Acquired Hemophilia Associated with Rheumatoid Arthritis: A Case Report and Review of the Literature.

A 63-year-old woman with rheumatoid arthritis and Hashimoto's thyroiditis was admitted to the emergency room, because of left leg pain associated with spontaneous subcutaneous hematomas, for 15 days. Their symptoms also occurred after the discontinuation of aspirin, which the patient had taken for a previous case of ocular papillitis. Laboratory tests showed anemia, a normal platelet count, but a prolonged activated partial thromboplastin time (aPTT) ratio; a computerized tomography scan of the left lower limb detected a recent hematoma in the left lateral rectus muscle, and subcutaneous soft tissue edema also involving the knee, without vascular involvement. Coagulation tests were performed showing normal levels of Lupus Anticoagulant, very low-factor FVIII activity (2.2%), normal FIX, FXI, and FXII activity, and the detection of FVIII inhibitors by a Bethesda assay (7.6 U). A diagnosis of acquired hemophilia A (AHA) was made, and hemostatic and immunosuppressive treatment was immediately started (activated prothrombin complex concentrates and methylprednisolone). Malignancies and infections were excluded. An autoantibodies panel confirmed the positivity to rheumatoid factor and anti-cyclic citrullinated peptide antibodies. In treatment, the patient did not present any new bruises, with aPTT normalizing, FVIII increasing, and inhibitors reducing until disappearance. A close follow-up continued every 1-2 week after discharge, with hemostatic treatment discontinuation and methylprednisolone decalage. Underlying autoimmune conditions induced this rare, autoimmune and life-threating disorder.