title: [Thrombocytosis: adverse effect of heparin treatment].
abstract: BACKGROUND
  Thrombocytosis induced by heparin is rarely reported in the literature.
  
  
  METHODS
  We report here four cases of thrombocytosis, three in patients under treatment for a stable myeloproliferative disorder. Thrombocytosis always regressed when heparin treatment was discontinued, and no thrombotic events occurred.
  
  
  CONCLUSIONS
  Following several reports suggesting an association between heparin and thrombocytosis, the French adverse drug reporting (pharmacovigilance) network identified 51 cases. Thrombocytosis associated with heparin is probably explained by the latter's potentiation of megakaryocytopoiesis, in particular, by inhibition of platelet factor 4 (PF4). Thrombocytosis is a further reason to monitor platelet counts during heparin treatment.
authors.affiliation: Clinique de médecine interne et maladies infectieuses, CHU Haut-Lévêque, Pessac. fabrice.camou@chu-bordeaux.fr
authors.forename: Fabrice
authors.initials: F
authors.lastname: Camou
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Viallard
authors.forename: Olivier
authors.initials: O
authors.lastname: Caubet
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Pellegrin
mesh_terms: D000328:Adult; D016907:Adverse Drug Reaction Reporting Systems; D000368:Aged; D000925:Anticoagulants / Q000009:adverse effects*; D017984:Enoxaparin / Q000009:adverse effects; D005260:Female; D005343:Fibrinolytic Agents / Q000009:adverse effects*; D005500:Follow-Up Studies; D005602:France; D006493:Heparin / Q000009:adverse effects*; D006495:Heparin, Low-Molecular-Weight / Q000009:adverse effects; D006801:Humans; D008297:Male; D009196:Myeloproliferative Disorders / Q000188:drug therapy; D010976:Platelet Count; D010978:Platelet Factor 4 / Q000037:antagonists & inhibitors; D013922:Thrombocytosis / Q000139:chemically induced*; D034061:Thrombopoiesis / Q000187:drug effects; D013997:Time Factors; D000078222:Tinzaparin
chemical_list: D000925:Anticoagulants; D017984:Enoxaparin; D005343:Fibrinolytic Agents; D006495:Heparin, Low-Molecular-Weight; D010978:Platelet Factor 4; D000078222:Tinzaparin; D006493:Heparin