DDAVP treatment in a child with von Willebrand disease type 2M.

Abstract

von Willebrand disease (vWD) type 2M is characterized by the decreased platelet-dependent function of the von Willebrand factor (vWF) that is not caused by the absence of HMW vWF multimers. We report here on a 4-year-old boy with vWD type 2M, who underwent adenotomy and paracentesis after correction of his hemostatic defect by stimulation with DDAVP. The decreased basal levels of vWF Antigen (Ag), ristocetin cofactor activity (RiCoF) and collagen binding activity (CBA) (32%, 14% and 9% respectively) could be stimulated to maximum levels of 69%, 70% and 95% 2 h post DDAVP administration. DDAVP was administered in a dosage of 0.4 microg/kg BW intravenously 30 min prior to surgery. No bleeding occurred intra- and perioperatively. vWF multimer analysis revealed supranormal multimers with an abnormal satellite banding pattern. The typical separation by gel electrophoresis into oligomers with a triplet structure was missing even after stimulation with DDAVP. Thus, the functional hemostatic defect was corrected in this patient after DDAVP administration, although the structural abnormalities of the vWF multimers were still persisting. In conclusion, type 2M vWD might be effectively treated with DDAVP administration in cases of elective surgery, dispensing with vWF replacement by pooled blood products.