Bleeding and Coagulation Disorders: Hemophilia B

Introduction

• Previous video: Hemophilia A (Problem with Factor VIII)
• Today’s topic: Hemophilia B (Problem with Factor IX)

Question Recap

• 5-year-old female, 46 XX, severe symptoms of hemophilia A, factor VIII activity very low.
• Discussion about Turner Syndrome (45, X0).
• Two possibilities for severe symptoms:
  1. Abnormal inactivation of the normal X chromosome.
  2. Mother carrier of hemophilia A and father has the disease.

Hemophilia Basics

• Hemophilia: Problems with secondary hemostasis and clotting factors.
• Hemophilia A: Factor VIII deficiency (X-linked recessive).
• Hemophilia B: Factor IX deficiency, also known as Christmas disease (X-linked recessive).
• Hemophilia C: Factor XI deficiency (Autosomal recessive).

Pathways and PTT

• Hemophilia affects the intrinsic pathway; hence, aPTT is prolonged while PT remains normal.
• Hemophilia A and B are X-linked recessive, more common in males.

Coagulation Factors

• Hemophilia A: Factor VIII (Classic Hemophilia).
• Hemophilia B: Factor IX (Christmas Disease).
• Hemophilia C: Factor XI (Rosenthal Syndrome).

Symptoms of Hemophilia

• Deep tissue bleeding: joint hemorrhage (hemarthrosis), muscle hemorrhage, brain hemorrhage, late bleeding after tooth extraction/surgery, retroperitoneal bleeding.
• Normal bleeding time and platelet count.

Diagnosis

• Hemophilia A/B: Mixing study to differentiate between deficiency and inhibitor.
• Intrinsic pathway problem: Prolonged aPTT.
• X-linked recessive diseases affect males more frequently.
• Hemophilia C (Autosomal recessive): Associated with consanguinity, affects both genders equally.

Case Study: Stephen Christmas

• First identified patient with Hemophilia B.
• Normal Factor VIII levels but prolonged aPTT led to the discovery of Factor IX deficiency.
• Died from HIV due to untested blood transfusions.

Management of Hemophilia

• Factor concentrate therapy (recombinant or plasma-derived).
• For inhibitors: Use active forms like Factor IXa.
• Other treatments: Desmopressin (especially for Hemophilia A to boost von Willebrand factor), anti-fibrinolytic therapy, analgesics, genetic counseling, injury prevention.

Conclusion

• Hemophilia A: Factor VIII deficiency
• Hemophilia B: Factor IX deficiency
• Hemophilia C: Factor XI deficiency
• Intrinsic pathway disorder causing prolonged aPTT
• Next video: Hemophilia C and consanguinity related issues.