Hemophilia B
Definition
Hemophilia is a disease that causes the body lacks the protein needed for blood clotting process when there is bleeding. This protein is commonly called a clotting factor or coagulation factors.
Hemophilia B constitutes about 20% of hemophilia cases, and about 50% of these cases have factor IX levels greater than 1%. Hemophilia B, or Christmas disease, is an inherited, X-linked, recessive disorder that results in deficiency of functional plasma coagulation factor IX. Spontaneous mutation and acquired immunologic processes can result in this disorder as well.
Signs and symptoms
The hallmark of hemophilia is hemorrhage into the joints. This bleeding is painful and leads to long-term inflammation and deterioration of the joint (typically the ankles in children, and the ankles, knees, and elbows in adolescents and adults), resulting in permanent deformities, misalignment, loss of mobility, and extremities of unequal lengths.
With mild hemophilia, hemorrhage is most likely to occur with trauma or surgery. A traumatic challenge relatively late in life may have to occur before mild or moderate hemophilia is suspected.
Signs and symptoms of moderate and severe hemophilia include the following:
- Neonates: Prolonged bleeding and/or severe hematoma following procedures such as circumcision, phlebotomy, and/or immunizations; intracranial hemorrhage
- Children: Hemarthrosis and hematomas with increasing physical activity; chronic arthropathy (late complication); traumatic intracranial hemorrhage (life threatening)
- Toddler: Trauma-related soft-tissue hemorrhage; oral bleeding during teething
Diagnosis
Examination in patients with hemophilia B may reveal the following signs of hemorrhage:
- Neurologic: Abnormal findings, altered mental status, meningismus
- Systemic: Tachycardia, tachypnea, hypotension, and/or orthostasis
- Gastrointestinal: Can be painless or present with hepatic/splenic tenderness and peritoneal signs
- Genitourinary: Bladder spasm/distention/pain, costovertebral angle pain
- Musculoskeletal: Joint tenderness, pain with movement, decreased range of motion, swelling, effusion, warmth
- Other: Hematoma leading to location-specific signs (eg, airway obstruction, compartment syndrome)
Laboratory tests
Laboratory studies for suspected hemophilia B include the following:
- Complete blood cell count: Normal or low hemoglobin/hematocrit levels; normal platelet count
- Factor IX (FIX) assay: Mild disease, result is over 5%; moderate, 1-5%; severe, below 1%
- von Willebrand factor (vWF) and factor VIII levels: To exclude vWF deficiency as primary diagnosis (low vWF and low FVIII)
- Coagulation studies: Do not delay coagulation correction pending test results; normal bleeding and prothrombin times; normal or prolonged activated partial thromboplastin time
- Screening tests for HIV and hepatitis ( caused there may also be signs and symptoms of infectious disease related to HIV/AIDS or hepatitis.)
- Genetic carrier and fetal testing
Imaging studies
After initiating coagulation therapy, perform early and aggressive imaging, even when there is a low suspicion for hemorrhage. Imaging choices are guided by clinical suspicion and the anatomic location of involvement, such as the following:
- Head computed tomography scanning (without contrast): To assess for spontaneous or traumatic intracranial hemorrhage
- Magnetic resonance imaging: To further evaluate spontaneous/traumatic hemorrhage in the head or spinal column; also to assess cartilage, synovia, and joint spaces
- Ultrasonography: To assess joints affected by acute or chronic effusions
- Joint radiography: Of limited value in acute hemarthrosis; to evaluate untreated or inadequately treated disease; in those with recurrent joint hemorrhages, chronic degenerative joint disease may be evident
See Also
Source :
http://emedicine.medscape.com/article/779434-overview
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