Acquired haemophilia masked by warfarin therapy

Abstract

Acquired haemophilia is a rare phenomenon and prompt diagnosis is essential for successful treatment. Early laboratory detection could minimize its potentially devastating consequences and reduce mortality but when a masking element such as anticoagulant therapy is present, delay in diagnosis is not uncommon. A prolonged activated partial thromboplastin time (APTT) may be falsely attributed to warfarin alone, particularly when it is associated with oral anticoagulant overdose. We describe two patients on treatment with warfarin who presented with a bleeding diathesis and disproportionately prolonged APTT, which led to the diagnosis of antibodies directed against factor VIII.

Acquired Hemophilia A in a Patient Undergoing Aortic Valve Replacement with Warfarin Anticoagulation Therapy

“…Fortunately, he achieved complete remission on prednisolone and no relapse has been noted after discontinuation of prednisolone. Furthermore, re-administration of warfarin did not induce relapse, while in previous reports, no data was shown on relapse in 2 patients who took warfarin again [4][5][6]. In the present case, because onset of acquired hemophilia occurred approximately 5 months after surgery, is it not thought to be surgery-associated [2].…”

“…Three reports have presented5 patients with acquired hemophilia A associated with anticoagulation with warfarin [4][5][6]; the 3 case reports are shown in Table 1. The 5 patients were elderly women (mean age, 68 years), while in the present case, the patient was a 66-year-old man.…”

Management of acquired haemophilia A

“…There have been reports of anticoagulant and anti‐platelet drugs either masking or being associated with AHA [17–20]. Patients who present with bruising or bleeding whilst taking anticoagulants or an anti‐platelet agent should have an activated partial thromboplastin time (aPTT) measured in addition to an INR and, if inappropriately prolonged, investigated further with mixing studies and factor levels.…”

“…There have been reports of anticoagulant and anti-platelet drugs either masking or being associated with AHA [17][18][19][20].…”

Advances in the understanding of acquired haemophilia A: implications for clinical practice

“…There have been a number of reports of anticoagulant and anti‐platelet drugs either masking or being associated with AHA (Uggla et al , 2003; Dragani et al , 2004; Haj et al , 2004; Vadikolia et al , 2007). Patients who present with bruising or bleeding whilst taking warfarin or an anti‐platelet agent should have an aPTT performed in addition to an International Normalized Ratio (INR) and, if inappropriately prolonged, investigated further with mixing studies and factor levels.…”