ISSN 2997-1036
International Journal of Hematology | Vol. 13, No. 5, May 2022 | pp. 33–40
DOI: 10.46882/2022/IJH/000147
Case Report
Title: Spontaneous massive retroperitoneal hemorrhage secondary to acquired Factor X inhibitor development in an elderly patient: Successful resolution with azathioprine
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 X is an exceptionally rare clinical 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 severe 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 specific common pathway inhibitor. Functional assays confirmed severely depressed Factor X activity (< 1.5%), and a Bethesda assay quantified a Factor X inhibitor titer of 22.0 Bethesda Units. Hemostasis was achieved using prothrombin complex concentrates alongside supportive measures. Subsequent immunosuppressive therapy with oral prednisone paired with azathioprine (100 mg daily) cleared the inhibitor (0 BU) and normalized Factor X activity by week 8. This case demonstrates that acquired common pathway autoantibodies require immediate diagnostic differentiation and multi-modal therapeutic strategies.
Keywords: Acquired factor X inhibitor, retroperitoneal hemorrhage, common pathway, prothrombin complex concentrate, azathioprine
Manuscript Timeline: Received: February 15, 2022; Revised: March 24, 2022; Accepted: April 11, 2022; Published: May 19, 2022