Inhibitors of coagulation in children

Acquired inhibitors of coagulation factor interaction in nonhemophilic children are usually nonspecific, transient, and unassociated with clinical bleeding. They occur with some frequency and are the most common cause for a prolonged APTT found by routine testing. In children, some association with viral infections and treatment with penicillin has been noted, but their interrelationship with the development of antibodies remains unclear. The exact nature of these antibodies, usually directed against coagulant factor phospholipid, is not clear and multiple antibodies both specific as well as nonspecific may occur. No therapy is generally required. Rarely has the acute development of antibodies directed against specific coagulation factors occurred. The laboratory evaluation of the type of inhibitor is, therefore, most important as specific inhibitors may be associated with life-threatening bleeding situations. Their therapy should probably include attempts at eradication of the inhibitor by immunosuppressive agents or other newer modalities. Unfortunately, little information is available regarding the nature and outcome of specific inhibitors in children. Acquired inhibitors in hemophilic patients occur in about 6 to 10% of patients. Newer approaches to their therapy include activated PCC which have generally improved the outlook for such patients. Treatment regimens involve a knowledge of inhibitor response and the concomitant use of plasmapheresis, high-dose or continuous i.v. Factor VIII, and porcine Factor VIII, followed by activated PCC. The role of immunosuppressive agents and other newer modalities appears promising, however, prospective controlled studies are necessary to evaluate their role in the overall management of such patients.