von Willwbrands Disease - Most Important Points

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Most common congenital bleeding disorder, affecting 1-2 percent of the population.

vWF - is synthesized by the vascular endothelium, and a cofactor for platelet adhesion and a co factor for factor VIII

Forms the clot for the vascular injury site - and attaches

3 types- I,II,III

  1. mild quantitative, 90 % present - most common - less serious 
  2. quantitative defect - less vWF - more serious
  3. Absent - vWF is almost absent - most serious
Clinical features: Bleeding particularly in children
  • Mild -
    •  asymptomatic 
    • Mucosal or cutaneoous bleeding - easy bruising, gingival bleeding, epistaxis, menorrhagia
  • Moderate to severe
    • Soft-tissue hematomas, petechiae (rare), GI Bleed and hemarthroses
Investigations:
  • Coagulation profile - increased bleeding time and PTT
  • low factor VIII (5 to 50%) (PT and factor VIII is normal - also blood group O has 30% less vWF)
  • platelet count normal
  • reduced ristocetin cofactor activity (normally causes vWF to bind platelets tightly)
  • analysis of vWF multimeres
Treatment
  • Avoid Asprin and Heparin
  • Desmopressin (DDAVP) for type I vWD
    • causes the release of vWF and factor VIII from endothelial cells
    • (after 4 doses patients develop tachyphylaxis)
  • Highly purified factor VIII concentrate containing vWF (HEMATE) in selected cases and Type II
  • conjugated estrogens (increase vWF - oral contraceptives)
  • Platelet transfusions cyroprecipitates
  • Control the bleeding - epistaxis - surgical strips
Prognosis
  • fluctuates and improves during pregnancy and with age

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