{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,29]],"date-time":"2025-12-29T22:23:42Z","timestamp":1767047022592,"version":"3.38.0"},"reference-count":31,"publisher":"American Veterinary Medical Association (AVMA)","issue":"6","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["javma"],"published-print":{"date-parts":[[2014,3,15]]},"abstract":"<jats:title>Abstract<\/jats:title>\n<jats:p><jats:bold>Case Description<\/jats:bold>\u2014A 23-year-old Thoroughbred mare was evaluated because of a coagulopathy causing hemoperitoneum, hematomas, and signs of blood loss\u2013induced anemia.<\/jats:p>\n<jats:p><jats:bold>Clinical Findings<\/jats:bold>\u2014The mare had tachycardia, pallor, hypoperfusion, and a large mass in the right flank. The mass was further characterized ultrasonographically as an extensive hematoma in the body wall with associated hemoabdomen. Coagulation testing revealed persistent, specific prolongation of the activated partial thromboplastin time (&gt; 100 seconds; reference interval, 24 to 44 seconds) attributable to severe factor VIII deficiency (12%; reference interval, 50% to 200%). On the basis of the horse's age, lack of previous signs of a bleeding diathesis, and subsequent quantification of plasma factor VIII inhibitory activity (Bethesda assay titer, 2.7 Bethesda units\/mL), acquired hemophilia A was diagnosed. The medical history did not reveal risk factors or underlying diseases; thus, the development of inhibitory antibodies against factor VIII was considered to be idiopathic.<\/jats:p>\n<jats:p><jats:bold>Treatment and Outcome<\/jats:bold>\u2014The mare was treated with 2 transfusions of fresh whole blood and fresh-frozen plasma. Immunosuppressive treatment consisting of dexamethasone and azathioprine was initiated. Factor VIII deficiency and signs of coagulopathy resolved, and the inhibitory antibody titer decreased. The mare remained healthy with no relapse for at least 1 year after treatment.<\/jats:p>\n<jats:p><jats:bold>Conclusions and Clinical Relevance<\/jats:bold>\u2014Horses may develop inhibitory antibodies against factor VIII that cause acquired hemophilia A. A treatment strategy combining transfusions of whole blood and fresh-frozen plasma and administration of immunosuppressive agents was effective and induced sustained remission for at least 1 year in the mare described here.<\/jats:p>","DOI":"10.2460\/javma.244.6.719","type":"journal-article","created":{"date-parts":[[2014,2,25]],"date-time":"2014-02-25T20:22:42Z","timestamp":1393359762000},"page":"719-723","source":"Crossref","is-referenced-by-count":10,"title":["Hemorrhage and blood loss\u2013induced anemia associated with an acquired coagulation factor VIII inhibitor in a Thoroughbred mare"],"prefix":"10.2460","volume":"244","author":[{"given":"Laramie S.","family":"Winfield","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Marjory B.","family":"Brooks","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1272","reference":[{"key":"ref1","series-title":"A critical evaluation of the prothrombin time for monitoring oral anticoagulant therapy","first-page":"43","volume":"33","author":"Jackson","year":"2003"},{"key":"ref2","series-title":"Evaluation of latex agglutination kits for detection of fibrin(ogen) degradation products and d-dimer in healthy horses and horses with severe colic","first-page":"375","volume":"34","author":"Stokol","year":"2005"},{"key":"ref3","series-title":"Incidence of transfusion reactions and retention of procoagulant and anticoagulant factor activities in equine plasma","first-page":"323","volume":"23","author":"Wilson","year":"2009"},{"key":"ref4","series-title":"Acquired hemophilia A: a current review of autoantibody disease","first-page":"19","volume":"10","author":"Sborov","year":"2012"},{"key":"ref5","series-title":"Acquired hemophilia A","first-page":"735","volume":"38","author":"Webert","year":"2012"},{"key":"ref6","series-title":"Pharmacokinetics of azathioprine following single-dose intravenous and oral administration and effects of azathioprine following chronic oral administration in horses","first-page":"1578","volume":"66","author":"White","year":"2005"},{"key":"ref7","series-title":"Azathioprine for treatment of immune-mediated diseases of dogs and cats","first-page":"1316","volume":"192","author":"Beale","year":"1988"},{"key":"ref8","series-title":"Development of a new modified Bethesda method for coagulation inhibitors: the Osaka modified Bethesda method","first-page":"185","volume":"22","author":"Torita","year":"2011"},{"key":"ref9","series-title":"Acquired factor VIII inhibitors in oncohematology: a systematic review","first-page":"194","volume":"66","author":"Franchini","year":"2008"},{"key":"ref10","series-title":"Development of factor VIII:C antibodies in dogs with hemophilia (factor VIII:C deficiency)","first-page":"451","volume":"63","author":"Giles","year":"1984"},{"key":"ref11","series-title":"Factor VIII inhibitors complicating treatment of postoperative bleeding in a dog with hemophilia A","first-page":"381","volume":"19","author":"O'Kelley","year":"2009"},{"key":"ref12","series-title":"Acquired haemophila: review and meta-analysis focused on therapy and prognostic factors","first-page":"21","volume":"121","author":"Delgado","year":"2003"},{"key":"ref13","series-title":"A survey of 215 non-hemophilic patients with inhibitors to factor VIII","first-page":"200","volume":"45","author":"Green","year":"1981"},{"key":"ref14","series-title":"Acquired haemophilia and its management","first-page":"231","volume":"89","author":"Morrison","year":"1995"},{"key":"ref15","series-title":"Acquired hemophilia due to a circulating anticoagulant. 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