Hematology · Coagulation Disorders
The facts most likely to be tested
Von Willebrand disease is the most common inherited bleeding disorder caused by a deficiency or dysfunction of von Willebrand factor (vWF).
Patients typically present with mucocutaneous bleeding, including epistaxis, gingival bleeding, and menorrhagia.
The bleeding time or PFA-100 closure time is characteristically prolonged due to impaired platelet adhesion.
The partial thromboplastin time (PTT) may be prolonged because vWF acts as a carrier protein for Factor VIII, protecting it from degradation.
The ristocetin cofactor assay is the gold standard diagnostic test, showing decreased platelet aggregation in the presence of ristocetin.
Desmopressin (DDAVP) is the first-line treatment for Type 1 vWD as it stimulates the release of stored vWF from Weibel-Palade bodies in endothelial cells.
Avoid aspirin and other NSAIDs in these patients to prevent exacerbation of bleeding due to impaired platelet function.
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A 22-year-old female presents to the clinic complaining of heavy menstrual bleeding lasting 8 days and frequent easy bruising. She reports a history of recurrent epistaxis since childhood. Physical examination reveals several ecchymoses on her lower extremities. Laboratory studies demonstrate a prolonged PTT and a prolonged bleeding time, while her platelet count and prothrombin time (PT) are within normal limits.
What is the most appropriate initial pharmacologic therapy for this patient?
Desmopressin (DDAVP)
The patient's presentation of mucocutaneous bleeding and prolonged PTT/bleeding time is classic for vWD; DDAVP is the first-line treatment for Type 1 disease to increase vWF and Factor VIII levels.
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Etiology / Epidemiology
Most common hereditary bleeding disorder; autosomal dominant inheritance.
Clinical Manifestations
Mucocutaneous bleeding; mucosal oozing, epistaxis, and menorrhagia.
Diagnosis
Ristocetin cofactor activity is the gold standard; low vWF antigen.
Treatment
Desmopressin (DDAVP) is first-line; avoid aspirin/NSAIDs.
Prognosis
Excellent prognosis; Type 3 is the most severe form.
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Epidemiology & Etiology
Affects approximately 1% of the population, making it the most common inherited bleeding disorder. It is typically inherited in an autosomal dominant pattern with variable penetrance. It results from a deficiency or dysfunction of the von Willebrand factor (vWF).
Pertinent Anatomy
vWF is a large multimeric glycoprotein synthesized by endothelial cells and megakaryocytes. It serves as the essential bridge between platelets and the subendothelial collagen matrix during primary hemostasis.
Pathophysiology
vWF performs two critical roles: it mediates platelet adhesion to injured vessel walls and acts as a carrier protein for Factor VIII, protecting it from rapid degradation. Deficiency leads to impaired platelet plug formation and a secondary reduction in Factor VIII levels. This dual defect explains the combination of primary and secondary hemostatic bleeding symptoms.
Clinical Manifestations
Patients typically present with mucocutaneous bleeding, including epistaxis, gingival bleeding, and menorrhagia. Post-surgical bleeding or excessive bruising is common. Red flags include severe, life-threatening hemorrhage in Type 3 disease, which mimics hemophilia A due to profound Factor VIII deficiency.
Diagnosis
The Ristocetin cofactor activity assay is the gold standard for measuring vWF function. Diagnostic criteria include a vWF antigen level <30-40 IU/dL and reduced activity. A prolonged bleeding time or PFA-100 closure time is often observed, while PT is typically normal.
Treatment
Desmopressin (DDAVP) is the first-line treatment for Type 1 disease as it stimulates the release of vWF from endothelial stores. For severe cases or Type 3, vWF-containing factor concentrates are required. Avoid aspirin and NSAIDs as they exacerbate platelet dysfunction and increase bleeding risk.
Prognosis
Most patients have a normal life expectancy with appropriate management. Type 3 patients require lifelong monitoring and prophylactic factor replacement to prevent hemarthrosis and internal bleeding.
Differential Diagnosis
Hemophilia A: X-linked recessive, normal platelet count/function
Hemophilia B: Factor IX deficiency, normal vWF levels
ITP: Isolated thrombocytopenia, no vWF deficiency
Glanzmann thrombasthenia: Normal vWF, abnormal platelet aggregation
DIC: Acquired, abnormal PT/PTT and low fibrinogen