BJH - volume 16, issue 3, may 2025
B. Calcoen MD, PhD, S. van Hecke MD, D. Labaere MD, S. Van Erum MD, L. Vynckier PharmD, L. Persijn PharmD
Introduction: Acquired von Willebrand syndrome (AVWS) is an underestimated bleeding disorder characterised by either a shortage or dysfunctional von Willebrand factor (VWF) and mostly associated with several cardiac, autoimmune and hematologic disorders, including myeloproliferative neoplasms (MPNs).
Case series: We describe three patients with MPN (i.e., two with essential thrombocytosis and one with secondary myelofibrosis from polycythaemia vera) of which one experienced unexpected bleeding after bone marrow puncture. Laboratory investigation showed normal-to-high VWF:Ag levels with a disproportional decrease in VWF activity in all three patients. These results represent a qualitative VWF defect due to secondary AVWS.
Conclusion: Although thrombotic events are a frequent complication found in MPN patients, unexplained and potentially severe bleedings are a not uncommon observation. In the latter situation, AVWS should always be excluded, minimally by determination of VWF:Ag and VWF activity (e.g., VWF:RCo and VWF:CB). MPN-patients with AVWS may benefit from additional prevention against bleeding.
(BELG J HEMATOL 2025;16(3):130–4)
Read moreBJH - volume 10, issue 6, october 2019
A. Louwagie PharmD, M. Tajdar PharmD, B. Cauwelier MD, PhD, H. Devos MD, J. Robbrecht MD, S. Van Erum MD, J. Emmerechts MD, PhD
We report a case of a falsely increased mean corpuscular volume (MCV) due to severe hyperglycaemia in a patient with diabetic ketoacidosis. This phenomenon results from in vitro swelling of hyperosmolar red blood cell size when diluted in an iso-osmolar buffer of a haematology analyser, and does not reflect a true macrocytosis in vivo. The magnitude of this effect is dependent on the glucose concentration of the sample and time of incubation prior to analysis. Haematology analysers from three different manufacturers were found equally sensitive to this phenomenon. Therefore, it is suggested to use reluctance when reporting and interpreting MCV results in the case of severe hyperglycaemia to avoid unnecessary additional investigation.
(BELG J HEMATOL 2019;10(6):250–4)
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