Acquired symptomatic inhibitors of plasma clotting factors in nonhemophilic children.

Three children presenting with severe symptomatic bleeding episodes (one child developing a life-threatening subdural hematoma) due to acquired coagulation inhibitors are reported. In two patients, there was a history of an antecedent viral syndrome. None had evidence of drug exposure or an underlying immune disorder. All responded to the administration of corticosteroids, although one patient was steroid-dependent and required immunosuppressive therapy to achieve a complete response. Laboratory characteristics did not clearly distinguish the type of circulating inhibitor present in these children. Since bleeding was a prominent feature, we suggest that the inhibitors noted represent multiple specific coagulation factor inhibitors, rather than a "lupus-like" inhibitor which represents a common antibody to phospholipid-dependent coagulation tests. Such inhibitors may not be as benign as the common lupus anticoagulant seen in adult patients and should be considered in the child with symptomatic bleeding and a prolonged partial thromboplastin time. The true incidence and exact mechanism of action of acquired inhibitors in children has not been established.