Successful management of a possible antibiotic-related acquired factor V inhibitor: a case report and review of the literature.

Acquired factor inhibitors are rare. We report a case of an elderly male who presented with a bleeding diathesis associated with an elevated prothrombin time and an activated partial thromboplastin time. Work-up revealed undetectable factor V activity and a factor V inhibitor level of >50 Bethesda units. The inhibitor may have been triggered by antibiotics. With a multimodality approach using steroids, platelet transfusions, intravenous immunoglobulin, factor VIII inhibitor bypass activity agent and cyclophosphamide, we successfully eliminated the inhibitor and controlled the bleeding.