Hemophilia vs Von Willebrand disease
How to tell Hemophilia and Von Willebrand disease apart when a board question makes them look alike.
Hemophilia causes deep bleeding and hemarthroses; vWD causes mucosal bleeding with platelet-adhesion defects.
Side by side
Deep tissue bleeding, hemarthroses, delayed bleeding after trauma, prolonged PTT, and normal platelet count.
Mucosal bleeding, epistaxis, menorrhagia, easy bruising, prolonged bleeding time, and sometimes prolonged PTT.
Intrinsic pathway factor deficiency, usually factor VIII or IX, impairs fibrin clot formation.
Defective von Willebrand factor impairs platelet adhesion and reduces factor VIII stability.
Normal PT with prolonged PTT and low factor activity supports hemophilia.
Abnormal platelet function testing with low vWF activity supports von Willebrand disease.
The trap
vWD can mimic mild hemophilia A on PTT because vWF carries and stabilizes factor VIII. Whenever PTT is prolonged with a mucocutaneous bleeding pattern (epistaxis, menorrhagia, easy bruising, postoperative oozing), send vWF antigen, ristocetin cofactor activity, and factor VIII activity together. vWF antigen alone misses qualitative (type 2) vWD, where antigen is normal but activity is low.
Watch it explained
The repair move
Sort bleeding by location first: deep joint/muscle bleeding means factor problem; mucosal bleeding means platelet/vWF problem.
Try a free question
CoreA boy has recurrent knee hemarthroses after minor trauma. Platelet count and PT are normal, but PTT is prolonged. Which disorder is most likely?
Show answer and explanation
Answer: A. Hemophilia. Deep bleeding and hemarthroses with prolonged PTT point to a coagulation factor disorder such as hemophilia.
Why the other choices are tempting
- B. vWD causes mucosal bleeding and platelet adhesion defects; PTT may be mildly prolonged but hemarthroses are less typical.
- C. ITP causes thrombocytopenia and mucocutaneous bleeding.
- D. DIC prolongs PT/PTT and lowers fibrinogen with systemic illness.
- E. Vitamin K deficiency prolongs PT first and causes multiple factor deficiencies.
Flashcards
Tap a card to flip it.
What mixing-study result supports a factor deficiency such as hemophilia?
A prolonged PTT that corrects with normal plasma supports factor deficiency rather than an inhibitor.
What bleeding location favors von Willebrand disease?
Epistaxis, menorrhagia, easy bruising, and other mucosal bleeding fit impaired platelet adhesion.
Quick answers
What is the fastest way to tell Hemophilia from Von Willebrand disease?
Hemophilia causes deep bleeding and hemarthroses; vWD causes mucosal bleeding with platelet-adhesion defects.
What is the key clue for Hemophilia?
Deep tissue bleeding, hemarthroses, delayed bleeding after trauma, prolonged PTT, and normal platelet count.
What is the key clue for Von Willebrand disease?
Mucosal bleeding, epistaxis, menorrhagia, easy bruising, prolonged bleeding time, and sometimes prolonged PTT.
What is the common trap with Hemophilia vs Von Willebrand disease?
vWD can mimic mild hemophilia A on PTT because vWF carries and stabilizes factor VIII. Whenever PTT is prolonged with a mucocutaneous bleeding pattern (epistaxis, menorrhagia, easy bruising, postoperative oozing), send vWF antigen, ristocetin cofactor activity, and factor VIII activity together. vWF antigen alone misses qualitative (type 2) vWD, where antigen is normal but activity is low.