Journal d'hématologie et des maladies thromboemboliques
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ISSN: 2329-8790
ISSN: 2329-8790
Jan Jacques Michiels
Aspirin responsive erythromelalgia is the presenting symptom of thrombocythemia in patients with essential thrombocythemia (ET) and polycythemia vera (PV). Skin punch biopsies taken from the affected areas of erythromelalgia and acrocyanotic compications show typical arteriolar inflammation, fibromuscular intimal proliferation and thrombotic occlusions. If left untreated both microvascular and major thrombosis frequently do occur in thrombocythemia in ET and PV patients, but can easily be cured and prevented by low dose aspirin. The stratification as low, intermediate and high thrombotic risk in the retrospective Bergamo studies has been performed in ET patients not treated with aspirin. The risk of thrombosis in aspirin treated ET and PV is not age dependent when on low dose aspirin, and does recur when not on low dose aspirin during follow-up. The persistence of the Bergamo definition of low, intermediate and high thrombotic risk in the 2012 International Prognostic Score of Thrombosis in ET (IPSET) is applicable for JAK2 mutated ET and PV patients not on aspirin and has led to significant overtreatment with hydroxyurea. MPN disease burden in patients with JAK2V617F positive ET and PV is related to JAK2 allele burden and associated leukocytosis, thrombocytosis, constitutional symptoms and splenomegaly. Low dose peglyated interferon (PegasysR, 45 μg/ ml once per week or every two weeks) is becoming the first line myeloreductive treatment option to postpone the useof hydroxyurea as long as possible. Von Willebrand factor (VWF) mediated platelet thrombi formation, as well as increased proteolysis of the VWF multimers in one and the same patient do occur simultaneously or in sequence leading to the paradoxical occurrence of thrombosis at platelet count aboe 400x109/L and bleeding at platelet counts above 1000x109/L due to an acquired von Willebrand disease type 2A.