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A PATIENT WITH FXII DEFICIENCY, JAK2-MUTATION POSITIVE CHRONIC MYELOPROLIFERATIVE NEOPLASM AND RECURRENT THROMBOEMBOLIC EVENTS

ENA RANKOVIĆ ; Zagreb University Hospital Center, Department of Internal Medicine, Division of Hematology, Zagreb, Croatia
DRAŽEN PULANIĆ ; Zagreb University Hospital Center, Department of Internal Medicine, Division of Hematology, University of Zagreb, School of Medicine, Zagreb and Josip Juraj Strossmayer University of Osijek, Faculty of Medicine, Osijek, Croatia

Abstract

Introduction and Aim: Factor XII (FXII) deficiency is a rare disorder associated with a prolonged coagulation test (aPTT) indicating bleeding diathesis but without clinically major bleeding tendencies. In opposite to this laboratory finding, it is clinically associated with an increased risk of developing thromboembolic events. The aim of this case report is to present a female patient with severe FXII deficiency, very prolonged aPTT, recurrent thromboembolic events and diagnosis of JAK2-mutation positive chronic myeloproliferative neoplasm (MPN), without hemorrhagic diathesis despite dual anticoagulation and antiaggregation therapy. We also performed review of the literature regarding FXII deficiency, its clinical significance and open questions regarding that rare coagulation disorder. Case Report: We present a female patient born in 1959, with a history of severe obesity and arterial hypertension, which in 2010 developed deep vein thrombosis (DVT) of the right arm during hormone replacement therapy. Laboratory findings showed prolonged aPTT. Warfarin was introduced into therapy for two years, followed by treatment with acetylsalicylic acid, without hemorrhagic complications. In January 2014, after cholecystectomy she developed pulmonary embolism, DVT of the right leg, with very prolonged aPTT verified again (>150 s), clinically without signs of hemorrhagic diathesis. She was treated with low molecular weight heparin with bridging to warfarin and was referred to a hematologist due to prolonged aPTT. Extended diagnostic workup revealed low activity of FXII (<0.02 KIU/L), elevated activity of FVIII (2.52-3.5 KIU/L) and VWF (VWF:RCo 251%, VWF:Ag 317%). Also JAK2V617F mutation was found indicating chronic MPN, and acetylsalicylic acid therapy was started along with warfarin, and later cytoreductive therapy with hydroxyurea was initiated because of JAK2-mutation positive chronic MPN. During subsequent 4-year follow-up, the patient was without thromboembolic incidents, adequately anticoagulated, without hemorrhagic diathesis despite dual anticoagulation and antiaggregation therapy and permanently prolonged aPTT. Conclusion: Repeating prolonged aPTT in a person with no signs of bleeding diathesis requires diagnostic workup for the possible lack of contact factors including FXII. The presented patient with acquired and hereditary thrombophilia and recurrent thrombotic incidents has an indication for long term dual anticoagulant and antiaggregation therapy that is well tolerated without bleeding complications.

Keywords

FXII deficiency; thromboembolic events; prolonged aPTT; bleeding; myeloproliferative neoplasm

Hrčak ID:

224712

URI

https://hrcak.srce.hr/224712

Publication date:

6.9.2019.

Article data in other languages: croatian

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