Lingual hemorrhage in a patient with hemophilia A complicated by a high titer inhibitor. Management by continuous infusion of monoclonal antibody-purified factor VIII.

PURPOSE

The management of oral bleeding in hemophilia A patients with high titer inhibitors can be challenging. Simultaneous administration of activated prothrombin complex concentrates and antifibrinolytic agents is potentially dangerous because both agents have thrombogenic properties. We report sustained control of life-threatening lingual hemorrhage in a hemophilic patient with a high titer inhibitor (100 Bethesda Units/ml) on continuous infusion of a monoclonal antibody-purified factor VIII concentrate (75 U/kg/h).

METHODS AND RESULTS

In vivo hemostasis was achieved without an initial increment in free plasma factor VIII:C. The biphasic nature of recovered factor VIII:C indicated initial antigen-antibody formation, a saturation point, then a rapid rise of free factor VIII in plasma. In vitro, rapid loss of factor VIII activity was noted in mixtures of patient's plasma and purified factor VIII during incubation at 37 degrees C. When an excess of purified factor VIII was added to patient's plasma, a plateau of stable residual factor VIII activity followed the initial loss of factor VIII activity, suggesting a second-order reaction.

CONCLUSION

This type I kinetic response is typical of alloantibodies induced by exposure to factor VIII concentrates.