ISSN 2997-1036
International Journal of Hematology | Vol. 10, No. 9, September 2019 | pp. 65–72
DOI: 10.46882/2019/IJH/000117
Case Report
Title: Acquired Factor V inhibitor development presenting with spontaneous massive retroperitoneal hemorrhage in an elderly patient: Successful resolution with plasma exchange and cyclophosphamide
Names of Authors: K. L. Musa¹, M. N. Lawal², O. P. Dikko³
Authors’ Affiliations: ¹Department of Haematology, Federal Medical Centre, Katsina, Nigeria; ²Department of Surgery, Bayero University, Kano, Nigeria; ³Department of Pathology, Ahmadu Bello University Teaching Hospital, Zaria, Nigeria
Abstract: Spontaneous development of neutralizing autoantibodies directed against coagulation Factor V is an exceptionally rare condition that causes catastrophic bleeding events in elderly populations. We report a 74-year-old male who presented with sudden, unprovoked left flank pain, lower abdominal distension, and hypovolemic shock. Abdominal computed tomography confirmed a massive retroperitoneal hematoma measuring 12.4 × 8.5 cm without prior trauma or anticoagulant exposure. Coagulation profiles demonstrated concurrent prolongation of both prothrombin time (52.4 seconds) and activated partial thromboplastin time (88.4 seconds). A 1:1 mixing study with normal pooled plasma failed to correct either parameter, indicating a common pathway inhibitor. Functional assays confirmed severely depressed Factor V activity (< 1.0%), and a Bethesda assay quantified a Factor V inhibitor titer of 24.5 Bethesda Units. Hemostasis was achieved using therapeutic plasma exchange to reduce inhibitor concentrations, combined with prothrombin complex concentrates. Subsequent immunosuppressive therapy with oral prednisone paired with cyclophosphamide (2 mg/kg/day) cleared the inhibitor (0 BU) by week 8. This case demonstrates that acquired Factor V autoantibodies can cause life-threatening retroperitoneal bleeding, requiring immediate diagnostic differentiation and multi-modal therapeutic strategies.
Keywords: Acquired factor V inhibitor, retroperitoneal hemorrhage, common pathway, plasma exchange, cyclophosphamide
Manuscript Timeline: Received: June 18, 2019; Revised: July 28, 2019; Accepted: August 14, 2019; Published: September 15, 2019