[hemo- + -philia]
Any of a group of X-linked bleeding disorders occurring only in boys and marked by deficiencies of blood-clotting proteins.
Hemophilias are rare. Hemophilia A affects 1 in 5,000 to 10,000 boys; hemophilia B is present in about 1 in 30,000 boys.
There are two principal types: hemophilia A (in which blood clotting factor VIII is either missing from the bloodstream or defective) and hemophilia B (in which blood-clotting factor IX is deficient or defective). Both of these disorders are X-linked, i.e., caused by X-chromosome mutations.
SYMPTOMS AND SIGNS
Bleeding after minor trauma is the hallmark of the hemophilias. Typically, bleeding occurs in the joints (hemarthrosis), in soft tissues, and in the urinary tract. Bleeding may also occur during dental procedures and surgery. Intracranial bleeding and bleeding into deep body sites may be life-threatening.
All patients who experience episodes of abnormal bleeding should have blood tested to assess their complete blood count, as well as their PT/PTT (prothrombin time and activated partial thromboplastin time). Abnormalities on these screening tests are used to guide further work up. When hemophilias are suggested by the results of the screening tests, assays for specific coagulation factors, e.g., factors VIII, IX, or XI, can determine the specific diagnosis.
Deficient clotting factors can be replaced intravenously, but doing so has carried significant risks. In the 1980s, for example, the injection of contaminated clotting factors spread hepatitis C and HIV to many patients with hemophilia. Before these epidemics, these patients had life expectancies of about 65 years. AIDS and other blood-borne infections decreased the average lifespan of patients with hemophilia to about 50 years. Today, the purification of clotting factors has resulted in safer treatment for patients with hemophilia.
Genetic counseling: Females are the carriers of X-linked hemophilias and have a 50% chance of transmitting the affected X gene to each daughter (who would then also be a carrier) and a 50% chance of transmitting the affected X gene to each son, who would be born with hemophilia.
Expression of the disease: The severity of hemophilia is determined by the degree of factor deficiency: mild-factor levels are 5% to 40% of normal; moderate-factor levels are 1% to 5% of normal; severe-factor levels are less than 1% of normal. Mild hemophilia may not be diagnosed until adulthood if the patient does not bleed spontaneously or after minor trauma.
Replacement of clotting factors: Factor replacement products include cryoprecipitate, lyophilized factor VIII or IX, and fresh frozen plasma. Other bypassing agents that aid blood clotting, such as monoclonal antibodies directed to clotting factors IXa or X, can prevent or decrease bleeding. The goal of treatment is to limit bleeding and prevent the irreversible destructive arthritis that results from repeated hemarthrosis and synovial hypertrophy.
Patients with hemophilia should avoid drugs that interfere with anticoagulation and should avoid sports or other activities in which there is a high likelihood of traumatic injury. In addition, they should wear bracelets identifying their illness to medical personnel.
In the bleeding patient, vital signs are monitored, and the patient is observed for signs and symptoms of decreased tissue perfusion, i.e., restlessness, anxiety, confusion, pallor, cool and clammy skin, chest pain, decreased urine output, hypotension, and tachycardia. Clotting factors are administered as prescribed. Repeat infusions are required until bleeding stops, as the body uses up these factors in 48 to 72 hr. The skin, mucous membranes, and wounds are inspected for bleeding. Emergency care is provided for external bleeding; wounds are cleaned; and gentle, consistent pressure is applied to stop the bleeding. The injured part is elevated, and cold compresses or ice bags are applied to the site. Oral analgesics are provided as prescribed to manage pain (intramuscular or subcutaneous administration could result in hematoma formation), and the patient and family are taught to avoid aspirin, aspirin-containing drugs, and NSAIDs because they decrease platelet adherence and thus may increase bleeding. Safety measures are instituted to prevent injury, and the patient and family are instructed in these measures. The patient is assessed for development of hemarthrosis; if the diagnosis is positive, appropriate care is provided, which includes elevating the affected part, immobilizing the joint in a slightly flexed position, and applying ice intermittently. Replacement of the deficient factor is needed before and after surgery. Dental extractions or other dental procedures may be necessary, for which 1-deamino(8-D-arginine) vasopressin (desmopressin) may be used. The patient is monitored for adverse reactions to blood products, such as flushing, headache, tingling, fever, chills, urticaria, and anaphylaxis. Movement of the injured part is restricted, and exercise and weight bearing are prohibited for 48 hr until bleeding has stopped and swelling has subsided. Gentle passive range-of-motion exercises are then provided, with gradual progression to active-assisted and then active exercise. Intracranial, muscle, subcutaneous, renal, and cardiac bleeding are monitored and managed according to protocols or as prescribed by the hematologist. Fluid balance is monitored throughout emergencies, and adequate fluid replacement is instituted as needed.
Both the patient and family are encouraged to verbalize their fears and concerns, and accurate information, realistic reassurance, and emotional support are provided. Health care providers should remain with the anxious or fearful patient or family. Gentle, careful, but thorough oral care is provided with a soft toothbrush or sponge-stick (toothette) to prevent inflamed and bleeding gums, and the patient is instructed in this method. Regular dental examinations are recommended. Regular isometric exercise is encouraged to strengthen muscles, which in turn protects joints by reducing the incidence of hemarthrosis. Use of safety measures to protect the patient from injury is encouraged, while unnecessary restrictions that impair normal development are discouraged. The patient should remain independent and self-sufficient; assistance is provided to both the patient and family to identify safe activities. Techniques are taught for managing bleeding episodes at home. The use of transfusion therapy is explained, and information is provided on all available methods of obtaining such therapy (including how to administer cryoprecipitate at home if appropriate). The seriousness of head injuries and the need for their immediate treatment are explained. Diversional activities and private time with family and friends are provided to help the patient overcome feelings of isolation. The patient's and family's knowledge of the disease, its treatment and impact on the patient, siblings, and parents are continually assessed. The patient and family are encouraged to talk with others in similar circumstances through local support groups and services, and they are referred for genetic counseling and for information and support to the National Hemophilia Foundation (800-42-HANDI; www.hemophilia.org).
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