(507) Rare Case of Acquired Clotting Factor Inhibitor From Bladder Cancer

Introduction: Acquired Clotting Factor Inhibitors (ACFI) are autoantibodies that inhibit the activity or increase the clearance of a clotting factor. Patients present with unexplained bleeding and prolonged clotting profile. Immune triggers include malignancy, pregnancy, connective tissue disorders with anti-factor VIII inhibitor being the most common. This case describes rare presentation of massive hematuria from acquired factor V inhibitor

Description: 80yr old man with hypertension, obstructive uropathy presented to the urology clinic with gross hematuria for 7 days. No history of genital trauma, instrumentation or bleeding from other sites. He was admitted with labs showing Hemoglobin (Hb) 7 (Hb 11, 2months prior), INR 6, aPTT 200, PT 54. He was not on any anticoagulation. Other labs were unremarkable. He received 7units of FFP, 2PRBC, Vitamin-K and KCENTRA over the first few days but hematuria and coagulopathy did not improve. Clotting profile failed to correct with mixing study, prompting factor activity assay. Factor V activity was < 1% (50-100). He was started on steroids and Factor eight inhibitor bypass activity (FEIBA) treatment for ACFI. His coagulation profile normalized and hematuria resolved about 2 days later. Obstructive uropathy work up revealed a bladder mass which was biopsied and was positive for rare plasmacytoid adenocarcinoma also believed to be the trigger for his ACFI formation

Discussion: ACFI is a rare autoimmune disorder from IgG antibodies neutralizing clotting factors, resulting in often unexplained bleeding. Malignancy is a risk factor. The most common solid cancers associated with ACFI are prostate and lung cancer. Lymphoproliferative disorders are the most common associated hematologic malignancies. Labs show prolonged clotting profile which remains uncorrected with mixing study. Factor activity assays can isolate deficiency. Bethesda assay quantifies antibody titer. Treatment is 3 prong ; 1) correct coagulopathy 2) replenish blood loss 3) stabilize/treat immune dyscrasia. Factor V inhibitors are rare but may arise from exposure to topical fibrin glues or bovine thrombin preparations that contain bovine factor V. Early recognition, confirmation and therapy initiation of ACFI is key to ensuring positive outcome and to avoid complications from life threatening bleed