Factor VIII is reduced whereas von Willebrand factor ristocetin cofactor is normal, as is binding of factor VIII to von Willebrand factor.
Pseudo (platelet type) von Willebrand disease
Pseudo von Willebrand disease is a platelet disease involving increased affinity of GPIb platelets for von Willebrand factor with variable levels of thrombocytopenia. Differential diagnosis between pseudo von Willebrand disease and type 2B von Willebrand disease can only be performed at specialised laboratories.
Acquired von Willebrand disease
Acquired VWF deficiency can be seen in certain clinical settings such as lymphoproliferative and myeloproliferative syndromes, certain types of cancer and certain autoimmune diseases, as well as in aortic valve stenosis.
This acquired deficiency may be related to the presence of auto-antibodies directed against VWF, to the adsorption of VWF at the surface of certain cells, or to degradation of VWF.
- Symptoms are generally moderate.
- Onset normally occurs after the age of 50 years.
- Laboratory signs are identical to those of von Willebrand disease.
- Disappearance of the disease following aetiological treatment may serve as a basis for retrospective diagnosis.
Table 1: Different types of von Willebrand disease and associated tests
LEGEND: N ou = N or ou = or forte dose = high dose/faible dose = low dose
diminué = decreased Multimères = Multimers IPM et HPM = IMW and HMW absents = absent