleeding after bleeding previously ceased.

Signs of excessive internal bleeding include blood in the urine or stools, and large, deep bruises.

Bleeding can also happen within joints, like knees and elbows, causing them to become swollen, hot to the touch, and painful to move.

A person with hemophilia may experience internal bleeding in the brain following a bump on the head.

Symptoms of brain bleeding can include headaches, vomiting, lethargy, behavioral changes, clumsiness, vision problems, paralysis, and seizures.

Diagnosis

Blood testing is key to diagnosing hemophilia.

Medical history and blood tests are key to diagnosing hemophilia.

If a person has bleeding problems, or if hemophilia is suspected, a physician will ask about the person's family and personal medical history, as this can help to identify the cause.

A physical examination will be carried out.

Blood tests can provide information about how long it takes for blood to clot, the levels of clotting factors, and which clotting factors, if any, are missing.

Blood test results can identify the type of hemophilia and its severity.

For pregnant women who are carriers of hemophilia, doctors are able to test the fetus for the condition after 10 weeks of pregnancy.

Treatment

Hemophilia is treated with replacement therapy.

This involves giving or replacing the clotting factors that are too low or missing in a patient with the condition. Patients receive clotting factors by injection or intravenously.

Clotting factor treatments for replacement therapy can be derived from human blood, or they can be synthetically produced in a laboratory.

Synthetically produced factors are called recombinant clotting factors.

Recombinant clotting factors are now considered the treatment of choice because they further reduce the risk of transmitting infections that are carried in human blood.

Some patients will need regular replacement therapy in order to prevent bleeding. This is called prophylactic therapy.

This is typically recommended for people with the severe forms of Hemophilia A.

Others receive demand therapy, a treatment that is given only after bleeding begins and remains uncontrollable.

Complications from treatment of hemophilia are possible, such as developing antibodies to treatments and viral infections from human clotting factors.

Damage to joints, muscles, and other body parts can occur if treatment is delayed. Other treatments, for moderate forms of hemophilia A, include desmopressin, a man-made hormone that stimulates the release of stored factor VIII, and antifibrinolytic medicines that prevent clots from breaking down.

In 2013, the U.S. Food and Drug Administration (FDA) approved Rixubis, a purified protein created with recombinant DNA technology, for patients with hemophilia B.

Rixubis, a lab produced blood factor IX, aims to prevent and control excessive bleeding by replacing the clotting factor missing or in low levels in hemophilia B patients.

In the future, gene therapies may be available. People who wish to join a clinical trial can contact the National Heart Lung and Blood Institute (NHLBI).

Living with hemophilia

There is no way to cure hemophilia, but there are ways to reduce the risk of excessive bleeding and to protect joints.

These include:

• Regular exercise 
• Avoiding certain medications, such as aspirin, no steroidal anti-inflammatory drugs, and heparin, which are blood thinners 
• Practicing good dental hygiene

As preventive treatment, a patient may receive regular injections of an engineered version of clotting factor VIII for hemophilia A, or IX for hemophilia B.

The Centers for Disease Control and Prevention (CDC) recommend regular testing for blood-borne infections like HIV and hepatitis, and vaccination against hepatitis A and B. People with hemophilia who receive donated blood products may be at risk of developing these diseases.

Hemophilia Treatment Centers (HTCs) are available for support. A CDC study of 3,000 people with hemophilia found that those who used a HTC were 40 percent less likely to die of a complication related to their condition.

To protect against injuries that can cause bleeding, a person can wear padding. Extra care is needed when participating in sports or high impact activities.

SOURCE: MEDICAL NEWS TODAY