Antiphospholipid antibody syndrome in pediatric patients

Antiphospholipid antibody syndrome (APS) is characterized by the association between recurrent arterial or venous thrombosis or recurrent pregnancy loss and the presence of circulating antiphospholipid antibodies (aPL), detected as anticardiolipin antibodies (aCL) or lupus anticoagulant (LA). The recognition of APS during the last 15 years has had an important clinical impact on almost every medical specialty because thrombosis can occur anywhere in the body. Symptoms may be heterogeneous depending on the type of organ and vessel (arterial or venous) involved, the vessel size, and the rapid or low course of the thrombotic process. The earliest descriptions of the association between a circulating anticoagulant and vascular thrombosis in pediatric patients were those of Olive in 1979 and St. Clair in 1981. In recent years, the features of APS have been increasingly recognized in children, and a growing number of reports have provided information on the prevalence and clinical significance of aPL in childhood disorders. Thrombotic events are relatively rare in children mainly because adult common prothrombotic factors such as cigarette smoking and atherosclerosis have no impact. For these same reasons, however, a higher incidence of aPL-related thrombosis could be expected. Two recent studies support this hypothesis. Angelini et al investigated 13 children with idiopathic cerebral ischemia and found that 10 (76%) met the criteria for the diagnosis of APS. Nuss retrospectively reviewed the history, physical examinations, and laboratory results of 61 children who had suffered a thrombotic event. About one third had evidence of circulating aPL, again suggesting a high prevalence of APS in children with thrombosis. This review considers the pediatric aspects of APS. For a detailed description of the syndrome, the reader is referred to several excellent studies published previously.