Hemophilia is a genetic disorder characterized by a deficiency or absence of one of the clotting proteins in plasma. The result is delayed clotting in the affected individual. While deficiencies of any of the clotting proteins can occur, factor VIII (FVIII) deficiency (hemophilia A or classic hemophilia) and factor IX (FIX) deficiency (hemophilia B or Christmas disease) are the most common.

One in 5,032 live male births in the United States tests positive for hemophilia. Based on this number, it is estimated that about 400 babies with hemophilia are born in the U.S. every year.  There are currently about 17,000 people living with hemophilia in the U.S. FVIII deficiency is approximately four times more common than FIX deficiency. Hemophilia occurs in all racial and ethnic groups.

Levels of severity
The amount of bleeding that can be expected in a person with hemophilia depends upon the severity of the deficiency. Normal plasma levels of FVIII and FIX range from 50-150 percent. People with no measurable FVIII or FIX (less than 1 percent) are considered to have the severe form of hemophilia. Severe hemophilia can result in frequent bleeding episodes. In many cases, bleeding, particularly into joints, can occur spontaneously, without any recalled trauma or injury.

Factor levels of 1-5 percent of normal are considered moderate hemophilia. These patients may have abnormal bleeding after minor trauma but should not experience spontaneous bleeding.

Persons with 6-49 percent of factor activity are considered to have mild hemophilia and are expected to have relatively few problems with bleeding, except during surgery or after severe trauma. Women who carry the hemophilia gene can have lower than normal plasma levels of FVII or FIX and can experience symptoms of mild hemophilia.

Inheritance patterns
Hemophilia is a recessive genetic disorder. The abnormal gene responsible for hemophilia is carried on the X chromosome. Females have two X chromosomes, and males only one. The presence of the hemophilia gene on one X chromosome in women does not necessarily cause hemophilia.  The female with one hemophilia gene is called a hemophilia carrier and has a 50 percent chance of passing the affected gene on to her children. The presence of the abnormal gene in a male results in hemophilia. Affected men do not transmit the disorder to their sons (they provided the Y chromosome), but all of their daughters are obligate carriers (they pass on an affected X chromosome). In approximately one-third of hemophilia cases, no family history of the disease exists. Such cases are thought to be the result of a recent genetic mutation.

Symptoms and diagnosis
If no family history is present, hemophilia may be suspected if prolonged bleeding from circumcision or from under the skin on the head (cephalohematomas) at birth occurs, or if easy bruising, raised bruises (hematomas) or prolonged mouth bleeding are problems in the first year.

• Patient history
  A detailed history is important to identify any history of bleeding from circumcision, heel or finger sticks, raised bruises or other incidents of prolonged oozing or swelling.
• Family history
  History of any abnormal bleeding is important, especially in male members of the maternal family. Because approximately 30 percent of children with hemophilia have no family history, absence of bleeding in relatives does not rule out hemophilia.
• Laboratory studies
  In a baby boy of a known or suspected carrier of FVIII deficiency, plasma can be obtained from umbilical cord blood for a FVIII test to diagnose or rule out hemophilia. Newborn testing is less reliable in FIX deficiency because full production of FIX relies on a mature liver. In older children and adults with a family history, specific factor assays can be performed with peripheral plasma samples.
  

Types of bleeding
Typically, hemophilia involves joint and muscle bleeding, prolonged, potentially fatal bleeding after surgery and numerous raised bruises. Excessive bleeding after minor cuts or scrapes is uncommon. Joints and muscles are the most common sites of bleeding, with knees, ankles, elbows and hips being the most frequently affected joints. However, bleeding can occur in any part of the body with complications dependent on the site of bleeding. Bleeding into the head, neck, abdomen or gastrointestinal tract is considered life threatening and must be treated as an emergency. Other episodes requiring appropriate treatment include nerve compression from muscle bleeding, hematuria, deep lacerations, epistaxis and bleeding from the mouth and tongue.
 
Treatment of bleeding
The treatment for bleeding in hemophilia involves replacing the deficient factor. This usually requires intravenous infusion of clotting factor. The traditional goal of hemophilia management has been to recognize the earliest signs of bleeding and to treat promptly with the appropriate product and dose to stop bleeding and avoid resulting complications. This is called “on-demand therapy.”

Preventing bleeding
There is an increasing emphasis on preventing bleeding episodes, especially in young children. Prevention of repeated bleeding episodes, particularly into joints, is the goal of primary prophylaxis. Primary prophylaxis is the regular infusion of factor replacement products from an early age to prevent bleeding. The goal of prophylaxis is to maintain FVIII or FIX levels above 1-2 percent to prevent spontaneous bleeding. Secondary prophylaxis is a similar program initiated after repeated bleeding in a particular area.

Complications
Of treatment

• Inhibitor development
• HIV—historical 
• Hepatitis A, B, C—historical

Of bleeding

• Chronic pain
• Muscle weakness
• Inability to fully extend a joint
• Joint arthritis

Portions of this material were reprinted with permission from the Nurses Guide to
Bleeding Disorders, published by the National Hemophilia Foundation.