See also: Haemophilia

Background

The most common inherited bleeding disorder affecting 0.1 - 1% of the population. Caused by a deficiency (either quantitative or functional) in von Willebrand Factor (vWF).  Deficiency of vWF causes inadequate platelet adhesion and secondary deficiency of Factor FVIII. Affects males and females equally.

Characterised by easy bruising, bleeding from mucous membranes (particularly epistaxis, oral mucosa, menorrhagia) and post-op bleeding.

There are three main phenotypes of vWD.

Notify Haem Inpatient Registrar (pager 5030) of patients presenting to Emergency between 0900-1700hrs, Monday to Friday. Notify Haematologist on call of patients presenting after hours with bleeding problems.

Assessment

Assess site and extent of bleeding.

Assess type and severity of vWD, if known. Refer to the RCH Emergency Department alert system for individual treatment plan.

Management

Antifibrinolytics (Tranexamic acid)

• Often helpful for mucosal bleeding (most common form of bleeding) - mouth, epistaxis, menorrhagia.  
• May be given alone or as adjunct therapy to Desmopressin/factor concentrate.
• Dose of tranexamic acid (500 mg tabs) 25 mg/kg/dose (max: 1.5 g/dose) tds orally for 5-7 days
  

  Weight (kg)	Tranexamic acid
  <20	250 mg tds
  20 - 30	500 mg tds
  30 - 40	750 mg tds
  >40	1 g tds

  
  

Desmopressin (DDAVP)

• Patients with mild to moderate Type 1 vWD can be treated with Desmopressin when there is documented evidence in the medical record of safe and satisfactory response (Desmopressin challenge). At the RCH Desmopressin challenge is performed from around 5 years of age.
• Occasionally effective in Type 2 vWD, never effective in Type 3 vWD.
• Expect two to three fold increase in Factor VIII/vWF level.
• Generally not recommended in young children (<3 years) due to documented reports of hyponatraemia and seizures. Relatively contraindicated in children with previous seizure disorders.
• Fluid restriction (2/3 maintenance daily fluid requirement) is recommended in the 24 hour period following Desmopressin administration 
• Dose: 0.3 microgram/kg (max 20 microgram) stat
  • When required pre-operatively administer 30 minutes before procedure
  • Daily dosing could be considered for up to 3 doses. Tachyphylaxis may be a concern after 48 hours.
  • Plasma derived Factor VIII/vWF (Biostate®) replacement may be required if bleeding not controlled with Desmopressin
• Administration: via intravenous infusion or subcutaneous injection
  • Intravenous infusion: dilute to a final volume of 50 mL with Sodium Chloride 0.9% and infuse over at least 30 minutes.
  • Subcutaneous injection: apply pressure to the site for 1 to 2 minutes post injection.
• Presentation:
  • 4 microgram/mL injection (Minirin®)
  • 15 microgram/mL injection (Octostim®). Octostim® is preferred for subcutaneous injection due to its higher concentration.

Von Willebrand Factor/FVIII Plasma Concentrate (Biostate®)

• A human plasma-derived product, available from blood bank
• May be required in Type 1 vWD if severe bleeding or unresponsive to DDAVP
• Used to treat bleeding in patients with Type 2 and Type 3 vWD.  
• Each reconstituted vial of Biostate® contains 50 IU/ml FVIII and 100 IU/ml von Willebrand factor
• Note that recombinant FVIII products do not contain von Willebrand factor

Recommended dosage

Please note that the vial will state both Factor VIII and von Willebrand Factor units.
Check that dosage is according to Factor VIII units,eg prescribe as 'Biostate® 2000 Factor VIII units'.

If there is uncertainty regarding correct dosage please contact Haem Inpatient Registrar (pager 5030) between 0900-1700hrs, Monday to Friday or Haematologist on call (via switch) after hours.

Notes

Please ask families to make contact with the Haemophilia Nurse on the next working day for a telephone review.
Instructions for preparation and administration of Clotting factor products