Risk factors for venous thromboembolism in children.

The incidence of venous thromboembolism (VTE) is increasing in children as a result of therapeutic advances and improved clinical outcome in primary illnesses that previously caused mortality. VTE is mostly diagnosed in hospitalized children, especially sick newborns with central venous catheters and older children with a combination of risk factors. Infants older than 3 months and teenagers are the largest groups developing VTE. The most important triggering risk factors are the presence of central venous lines, cancer and chemotherapy. Pathological conditions such as severe infection, sickle cell disease, trauma and antiphospholipid syndrome are associated with the presence of a hypercoagulable state in children. The thrombotic risk in otherwise healthy children with a single identified thrombophilic defect appears to be extremely low. Venous thromboembolism in pediatric patients is mainly caused by combinations of at least 2 prothrombotic risk factors for venous thromboembolic events in children are usually associated with underlying clinical conditions and a triggering risk factor. In addition, recurrence of VTE after withdrawal of anticoagulant treatment occurs in about 20% of patients after re-exposure to a triggering risk factor. A non negligible mortality and morbidity is related to VTE in childhood. This supports the need for international multicenter randomized clinical trials to determine optimal prophylactic and therapeutic treatment for children with VTE. Risk factor assessment for VTE in children has to be improved in order to optimize the prophylactic and therapeutic strategies. The specific evolutionary characteristics of the hemostasis in children has to be taken into consideration when a prophylactic or therapeutic strategy is applied.The incidence of venous thromboembolism (VTE) is increasing in children as a result of therapeutic advances and improved clinical outcome in primary illnesses that previously caused mortality. VTE is mostly diagnosed in hospitalized children, especially sick newborns with central venous catheters and older children with a combination of risk factors. Infants older than 3 months and teenagers are the largest groups developing VTE. The most important triggering risk factors are the presence of central venous lines, cancer and chemotherapy. Pathological conditions such as severe infection, sickle cell disease, trauma and antiphospholipid syndrome are associated with the presence of a hypercoagulable state in children. The thrombotic risk in otherwise healthy children with a single identified thrombophilic defect appears to be extremely low. Venous thromboembolism in pediatric patients is mainly caused by combinations of at least 2 prothrombotic risk factors for venous thromboembolic events in children are usually associated with underlying clinical conditions and a triggering risk factor. In addition, recurrence of VTE after withdrawal of anticoagulant treatment occurs in about 20% of patients after re-exposure to a triggering risk factor. A non negligible mortality and morbidity is related to VTE in childhood. This supports the need for international multicenter randomized clinical trials to determine optimal prophylactic and therapeutic treatment for children with VTE. Risk factor assessment for VTE in children has to be improved in order to optimize the prophylactic and therapeutic strategies. The specific evolutionary characteristics of the hemostasis in children has to be taken into consideration when a prophylactic or therapeutic strategy is applied.