Chapter 18 - Pediatric Antiphospholipid Syndrome

Abstract

Pediatric antiphospholipid syndrome (APS) is a multisystemic autoimmune disease characterized by thromboembolic events, hematologic, dermatologic, neurologic, and other manifestations in the presence of elevated titers of antiphospholipid antibodies (aPL). This disease may occur as an isolated clinical entity (primary APS) or in association with autoimmune diseases, infections, and malignancies. Multiple pathogenic mechanisms have been proposed by which aPL may predispose to thrombosis including interaction between aPL and cellular components, activation of the coagulation cascade, inhibition of the fibrinolytic system, inhibition of natural anticoagulants, and activation of the complement system. APS may present in the neonatal period due to the transplacental passage of maternal aPL or later during childhood and adolescence due to de novo synthesis of aPL. Modified adult recommendations remain the primary guide for treatment of pediatric APS, but several differences specific to children must be considered including different concentrations of plasma procoagulant and anticoagulant proteins and higher risk of hemorrhage during play and sports activities. Patients with persistently positive aPL, in particular those with multiple aPL antibodies, high titers of aPL, and/or presence of lupus anticoagulants have a high risk for recurrent thrombosis and should receive long-term anticoagulation.