Thrombotic disorders

Thromboembolism occurs as a consequence of the genetic predisposition, underlying diseases, and triggers of dehydration, infection, and injury. Thrombotic events are much rarer in infants and children than in adults. Aging is a potent risk factor for the development of venous thrombosis and stroke. The genetic effects on the hypercoagulability in pediatric patients are thus more carefully considered than in adult patients. The genetic predisposition of thromboembolism depends on the racial background. Factor V Leiden (G1691A) and factor II variant (G20210A) are the common thrombophilias in Caucasians, but not found in Asian ancestries. The incidence of pediatric thrombosis is increasing because of the advances in neonatal intensive care, cardiovascular surgery, and imaging techniques. There is an increasing number of reports on the molecular epidemiology of constitutional thrombophilias also in Asian countries. On the other hand, the treatment and prophylaxis of pediatric thrombosis have not been established. The advent of direct oral anticoagulants (DOACs) has opened a new era of anticoagulation for adult patients with thrombosis, while the management of heritable thrombophilia is under investigation. This chapter briefly introduces the thrombotic disorders in neonates, infants, and children, with special reference to the high-risk-inherited thrombophilia of natural anticoagulant deficiency.