Hemophilia is a sex- linked recessive disorder
Hemophilia
Hemophilia is a sex- linked recessive disorder which is characterized by reduced or absent factor VIII activity .Hemophilia -B is similar and it is due to reduced or absent factor IX activity . 85 % are having factor VIII deficiency and 15% having factor IX deficiency . The hallmark of the severe disease is recurrent spontaneous bleeding in to joints and muscles . Hemophilia occur in 1 in 5000 – 10000 males . In about 30% there is no family history . Identifying female carriers require detailed family history ,analysis of coagulating factors and DNA analysis . Prenatal diagnosis is available using DNA analysis .
Inheritent pattern
Carrier female normal male
Severity of the disease is classified on the basis of the patients baseline of factor VIII or IX with 1 unit of factor defined as the amount in 1 ml of normal person .
Factor VIII :C level
severity
Bleeding tendency
< 2 %
severe
Spontaneous joints/
Muscle bleeds
2 -10 %
moderate
Bleeds after minor trauma
> 10 %
mild
Bleed after surgery
Pathophysiology
Following injury , the initial haemostatic event is the formation of the platelet plug together with generation of the fibrin clot that prevent further hemorrhage . In hemophilia A or B clot formation is delayed and is not robust .Thus patients with hemophilia do not bleed rapidly . There is , instead, a slowing of the rate of clot formation . When untreated bleeding occurs in closed spaced such as joints , cessation of the bleeding may be the result of tamponade. With open wounds profuse bleeding may result in significant biood loos. The clot that is formed may be friable and rebleeding occur during the physiologic lyses of clots or with minimal trauma
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Clinical features of Hemophilia
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