Updated: 7/9/2020

Von Willebrand Disease

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  • A 25-year-old woman presents to the emergency room with prolonged bleeding after a dental procedure early that day. She has gone through several gauze packing with no success. Her past medical history includes heavy and prolonged menses. As a child, she had several episodes of unexplained nosebleeds. Labs show normal PT, PTT, and platelet count.
Introduction

This illustration depicts the basic mechanism behind platelet aggregation. This image is also integrated with pathology and pharmacology that alters this cascade of events. vWF = von Willebrand factor; TXA2 = Thromboxane A2; COX = Cyclooxygenase.

  • Inherited mixed platelet and coagulation disorder from deficiency in von Willebrand factor (vWF)
  • Genetics
    • autosomal dominant
  • Epidemiology
    • most common inherited bleeding disorder
    • more likely in Caucasians
  • Pathogenesis
    • affects coagulation - vWF carries and protects factor VIII 
      • produced by endothelial cells and megakaryocytes
      • intrinsic pathway coagulation defect
    • affects platelets – vWF is important in platelet adherence to endothelial lining
      • platelet aggregation is normal (mediated by fibrinogen)
Presentation
  • Symptoms
    • mucocutaneous bleeding
      • epistaxis
      • gingival bleeding
      • petechiae
      • easy bruising
      • menorrhagia
    • increased bleeding after aspirin use
Evaluation
  • Normal or ↑ PTT (like hemophilia) 
  • Normal PT
  • ↑ bleeding time (unlike hemophilia)
  • CBC
    • normal platelet count and appearance
    • may have anemia
  • Diagnosis by ristocetin cofactor assay
    • tests ability of platelets to bind to ristocetin (artificial endothelial surface)
    • ↓ platelet agglutination
Differential Diagnosis
  • Bernard-Soulier syndrome
  • Glanzmann thrombasthenia
  • Hemophilia
Treatment
  • DDAVP (desmopressin acetate) 
    • releases vWF stored in endothelial cells
  • Factor VIII replacement if refractory to DDAVP
    • contains vWF
Prognosis, Prevention, and Complications
  • Prognosis
    • most are mild or moderate in severity
  • Prevention
    • avoid aspirin
  • Complications
    • excessive bleeding
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(M1.HE.17.4707) A 16-year-old male presents to the emergency department with a hematoma after falling during gym class. He claims that he has a history of prolonged nosebleeds and bruising/bleeding after minor injuries. Physical exam is unrevealing other than the hematoma. Labs are obtained showing an increased bleeding time and an abnormal ristocetin cofactor assay. Coagulation assays reveal an increased partial thromboplastin time (PTT) and but a normal prothrombin time (PT). The patient is given desmopressin and is asked to avoid aspirin. Which of the following findings is most likely directly involved in the etiology of this patient's presentation? Tested Concept

QID: 108426
1

Decreased platelet count

8%

(25/308)

2

Decreased levels of factor VIII

62%

(192/308)

3

Decreased levels of factor IX

7%

(21/308)

4

Decreased activity of ADAMTS13

13%

(40/308)

5

Decreased plasma fibrinogen

5%

(16/308)

M 2 B

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