What should be given to a child with von Willebrand factor deficiency during an acute bleeding episode?

Treatment for Acute Bleeding in Children with von Willebrand Factor Deficiency

For a child with von Willebrand factor deficiency experiencing acute bleeding, the treatment depends on the VWD subtype: DDAVP (desmopressin) is first-line for Type 1 VWD, while VWF-containing factor concentrates are required for Type 3 and most Type 2 variants (except Type 2B where DDAVP is contraindicated). 1

Treatment Algorithm by VWD Subtype

Type 1 VWD (Most Common - 70-80% of cases)

• First-line: DDAVP (desmopressin) 0.3 mcg/kg IV over 20-30 minutes 1, 2

  • DDAVP stimulates release of stored VWF from endothelial cells
  • Effective in 93.4% of children with Type 1 VWD 3
  • Can be repeated, though tachyphylaxis may occur with frequent dosing
  • Critical safety consideration in young children: Use with extreme caution in infants and children under 18 months due to risk of water intoxication and hyponatremia 2. Restrict fluid intake and monitor electrolytes closely 4

• If DDAVP fails or is unavailable: VWF-containing clotting factor concentrates (plasma-derived or recombinant VWF/FVIII concentrates) 1

• Adjunctive therapy: Antifibrinolytics (tranexamic acid) can be added to enhance hemostasis 1

Type 2 VWD (Qualitative Defects)

Treatment varies by subtype 1:

• Type 2A, 2M, 2N: VWF-containing factor concentrates (plasma-derived or recombinant VWF with FVIII)

  • DDAVP may be tried in Type 2A but is often less effective
  • Antifibrinolytics as adjunct 1

• Type 2B: DDAVP is CONTRAINDICATED 1

  • DDAVP causes platelet clumping and consumption, worsening bleeding
  • Use VWF concentrates only
  • May require platelet transfusions in addition to VWF concentrates 1

Type 3 VWD (Severe - Near-Total VWF Absence)

• VWF/FVIII concentrates are mandatory 1
  • Dose: 40-60 IU/kg initially, then adjust to maintain VWF and FVIII levels >50 IU/dL 1
  • Regular infusions required for severe bleeding
  • These patients have the most severe bleeding phenotype with spontaneous bleeding into joints and muscles 1

Alternative Treatments When Primary Options Unavailable

If specific VWF concentrates are not immediately available 5:

1. Cryoprecipitate: Contains VWF and FVIII

   • Use for Type 1 and 2A if no response to DDAVP or VWF concentrates unavailable
   • Use for Type 2B, 2M, 2N, and Type 3 if VWF/FVIII concentrate unavailable 5

2. Fresh Frozen Plasma (FFP): Less concentrated source of VWF

   • Dose: 20 mL/kg followed by 3-6 mL/kg twice daily to target trough VWF levels >10-20 IU/dL 6
   • Less preferred due to volume requirements

Critical Pitfalls to Avoid

• Never use DDAVP in Type 2B VWD - causes dangerous platelet aggregation and consumption 1
• Monitor for hyponatremia with DDAVP - especially in children under 18 months; restrict fluids and monitor electrolytes 2, 4
• Test DDAVP response before relying on it - approximately 34.6% of Type 1 patients may not respond adequately 3
• Consult hematology - particularly for Type 2 and Type 3 VWD, and when choosing between recombinant VWF (which may require additional recombinant FVIII) versus plasma-derived concentrates 1

Special Consideration: Acquired von Willebrand Syndrome

In children with underlying conditions (malignancy, particularly CML with high platelet counts), acquired VWS may occur 7. Treatment options include DDAVP, VWF concentrates, fresh frozen plasma, intravenous immunoglobulin, or recombinant factor VIIa depending on severity 7, 8.